JP2012161239A - Motor driving force transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor driving force transmission device that can be continuously used by suppressing the excessive heat generation of an electric motor due to continuous operation over a long period of time.SOLUTION: The motor driving force transmission device 1 includes a deceleration transmission mechanism 2 which transmits a motor driving force to a rear differential 107, a first electric motor 3 which is coupled to the rear differential 107 via the deceleration transmission mechanism 2 and generates a first motor driving force (a), a second electric motor 4 which is coupled to the first electric motor 3 and the deceleration transmission mechanism 2 and generates a second motor driving force (b), and an ECU 5 which outputs a control signal to drive the first electric motor 3 and the second electric motor 4 together when a drive torque to the rear differential 107 requires a torque equal to or more than a predetermined torque and which outputs a control signal for alternately driving the first electric motor 3 and the second electric motor 4 when the drive torque requires the torque less than the predetermined torque.

Description

  The present invention relates to a motor driving force transmission device suitable for use in, for example, an electric vehicle having an electric motor as a driving source.

  A conventional motor driving force transmission device includes an electric motor that generates a motor driving force, and a deceleration transmission mechanism that transmits the motor driving force of the electric motor to a differential mechanism, and is mounted on an automobile (for example, Patent Document 1).

  The electric motor has an output shaft that is rotated by the power of the in-vehicle battery, and is disposed on one side of the differential mechanism.

  The reduction transmission mechanism is composed of a two-stage gear reduction set and is connected to the electric motor and the differential mechanism. The first gear reduction set is connected to the output shaft of the electric motor, and the second gear reduction set is connected to the differential case of the differential mechanism.

  With the above configuration, the output shaft of the electric motor is rotated by the power of the on-vehicle battery, and accordingly, the motor driving force is transmitted from the electric motor to the differential mechanism via the deceleration transmission mechanism, and the left and right wheels are transmitted from this differential mechanism. To be distributed.

JP 2004-17807 A

  However, according to the motor driving force transmission device disclosed in Patent Document 1, the electric motor excessively generates heat due to continuous operation for a long time, and may not be used continuously.

  Accordingly, an object of the present invention is to provide a motor driving force transmission device that can suppress excessive heat generation of an electric motor due to continuous operation for a long time and can be used continuously.

  In order to achieve the above object, the present invention provides motor drive force transmission devices (1) to (3).

(1) A reduction transmission mechanism that transmits at least one of the first motor driving force and the second motor driving force to the differential mechanism, and the differential mechanism via the reduction transmission mechanism. A first electric motor that generates the first motor driving force; a second electric motor that is coupled to the first electric motor and the deceleration transmission mechanism and generates the second motor driving force; And a control unit that outputs a control signal for controlling the second electric motor and the first electric motor, and the control unit is configured such that a driving torque for the differential mechanism requires a torque that is greater than or equal to a predetermined torque. A control signal for driving both the first electric motor and the second electric motor, and when the driving torque requires a torque less than a predetermined torque, the first electric motor and the second electric motor. Motor driving force transmission device for outputting respectively control signals for driving alternately.

(2) In the motor driving force transmission device according to (1), the deceleration transmission mechanism is a pair of rotating by driving at least one of the first electric motor and the second electric motor. An eccentric cam and a pair of transmission members that rotate by the rotation of the pair of eccentric cams, and the pair of transmission members are connected to the differential mechanism at portions spaced apart from each other at equal intervals around the rotation axis. .

(3) In the motor driving force transmission device according to (2), each of the first electric motor and the second electric motor has a stator and a rotor, and each stator has the pair of transmission members. The rotors are connected to each other by the second connecting member by the first connecting member to be inserted and the outer periphery of each stator.

  According to the present invention, excessive heat generation of the electric motor due to continuous operation over a long period of time can be suppressed, and the apparatus can be used continuously.

The top view shown in order to demonstrate the outline of the vehicle carrying the motor driving force transmission apparatus which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the motor drive force transmission apparatus which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the deceleration transmission mechanism of the motor drive force transmission apparatus which concerns on the 1st Embodiment of this invention (AA sectional drawing of FIG. 2). Sectional drawing which shows the operation state of the deceleration transmission mechanism in the motor drive force transmission apparatus which concerns on the 1st Embodiment of this invention. The block diagram shown in order to demonstrate the motor drive force transmission apparatus which concerns on the 1st Embodiment of this invention. The graph shown in order to demonstrate the advantage on the heat countermeasure of the motor drive force transmission apparatus which concerns on the 1st Embodiment of this invention. Sectional drawing which shows the deceleration transmission mechanism of the motor drive force transmission apparatus which concerns on the 2nd Embodiment of this invention. Sectional drawing which shows the operation state of the deceleration transmission mechanism in the motor drive force transmission apparatus which concerns on the 2nd Embodiment of this invention.

[First embodiment]
Hereinafter, a motor driving force transmission device according to a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 schematically shows a four-wheel drive vehicle. As shown in FIG. 1, a four-wheel drive vehicle 101 uses a front-wheel-side power system with a drive source as an engine and a rear-wheel-side power system with a drive source as an electric motor. , An engine 102, a transaxle 103, a pair of front wheels 104, and a pair of rear wheels 105.

  The motor driving force transmission device 1 is disposed in a power system on the rear wheel side of the four-wheel drive vehicle 101 and is supported on a vehicle body (not shown) of the four-wheel drive vehicle 101 together with a rear differential 107 via a differential carrier 106. ing.

  The motor driving force transmission device 1 is configured to transmit a motor driving force of an electric motor (described later) to the pair of rear wheels 105. As a result, the motor driving force of the electric motor is output to the rear axle shaft 108 via the motor driving force transmission device 1 and the rear differential 107, and the pair of rear wheels 105 are driven. Details of the driving force transmission device 1 and the like will be described later.

  The engine 102 is disposed in the power system on the front wheel side of the four-wheel drive vehicle 101. As a result, the driving force of the engine 102 is output to the front axle shaft 109 via the transaxle 103, and the pair of front wheels 104 are driven.

(Overall configuration of motor driving force transmission device 1)
FIG. 2 shows the entire motor driving force transmission device. As shown in FIG. 2, the motor driving force transmission device 1 transmits at least one of the first motor driving force a and the second motor driving force b (both shown in FIG. 5) to the rear differential 107. The speed reduction transmission mechanism 2, the first electric motor 3 that generates the first motor driving force a, the second electric motor 4 that generates the second motor driving force b, the first electric motor 3, and The vehicle is generally configured by an ECU (Electronic Control Unit) 5 for a vehicle as a control unit that outputs a control signal for controlling the second electric motor 4.

  The rear differential 107 is a bevel gear type differential mechanism having a differential case (input member) 110, a pinion gear shaft 111, a pair of pinion gears 112, and a pair of side gears 113, and is housed in a differential carrier 106.

  As a result, the rotational force of the differential case 110 is distributed from the pinion gear shaft 111 to the side gear 113 via the pinion gear 112 and further transmitted from the rear axle shaft 108 to the left and right rear wheels 105.

  On the other hand, when a driving resistance difference occurs between the left and right rear wheels 105, the rotational force of the differential case 110 is differentially distributed to the left and right rear wheels 105 by the rotation of the pinion gear 112.

  The differential case 110 has an accommodation space 110 a and a shaft insertion hole 110 b inside, and is rotatably disposed in the differential carrier 106 via a tapered roller bearing 114. The differential case 110 is configured to receive at least one of the first motor driving force a and the second motor driving force b and rotate around the rotation axis O. The differential case 110 is provided with an involute external gear 110c having a rotation axis O as a gear axis.

  The pinion gear shaft 111 is disposed on the axis L perpendicular to the rotation axis O in the accommodation space 110a of the differential case 110, and the rotation about the axis L is restricted.

  The pair of pinion gears 112 is rotatably supported by the pinion gear shaft 111 and is housed in the housing space 110 a of the differential case 110.

  The pair of side gears 113 is housed in the housing space 110a of the differential case 110, and is connected to the rear axle shaft 108 through the shaft insertion hole 110b by spline fitting. The pair of side gears 113 are configured so that their gear shafts are orthogonal to the gear shafts of the pair of pinion gears 112 and mesh with the pair of pinion gears 112.

(Configuration of deceleration transmission mechanism 2)
3 and 4 show a deceleration transmission mechanism. As shown in FIGS. 3 and 4, the speed reduction transmission mechanism 2 includes a pair of eccentric cams 6 and 7 that rotate by driving the first electric motor 3 and the second electric motor 4 (both shown in FIG. 2), and The pair of transmission members 8 and 9 that swings by the rotation of the pair of eccentric cams 6 and 7 have a first electric motor 3 and a second electric motor 4 on a rotation axis O (shown in FIG. 2). Are arranged around the outer periphery of the rear differential 107.

  The pair of eccentric cams 6 and 7 are arranged in parallel with each other on the rotation axis O and are integrally formed on the inner peripheral surface of the second connecting member (connecting cylinder) 10.

One eccentric cam 6 has a through hole 6a centered on a point (axis line) O ₁ that is eccentric with an amount of eccentricity δ ₁ (δ ₁ = δ) rather than the center (point on the rotation axis O). 1 is arranged on the electric motor 3 side. The one eccentric cam 6 receives at least one of the first motor driving force a and the second motor driving force b, and causes the transmission member 8 to perform a circular motion with an eccentricity δ. It is configured as follows. When the eccentric cam 6 is rotated in the circumferential direction of the one direction (arrow m ₁ direction), the transmission member 8 is swung to its axis O ₁ is moved in the arrow n ₁ direction around a rotational axis O. Other direction of the eccentric cam 6 is circumferentially rotates (arrow m ₂ direction), the transmission member 8 (opposite to the direction of the arrow n ₁ direction) the axis O ₁ arrow n ₂ direction about the rotation axis O Swing to move to. The transmission member 8 is centered on the rotation axis O, moves the axis O ₁ along the circumferential direction of a circle having a radius of eccentricity δ, and makes one rotation with respect to the differential carrier (device main body) 106. Revolve without rotating.

The other eccentric cam 7 has a through hole 7a centered on a point (axis line) O ₂ that is eccentric with an amount of eccentricity δ ₂ (δ ₂ = δ) rather than the center (point on the rotation axis O). 2 on the side of the electric motor 4. The other eccentric cam 7 receives at least one of the first motor driving force a and the second motor driving force b, and causes the transmission member 9 to perform a circular motion with an eccentricity δ. It is configured as follows. When the eccentric cam 7 is rotated in the circumferential direction of the one direction (arrow m ₁ direction), the transmission member 9 swings so that its axis O ₂ is moved in the arrow n ₁ direction around a rotational axis O. Other direction of the eccentric cam 7 is circumferentially rotates (arrow m ₂ direction), the transmission member 9 (direction opposite to the arrow n ₁ direction) the axis O ₂ by the arrow n ₂ direction about the rotation axis O Swing to move to. The transmission member 9 is centered on the rotation axis O, moves the axis O ₂ along the circumferential direction of a circle having a radius of eccentricity δ, and makes one rotation with respect to the differential carrier (device main body) 106. Revolve without rotating.

  The pair of transmission members 8 and 9 are internal gears that mesh with the external gear 110c of the differential case 110, are arranged in parallel with each other on the rotation axis O, and are arranged around the rotation axis (rotation axis O) on the external gear 110c. They are connected to each other at parts spaced apart at equal intervals (180 °). As a result, the deceleration transmission mechanism 2 and the differential 107 are connected in a well-balanced state. As the pair of transmission members 8 and 9, an involute toothed internal gear having a larger number of teeth than the external gear 110 c and constantly meshing with the external gear 110 c is used.

  One transmission member 8 is rotatably disposed on the inner surface of one eccentric cam 6 via a needle roller bearing 12. A plurality of first connection members (connection pins) 11 are inserted into one transmission member 8, and a plurality of pins having a hole diameter larger than the dimension obtained by adding an eccentric amount δ to the pin diameter of each connection pin 11. The insertion holes 8a are arranged at equal intervals in the circumferential direction.

  The other transmission member 9 is rotatably disposed on the inner surface of the other eccentric cam 7 via a needle roller bearing 12. Similarly to the one transmission member 8, a plurality of connection pins 11 are inserted into the other transmission member 9, and a plurality of holes having a diameter larger than the dimension obtained by adding the eccentric amount δ to the pin diameter of each connection pin 11. The pin insertion holes 9a are arranged at equal intervals in the circumferential direction.

(Configuration of the first electric motor 3)
FIG. 5 shows a control system of the deceleration transmission mechanism. As shown in FIG. 5, the first electric motor 3 has a stator 3a and a rotor 3b (both shown in FIG. 2), and the reduction transmission mechanism 2 is provided to the differential 107 on the rotation axis O (shown in FIG. 2). And the stator 3 a is connected to the ECU 5. The first electric motor 3 causes the stator 3a to input a control signal from the ECU 5 to generate a first motor driving force a for operating the differential 107 with the rotor 3b, and rotates the rotor 3b. It is configured as follows.

  The stator 3 a has a coil (not shown) that receives power supplied from an in-vehicle battery (not shown), and is disposed on the inner peripheral side of the first electric motor 3.

  The rotor 3 b is made of a magnet having a magnetic pole in the circumferential direction, and is disposed on the outer peripheral side of the first electric motor 3.

  The second electric motor 4 has a stator 4a and a rotor 4b (both shown in FIG. 2), is connected to a differential 107 via a reduction transmission mechanism 2 on a rotation axis O (shown in FIG. 2), and the stator 4a is connected to ECU5. The first electric motor 4 causes the stator 4a to input a control signal from the ECU 5 to generate a second motor driving force b for operating the differential 107 between the rotor 4b and rotate the rotor 4b. It is configured as follows.

  The stator 4 a has a coil (not shown) that receives power supplied from an in-vehicle battery (not shown), is disposed on the inner peripheral side of the second electric motor 4, and is a stator of the first electric motor 3. It is connected to 3 a via a plurality of connecting pins 11.

  The rotor 4 b is made of a magnet having a magnetic pole in the circumferential direction, is arranged on the outer peripheral side of the second electric motor 4, and is connected to the rotor 3 b of the first electric motor 3 via a connecting cylinder 10.

(Configuration of ECU 5)
The ECU 5 is connected to a sensor (not shown) in addition to the first electric motor 3 and the second electric motor 4. Then, the ECU 5 inputs a detection signal from the sensor and controls to alternately drive the first electric motor 3 and the second electric motor 4 when the driving torque for the rear differential 107 requires a torque less than a predetermined torque. And a control signal for driving both the first electric motor 3 and the second electric motor 4 when the driving torque for the rear differential 107 requires a torque greater than a predetermined torque. .

  As a result, the ECU 5 drives at least one of the first drive motor 3 and the second drive motor 4 to operate the power system on the rear wheel side, and drives the front wheels 104 with the engine 102. The four-wheel drive vehicle 101 is brought into a four-wheel drive state by the front wheel side power system and the rear wheel side power system.

  Further, the ECU 5 stops driving the first electric motor 3 and the second electric motor 4 during normal traveling of the four-wheel drive vehicle 101 to stop the operation of the power system on the rear wheel side, and the front wheel 104 is connected to the engine 102. And the four-wheel drive vehicle 101 is brought into a two-wheel drive state by the power system on the front wheel side.

(Operation of the motor driving force transmission device 1)
Next, the operation of the motor driving force transmission apparatus shown in the present embodiment will be described with reference to FIGS. FIG. 6 shows the relationship between the continuous operation possible time of the electric motor and the motor phase current.

  In FIG. 2, power is supplied to one of the first electric motor 3 and the second electric motor 4 of the four-wheel drive vehicle 101 (shown in FIG. 1) (for example, the first electric motor 3). When the first electric motor 3 is driven, the first motor driving force a is applied to the deceleration transmission mechanism 2 via the connecting cylinder 10, and the deceleration transmission mechanism 2 is activated.

Therefore, the speed reduction transmission mechanism 2, rotates the eccentric cam 6 is for example an arrow m ₁ direction, as shown in FIGS. 3 and 4, eccentric in an arrow n ₁ direction while the transmission members 8 and 9 to slide relative to each other Perform a circular motion with the quantity δ.

Accordingly, the first motor driving force a is transmitted from the transmission members 8 and 9 to the external gear 110c of the rear differential 107 (shown in FIG. 1), and the external gear 110c is rotated in the rotational direction of the eccentric cams 6 and 7. It rotates in the opposite direction (arrow _{m 2} direction).

  As a result, the differential 107 is operated, and the first motor driving force a is distributed to the rear axle shaft 108 and transmitted to the left and right rear wheels 105.

  Here, when the driving torque for the rear differential 107 requires a torque less than a predetermined torque, in order to continue the continuous operation of the motor driving force transmission device 1, the time for continuously driving the first electric motor 3 is a predetermined time. When the time has elapsed, the power supply to the first electric motor 3 is stopped, and the second electric motor 4 as the other electric motor is driven. This is because if the electric power supply to the first electric motor 3 is continued after the predetermined time has elapsed, the first electric motor 3 will generate excessive heat, so the electric power supply to the first electric motor 3 will be reduced. This is for stopping and avoiding excessive heat generation of the first electric motor 3.

  This can be understood from the graph shown in FIG. FIG. 6 shows the results (a) to (f) of analyzing the relationship between the time during which the electric motor can be operated continuously and the current supplied to the electric motor. According to this, it is possible to determine a unique motor continuation time according to the magnitude of each supply current to the electric motor. In FIG. 6, the vertical axis represents the continuous possible time of the electric motor, and the horizontal axis represents the supply current to the electric motor.

  When electric power is supplied to the second electric motor 4 and the second electric motor 4 is driven, the second motor driving force b is applied to the speed reduction transmission mechanism 2 via the connecting cylinder 10, and the speed reduction transmission mechanism. 2 is activated. For this reason, the second motor driving force b is transmitted to the differential 107 via the deceleration transmission mechanism 2 as in the case where the first electric motor 4 is driven. As a result, the differential 107 operates, and the second motor driving force b is distributed to the rear axle shaft 108 and transmitted to the left and right rear wheels 105.

  Here, in order to continue the continuous operation of the motor driving force transmission device 1 when the driving torque for the rear differential 107 requires less than a predetermined torque, the time for continuously driving the second electric motor 4 is predetermined. When the time elapses, the power supply to the second electric motor 4 is stopped and the first electric motor 3 is driven.

  In this way, by driving the first electric motor 3 and the second electric motor 4 alternately, excessive heat generation of the first electric motor 3 and the second electric motor 4 is suppressed, and the motor driving force is reduced. The transmission device 1 can be operated continuously.

In the above embodiment has described the case in which the eccentric cam 6 is rotated in the arrow m ₁ direction operates the motor driving force transmission device 1, rotating the eccentric cam 6 and 7 in the arrow m ₂ Direction Even if it makes it, the motor drive force transmission apparatus 1 can be operated similarly to the said embodiment. At this time, the external gear 110c is the rotational direction of the eccentric cam 6 rotates in the opposite direction (arrow _{m 1} direction).

  In the present embodiment, the case where the first motor driving force a or the second motor driving force b is transmitted from the deceleration transmission mechanisms 2 and 71 to the rear differential 107 has been described. Without being limited thereto, when the driving torque for the rear differential 107 requires more than a predetermined torque, the first electric motor 3 and the second electric motor 4 are both driven to drive the first motor driving force a or It is also possible to transmit a motor driving force larger than the motor driving force b of 2 from the deceleration transmission mechanism 2 to the rear differential 107.

[Effect of the first embodiment]
According to the first embodiment described above, the following effects can be obtained.

(1) Excessive heat generation of the first electric motor 3 and the second electric motor 4 due to continuous operation of the motor driving force transmission device 1 over a long time can be suppressed, and the first electric motor 3 and the second electric motor 3 can be suppressed. The electric motor 4 can be used alternately, and the motor driving force transmission device 1 can be used continuously.

(2) The speed reduction transmission mechanism 2 and the first electric motor 3 and the second electric motor 4 can be arranged on the rotation axis O to reduce the radial dimension of the motor driving force transmission device 1, Miniaturization can be achieved.

[Second Embodiment]
Next, a motor driving force transmission device according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 8 show the speed reduction transmission mechanism. 7 and 8, the same or equivalent members as in FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 7 and 8, the reduction transmission mechanism 71 of the motor driving force transmission device according to the second embodiment of the present invention has a pair of transmission members 72 and 73 formed by internal gears having a cycloidal tooth profile. There is a feature in that.

  For this reason, the external gear 110c of the differential case 110 in the differential 107 has a smaller number of teeth than the pair of transmission members 72 and 73, and is formed by a cycloid tooth-shaped external gear that is always meshed with the pair of transmission members 72 and 73. Has been.

  The pair of transmission members 72 and 73 are arranged in parallel with each other on the rotation axis O (shown in FIG. 2), and are separated from the external gear 110c by 180 ° around the rotation axis (rotation axis O). It is connected at the site.

  In the motor driving force transmission device configured as described above, the first electric motor 3 and the second electric motor 4 are alternately driven, similarly to the motor driving force transmission device 1 shown in the first embodiment. Thus, it is possible to continuously operate while suppressing excessive heat generation of the first electric motor 3 and the second electric motor 4.

[Effect of the second embodiment]
According to the second embodiment described above, the same effect as that of the first embodiment can be obtained.

  As mentioned above, although the motor drive force transmission apparatus of this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment, In various aspects in the range which does not deviate from the summary. For example, the following modifications are possible.

(1) In the above embodiment, the first electric motor 3 and the second electric motor 4 are alternately driven every time a predetermined time has elapsed, but the present invention is not limited to this, and the first The electric motor to be driven may be switched when the integral value of the motor current of the electric motor 3 or the second electric motor 4 becomes a predetermined threshold value or more. Or you may switch the electric motor to drive, when the temperature of the 1st electric motor 3 or the 2nd electric motor 4 becomes more than a predetermined threshold value.

(2) In the above embodiment, the case where the engine 102 and the electric motors 3 and 4 are applied to the four-wheel drive vehicle 101 using the drive source together has been described. However, the present invention is not limited to this, and only the electric motor is used. The present invention can also be applied to an electric vehicle used as a drive source in the same manner as in the above embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Motor drive force transmission device, 2 ... Deceleration transmission mechanism, 3 ... 1st electric motor, 3a ... Stator, 3b ... Rotor, 4 ... 2nd electric motor, 4a ... Stator, 4b ... Rotor, 5 ... ECU, DESCRIPTION OF SYMBOLS 6,7 ... Eccentric cam, 8,9 ... Transmission member, 10 ... Connection cylinder, 11 ... Connection pin, 12 ... Needle roller bearing, 71 ... Reduction transmission mechanism arrangement, 72, 73 ... Transmission member, 101 ... Four-wheel drive vehicle , 102 ... Engine, 103 ... Transaxle, 104 ... Front wheel, 105 ... Rear wheel, 106 ... Differential carrier, 107 ... Rear differential, 108 ... Rear axle shaft, 109 ... Front axle shaft, 110 ... Differential case, 110a ... Housing space, 110b ... shaft insertion hole, 110c ... external gear, 111 ... pinion gear shaft, 112 ... pinion gear, 11 ... side gears, 114 ... tapered roller bearings, a ... first motor driving force, b ... second motor driving force, O ... Rotation axis, L ... axis, [delta] ... eccentricity

Claims (3)

A deceleration transmission mechanism that transmits at least one of the first motor driving force and the second motor driving force to the differential mechanism;
A first electric motor coupled to the differential mechanism via the deceleration transmission mechanism and generating the first motor driving force;
A second electric motor coupled to the first electric motor and the deceleration transmission mechanism and generating the second motor driving force;
A control unit that outputs a control signal for controlling the second electric motor and the first electric motor;
The control unit outputs a control signal for driving both the first electric motor and the second electric motor when the driving torque for the differential mechanism requires a torque greater than or equal to a predetermined torque, and the driving torque is predetermined. A motor driving force transmission device that outputs a control signal for alternately driving the first electric motor and the second electric motor when a torque less than a predetermined torque is required.   The deceleration transmission mechanism includes a pair of eccentric cams that rotate by driving at least one of the first electric motor and the second electric motor, and a pair of transmissions that rotate by rotation of the pair of eccentric cams. 2. The motor driving force transmission device according to claim 1, further comprising a member, wherein the pair of transmission members are connected to the differential mechanism at portions spaced apart from each other at equal intervals around a rotation axis thereof.   Each of the first electric motor and the second electric motor has a stator and a rotor, and each stator has a first connecting member through which the pair of transmission members are inserted, and each rotor has each stator. The motor driving force transmission device according to claim 2, wherein the motor driving force transmission devices are connected to each other by a second connecting member on an outer periphery.

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