JP7063637B2 - Rotating machine rotor - Google Patents

Description

The present specification discloses a rotor of a rotary electric machine including a rotor core, a magnet embedded in the rotor core, and a rotary shaft inserted and fixed in a shaft hole of the rotor core.

In the rotor of a rotary electric machine, a rotating shaft is inserted and fixed in the center of a rotor core in which a permanent magnet is embedded. Since the rotating shaft rotates with the rotor core, it is required to be firmly fixed to the rotor core. Therefore, various techniques for fixing the rotating shaft have been conventionally proposed.

For example, Patent Document 1 discloses a technique for fastening a rotating shaft to a rotor core using a nut. That is, in Patent Document 1, a large-diameter portion that supports one end surface in the axial direction of the rotor core and a female screw into which a nut is screwed are formed on the rotating shaft. Then, after inserting the rotor core and the nut into the rotating shaft, the nut is tightened, and the rotor core is sandwiched between the nut and the large diameter portion. As a result, a frictional force is generated between the axial end surface of the rotor core and the large diameter portion and the nut of the rotating shaft. Due to this frictional force, the rotational force is transmitted between the rotor core and the rotating shaft.

JP-A-2015-27119

However, in the case of fastening using such a nut, a dedicated facility for tightening the nut with an appropriate torque is required, which has led to an increase in manufacturing cost. In addition, in order to transmit the rotational force by the frictional force generated on the axial end face 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 the load on the rotor core. ..

Therefore, this specification discloses a rotor of a rotary electric machine which can reduce the size of parts and the manufacturing cost.

The rotor of a rotary electric machine disclosed in the present specification is a rotor of a rotary electric machine, and has a rotor core having a shaft hole extending to the center, a plurality of magnetic pole holes, and a permanent magnet inserted in the magnetic pole holes. A rotating shaft that is inserted into the shaft hole and fixed to the shaft hole via a plurality of fitting portions. In the fitting portion, the outer peripheral surface of the rotating shaft and the inner circumference of the shaft hole are provided. A fitting groove provided on one of the surfaces and recessed in the radial direction and a fitting projection provided on the other side 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 fitted to each other. A bridge portion, which is a minute gap portion, exists between two magnetic pole holes that are close to each other in the circumferential direction, and the fitting portion is a minute gap portion between two magnetic pole holes that are close to each other in the circumferential direction. It is arranged at a position that does not overlap with the bridge portion in the circumferential direction, and the plurality of fitting portions are the peripheral fitting portion in which the circumferential dimension of the fitting protrusion is larger than the circumferential dimension of the fitting groove. The fitting portion is different from the peripheral fitting portion, and has a radial fitting portion in which the radial dimension of the fitting protrusion is larger than the radial dimension of the fitting groove. ..

With such a configuration, the rotational force can be transmitted between the rotor core and the rotating shaft via the fitting portion, so that a nut is not required. As a result, the parts can be miniaturized and the manufacturing cost can be reduced. Further, since the fitting portion is arranged at a position where it does not overlap with the bridge portion having weak strength in the circumferential direction, damage to the rotor core can be effectively prevented.

With such a configuration, the rotation is transmitted at the peripheral fitting portion, and the centering of the rotating shaft can be performed at the radial fitting portion.

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

With such a configuration, the stress in the circumferential direction and the stress in the radial direction are alternately generated in the circumferential direction, so that the load applied to the rotor core can be evenly distributed.

Further, the outer peripheral surface of the rotating shaft has an involut spline shape in which teeth and tooth grooves functioning as fitting protrusions and fitting grooves are continuously arranged in the circumferential direction, and the inner peripheral surface of the shaft hole has the above-mentioned The tooth grooves and teeth that function as fitting grooves and fitting protrusions may be intermittently arranged so as to be located within a range that does not overlap with the bridge portion in the circumferential direction.

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

Further, the fitting portion may be arranged at a position overlapping the magnetic pole boundary position in the circumferential direction.

Normally, since there is no bridge portion at the magnetic pole boundary position, it is possible to reliably prevent the fitting portion from overlapping with the bridge portion by adopting such a configuration.

According to the rotor disclosed herein, a nut is not required because the rotational force can be transmitted between the rotor core and the rotating shaft via the fitting portion. As a result, the parts can be miniaturized and the manufacturing cost can be reduced. Further, since the fitting portion is arranged at a position where it does not overlap with the bridge portion having weak strength in the circumferential direction, damage to the rotor core can be effectively prevented.

It is a vertical sectional view of a rotor. FIG. 3 is a cross-sectional view taken along the line AA in FIG. It is a figure around the shaft hole of a rotor core. It is sectional drawing of the rotation axis. It is a figure explaining the peripheral side fitting part. It is a figure explaining the diameter side fitting part. It is a figure which shows an example of another rotation axis.

Hereinafter, the configuration of the rotor 10 of the rotary electric machine will be described with reference to the drawings. FIG. 1 is a schematic vertical sectional view of a rotor 10 of a rotary electric machine. Further, FIG. 2 is a cross-sectional view taken along the line AA in FIG. Further, FIG. 3 is a view of the periphery of the shaft hole 26 of the rotor core 12, and FIG. 4 is a cross-sectional view of the rotating shaft 16. The rotor 10 is used in a rotary electric machine, for example, a three-phase synchronous rotary electric machine mounted on an electric vehicle as one of the 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 sheets (for example, silicon steel sheets or the like) in the axial direction. A plurality of electrical steel sheets are connected to each other by, for example, caulking. In order to enable this caulking bond, each electromagnetic steel sheet is formed with a caulking portion 28 projecting on one surface and projecting 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, 24b are arranged at positions near the outer periphery of the rotor core 12 at intervals in the circumferential direction. Each magnetic pole hole is a hole used to form a magnetic pole and penetrates in the axial direction. The magnetic flux holes include magnet holes 22a and 22b into which magnets are inserted, and magnetic flux leakage prevention holes 24a and 24b that suppress magnetic flux leakage. One or more permanent magnets 14 are inserted into the magnet holes 22a and 22b to form magnetic poles.

As shown in FIG. 2, the rotor 10 of this example has eight magnetic poles. However, this number of magnetic poles is an example, and if it is an even number, 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 near the outer peripheral end. It has magnet holes 22b, and one or more permanent magnets 14 are inserted into the magnet holes 22a and 22b.

Two second magnetic flux leakage prevention holes 24b are formed on both sides of the second magnet hole 22b in the circumferential direction. Further, a first magnetic flux leakage prevention hole 24a is provided between the radial inner end portion of the first magnet hole 22a and the radial inner end portion 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, which is a minute gap, is formed between the first magnetic flux leakage prevention hole 24a and the first magnet hole 22a. 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, if the magnetic characteristics are emphasized. In this example, the bridge portion 25 is composed of a part of the rotor core 12, but a through hole is formed in the portion of the bridge portion 25 and a component different from the rotor core 12 is formed in the through hole. The bridge portion 25 may be configured by inserting. In this case, the material of the component inserted as the bridge portion 25 is not particularly limited, but it is desirable that it is a non-magnetic 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 rotating shaft 16 is inserted. On the inner peripheral surface of the shaft hole 26, core internal teeth 30 that mesh with the external teeth 36 of the rotating shaft 16 described later are formed (see FIGS. 3 and 4). The rotating shaft 16 is fixed to the rotor core 12 by fitting the core internal teeth 30 and the external teeth 36 of the rotating shaft 16 to each other, which 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 (neither is shown) or the like via bearings. A large diameter portion 38 having a diameter larger than that of the shaft hole 26 is formed in the middle of the rotating shaft 16. One end surface of the rotor core 12 in the axial direction is pressed against the large diameter portion 38. Further, 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-fit ring 18 is a component that is press-fitted and fixed to the rotating shaft 16. By sandwiching the rotor core 12 between the press-fit ring 18 and the large diameter portion 38, the rotor core 12 is prevented from moving in the axial direction.

The portion of the rotating shaft 16 located in the shaft hole 26 has an involute spline shape. That is, on the outer periphery of the portion of the rotating shaft 16, the fitting protrusion 32 (teeth) protruding outward in the radial direction and the fitting groove 34 (tooth groove) recessing inward in the radial direction are continuous in the circumferential direction. External teeth 36 arranged side by side are formed (see FIG. 4). The rotating shaft 16 is fixed to the rotor core 12 by engaging and fitting the external teeth 36 with the core internal teeth 30 of the rotor core 12. That is, the fitting projection 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 projection 32 of the rotor core 12, respectively. The rotating shaft 16 is fixed to the rotor core 12.

Then, by fitting the fitting protrusion 32 and the fitting groove 34 in this way, the rotational force is transmitted between the rotor core 12 and the rotating shaft 16 via the fitting protrusion 32 and the fitting groove 34. Will be 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 rotating shaft 16. Therefore, according to this example, a nut for strongly tightening the rotor core 12 in the axial direction is not required, and equipment for tightening the nut is not required. As a result, the cost for manufacturing the rotor 10 can be reduced. In this example, the press-fit ring 18 is provided instead of the nut, but the press-fit ring 18 has a simpler mounting process than the nut, and the equipment for mounting can be configured at a relatively low cost.

By the way, the fitting portions 20c and 20r in which the fitting protrusion 32 and the fitting groove 34 are fitted (hereinafter, when the fitting portion 20c and the fitting portion 20r are not distinguished, they are simply referred to as "fitting portion 20"). If it exists near the bridge portion 25, residual stress is likely to occur around the bridge portion 25. Then, 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 are fitted 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 (teeth) and the fitting groove 34 (tooth groove) are continuous over the entire circumference. are doing. On the other hand, as shown in FIG. 3, 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. More specifically, on the inner peripheral surface of the shaft hole 26, a set of protrusions and grooves having one fitting groove 34 between the two fitting protrusions 32 is spaced apart in the circumferential direction. One (that is, the same number as the magnetic poles) is formed. On the other hand, in the place where the set of the protrusion and the groove is not formed, the inner diameter of the shaft hole 26 is larger than the outer diameter of the rotating shaft 16, and at that place, the shaft hole 26 and the rotating shaft 16 are fitted. No match has occurred. Therefore, the place where the set of the protrusion and the groove exists is the fitting portion 20 in which the fitting protrusion / groove 32, 34 of the rotating shaft 16 and the fitting groove / protrusion 34, 32 of the shaft hole 26 are fitted. Will be.

As shown in FIG. 2, the fitting portion 20 is provided at a position that does not overlap with the bridge portion 25 in the circumferential direction. More specifically, the fitting portion 20 is provided on the q-axis passing between two magnetic poles adjacent to each other in the circumferential direction. In this example, since the fitting portions 20 are provided on all q axes, the number of fitting portions 20 is the same as the number of magnetic poles. However, the number of the fitting portions 20 is not particularly limited as long as they are displaced from the bridge portions 25 in the circumferential direction. However, in order to equalize the influence of stress caused by fitting, it is desirable that the fitting portions 20 are evenly arranged in the circumferential direction. Further, it is desirable that the number of fitting portions 20 is a divisor of the number of magnetic poles. Further, as will be described later, as the fitting portion 20, a peripheral fitting portion 20c that fits in the circumferential direction and a radial fitting portion 20r that fits in the radial direction are provided, and if provided, the peripheral fitting portion 20c. It is desirable that the number of the radial fitting portions 20r to be fitted in the radial direction is the same, and the total number of the fitting portions 20 is an even number.

In any case, by providing the fitting portion 20 at a position deviated from the bridge portion 25 in the circumferential direction, the distance between the fitting portion 20 and the bridge portion 25 becomes large. Therefore, the stress generated by the fitting is less likely to act on the bridge portion 25 whose mechanical strength is reduced. As a result, residual stress is less likely to occur in the bridge portion 25, and the strength of the rotor core 12 can be maintained high.

By the way, in this example, as the fitting portion 20, a peripheral fitting portion 20c that mainly fits in the circumferential direction and a radial fitting portion 20r that mainly fits in the radial direction are provided. In FIG. 2, the portion surrounded by the broken line ellipse is the peripheral side fitting portion 20c, and the portion surrounded by the broken line rectangle is the radial side fitting portion 20r. The configuration of the peripheral fitting portion 20c and the radial fitting portion 20r will be described with reference to FIGS. 5 and 6.

FIG. 5 is a diagram illustrating a peripheral fitting portion 20c. In FIG. 5, the hatching range indicates the rotation axis 16. In the example of FIG. 5, the rotating shaft 16 is formed with a fitting projection 32 protruding outward in the radial direction, and the shaft hole 26 is formed with a fitting groove 34 recessed outward in the radial direction. 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 protrusion 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, the rotation is transmitted between the fitting protrusion 32 and the fitting groove 34. There is. By providing the peripheral fitting portion 20c whose circumferential dimension of the fitting projection 32 is larger than the circumferential dimension of the fitting groove 34 in this way, the rotational torque is reliably transmitted.

FIG. 6 is a diagram illustrating a diameter-side fitting portion 20r. Also in FIG. 6, the hatched portion indicates the rotating shaft 16, the fitting projection 32 is formed in the rotating shaft 16, and the fitting groove 34 is formed in the shaft hole 26. In the radial fitting portion 20r, the circumferential dimension of the fitting projection 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. By providing 2 or more, more preferably 3 or more, such radial fitting portions 20r in the circumferential direction, the rotating shaft 16 can be easily centered.

In this example, as shown in FIG. 2, the peripheral side fitting portion 20c (broken line elliptical portion) and the radial side fitting portion 20r (broken line rectangular portion) are alternately arranged in the circumferential direction. By alternately arranging the two types of fitting portions 20 in this way, 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 projection 32 formed on one of the outer periphery of the rotating shaft 16 and the inner circumference of the shaft hole 26 is fitted into the fitting groove 34 formed on the other. If the joint portion 20 is provided at a position that does not overlap with the bridge portion 25 in the circumferential direction, other configurations may be appropriately changed. 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 external teeth 36 of the rotating shaft 16 also have the same shape as the core internal teeth 30 of the rotor core 12, and as shown in FIG. 7, the fitting projections 32 and / or the fitting grooves 34 are arranged intermittently. May be good. Further, the outer teeth 36 of the rotating shaft 16 are shaped so that the fitting protrusions 32 and / or the fitting grooves 34 are intermittently arranged, and the core internal teeth 30 of the rotor core 12 are formed with the fitting protrusions 32 and the fitting grooves 34. May be in the shape of a gear in which is continuously arranged. However, as in this example, if the rotating shaft 16 has a gear shape and the core internal teeth 30 have a shape in which protrusions / grooves are intermittently arranged, one type of rotating shaft 16 can have the position and number of bridge portions 25. It can be applied to a plurality of different types of rotor cores 12.

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

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 teeth, 32 fitting protrusions, 34 fitting grooves, 36 external teeth, 38 large diameter parts.

Claims (1)

It is a rotor of a rotary electric machine,
A rotor core having a centrally extending shaft hole and a plurality of magnetic pole holes,
The permanent magnet inserted in the magnetic pole hole and
A rotating shaft inserted through the shaft hole and fixed to the shaft hole via a plurality of fitting portions,
Equipped with
In the fitting portion, a fitting groove provided on one of the outer peripheral surface of the rotating shaft and the inner peripheral surface of the shaft hole and recessed in the radial direction, and the outer peripheral surface of the rotating shaft and the inner peripheral surface of the shaft hole. The fitting protrusions provided on the other side of the above and protruding in the radial direction are fitted to each other.
There is a bridge part, which is a minute gap, between the two magnetic pole holes that are close to each other in the circumferential direction.
The fitting portion is arranged at a position that does not overlap with the bridge portion in the circumferential direction.
The plurality of fitting portions are
A peripheral fitting portion whose circumferential dimension of the fitting protrusion is larger than the circumferential dimension of the fitting groove ,
It has a fitting portion that is different from the peripheral fitting portion and has a radial fitting portion in which the radial dimension of the fitting protrusion is larger than the radial dimension of the fitting groove.
A rotor of a rotary electric machine characterized by that.

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