JP2019129601A - Rotor for rotary electric machine - Google Patents

Abstract

To provide a rotor for a rotary electric machine which allows a reduction in component size and manufacturing cost.SOLUTION: A rotor 10 for a rotary electric machine comprises: a rotor core 12 which has a shaft hole 26 extending to the center, and a plurality of magnet holes 22 and 24; a permanent magnet 14 inserted into the magnet hole 22; and a rotary shaft 16 inserted through the shaft hole 26 so as to be fixed to the shaft hole via one or more fitting parts 20. In each of the fitting parts 20, fitting grooves 34 provided on one of an outer peripheral surface of the rotary shaft 16 and an inner peripheral surface of the shaft hole are fitted to fitting projections 32 provided on the other one of the two surfaces. Each of the fitting parts 20 is arranged at a position that does not circumferentially overlap with a bridge part 25, which is a minute gap between two magnet holes 22a and 24a circumferentially adjacent to each other.SELECTED DRAWING: Figure 1

Description

  The present specification discloses a rotor of a rotating electrical machine including a rotor core, a magnet embedded in the rotor core, and a rotating shaft that is inserted into and fixed to a shaft hole of the rotor core.

  In a rotor of a rotating electrical machine, a rotating shaft is inserted and fixed at the center of a rotor core in which permanent magnets are embedded. The rotation shaft is required to be firmly fixed to the rotor core in order to rotate together with the rotor core. Therefore, conventionally, various techniques have been proposed for fixing the rotating shaft.

  For example, Patent Document 1 discloses a technique of fastening a rotating shaft to a rotor core using a nut. That is, in patent document 1, the large diameter part which supports the axial direction one end surface of a rotor core, and the internal thread with which a nut is screwed are formed in the rotating shaft. And after inserting a rotor core and a nut in a rotating shaft, a nut is tightened and a rotor core is inserted | pinched between a nut and a large diameter part. Thus, a frictional force is generated between the axial end surface of the rotor core and the large diameter portion of the rotation shaft and the nut. By this frictional force, the rotational force is transmitted between the rotor core and the rotating shaft.

Japanese Patent Laying-Open No. 2015-27119

  However, in the case of fastening using such a nut, a dedicated facility for fastening the nut with an appropriate torque is required, resulting in an increase in manufacturing cost. Further, in order to transmit the rotational force by the frictional force generated on the axial end surface of the rotor core, it is necessary to increase the tightening torque of the nut, which causes problems such as an increase in the size of the nut and an increase in load on the rotor core. .

  Therefore, the present specification discloses a rotor of a rotating electrical machine that can reduce the size of components and reduce the manufacturing cost.

  A rotor of a rotating electrical machine disclosed in the present specification is a rotor of a rotating electrical machine, and includes a rotor core having a shaft hole extending in the center and a plurality of magnetic pole holes, and a permanent magnet inserted into the magnetic pole hole. A rotating shaft that is inserted through the shaft hole and is fixed to the shaft hole via one or more fitting portions, wherein the fitting portion includes an outer peripheral surface of the rotating shaft and an inner portion of the shaft hole. A fitting groove provided on one of the peripheral surfaces and recessed in the radial direction, and a fitting protrusion provided on the other of the outer peripheral surface of the rotating shaft and the inner peripheral surface of the shaft hole and protruding in the radial direction are mutually connected. The fitting portion is arranged at a position that does not overlap in the circumferential direction with a bridge portion that is a minute gap portion between two magnetic pole holes adjacent in the circumferential direction.

  With such a configuration, a rotational force can be transmitted between the rotor core and the rotation shaft via the fitting portion, so that a nut is not necessary. As a result, the parts can be reduced in size and the manufacturing cost can be reduced. Further, since the fitting portion is disposed at a position that does not overlap with the bridge portion that is weak in strength in the circumferential direction, the rotor core can be effectively prevented from being damaged.

  The fitting portion includes a circumferential fitting portion in which a circumferential dimension of the fitting protrusion is larger than a circumferential dimension of the fitting groove, and a radial dimension of the fitting protrusion is larger than a radial dimension of the fitting groove. You may have a large diameter side fitting part.

  With such a configuration, rotation is transmitted by the circumferential fitting portion, and the rotation shaft can be centered by the radial fitting portion.

  In this case, the circumferential side fitting portions and the radial side fitting portions may be alternately arranged in the circumferential direction.

  With this configuration, the circumferential stress and the radial stress are alternately generated in the circumferential direction, so the load applied to the rotor core can be evenly dispersed.

  The outer peripheral surface of the rotating shaft has an involute spline shape in which teeth and tooth grooves functioning as the fitting protrusion and the fitting groove are continuously arranged in the circumferential direction, and the inner peripheral surface of the shaft hole has the The tooth grooves and teeth functioning as the fitting grooves and the fitting protrusions may be intermittently arranged so as to be located in a range not overlapping with the bridge portion in the circumferential direction.

  By providing a fitting protrusion and a fitting groove on the entire circumference of the rotation shaft, one type of rotation shaft can be applied to a plurality of types of rotor cores having different positions and numbers of bridge portions.

  The fitting portion may be disposed at a position overlapping the magnetic pole boundary position in the circumferential direction.

  Usually, since there is no bridge portion at the magnetic pole boundary position, such a configuration can reliably prevent overlapping of the fitting portion and the bridge portion.

  According to the rotor disclosed in the present specification, the rotational force can be transmitted between the rotor core and the rotating shaft via the fitting portion, so that a nut is not necessary. As a result, the parts can be reduced in size and the manufacturing cost can be reduced. Further, since the fitting portion is disposed at a position that does not overlap with the bridge portion that is weak in strength in the circumferential direction, the rotor core can be effectively prevented from being damaged.

It is a longitudinal cross-sectional view of a rotor. It is AA sectional drawing in FIG. It is a figure of the axial hole periphery of a rotor core. It is sectional drawing of a rotating shaft. It is a figure explaining a circumference side fitting part. It is a figure explaining a diameter side fitting part. It is a figure which shows an example of another rotating shaft.

  Hereinafter, the configuration of the rotor 10 of the rotating electrical machine will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of a rotor 10 of a rotating electrical machine. FIG. 2 is a cross-sectional view taken along the line AA in FIG. Further, FIG. 3 is a view around the shaft hole 26 of the rotor core 12, and FIG. 4 is a cross-sectional view of the rotation shaft 16. The rotor 10 is used as a rotating electrical machine, for example, a three-phase synchronous type rotating electrical machine or the like mounted on an electric vehicle as one of drive sources. The rotor 10 includes a rotor core 12, a permanent magnet 14 embedded in the rotor core 12, and a rotating shaft 16 fixed to the rotor 10.

  The rotor core 12 is a substantially annular body having a shaft hole 26 formed in the center thereof. The rotor core 12 is formed by laminating a plurality of electromagnetic steel plates (for example, silicon steel plates) in the axial direction. The plurality of electromagnetic steel sheets are connected to each other by caulking, for example. In order to enable this caulking, each electromagnetic steel sheet is formed with a caulking portion 28 that protrudes on one surface and protrudes on the other surface. In the illustrated example, the caulking portion 28 is provided between two adjacent magnetic poles, that is, on the q-axis Lq.

  A plurality of magnetic pole holes 22a, 22b, 24a, and 24b are arranged at intervals in the circumferential direction at positions near the outer periphery of the rotor core 12. Each magnetic pole hole is a hole used for constituting a magnetic pole, and penetrates in the axial direction. The magnetic pole holes include magnet holes 22a and 22b into which magnets are inserted, and magnetic flux leakage prevention holes 24a and 24b that suppress leakage of magnetic flux. One or more permanent magnets 14 are inserted into the magnet holes 22a and 22b to form magnetic poles.

  The rotor 10 of this example has eight magnetic poles as shown in FIG. However, the number of magnetic poles is an example, and if the number is even, the number of magnetic poles may be changed as appropriate. In this example, one magnetic pole is composed of a plurality of permanent magnets 14, and the permanent magnets 14 belonging to one magnetic pole are arranged in a substantially inverted triangular shape. That is, the magnet holes 22a and 22b are arranged between the pair of first magnet holes 22a arranged in a substantially V shape so as to spread outward and the pair of first magnet holes 22a in the vicinity of the outer peripheral end. And one or more permanent magnets 14 are inserted into the respective magnet holes 22a and 22b.

  Two second magnetic flux leakage prevention holes 24b are formed on both sides in the circumferential direction of the second magnet hole 22b. A first magnetic flux leakage prevention hole 24a is provided between the radially inner end of the first magnet hole 22a and the radially inner end of the adjacent first magnet hole 22a. The first magnetic flux leakage prevention hole 24a and the first magnet hole 22a are adjacent to each other in the circumferential direction, and a bridge portion 25 that is a minute gap is formed between them. It is desirable that the bridge portion 25 be as small as possible within the range in which the strength of the rotor core 12 can be maintained, in consideration of the magnetic characteristics. In this example, the bridge portion 25 is constituted by a part of the rotor core 12, but a through hole is formed at a location to be the bridge portion 25, and a part different from the rotor core 12 is formed in the through hole. You may comprise the bridge part 25 by inserting. In this case, although the material of the part inserted as the bridge part 25 is not particularly limited, it is desirable that it be a nonmagnetic material.

  A shaft hole 26 penetrating in the axial direction is formed in the center of the rotor core 12. The shaft hole 26 is a hole through which the rotary shaft 16 is inserted. On the inner peripheral surface of the shaft hole 26, core inner teeth 30 are formed that mesh with outer teeth 36 of the rotating shaft 16 described later (see FIGS. 3 and 4). The core inner teeth 30 and the outer teeth 36 of the rotary shaft 16 are fitted to each other, so that the rotary shaft 16 is fixed to the rotor core 12. This will be described later.

  The rotary shaft 16 is a shaft member that is press-fitted into the shaft hole 26 of the rotor core 12, and both ends thereof are pivotally supported by a motor case (none of which is shown) through bearings. A large diameter portion 38 larger in diameter than the shaft hole 26 is formed in the middle of the rotary shaft 16. One end surface in the axial direction of the rotor core 12 is pressed against the large diameter portion 38. A press-fit ring 18 is attached to the opposite side of the large diameter portion 38 with the rotor core 12 interposed therebetween. The press-fitting ring 18 is a component that is press-fitted to the rotary shaft 16 and fixed. By the rotor core 12 being sandwiched between the press-in ring 18 and the large diameter portion 38, the axial movement of the rotor core 12 is prevented.

  A portion of the rotary shaft 16 located in the shaft hole 26 has an involute spline shape. That is, on the outer periphery of the portion of the rotary shaft 16, a fitting protrusion 32 (tooth) protruding radially outward and a fitting groove 34 (tooth groove) recessed radially inward are continuous in the circumferential direction. External teeth 36 are formed side by side (see FIG. 4). The outer teeth 36 mesh with and engage with the core inner teeth 30 of the rotor core 12, so that the rotating shaft 16 is fixed to the rotor core 12. That is, the fitting protrusion 32 of the rotating shaft 16 is fitted into the fitting groove 34 of the rotor core 12, and the fitting groove 34 of the rotating shaft 16 is fitted into the fitting protrusion 32 of the rotor core 12, respectively. The rotating shaft 16 is fixed to the rotor core 12.

  In this way, when the fitting protrusion 32 and the fitting groove 34 are fitted, the rotational force is transmitted between the rotor core 12 and the rotary shaft 16 via the fitting protrusion 32 and the fitting groove 34. Is done. In other words, according to this example, even if the frictional force between the rotor core 12 and the large diameter portion 38 is small, the rotational force is transmitted between the rotor core 12 and the rotary shaft 16. Therefore, according to this example, a nut that strongly tightens the rotor core 12 in the axial direction becomes unnecessary, and equipment for tightening the nut becomes unnecessary. As a result, the cost for manufacturing the rotor 10 can be reduced. In this example, the press-fit ring 18 is provided in place of the nut. However, the press-fit ring 18 has a simpler mounting process than the nut, and the equipment for mounting can be configured relatively inexpensively.

  By the way, the fitting portions 20c and 20r in which the fitting protrusion 32 and the fitting groove 34 are fitted (hereinafter simply referred to as “fitting portion 20” when the fitting portion 20c and the fitting portion 20r are not distinguished from each other) If present near the bridge portion 25, residual stress is likely to be generated around the bridge portion 25. Such residual stress may cause deterioration or damage of the bridge portion 25.

  Therefore, in this example, the fitting portion 20 in which the fitting protrusion 32 and the fitting groove 34 fit is arranged at a position that does not overlap with the bridge portion 25 in the circumferential direction. This will be specifically described. As shown in FIG. 4 and as described above, the outer peripheral surface of the rotating shaft 16 has an involute spline shape, and the fitting protrusion 32 (tooth) and the fitting groove 34 (tooth groove) are continuous over the entire circumference. doing. On the other hand, fitting protrusions 32 and fitting grooves 34 are intermittently formed on the inner peripheral surface of the shaft hole 26 of the rotor core 12 as shown in FIG. More specifically, on the inner peripheral surface of the shaft hole 26, a set of protrusions and grooves in which one fitting groove 34 exists between the two fitting protrusions 32 is spaced apart in the circumferential direction. (Ie, the same number as the magnetic poles). On the other hand, the inner diameter of the shaft hole 26 is larger than the outer diameter of the rotating shaft 16 at a location where the set of protrusions and grooves is not formed, and the fitting between the shaft hole 26 and the rotating shaft 16 is performed at that location. No match has occurred. Therefore, the portion where the set of the protrusion and the groove exists is the fitting portion 20 where the fitting protrusion / grooves 32 and 34 of the rotating shaft 16 and the fitting groove / protrusion 34 and 32 of the shaft hole 26 are fitted. It becomes.

  The fitting portion 20 is provided at a position not overlapping the bridge portion 25 in the circumferential direction, as shown in FIG. More specifically, the fitting portion 20 is provided on the q-axis passing between two circumferentially adjacent magnetic poles. In the present example, since the fitting portions 20 are provided on all q axes, the number of the fitting portions 20 is the same as the number of magnetic poles. However, the number of fitting portions 20 is not particularly limited as long as the fitting portions 20 and the bridge portion 25 are shifted in the circumferential direction. However, in order to equalize the influence of the stress caused by the fitting, it is desirable that the fitting portion 20 be evenly arranged in the circumferential direction. In addition, the number of fitting portions 20 is desirably a divisor of the number of magnetic poles. Further, as will be described later, when the fitting portion 20 is provided with a circumferential fitting portion 20c fitted in the circumferential direction and a radial fitting portion 20r fitted in the radial direction, the circumferential fitting portion 20c is provided. It is desirable that the number of the radial side fitting portions 20r fitted in the radial direction is the same, and the total number of the fitting portions 20 is an even number.

  In any case, the distance between the fitting portion 20 and the bridge portion 25 is increased by providing the fitting portion 20 at a position shifted in the circumferential direction from the bridge portion 25. Therefore, the stress generated due to the fitting hardly acts on the bridge portion 25 whose mechanical strength is reduced. As a result, residual stress is hardly generated in the bridge portion 25, and the strength of the rotor core 12 can be maintained high.

  By the way, in this example, the peripheral side fitting part 20c mainly fitted in the circumferential direction and the radial side fitting part 20r mainly fitted in the radial direction are provided as the fitting part 20. In FIG. 2, a portion surrounded by a broken-line ellipse is a circumferential fitting portion 20 c, and a portion surrounded by a broken-line rectangle is a radial-side fitting portion 20 r. The configuration of the circumferential fitting portion 20c and the radial fitting portion 20r will be described with reference to FIGS.

  FIG. 5 is a diagram for explaining the peripheral side fitting portion 20c. In FIG. 5, the hatched range indicates the rotating shaft 16. In the example of FIG. 5, a fitting protrusion 32 that protrudes radially outward is formed on the rotary shaft 16, and a fitting groove 34 that is recessed radially outward is formed on the shaft hole 26. The radial dimension of the fitting projection 32 is the same as or slightly smaller than the radial dimension of the fitting groove 34. On the other hand, the circumferential dimension of the fitting projection 32 is slightly larger than the circumferential dimension of the fitting groove 34. As a result, the fitting protrusion 32 and the fitting groove 34 are in close contact with each other in the circumferential direction, and the movement in the circumferential direction, that is, rotation is transmitted between the fitting protrusion 32 and the fitting groove 34. Yes. Thus, by providing the circumferential side fitting portion 20c in which the circumferential dimension of the fitting protrusion 32 is larger than the circumferential dimension of the fitting groove 34, the rotational torque is reliably transmitted.

  FIG. 6 is a diagram illustrating the radial side fitting portion 20r. Also in FIG. 6, the hatched portion shows the rotating shaft 16, the fitting protrusion 32 is formed on the rotating shaft 16, and the fitting groove 34 is formed on the shaft hole 26. In the radial side fitting portion 20r, the circumferential dimension of the fitting protrusion 32 is the same as or slightly smaller than the circumferential dimension of the fitting groove 34. On the other hand, the radial dimension of the fitting projection 32 is slightly larger than the radial dimension of the fitting groove 34. As a result, the fitting protrusion 32 and the fitting groove 34 are in close contact with each other in the circumferential direction. Centering of the rotary shaft 16 can be easily performed by providing two or more, and more preferably three or more of the diameter side fitting portions 20r in the circumferential direction.

  In this example, as shown in FIG. 2, the circumferential side fitting portions 20 c (broken line oval portions) and the radial side fitting portions 20 r (broken line rectangular portions) are alternately arranged in the circumferential direction. Thus, by arranging the two types of fitting portions 20 alternately, the stress applied to the rotor core 12 can be evenly distributed, and the load applied to the rotor core 12 can be reduced.

  The configuration described so far is an example, and the fitting protrusion 32 formed on one of the outer periphery of the rotating shaft 16 and the inner periphery of the shaft hole 26 is fitted in the fitting groove 34 formed on the other. As long as the joint portion 20 is provided at a position not overlapping the bridge portion 25 in the circumferential direction, the other configuration may be changed as appropriate. For example, in this example, the external teeth 36 of the rotating shaft 16 have a gear shape (involute spline shape) in which the fitting protrusion 32 and the fitting groove 34 are continuously arranged. However, the outer teeth 36 of the rotary shaft 16 are also formed in a shape in which the fitting protrusions 32 and / or the fitting grooves 34 are intermittently arranged as in the core inner teeth 30 of the rotor core 12 as shown in FIG. Also good. Further, the outer teeth 36 of the rotating shaft 16 are formed in a shape in which the fitting protrusions 32 and / or the fitting grooves 34 are arranged intermittently, and the core inner teeth 30 of the rotor core 12 are changed to the fitting protrusions 32 and the fitting grooves 34. It is good also as the gear shape which arranges continuously. However, as in this example, the rotation shaft 16 has a gear shape and the core inner teeth 30 have a shape in which protrusions / grooves are intermittently arranged. The present invention can be applied to different types of rotor cores 12.

  In the description so far, the rotor core 12 in which the bridge portion 25 is formed between the first magnet hole 22a and the first magnetic flux leakage prevention hole 24a is taken as an example. However, the rotor core 12 has other forms as long as the bridge portion 25 that is a minute gap is formed between the magnetic pole holes (the magnet hole 22 and the magnetic flux leakage prevention hole 24) adjacent to each other in the circumferential direction. It may be. For example, the rotor core 12 may not have the magnetic flux leakage prevention hole but may have two magnet holes arranged in a substantially V shape. In this case, a minute gap between the radially inner end portion of one magnet hole and the radially inner end portions of the adjacent magnet holes 22a and 22b becomes a bridge portion. In the above description, the fitting protrusion and the fitting groove are both substantially trapezoidal, but these shapes may be changed as appropriate.

DESCRIPTION OF SYMBOLS 10 Rotor, 12 Rotor core, 14 Permanent magnet, 16 Rotating shaft, 18 Press-fit ring, 20 Fitting part, 22 Magnet hole, 24 Magnetic flux leakage prevention hole, 25 Bridge part, 26 Shaft hole, 28 Caulking part, 30 Core internal tooth, 32 mating projections, 34 mating grooves, 36 external teeth, 38 large diameter parts.

Claims (1)

A rotor of a rotating electric machine,
A rotor core having a centrally extending axial hole and a plurality of magnetic pole holes;
A permanent magnet inserted into the magnetic pole hole;
A rotary shaft inserted into the shaft hole and fixed to the shaft hole via one or more fitting parts;
With
In the fitting portion, a fitting groove which is provided on one of the outer peripheral surface of the rotary shaft and the inner peripheral surface of the axial hole and which is recessed in the radial direction, the outer peripheral surface of the rotary shaft and the inner peripheral surface of the axial hole And fitting projections, which are provided on the other side of the housing and radially project, are fitted to each other,
The fitting portion is arranged at a position that does not overlap in the circumferential direction with a bridge portion that is a minute gap portion between two magnetic pole holes adjacent in the circumferential direction.
A rotor of a rotating electrical machine characterized by that.

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