JP2020167763A - Fixing structure in rotary electric machine, and right and left wheels driving device - Google Patents

Abstract

To improve axis accuracy of a shaft with a simple configuration according to a fixing structure in a rotary electric machine, and a right and left wheels driving device.SOLUTION: A rotary electric machine comprising a rotor 1 and a stator 2 is provided with a shaft 3, a housing 4, a flange 5, a retainer 7 and a fixture 13. The shaft 3 is connected to the rotor 1 so as to rotate integrally with the rotor 1. The housing 4, in which the rotor 1 and the stator 2 are provided, supports the shaft 3 via a first bearing 11 in a rotatable manner. The flange 5 is extended toward outside in a radial direction of the shaft 3 from the stator 2 to fix the stator 2 to the housing 4. The retainer 7 supports the shaft 3 in the rotatable manner, via a second bearing 12 arranged on an opposite side of the first bearing 11, with a position of the rotor 1 in an extension direction of the shaft 3 as a reference. The fixture 13 fixes the flange 5 and the retainer 7 at the same position in the housing 4 in a contact state with one another.SELECTED DRAWING: Figure 1

Description

The present invention relates to a fixed structure of a rotating electric machine having a rotor and a stator, and a left and right wheel drive device.

Conventionally, in rotating electric machines (rotating electric machines) such as electric motors and generators, it is known that a rotor and a stator are housed in a space surrounded by a bottomed tubular housing and a lid-shaped retainer. .. That is, when the rotary electric machine is integrally fixed to another device, the rotary electric machine and the other device are partitioned by a retainer, and the shaft connected to the rotor is supported by the housing and the retainer. .. With such a structure, the rotary electric machine and other devices can be compactly integrated, and space saving can be improved (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-184341

When the stator is fixed to the casing by using fasteners such as bolts and nuts, the casing is provided with a mounting hole for mounting the stator and a mounting hole for mounting the retainer. On the other hand, variations in the positional degree (tolerance of misalignment) of each mounting hole affect the degree of axial misalignment of the rotor and the stator, so that good axial accuracy may not be obtained. In addition, it is difficult to improve the shaft accuracy of the shaft because a relatively large rotor or stator may be used in the rotary electric machine mounted on the vehicle and the shape of the housing or retainer tends to be large. ..

One of the purposes of this case is to improve the shaft accuracy of the shaft with a simple configuration, which was created in view of the above problems. Not limited to this purpose, it is also an action and effect derived from each configuration shown in the "form for carrying out the invention" described later, and it is also another purpose of the present invention to exert an action and effect that cannot be obtained by the conventional technique. Can be positioned as.

(1) The disclosed fixed structure of a rotary electric machine is a fixed structure of a rotary electric machine having a rotor and a stator, in which a shaft connected to the rotor so as to rotate integrally with the rotor, and the rotor and the said rotor. A stator is built in and includes a housing that rotatably supports the shaft via a first bearing. Further, the first is based on a flange extending from the stator toward the outside in the radial direction of the shaft and fixing the stator to the housing and the position of the rotor in the extending direction of the shaft. It includes a retainer that rotatably supports the shaft via a second bearing arranged on the opposite side of the bearing. Further, a fixture for fixing the flange and the retainer in contact with each other at the same position in the housing is provided.

(2) The position of the fixture in the extending direction of the shaft is the second distance to the center of the rotor rather than the first distance to the center of the second bearing in the cross section passing through the rotation axis of the shaft. Is preferably set within a smaller range.
(3) It is preferable that the position of the fixture in the extending direction of the shaft is set within a range that overlaps with the stator in the cross section passing through the rotation axis of the shaft.

(4) It is preferable that the retainer has an oblique portion having a shape in which the outer side in the radial direction of the shaft is inclined toward the first bearing side with reference to a state perpendicular to the rotation axis of the shaft.
(5) The retainer forms a fan-shaped region surrounded by a sector having a central angle larger than 180 ° and a first radius and a circle having a second radius smaller than the first radius in the axial view of the shaft. It is preferable that the contour shape is equivalent to the region corresponding to the logical sum when the enclosed circular regions are arranged concentrically.
(6) It is preferable that the fixture is arranged only on the outer edge of the fan-shaped region along the arc.

(7) Further, the disclosed left and right wheel drive device includes a rotor having a rotor and a stator, a shaft connected to the rotor so as to rotate integrally with the rotor, and the rotor. The shaft is rotatably supported via the first bearing, and the stator is fixed via a flange extending outward in the radial direction of the shaft, parallel to the shaft. It includes an output shaft arranged and connected to a drive wheel, and a transmission mechanism for transmitting the torque of the rotary electric machine to the output shaft. The rotary electric machine includes a retainer that rotatably supports the shaft via a second bearing arranged on a side opposite to the first bearing with reference to the position of the rotor in the extending direction of the shaft. It has a fixture that fixes the flange and the retainer in contact with each other at the same position in the housing.

By fixing the flange extending from the stator and the retainer at the same position in the housing in contact with each other, the shaft accuracy of the rotary electric machine can be improved. In particular, the position accuracy of the shaft can be improved as compared with the case where the flange and the retainer are fixed at different positions of the housing.

It is a horizontal sectional view of the rotary electric machine as an embodiment. It is a vertical sectional view of a rotary electric machine. It is an exploded perspective view of a flange and a retainer. (A) to (C) are reference views for explaining the shape of the retainer. It is a side view for demonstrating the shape of a retainer. It is a horizontal sectional view of the rotary electric machine as a comparative example.

[1. Constitution]
Hereinafter, a fixed structure of the rotary electric machine 10 as an embodiment and a left and right wheel drive device provided with the rotary electric machine 10 will be described with reference to the drawings. The rotary electric machine 10 is applied to a differential device (left and right wheel drive device) for a vehicle having an AYC (active yaw control) function. The AYC function is a function that adjusts the magnitude of the yaw moment by positively controlling the sharing ratio of the driving force (driving torque) in the left and right driving wheels, thereby stabilizing the posture of the vehicle. The differential device has a built-in differential mechanism (a mechanism in which a differential gear is interposed between the left axle connected to the left wheel and the right axle connected to the right wheel).

The rotary electric machine 10 may be used to generate a driving force transmitted to the left and right drive wheels, or may be used to generate a torque difference (rotation speed difference) between the left and right drive wheels. That is, the rotary electric machine 10 may be a traveling motor (preferably a generator for regenerative power generation), or a control motor (other) for changing the amount of torque transferred from one drive wheel to the other. It may be a motor for auxiliary changing the driving force transmitted from the driving source of the above to the left and right driving wheels).

The rotary electric machine 10 includes a rotor 1 (rotor) and a stator 2 (stator) fixed around the rotor 1. The rotor 1 has, for example, a permanent magnet inserted in a laminated iron core formed by laminating insulating steel plates. Further, the stator 2 has a structure in which a coil is wound around a laminated iron core similar to that of the rotor 1, and a plurality of stators 2 are arranged around the rotor 1. A rotating magnetic field is generated around the rotor 1 by controlling the energization timing of each stator 2 and the phase of the AC voltage. As a result, the rotor 1 rotates according to the direction of the rotating magnetic field.

As shown in FIG. 1, the rotary electric machine 10 of the present embodiment is provided with a shaft 3, a housing 4, a flange 5, a retainer 7, and a fixture 13. The shaft 3 is a member that is connected to the rotor 1 and rotates integrally with the rotor 1. In the example shown in FIG. 1, the rotor 1 is fixed to the peripheral surface of the shaft 3, and the rotation axis C of the shaft 3 is coaxial with the central axis of the rotor 1 and the central axis of the stator 2. The shaft 3 may be connected to at least the rotor 1 so that the rotational motion of the rotor 1 can be transmitted. Therefore, the rotor 1 and the shaft 3 may not be fixed to each other. For example, a gear train, a speed change mechanism (reduction mechanism), or the like may be interposed between the rotor 1 and the shaft 3.

The housing 4 is a container-shaped member in which the rotary electric machine 10 is housed. For example, a rotor 1 and a stator 2 are arranged inside the housing 4. The shaft 3 is rotatably supported by the housing 4 via the first bearing 11. The housing 4 of FIG. 1 is formed in a rotating body shape (conical truncated cone shape) with respect to the rotating shaft C of the shaft 3. Further, the housing 4 is perforated with a mounting hole 16 into which a fixture 13 for fixing the stator 2 and the retainer 7 is mounted. The layout of the mounting holes 16 will be described later.

The flange 5 is a member having a portion extending from at least the stator 2 toward the outer side in the radial direction of the shaft 3. The flange 5 may be integrally formed with the stator 2, or may be a separate member attached to the stator 2. As shown in FIG. 3, the flange 5 of the present embodiment has a tubular fixing portion 17 formed in a hollow cylindrical shape and fixed to the side surface of the stator 2, and its end faces outward in the radial direction of the shaft 3. It has an extended flange portion 18. The flange portion 18 is shaped like an annular disk, and its plate surface is perpendicular to the rotation axis C of the shaft 3. The flange portion 18 is perforated with a flange hole 6 through which a fixture 13 for fixing the stator 2 to the housing 4 is inserted. The layout of the flange holes 6 will be described later.

The retainer 7 is a lid-shaped member fixed to the housing 4 to form a space in which the rotor 1 and the stator 2 are housed. The retainer 7 has a function of rotatably supporting the shaft 3 via the second bearing 12. As shown in FIG. 1, the second bearing 12 is arranged on the side opposite to the first bearing 11 with reference to the position of the rotor 1 in the extending direction of the shaft 3. Therefore, the position on the shaft 3 to which the rotor 1 is connected is within the range sandwiched between the first bearing 11 and the second bearing 12.

As shown in FIGS. 1 to 3, the retainer 7 of the present embodiment is provided with a shaft support portion 19, an oblique portion 9, a tubular portion 20, and a second flange portion 21. The shaft support portion 19 is a hollow cylindrical portion to which the second bearing 12 is fixed. A shaft hole 22 having a diameter larger than that of the shaft 3 is drilled in the end surface of the shaft support portion 19, and the shaft 3 is inserted through the shaft hole 22. The oblique portion 9 is a portion formed so as to form a conical surface whose diameter is expanded from the end side of the shaft support portion 19. As shown in FIG. 2, the shape of the oblique portion 9 is such that the outer side of the shaft 3 in the radial direction is inclined toward the first bearing 11 side with respect to the state perpendicular to the rotation axis C of the shaft 3.

The tubular portion 20 is a hollow cylindrical portion in which the end side of the oblique portion 9 extends in a direction parallel to the rotation axis C of the shaft 3. Further, the second flange portion 21 is a portion in which the end side of the tubular portion 20 extends outward in the radial direction of the shaft 3. The plate surface of the second flange portion 21 is perpendicular to the rotation axis C of the shaft 3. However, the oblique portion 9, the tubular portion 20, and the second flange portion 21 of the present embodiment have a partially formed shape. As shown in FIG. 2, the missing portion is a portion that can interfere with the gear 14 fixed to the shaft 3 and other gears 15. Due to such a deficiency, the retainer 7 of the present embodiment has a contour shape equivalent to a region corresponding to the logical sum of the fan-shaped region and the circular region in the axial view of the shaft 3.

As shown in FIG. 4A, the fan-shaped region referred to here is a region surrounded by a fan shape having a central angle larger than 180 ° and a first radius R ₁ . Further, as shown in FIG. 4 (B), the above-mentioned circular region is an region surrounded by a circle having a second radius R ₂ smaller than the first radius R ₁ . As shown in FIG. 4 (C), the region corresponding to the logical sum in the superposed state (concentric arrangement state) so that the respective center positions coincide is outside the circular region of the second radius R _2. The fan-shaped region of the first radius R ₁ has a partially expanded shape. The contour shape of the retainer 7 has a contour shape equivalent to that of the OR region shown in FIG. 4 (C).

FIG. 5 is a side view showing the retainer 7 in the axial view of the shaft 3. The alternate long and short dash line is the contour line of the gear 14 fixed to the shaft 3, and the alternate long and short dash line is the contour line of another gear 15 that meshes with the gear 14. The retaining angle of the retainer 7 (the angle obtained by subtracting the central angle of the fan-shaped region from 360 °) is set so as not to come into contact with the gears 14 and 15. Further, the second flange portion 21 is perforated with a retainer hole 8 into which a fixture 13 for fixing the retainer 7 to the housing 4 is inserted.

As shown in FIG. 5, the retainer holes 8 are arranged only in the outer edge portion of the fan-shaped region along the arc. Preferably, the retainer holes 8 are arranged at both ends close to the missing portion in the portion along the arc, and the retainer holes 8 are also arranged at positions that divide the portions at equal intervals. The retainer holes 8 are aligned with the flange holes 6 and the mounting holes 16 described above. That is, the layout of the flange hole 6 and the mounting hole 16 is the same as that of the retainer hole 8. Therefore, the fixture 13 is arranged only on the outer edge of the fan-shaped region of the retainer 7 along the arc.

The fixture 13 fixes the flange 5 and the retainer 7 to the same position of the housing 4 in a contact state, and is, for example, a screw, a bolt, a rivet, or the like. As shown in FIG. 1, the flange 5 and the retainer 7 are fastened and fixed to the housing 4 in a state where the flange portion 18 and the second flange portion 21 are in surface contact with each other. In other words, the flange portion 18 of the flange 5 is fixed to both the housing 4 and the retainer 7 in a state of being sandwiched between the housing 4 and the second flange portion 21 of the retainer 7.

The arrangement position of the fixture 13 is preferably set near the rotor 1 and the stator 2. Here, the layout of the fixture 13 will be described in detail with reference to FIG. 1 (cross-sectional view of the shaft 3 passing through the rotation axis C). First, the position of the fixture 13 in the extending direction of the shaft 3 is set within a range in which the second distance to the center of the rotor 1 is smaller than the first distance to the center of the second bearing 12. Is preferable. For example, if the distance from the center of the rotor 1 to the second bearing 12 is 2A in the extending direction of the shaft 3, the fixed position is set within the range from the center of the rotor 1 to A. As a result, the flange 5, the retainer 7, and the housing 4 are fixed in the vicinity of the rotor 1.

Further, the position of the fixture 13 in the extending direction of the shaft 3 is preferably set within a range in which it overlaps with the stator 2. For example, a parallel projection of the rotor 1 and the stator 2 is obtained from the rotation axis C of the shaft 3 toward the outside in the radial direction, and a parallel projection drawing is drawn on the inner surface of the housing 4. Then, a fixed position is set within the area of the drawn parallel projection drawing (within the range of B in FIG. 1). As a result, the flange 5, the retainer 7, and the housing 4 are fixed in the vicinity of the stator 2.

In addition to the rotary electric machine 10, the left and right wheel drive device is provided with an output shaft connected to the drive wheels of the vehicle and a transmission mechanism for transmitting the torque generated by the rotary electric machine 10 to the output shaft. The output shaft is arranged parallel to the shaft 3 of the rotary electric machine 10. Further, the transmission mechanism includes a gear 14 fixed to the shaft 3 and other gears 15, as well as a differential mechanism, a reduction gear mechanism, a planetary gear mechanism, and the like. The transmission mechanism has a function of changing the distribution state of torque to the left and right wheels and the amount of amplification. Through such a transmission mechanism, the torque of the rotary electric machine 10 is transmitted to the drive wheels to drive the vehicle.

[2. Action / effect]
(1) In the rotary electric machine 10 described above, the flange 5 extending from the stator 2 and the retainer 7 are fastened and fixed together at the same position in the housing 4 in a contact state. With such a structure, the shaft accuracy of the rotary electric machine 10 can be improved. For example, as shown in FIG. 6, when the flange 5 and the retainer 7 are fixed at different positions in the housing 4, not only the variation in the position of the flange hole 6 but also the variation in the position of the retainer hole 8 rotates. It affects the coaxiality of the child 1 and the stator 2, and it is difficult to secure the shaft accuracy. On the other hand, in the above structure, since the three members are integrally fixed at the same position, it becomes easy to secure the coaxiality of the rotor 1 and the stator 2. Therefore, the shaft accuracy of the rotor 1 and the stator 2 and the position accuracy of the shaft 3 can be improved.

(2) In the rotary electric machine 10 described above, the position of the fixture 13 is set within the range A in FIG. By setting the position of the fixture 13 near the rotor 1 in this way, the supporting state of the shaft 3 can be made more stable, and the supporting accuracy of the shaft 3 can be improved. Therefore, the positional accuracy of the shaft 3 can be maintained for a long period of time, and the axial accuracy of the rotor 1 and the stator 2 can also be maintained for a long period of time.

(3) In the rotary electric machine 10 described above, the position of the fixture 13 is set within the range B in FIG. By setting the position of the fixture 13 near the stator 2 in this way, the fixed state of the stator 2 can be made more stable, and the axial accuracy of the rotor 1 and the stator 2 can be improved. it can. Therefore, the axial accuracy of the rotor 1 and the stator 2 can be maintained for a long period of time, and the position accuracy of the shaft 3 can also be maintained for a long period of time.

(4) In the rotary electric machine 10 described above, the retainer 7 is provided with a skew portion 9 as shown in FIGS. 1 to 3. The skew portion 9 acts to increase the rigidity of the retainer 7 against an axial force that may be slightly input from the shaft 3 via the second bearing 12. As a result, vibration during operation of the rotary electric machine 10 can be suppressed, the position accuracy of the shaft 3 can be maintained for a long period of time, and the shaft accuracy of the rotor 1 and the stator 2 can be maintained for a long period of time. Can be done. Further, in the configuration in which the shaft 3 is connected to the axle, the resistance to the axial force of the axle can be increased, and the stability of the traveling state can be further improved.

(5) In the rotary electric machine 10 described above, the contour shape of the retainer 7 in the axial view of the shaft 3 is a shape as shown in FIG. 4 (C) [the logical sum of FIG. 4 (A) and FIG. 4 (B). Corresponding shape]. With such a setting, even if other parts or devices exist in the vicinity of the stator 2, they are as close to the rotor 1 and the stator 2 as possible while avoiding interference with them. It becomes easy to arrange the retainer 7. Therefore, the shaft accuracy of the rotor 1 and the stator 2 and the position accuracy of the shaft 3 can be improved.

(6) In the rotary electric machine 10 described above, as shown in FIG. 5, the fixture 13 is arranged only on the outer edge of the fan-shaped region of the retainer 7 along the arc. By arranging the fixture 13 only in the arc portion in this way, the flange 5 and the retainer 7 can be fixed to the housing 4 at a position where they surely overlap each other, and the position accuracy of the shaft 3 can be improved. Further, since there is no place where only the flange 5 is fixed to the housing 4 or only the retainer 7 is fixed to the housing 4, the flange 5 and the retainer 7 are substantially integrated, and the mounting accuracy is high. There is an advantage that it is easy to improve the shaft accuracy.

[3. Modification example]
The above embodiment is merely an example, and there is no intention of excluding the application of various modifications and techniques not specified in the present embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the gist thereof. In addition, it can be selected as needed, or can be combined as appropriate.

In the above-described embodiment, the rotary electric machine 10 applied to the differential device for a vehicle is illustrated, but the structure of the present invention can also be applied to a traveling motor of a vehicle, a generator for power generation, and the like. It can also be applied to, for example, electric motors and generators mounted on ships, aircraft, industrial machines, and the like. At least, if it is a rotary electric machine having a rotor 1 and a stator 2, by applying the structure of the present invention, the same operation and effect as those of the above-described embodiment can be obtained.

1 Rotor 2 Fixture 3 Shaft 4 Housing 5 Flange 6 Flange hole 7 Retainer 8 Retainer hole 9 Diagonal part 10 Rotor 11 First bearing 12 Second bearing 13 Fixture 14 Gear 15 Gear 16 Mounting hole 17 Cylindrical fixing part 18 Flange 19 Shaft support 20 Cylindrical portion 21 Second flange 22 Shaft hole
C Rotating shaft (of shaft 3)

Claims (7)

In the fixed structure of a rotating electric machine having a rotor and a stator,
A shaft connected to the rotor so as to rotate integrally with the rotor,
A housing in which the rotor and the stator are installed and rotatably support the shaft via a first bearing.
A flange extending from the stator toward the outside in the radial direction of the shaft and fixing the stator to the housing.
A retainer that rotatably supports the shaft via a second bearing arranged on the side opposite to the first bearing with reference to the position of the rotor in the extending direction of the shaft.
A fixing structure for a rotary electric machine, which comprises a fixture for fixing the flange and the retainer at the same position in the housing in a contact state. The position of the fixture in the extending direction of the shaft is such that the second distance to the center of the rotor is larger than the first distance to the center of the second bearing in the cross section passing through the rotation axis of the shaft. The fixed structure of a rotary electric machine according to claim 1, wherein the rotary electric machine is set within a small range. The rotary electric machine according to claim 1 or 2, wherein the position of the fixture in the extending direction of the shaft is set within a range of overlapping with the stator in a cross section passing through the rotation axis of the shaft. Fixed structure. Claims 1 to 3 include that the retainer has an oblique portion having a shape in which the outer side in the radial direction of the shaft is inclined toward the first bearing side with reference to a state perpendicular to the rotation axis of the shaft. The fixed structure of the rotary electric machine according to any one of the above items. The retainer is surrounded by a fan-shaped region having a central angle larger than 180 ° and a first radius and a circle having a second radius smaller than the first radius in the axial view of the shaft. The fixed structure of a rotary electric machine according to any one of claims 1 to 4, wherein the rotary electric machine has a contour shape equivalent to a region corresponding to a logical sum when the circular regions are arranged concentrically. The fixing structure for a rotary electric machine according to claim 5, wherein the fixture is arranged only in a portion of the outer edge portion of the fan-shaped region along an arc. A rotating electric machine with a rotor and a stator,
A shaft connected to the rotor so as to rotate integrally with the rotor,
A housing in which the rotary electric machine is installed, the shaft is rotatably supported via a first bearing, and the stator is fixed via a flange extending outward in the radial direction of the shaft.
An output shaft arranged parallel to the shaft and connected to the drive wheels,
A transmission mechanism for transmitting the torque of the rotary electric machine to the output shaft is provided.
A retainer that rotatably supports the shaft via a second bearing arranged on the side opposite to the first bearing, based on the position of the rotor in the extending direction of the shaft. A left and right wheel drive device comprising a fixture for fixing the flange and the retainer at the same position in the housing in contact with each other.

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