JP6596897B2 - Motor drive device - Google Patents

Description

  The present invention relates to a motor drive device that rotatably supports an input shaft and an output side rotation member of a speed change mechanism via a bearing provided in a unit case incorporating a motor mechanism and a speed change mechanism.

  Conventionally, a motor mechanism and a transmission mechanism are arranged coaxially in a unit case, an input side bearing that rotatably supports an input shaft on the unit case, and an output that rotatably supports an output side rotating member of the transmission mechanism on the unit case. There is known a motor drive device in which a side bearing and an intermediate bearing interposed between an input shaft and an output side rotation member of a speed change mechanism are arranged side by side in the axial direction (see, for example, Patent Document 1).

JP 2009-190440 A

However, in the conventional motor drive device, the output side bearing and the intermediate bearing are arranged at positions shifted in the axial direction. For this reason, when a radial force is applied to the input shaft, a moment force is applied to the output side rotation member of the transmission mechanism, and a relative fall (axial deviation) occurs between the input shaft and the input shaft.
As a result, problems such as noise and vibration due to poor meshing of the gears in the transmission mechanism, and damage to the gear tooth surfaces occur.

  The present invention has been made paying attention to the above problem, and an object of the present invention is to provide a motor drive device that can prevent a moment force from being applied to a transmission mechanism.

In order to achieve the above object, a motor drive device of the present invention includes a motor mechanism, a speed change mechanism, a unit case, an input side bearing, an output side bearing, and an intermediate bearing.
The motor mechanism rotationally drives the input shaft.
The speed change mechanism includes an input side rotation member connected to the input shaft, a speed change portion that changes the rotation of the input side rotation member, and an output side rotation member that outputs rotation changed by the speed change portion.
The unit case includes a motor mechanism and a speed change mechanism.
The input-side bearing is provided in the unit case and rotatably supports the input shaft.
The output side bearing is provided in the unit case and rotatably supports the output side rotation member of the speed change mechanism.
The intermediate bearing is provided between the input shaft and the output side rotating member, and supports the input shaft and the output side rotating member so as to be rotatable relative to each other.
Then, the rotation axis of the input side rotation member, the rotation axis of the transmission unit, and the rotation axis of the output side rotation member are arranged in the same direction with respect to the axial direction of the input shaft, respectively. Are arranged coaxially. In addition, an oil seal is interposed between the unit case and the output side rotating member to prevent leakage of oil sealed inside the unit case. And the arrangement | positioning area | region of the output side bearing in the axial direction of a transmission mechanism and the arrangement | positioning area | region of the intermediate bearing in the axial direction of a transmission mechanism are mutually overlapped seeing from the direction perpendicular | vertical to the axial direction of the said transmission mechanism. Furthermore, the arrangement region in the axial direction of the oil seal and the arrangement region in the axial direction of the output side bearing are set at positions overlapping each other when viewed from the direction perpendicular to the axial direction of the transmission mechanism, and the output side bearing Place an oil seal inside.

Therefore, in the motor driving device of the present invention, the arrangement region in the axial direction of the speed change mechanism of the output side bearing that rotatably supports the output side rotary member of the speed change mechanism in the unit case, and the input shaft and the output side rotary member are relatively relative to each other. An arrangement region in the axial direction of the transmission mechanism of the intermediate bearing that is rotatably supported is set to an overlapping position when viewed from a direction perpendicular to the axial direction of the transmission mechanism.
Here, the radial load generated by the radial force acting on the input shaft is input to the output side rotation member of the transmission mechanism via the intermediate bearing. On the other hand, the radial displacement of the speed change mechanism is the smallest in the region where the output side bearing that supports the output side rotating member with respect to the unit case is disposed.
Therefore, the radial displacement of the speed change mechanism is minimized in the area where the radial load is input from the input shaft by overlapping the output area of the output side bearing and the arrangement area of the intermediate bearing in the axial direction of the speed change mechanism. It can be provided in the region. As a result, it is possible to prevent a moment force from being applied to the output side rotating member of the speed change mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. It is a top view which shows the stepped pinion of Example 1. FIG. It is an enlarged view of the X section in FIG. It is an enlarged view of the Y section in FIG. It is an enlarged view of the Z section in FIG. It is explanatory drawing which shows the meshing reaction force which arises in a stepped pinion at the time of the power running of a motor / generator. It is explanatory drawing which shows the meshing reaction force which arises in a stepped pinion at the time of regeneration of a motor / generator.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out a motor drive device of the present invention will be described based on a first embodiment shown in the drawings.

Example 1
First, the configuration will be described.
The configuration of the motor drive device in the first embodiment will be described by dividing it into “the overall configuration of the motor drive device”, “the detailed configuration of the input side bearing”, “the detailed configuration of the output side bearing”, and “the detailed configuration of the intermediate bearing”. .

[Overall configuration of motor drive unit]
FIG. 1 is an overall cross-sectional view illustrating a motor drive device according to a first embodiment. Hereinafter, based on FIG. 1, the whole structure of the motor drive device of Example 1 is demonstrated.

  The motor drive device according to the first embodiment is applied to, for example, an in-wheel motor provided on the left and right rear wheels of an electric vehicle. As shown in FIG. 1, the motor drive device includes a drive unit main body A and a displacement absorbing mechanism B.

The drive unit body A has a function as a travel drive source, and includes a motor case Case (unit case), a motor / generator MG (motor mechanism) having a three-phase AC embedded magnet synchronous motor structure, and a planetary gear. It is configured by incorporating a gear train GT (transmission mechanism).
The drive unit main body A rotates the motor shaft 6 (input shaft) integrally having the rotor 7 by applying a three-phase alternating current to the stator coil 8b wound around the stator 8 when the motor / generator MG is powered. Then, the rotation of the motor shaft 6 is decelerated (shifted) by the gear train GT and output from the carrier 15 (output side rotating member). During regeneration of the motor / generator MG, the rotation input from the carrier 15 is accelerated by the gear train GT and the motor shaft 6 and the rotor 7 are rotated, whereby the stator 8 disposed in the rotor 7 via the air gap. A three-phase alternating current is generated in the stator coil 8b.

The motor case Case includes a case body 1, an input side cover 2, a lid member 3, and an output side cover 4.
The case body 1 is a hollow cylindrical member whose both ends are open, and a stator coil 8b and a ring gear 13 of the gear train GT are fixed to the inner surface.
The input side cover 2 is bolted to the case body 1 so as to close the opening on one end side of the case body 1. The input side cover 2 has an opening 2a into which one end of the motor shaft 6 is inserted. An input side bearing 20 that rotatably supports one end of the motor shaft 6 is provided inside the opening 2a.
The lid member 3 is bolted to the input side cover 2 so as to close the opening 2 a of the input side cover 2.
The output side cover 4 is bolted to the case body 1 so as to close the opening on the other end side of the case body 1. The output side cover 4 has an opening 4a from which the small diameter cylindrical portion 15a of the carrier 15 protrudes. An oil seal 5 is mounted inside the opening 4a. The oil seal 5 has an inner diameter portion that contacts the outer peripheral surface of the small-diameter cylindrical portion 15a with a predetermined sealing pressure, and prevents leakage of oil sealed in the motor case Case. Further, a cylindrical wall portion 4 b that protrudes toward the case body 1 is formed on the surface (inner side surface) of the output side cover 4 on the case body 1 side. The cylindrical wall 4b surrounds the opening 4a. An output-side bearing 30 that rotatably supports the large-diameter cylindrical portion 15c of the carrier 15 is provided inside the cylindrical wall portion 4b.

The motor / generator MG includes a motor shaft 6 (input shaft), a rotor 7, and a stator 8.
One end of the motor shaft 6 is inserted into the opening 2 a of the input side cover 2 of the motor case Case, and is rotatably supported on the inner peripheral surface of the opening 2 a via the input side bearing 20. The other end portion is inserted inside the small diameter cylindrical portion 15a of the carrier 15 of the gear train GT, and is supported by the intermediate bearing 40 interposed between the small diameter cylindrical portion 15a so as to be relatively rotatable with each other. Yes.
The rotor 7 is fitted on the outer periphery of a rotor flange 9 that extends in the radial direction from an intermediate portion of the motor shaft 6, and can rotate integrally with the motor shaft 6. The rotor 7 is composed of a laminated steel plate in which a permanent magnet (not shown) is embedded.
The stator 8 is fixed to the inner side surface of the case body 1 and is disposed with respect to the rotor 7 via an air gap. The stator 8 is configured by winding a stator coil 8b around each stator tooth 8a made of a punched laminated steel sheet.
Note that a harness (not shown) is connected to the stator coil 8b via connection terminals 10 divided into a U phase, a V phase, and a W phase. Further, an axial core oil passage 11 through which oil for lubricating and cooling necessary portions such as a gear meshing portion of the gear train GT and a bearing is formed at the center of the motor shaft 6. Oil is supplied from an oil pump O / P provided on the input side cover 2.

  The gear train GT is disposed in a space between the rotor flange 9 and the output side cover 4, and includes a sun gear 12, a ring gear 13, a stepped pinion 14, and a carrier 15. The input rotation from the motor shaft 6 is decelerated and output by setting the sun gear input, ring gear fixed, and carrier output.

  The sun gear 12 is integrally formed on the outer peripheral surface of the motor shaft 6 and rotates integrally with the motor shaft 6. That is, the sun gear 12 corresponds to an input side rotating member connected to the motor shaft 6.

  The ring gear 13 is fixed to the inner side surface of the case body 1 so as not to rotate by serration coupling. Further, the ring gear 13 has a retaining ring 13a mounted on the outer peripheral surface thereof abutting against the case body 1 via the spacer 13b, and an end surface on the displacement absorbing mechanism B side abutting against the output side cover 4 via the output side bearing 30. Thus, it is impossible to move in the axial direction.

A plurality of the stepped pinions 14 are arranged between the sun gear 12 and the ring gear 13, meshed with each other, and supported rotatably by the carrier 15. The stepped pinion 14 has a large pinion 14a (first pinion) that meshes with the sun gear 12, and a small pinion 14b (second pinion) that is set to have a smaller diameter than the large pinion 14a and meshes with the ring gear 13. ing. Here, the sun gear 12, the ring gear 13, and the large pinion 14a and the small pinion 14b of the stepped pinion 14 are all helical gears (helical gears) whose teeth are cut obliquely with respect to the axis. is there.
Further, in the stepped pinion 14, as shown in FIG. 2, the twist direction of the teeth of the large pinion 14a and the twist direction of the teeth of the small pinion 14b are set to be opposite to each other. Further, the ratio (twist angle ratio) between the twist angle θ1 of the large pinion 14a and the twist angle θ2 of the small pinion 14b and the ratio (pitch circle) of the pitch circle diameter R1 of the large pinion 14a and the pitch circle diameter R2 of the small pinion 14b. The diameter ratio is set to be the same value. That is, each value is set so that the following formula (1) is established.
θ1: θ2 = R1: R2 (1)
The ring gear 13 and the stepped pinion 14 correspond to a transmission unit that changes the rotation of the sun gear 12.

The carrier 15 is rotated by the rotation (revolution) of the stepped pinion 14 that rotates around the motor shaft 6, and the gear coupling shaft 17 of the displacement absorbing mechanism B is coupled thereto. The carrier 15 corresponds to an output-side rotating member that outputs rotation decelerated (shifted) by the ring gear 13 and the stepped pinion 14.
The carrier 15 includes a small diameter cylindrical portion 15a, a connecting flange portion 15b, a large diameter cylindrical portion 15c, a support disk portion 15d, and a connecting portion 15e.

  The small-diameter cylindrical portion 15a is a cylindrical sleeve member whose both ends are open, and is arranged coaxially with the motor shaft 6. The tip portion 15f projects from the opening 4a of the output side cover 4 of the motor case Case to the outside of the motor case Case. Yes. The motor shaft 6 is inserted into the small-diameter cylindrical portion 15a via an intermediate bearing 40 and supported so as to be relatively rotatable with respect to each other. A first inner tooth portion 15g is formed on the inner peripheral surface of the tip portion 15f of the small diameter cylindrical portion 15a, and a first outer tooth portion 17b formed on the outer peripheral surface of the gear coupling shaft 17 is meshed and coupled. . Thereby, the carrier 15 and the gear coupling shaft 17 can be rotated integrally. A partition seal member 15h is disposed in an oil-tight state at a position separating the motor shaft 6 and the gear coupling shaft 17.

  The connecting flange portion 15b protrudes in the radial direction from the motor / generator MG side end portion of the small diameter cylindrical portion 15a. An oil passage through which oil flows is formed inside the connecting flange portion 15b. Further, a large-diameter cylindrical portion 15c that protrudes toward the displacement absorbing mechanism B is formed at the peripheral edge portion of the connecting flange portion 15b.

  The large-diameter cylindrical portion 15 c is a cylindrical sleeve member that surrounds the small-diameter cylindrical portion 15 a and is inserted into the cylindrical wall portion 4 b of the output side cover 4. And this large diameter cylindrical part 15c is rotatably supported by the internal peripheral surface of the cylindrical wall part 4b via the output side bearing 30. As shown in FIG.

The support disk portion 15d is a donut-shaped disk that surrounds the motor shaft 6 and faces the connection flange portion 15b, and is connected to the tip of a connection portion 15e extending from the connection flange portion 15b toward the rotor flange 9. Has been.
A stepped pinion 14 is disposed between the support disk portion 15d and the connecting flange portion 15b. The stepped pinion 14 is rotatably supported by a rotating shaft 15j that penetrates the connecting flange portion 15b and the support disk portion 15d. Has been.

  A resolver 16a for detecting the rotation angle of the rotor 7 is disposed in the space between the rotor flange 9 and the input side cover 2, and a park gear 16c for fixing the motor shaft 6 by meshing with the parking pole 16b. The motor shaft 6 is splined.

The displacement absorbing mechanism B has a function of preventing or suppressing the transmission and displacement of the wheel hub shaft 18 fixed to a wheel (not shown) to the motor / generator MG and the gear train GT of the drive unit main body A. A coupling shaft 17 is provided. The gear coupling shaft 17 connects the small diameter cylindrical portion 15a of the drive unit main body A and the wheel hub shaft 18 so as to be able to absorb displacement.
The wheel hub shaft 18 is rotatably supported via a hub bearing 19a with respect to an axle case 19 fixed to the outer surface of the output side cover 4 of the motor case Case.

  The displacement absorbing mechanism B shown in FIG. 1 is configured by fitting a gear coupling shaft 17 that can be replaced independently to the small diameter cylindrical portion 15a and the wheel hub shaft 18 so as to be able to transmit drive while absorbing displacement. The

The gear coupling shaft 17 is configured by providing a first external tooth portion 17b and a second external tooth portion 17c on both side positions of the gear coupling shaft portion 17a. The first outer tooth portion 17b is serrated to the first inner tooth portion 15g of the small diameter cylindrical portion 15a so as to be capable of absorbing displacement. The second outer tooth portion 17c is serrated to the second inner tooth portion 18a formed on the inner peripheral surface of the wheel hub shaft 18 so as to absorb displacement.
Both end surfaces of the gear coupling shaft 17 are curved in an arc shape, and are in spherical contact with the partition wall seal member 15 h and the end cap seal member 18 b provided on the wheel hub shaft 18, respectively. Further, the gear coupling shaft 17 is mounted together with lubricating grease (not shown) in a coupling space whose entire circumference is sealed.

[Detailed configuration of input side bearing]
FIG. 3 is an enlarged view of a portion X in FIG. Hereinafter, based on FIG. 3, the detailed structure of the input side bearing of Example 1 is demonstrated.

  As shown in FIG. 3, the input side bearing 20 is interposed between one end portion of the motor shaft 6 and the opening 2 a of the input side cover 2, and an inner ring 20 a that contacts the outer peripheral surface of the motor shaft 6. It has an outer ring 20b that contacts the inner peripheral surface of the opening 2a of the side cover 2, a rolling element 20c disposed between the inner ring 20a and the outer ring 20b, and a rolling element holder (not shown).

Here, the inner ring 20a of the input side bearing 20 has an axial end on the side of the displacement absorbing mechanism B in contact with a park gear 16c splined to the motor shaft 6, and is formed on the motor shaft 6 via the park gear 16c. It is abutted against the stepped portion 6a. Further, a first annular groove 22 is formed on the outer peripheral surface of the motor shaft 6, and a first annular retaining ring 23 is attached. And the axial direction edge part by the side of the cover member 3 of the inner ring | wheel 20a is contacting the 1st retaining ring 23 with which the 1st annular groove 22 was mounted | worn.
As described above, the inner ring 20a interferes with the park gear 16c and the first retaining ring 23, so that movement of the inner ring 20a toward both axial sides with respect to the motor shaft 6 is restricted. That is, the inner ring 20a and the motor shaft 6 can move integrally in the axial direction.

  On the other hand, a second annular groove 24 is formed in the outer ring 20 b of the input side bearing 20, and a second retaining ring 25 is attached to the second annular groove 24. The second retaining ring 25 interferes with the notch 2b formed on the inner peripheral surface of the opening 2a of the input side cover 2, and restricts the movement of the outer ring 20b to the displacement absorbing mechanism B side. The axial end of the outer ring 20 b on the lid member 3 side is in contact with the lid member 3 via the annular plate 26 and the rectifying plate 27. Here, the lid member 3 is fixed to the input side cover 2 by a screw N 1 and is integrated with the input side cover 2. In other words, the movement of the outer ring 20b in the axial direction with respect to the motor case Case is restricted by the second retaining ring 25 and the lid member 3.

Further, the inner ring 20a and the outer ring 20b sandwich the rolling element 20c and are not displaced in the axial direction. Therefore, the movement of the outer ring 20b in the axial direction on both sides in the motor case Case is restricted, so that the movement of the inner ring 20a in the axial direction on the motor case Case is restricted. Further, the motor shaft 6 that can move integrally with the inner ring 20a in the axial direction is also restricted from moving in the axial direction with respect to the motor case Case.
As described above, the movement of the motor shaft 6 to both sides in the axial direction with respect to the motor case Case is restricted via the input side bearing 20.

[Detailed configuration of output bearing]
FIG. 4 is an enlarged view of a Y portion in FIG. Hereinafter, based on FIG. 4, the detailed structure of the output side bearing of Example 1 is demonstrated.

  As shown in FIG. 4, the output side bearing 30 is interposed between the large diameter cylindrical portion 15 c of the carrier 15 of the gear train GT and the cylindrical wall portion 4 b of the output side cover 4. An inner ring 30a in contact with the outer peripheral surface of the portion 15c, an outer ring 30b in contact with the inner peripheral surface of the cylindrical wall portion 4b, a rolling element 30c disposed between the inner ring 30a and the outer ring 30b, and a rolling element retainer (not shown). And have.

Here, a third annular groove 32 is formed on the outer peripheral surface of the large-diameter cylindrical portion 15c, and a third retaining ring 33 having an annular shape is mounted. The inner ring 30 a of the output side bearing 30 is in contact with the third retaining ring 33 attached to the third annular groove 32 at the axial end on the displacement absorbing mechanism B side. The axial end of the inner ring 30a on the lid member 3 side is in contact with a step portion 15k protruding in the radial direction from the large diameter cylindrical portion 15c.
In this manner, the inner ring 30a interferes with the third retaining ring 33 and the step portion 15k, respectively, so that the movement of the inner ring 30a on both sides in the axial direction is restricted. That is, the inner ring 30a and the carrier 15 can move integrally in the axial direction.

On the other hand, in the outer ring 30b of the output side bearing 30, the axial end surface on the displacement absorbing mechanism B side is in contact with a stepped portion 34 formed at the root position of the cylindrical wall portion 4b. The axial end of the outer ring 30 b on the lid member 3 side is in contact with the ring gear 13. Here, the ring gear 13 is restricted from moving in the axial direction toward the lid member 3 by the retaining ring 13a mounted on the outer peripheral surface thereof striking the case body 1 via the spacer 13b. That is, the outer ring 30b is restricted from moving in the axial direction toward the lid member 3 via the ring gear 13, the retaining ring 13a, and the spacer 13b.
As described above, the outer ring 30b interferes with the stepped portion 34 and the ring gear 13, respectively, so that movement of the outer ring 30b in both axial directions with respect to the motor case Case is restricted.

Furthermore, the inner ring 30a and the outer ring 30b sandwich the rolling element 30c and are not displaced in the axial direction. Therefore, by restricting the movement of the outer ring 30b in the axial direction on both sides of the motor case Case, the movement of the inner ring 30a in the axial direction on both sides of the motor case Case is restricted. Furthermore, the carrier 15 that can move integrally with the inner ring 30a in the axial direction is also restricted from moving in the axial direction with respect to the motor case Case.
In this manner, the movement of the gear train GT carrier 15 to both sides in the axial direction with respect to the motor case Case is restricted via the output side bearing 30.

[Detailed configuration of intermediate bearing]
FIG. 5 is an enlarged view of a portion Z in FIG. Hereinafter, based on FIG.4 and FIG.5, the detailed structure of the intermediate bearing of Example 1 is demonstrated.

  As shown in FIG. 4, the intermediate bearing 40 is interposed between an end of the motor shaft 6 and a small diameter cylindrical portion 15a of the carrier 15 of the gear train GT, and an outer ring 40b that contacts the carrier 15, and a motor shaft. 6 and a rolling element 40c disposed between the outer ring 40b and a rolling element holder (not shown).

  The outer ring 40 b is fitted on the inner periphery of the small diameter cylindrical portion 15 a of the carrier 15. One end of the outer ring 40b in the axial direction on the displacement absorbing mechanism B side contacts a partition wall seal member 15h disposed inside the small diameter cylindrical portion 15a, and the other end in the axial direction on the lid member 3 side is in contact with the carrier 15 It contacts the fourth annular retaining ring 42 which is attached to a fourth annular groove 41 formed on the inner peripheral surface of the small diameter cylindrical portion 15a. Thereby, the outer ring 40b is restricted from moving to both sides in the axial direction with respect to the carrier 15. That is, the outer ring 40b and the carrier 15 can move integrally in the axial direction.

On the other hand, the rolling element 40 c is in contact with the outer periphery of the motor shaft 6. Here, this rolling element 40c and the motor shaft 6 are in direct contact, and the motor shaft 6 is used as a raceway surface. Further, the rolling element 40 c is not restricted in its axial position, and can move relative to the motor shaft 6 in the axial direction.
On the other hand, the outer ring 40b and the rolling element 40c are not displaced in the axial direction. Therefore, since the axial position of the rolling element 40 c is not restricted with respect to the motor shaft 6, the axial position of the outer ring 40 b is not restricted with respect to the motor shaft 6. Further, the position of the carrier 15 that can move integrally with the outer ring 40 b in the axial direction is not restricted with respect to the motor shaft 6.
That is, the intermediate bearing 40 provides free support in the axial direction when supporting the motor shaft 6 and the carrier 15 so as to be relatively rotatable.

As shown in FIG. 5, the arrangement region W2 of the intermediate bearing 40 in the gear train axial direction is perpendicular to the axial direction of the gear train GT with respect to the arrangement region W1 of the output side bearing 30 in the gear train axial direction. At least partly overlaps when viewed from different directions.
Furthermore, as shown in FIG. 5, the arrangement region W1 in the gear train axial direction of the output side bearing 30 and the arrangement region W2 in the gear train axial direction of the intermediate bearing 40 are both in the gear train axial direction of the oil seal 5. At least a part of the arrangement region W3 overlaps when viewed from a direction perpendicular to the axial direction of the gear train GT.
That is, the oil seal 5 is disposed inside the output side bearing 30, and the intermediate bearing 40 is disposed inside the oil seal 5.

Next, the operation will be described.
The operation of the motor driving apparatus according to the first embodiment will be described by dividing it into “a load supporting operation when a radial load is input” and “other characteristic operations”.

`` Load support action when inputting radial load ''
In the motor drive device of the first embodiment, when the motor / generator MG is driven to rotate, it is caused by an unbalance force acting on the motor shaft 6, a load acting on the rotor 7 or the like due to its own weight, an excitation force, or a dimensional error of parts. The radial force may act on the motor shaft 6 of the motor / generator MG due to the influence of the gear meshing component force generated between the sun gear 12 and the large pinion 14a and the skew generated in each bearing.

Here, one end of the motor shaft 6 is supported by the motor case Case via the input side bearing 20. The other end portion of the motor shaft 6 is supported by the carrier 15 of the gear train GT via the intermediate bearing 40.
That is, the radial force (radial load) acting on the motor shaft 6 is supported by the motor case Case via the input side bearing 20 and input to the carrier 15 of the gear train GT via the intermediate bearing 40. .

  On the other hand, the carrier 15 of the gear train GT is supported by the motor case Case via the output side bearing 30. That is, the radial displacement of the carrier 15 of the gear train GT is the smallest in the arrangement region W1 of the output side bearing 30 that rotatably supports the carrier 15 with respect to the motor case Case.

In the first embodiment, the intermediate bearing 40 is disposed inside the output-side bearing 30, and the arrangement region W1 of the output-side bearing 30 in the gear train axial direction and the arrangement region W2 of the intermediate bearing 40 in the gear train axial direction. Are set at positions overlapping each other when viewed from the direction perpendicular to the axial direction of the gear train GT.
Thereby, the position where the radial force acting on the motor shaft 6 is input to the carrier 15 of the gear train GT can be arranged in a region where the radial displacement of the carrier 15 is minimized.

  As a result, when a radial force acts on the motor shaft 6, it is possible to prevent a moment force from being applied to the carrier 15 of the gear train GT. Further, by preventing the moment force from being applied to the carrier 15, the radial inclination of the carrier 15 can be suppressed. Then, the inclination of the stepped pinion 14 supported by the carrier 15 is suppressed, and the gear meshing in each gear (sun gear 12, ring gear 13, stepped pinion 14) in the gear train GT is not properly meshed or the gear tooth surface is damaged. Can be suppressed.

  Furthermore, since the output side bearing 30 and the intermediate bearing 40 are arranged so as to overlap in the axial direction of the gear train GT, the space efficiency in the motor case Case can be improved, and the motor case Case can be reduced in size. Can do. That is, the shaft length of the motor drive unit is shortened, and a so-called flat shape is easily obtained. In particular, when this motor drive unit is arranged in the wheel of a vehicle, the flat shape is more advantageous in terms of vehicle layout and can be made into a shape suitable for an in-wheel motor.

[Other characteristic effects]
In the first embodiment, as shown in FIG. 5, the arrangement area W1 of the output side bearing 30 and the arrangement area W2 of the intermediate bearing 40 both overlap with the arrangement area W3 of the oil seal 5 in the axial direction of the gear train GT. Is set to
Therefore, the space efficiency in the motor case Case can be further improved, and the axial length of the motor case Case can be shortened to further reduce the size.

  Furthermore, in the first embodiment, the movement of the motor shaft 6 to both sides in the axial direction with respect to the motor case Case is restricted via the input side bearing 20. Further, the movement of the gear train GT to both sides in the axial direction with respect to the motor case Case is restricted via the output side bearing 30.

  That is, in the motor driving apparatus of the first embodiment, when the motor / generator MG is rotationally driven, the lid member is attached to the motor / generator MG due to the influence of the component load of the driving reaction force, the skew generated by each bearing, the vibration, and the like. Consider a case where an axial force toward 3 (force toward the left side in FIG. 1) is applied. At this time, the motor shaft 6 presses the inner ring 20a of the input side bearing 20 toward the lid member 3 via the park gear 16c. The outer ring 20b moves toward the lid member 3 by the axial force acting on the inner ring 20a. The outer ring 20b abuts against the lid member 3 via the annular plate 26 and the rectifying plate 27 and moves in the axial direction. Is regulated. Then, the axial movement of the outer ring 20b is restricted, whereby the axial movement of the inner ring 20a is also restricted, and the axial movement of the motor shaft 6 that abuts the inner ring 20a via the park gear 16c is also restricted.

  Therefore, when the axial force toward the cover member 3 is applied to the motor / generator MG, the motor shaft 6 has a tolerance between the motor shaft 6 and the input side bearing 20 and the input side bearing 20 and the cover member 3. Therefore, it moves to the lid member 3 side by the tolerance.

  On the other hand, when an axial force toward the lid member 3 is applied to the gear train GT, the third retaining ring 33 provided on the carrier 15 interferes with the inner ring 30a of the output side bearing 30, and this inner ring 30a is moved to the lid member 3 side. Press. And the outer ring | wheel 30b moves to the cover member 3 side with the force of the axial direction which acted on this inner ring | wheel 30a. At this time, the outer ring 30b abuts against the ring gear 13, but the ring gear 13 is abutted against the case body 1 via the retaining ring 13a and the spacer 13b, so that the axial movement toward the lid member 3 is restricted. That is, the outer ring 30b is restricted from moving in the axial direction toward the lid member 3 via the ring gear 13, the retaining ring 13a, and the spacer 13b. Then, the axial movement of the outer ring 30b is restricted, so that the axial movement of the inner ring 30a is also restricted. The axial movement of the carrier 15 that interferes with the inner ring 30a by the third retaining ring 33 provided on the peripheral surface. Are also regulated.

  Therefore, when the axial force toward the cover member 3 is applied to the gear train GT, the carrier 15 has a tolerance between the carrier 15 and the output side bearing 30 and between the output side bearing 30 and the case body 1. Therefore, it moves to the lid member 3 side by the tolerance.

  Further, when an axial force toward the displacement absorbing mechanism B (force toward the right side in FIG. 1) is applied to the motor / generator MG, the first retaining ring 23 provided on the motor shaft 6 is applied to the inner ring 20a of the input side bearing 20. Interference occurs, and this inner ring 20a is pressed against the displacement absorbing mechanism B side. And the outer ring | wheel 20b moves to the displacement absorption mechanism B side with the force of the axial direction which acted on this inner ring | wheel 20a. At this time, the second retaining ring 25 provided on the outer ring 20b interferes with the notch 2b formed in the input side cover 2, and the movement of the outer ring 20b toward the displacement absorbing mechanism B is restricted. And by restricting the axial movement of the outer ring 20b, the axial movement of the inner ring 20a is also restricted, and the axial direction of the motor shaft 6 with which the first retaining ring 23 provided on the peripheral surface interferes with the inner ring 20a. Movement is also restricted.

  Therefore, when the axial force toward the displacement absorbing mechanism B is applied to the motor / generator MG, the motor shaft 6 has a tolerance between the motor shaft 6 and the input side bearing 20, and the input side bearing 20 and the input side bearing. It moves to the displacement absorption mechanism B side by the amount of tolerance with the cover 2.

  On the other hand, when an axial force directed toward the displacement absorbing mechanism B is applied to the gear train GT, the step portion 15k formed on the carrier 15 abuts against the inner ring 30a of the output side bearing 30 and presses the inner ring 30a toward the displacement absorbing mechanism B side. To do. And the outer ring | wheel 30b moves to the displacement absorption mechanism B side with the force of the axial direction which acted on this inner ring | wheel 30a. At this time, the outer ring 30b hits the stepped portion 34 formed at the root position of the cylindrical wall portion 4b, and the axial movement toward the displacement absorbing mechanism B side is restricted. Then, the axial movement of the outer ring 30b is restricted, whereby the axial movement of the inner ring 30a is also restricted, and the axial movement of the carrier 15 with which the step portion 15k abuts against the inner ring 30a is also restricted.

  Therefore, when the axial force toward the displacement absorbing mechanism B is applied to the gear train GT, the carrier 15 has a tolerance between the carrier 15 and the output side bearing 30, and the output side bearing 30 and the output side cover 4. Therefore, it moves to the displacement absorbing mechanism B side by the tolerance.

As described above, in the motor shaft 6 and the carrier 15, the axial movement toward the lid member 3 side and the axial movement toward the displacement absorbing mechanism B side are independently regulated. The axial meshing reaction force generated by the gear train GT is not input. Further, neither the load of the motor / generator MG when moving in the axial direction nor the load of the gear train GT when moving in the axial direction is input to the intermediate bearing 40.
Therefore, the intermediate bearing 40 can be reduced in size, and the motor drive unit can be further reduced in size.

  Even if the axial driving reaction force in the gear train GT is input to the motor shaft 6, the motor shaft 6 and the carrier 15 are independently restricted from moving in the axial direction. Does not occur. Therefore, it is possible to suppress the amount of play in the axial direction of the motor / generator MG and the gear train GT that are particularly large when the direction of the driving force is reversed, and it is possible to reduce noise and vibration when the play is clogged.

  Further, in the first embodiment, the gear train GT is composed of a planetary gear provided with a stepped pinion 14 having a large pinion 14 a meshing with the sun gear 12 and a small pinion 14 b meshing with the ring gear 13. As shown in FIG. 2, the stepped pinion 14 is a helical gear, and the gear twist direction of the large pinion 14a and the gear twist direction of the small pinion 14b are set to be opposite to each other. Further, the torsion angle ratio of the large pinion 14a and the small pinion 14b and the pitch circle diameter ratio of the large pinion 14a and the small pinion 14b are set to the same value.

  Therefore, as shown in FIG. 6, when driving force is transmitted between the motor / generator MG and the gear train GT, the axial component force load F1 generated at the meshing portion between the large pinion 14a and the sun gear 12 is reduced. The axial component force load F2 generated at the meshing portion of the pinion 14b and the ring gear 13 is a reverse force of the same magnitude. That is, these axial component force loads F1 and F2 cancel each other within the stepped pinion 14, and no axial load acting on the outside is generated.

Further, as shown in FIG. 7, even when the motor / generator MG is regenerating (when drive torque is input from the carrier 15), the axial component force generated at the meshing portion of the large pinion 14a and the sun gear 12 is generated. The load F1 and the axial component force load F2 generated at the meshing portion of the small pinion 14b and the ring gear 13 become opposite forces of the same magnitude and cancel each other out in the stepped pinion 14.
6 and 7, F3 is an axial meshing reaction force acting on the sun gear 12, and F4 is an axial meshing reaction force acting on the ring gear 13.

The axial component loads F1 and F2 generated at the meshed portion of the stepped pinion 14 are offset in the stepped pinion 14 in this way, so that the axial load is positively input to the carrier 15. This can be prevented, and the movement of the carrier 15 in the axial direction can be suppressed.
Since the axial gear meshing reaction force input to the output side bearing 30 that supports the carrier 15 is also suppressed, the output side bearing 30 can be reduced in size, and the motor drive unit can be further reduced in size. Can be planned.
In addition, since the force that moves the carrier 15 in the axial direction is suppressed, it is possible to further reduce noise and vibration when the backlash of the gear train GT is clogged.

Next, the effect will be described.
In the motor drive device of the first embodiment, the effects listed below can be obtained.

(1) a motor mechanism (motor / generator MG) that rotationally drives the input shaft (motor shaft 6);
An input-side rotating member (sun gear 12) connected to the input shaft (motor shaft 6), and a transmission unit (ring gear 13 and stepped pinion 14) for changing the speed of the input-side rotating member (sun gear 12). A transmission mechanism (gear train GT) having an output-side rotation member (carrier 15) that outputs rotation (decelerated) that has been shifted (decelerated) by the transmission unit (ring gear 13, stepped pinion 14);
A unit case (motor case Case) incorporating the motor mechanism (motor / generator MG) and the speed change mechanism (gear train GT);
An input side bearing 20 provided in the unit case (motor case Case) and rotatably supporting the input shaft (motor shaft 6);
An output side bearing 30 provided in the unit case (motor case Case) and rotatably supporting an output side rotation member (carrier 15) of the speed change mechanism (gear train GT);
It is provided between the input shaft (motor shaft 6) and the output side rotating member (carrier 15), and supports the input shaft (motor shaft 6) and the output side rotating member (carrier 15) so that they can rotate relative to each other. An intermediate bearing 40,
An arrangement region W1 of the output-side bearing 30 in the axial direction of the transmission mechanism (gear train GT) and an arrangement region W2 of the intermediate bearing 40 in the axial direction of the transmission mechanism (gear train GT) are combined with the transmission mechanism ( The configuration is such that the positions overlap each other when viewed from the direction perpendicular to the axial direction of the gear train GT).
Thereby, it is possible to prevent a moment force from being applied to the speed change mechanism (gear train GT).

(2) An oil seal 5 is provided between the unit case (motor case Case) and the output side rotating member (carrier 15) to prevent leakage of oil sealed inside the unit case (motor case Case). Intervening,
The arrangement region W3 in the axial direction of the oil seal 5 and the arrangement region W1 in the axial direction of the output side bearing 30 overlap each other when viewed from a direction perpendicular to the axial direction of the transmission mechanism (gear train GT). It was set as the structure set to the position to do.
Thereby, in addition to the effect of (1), the space efficiency in the unit case (motor case Case) can be improved, and the unit case (motor case Case) can be downsized.

(3) The movement of the motor mechanism (motor / generator MG) in the axial direction with respect to the unit case (motor case Case) is restricted via the input side bearing 20, and the unit case (motor case Case) is restricted. The movement of the speed change mechanism (gear train GT) in both axial directions is restricted via the output side bearing 30.
Thereby, in addition to the effect of (1) or (2), the intermediate bearing 40 can be miniaturized, the unit case (motor case Case) can be further miniaturized, and the motor when the direction of the driving force is reversed, etc. The amount of movement in the axial direction of the mechanism (motor / generator MG) and the speed change mechanism (gear train GT) can be reduced.

(4) The transmission mechanism (gear train GT) has a diameter different from that of the sun gear 12, the ring gear 13, the first pinion (large pinion 14a) meshing with the sun gear 12, and the first pinion (large pinion 14a). And a stepped pinion 14 having a second pinion (small pinion 14b) that meshes with the ring gear 13, and a planetary gear comprising:
The stepped pinion 14 is a helical gear, the gear twist direction of the first pinion (large pinion 14a) and the gear twist direction of the second pinion (small pinion 14b) are set opposite to each other, and the first pinion 14 A torsion angle ratio between one pinion (large pinion 14a) and the second pinion (small pinion 14b), and a pitch circle diameter ratio between the first pinion (large pinion 14a) and the second pinion (small pinion 14b). The configuration is set to the same value.
As a result, in addition to any of the effects (1) to (3), the axial component force loads F1 and F2 generated at the meshing portion of the first pinion (large pinion 14a) and the second pinion (small pinion 14b) are offset. Thus, it is possible to prevent an axial load from being positively input to the carrier 15. In addition, it is possible to prevent the generation of sound and vibration associated with the axial movement of the stepped pinion 14 and the deterioration of controllability associated with an increase in backlash.

  As mentioned above, although the motor drive device of the present invention has been described based on the first embodiment, the specific configuration is not limited to the first embodiment, and the gist of the invention according to each claim of the claims. As long as they do not deviate, design changes and additions are permitted.

  In Example 1, the arrangement | positioning area | region W1 of the output side bearing 30 and the arrangement | positioning area | region W3 of the oil seal 5 showed the example set to the position which overlaps seeing from the direction perpendicular | vertical with respect to the axial direction of the gear train GT. However, it is not limited to this. For example, the oil seal 5 is interposed between the motor shaft 6 and the motor case Case, and the axial position of the arrangement area W3 of the oil seal 5 and the arrangement area of the input side bearing 20 is set to an overlapping position. Good. Furthermore, the oil seal 5 is interposed between the motor shaft 6 and the motor case Case and between the carrier 15 and the motor case Case. Then, the axial position of the arrangement area of one oil seal 5 and the arrangement area of the input side bearing 20 are overlapped, and the axial position of the arrangement area of the other oil seal 5 and the arrangement area of the output side bearing 30 is set. You may overlap.

  In the first embodiment, the positional relationship between the axial load center position (axial center position) of the output-side bearing 30 and the axial load center position (axial central position) of the intermediate bearing 40 is mentioned. Not. However, by matching the axial load center position of the output side bearing 30 with the axial load center position of the intermediate bearing 40, the effect of preventing the moment force from being applied to the gear train GT is maximized. Can get to. That is, it is desirable to make the load center positions of both bearings coincide with each other in the axial direction.

  Further, by aligning the axial load center position of the output-side bearing 30 with the axial load center position of the oil seal 5, the arrangement area W1 of the output-side bearing 30 and the arrangement area W3 of the oil seal 5 are matched. When the position in the axial direction is overlapped, the effect of improving the space efficiency in the motor case Case can be maximized.

  In the first embodiment, in the stepped pinion 14, the torsion angle ratio between the large pinion 14a and the small pinion 14b and the pitch circle diameter ratio between the large pinion 14a and the small pinion 14b are set to be the same value. Although an example is shown in which each value is set so that the above-described equation (1) is established, the torsion angle ratio and the pitch circle diameter ratio do not have to be completely the same value. As the value of the torsion angle ratio and the value of the pitch circle diameter ratio become closer to the same value, the axial component force load F1 generated at the meshing portion of the large pinion 14a and the sun gear 12, the small pinion 14b, and the ring gear 13 The axial component force load F2 generated at the meshing portion is the same magnitude. For this reason, the axial component force load F1 and the axial component force load F2 can be made close to each other by setting the torsion angle ratio and the pitch circle diameter ratio to approximate values, and the stepped pinion 14 An axial load acting on the outside can be suppressed. That is, the twist angle ratio and the pitch circle diameter ratio may be set to approximate values.

Further, in the first embodiment, an example in which the motor driving device of the present invention is applied to an in-wheel motor of an electric vehicle is shown, but the present invention is not limited to this. You may apply to the motor drive unit arrange | positioned in the motor room formed in the vehicle front part.
Moreover, although the gear train GT as a speed change mechanism has shown the example which decelerates and outputs the rotation of the motor shaft 6 by one step, the gear train GT may change at a plurality of steps or may increase the speed. .

A Drive unit body B Displacement absorption mechanism
Case Motor case (unit case)
MG motor / generator (motor mechanism)
GT gear train (transmission mechanism)
DESCRIPTION OF SYMBOLS 1 Case main body 2 Input side cover 2a Opening 3 Cover member 4 Output side cover 4a Opening 5 Oil seal 6 Motor shaft (input shaft)
7 Rotor 8 Stator 12 Sun gear (input side rotating member)
13 Ring gear (transmission)
14 Stepped pinion (transmission part)
14a Large pinion (first pinion)
14b Small pinion (second pinion)
15 Carrier (output side rotating member)
20 Input side bearing 30 Output side bearing 40 Intermediate bearing

Claims (3)

A motor mechanism for rotationally driving the input shaft;
A transmission mechanism comprising: an input-side rotation member coupled to the input shaft; a transmission unit that shifts the rotation of the input-side rotation member; and an output-side rotation member that outputs rotation shifted by the transmission unit;
A unit case containing the motor mechanism and the speed change mechanism;
An input-side bearing provided in the unit case and rotatably supporting the input shaft;
An output-side bearing provided in the unit case and rotatably supporting an output-side rotating member of the speed change mechanism;
An intermediate bearing that is provided between the input shaft and the output-side rotating member and supports the input shaft and the output-side rotating member so as to be relatively rotatable with respect to each other;
With respect to the axial direction of the input shaft, the rotating shaft of the input side rotating member, the rotating shaft of the transmission unit, and the rotating shaft of the output side rotating member are arranged in the same direction, and the motor mechanism The transmission mechanism is arranged coaxially,
Between the unit case and the output side rotating member, an oil seal that prevents leakage of oil sealed inside the unit case is interposed,
The arrangement area of the output side bearing in the axial direction of the transmission mechanism and the arrangement area of the intermediate bearing in the axial direction of the transmission mechanism overlap each other when viewed from a direction perpendicular to the axial direction of the transmission mechanism. Set to position ,
An arrangement region in the axial direction of the oil seal and an arrangement region in the axial direction of the output side bearing are set at positions overlapping each other when viewed from a direction perpendicular to the axial direction of the transmission mechanism. A motor driving device , wherein the oil seal is disposed inside a side bearing . In the motor drive device according to claim 1 ,
Movement of the motor mechanism to both sides in the axial direction with respect to the unit case is restricted via the input side bearing, and movement of the speed change mechanism with respect to the unit case to both sides in the axial direction is restricted via the output side bearing. A motor drive device characterized by that. In the motor drive device according to claim 1 or 2 ,
The transmission mechanism includes a planetary gear including a sun gear, a ring gear, a stepped pinion having a first pinion meshing with the sun gear and a second pinion having a diameter different from that of the first pinion and meshing with the ring gear. Configure
The stepped pinion is a helical gear, the gear twist direction of the first pinion and the gear twist direction of the second pinion are set opposite to each other, and the twist angle between the first pinion and the second pinion The motor drive device is characterized in that the ratio and the pitch circle diameter ratio of the first pinion and the second pinion are set to approximate values.