JP3133165B2 - Electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, there has been provided an electric vehicle in which an engine is replaced with a motor to prevent generation of noise and exhaust gas. In this case, the electric vehicle has a driving device that drives the motor by the motor current from the battery. However,
There is a limit to the amount of electricity that can be charged to the battery, and it is necessary to mount a large-capacity battery to obtain a sufficient cruising distance. In addition, when a motor having a size large enough to be mounted on a conventional gasoline engine type vehicle is used, the value of the generated torque is smaller than that of the case using an engine, and sudden start, high load running, and high speed running are performed. Etc. cannot be performed.

In addition, a motor is arranged coaxially with the drive shaft,
When the electric vehicle is driven by rotating the drive shaft by the motor, the diameter of the motor is limited in securing the minimum ground clearance and cannot be increased. Therefore, a drive device in which a plurality of motors are provided, each motor is downsized, and the power performance is improved can be considered. In this case, for example, two motors, a reduction gear, and a differential device are arranged on one shaft, so that the motor can be reduced in size, the electric vehicle can be reduced in weight, and the motor can be mounted. Performance can be improved.

[0004]

However, in the conventional electric vehicle, unlike a gasoline engine type vehicle, noise due to an explosion in the internal combustion engine does not occur, so that the driver can easily hear gear noise. . Therefore, in order to suppress gear noise, the meshing ratio between gears such as a planetary gear unit constituting a speed reducer is improved.

However, when a spur gear is used to improve the meshing ratio, the tooth width must be increased. Therefore, it is effective to use a helical gear to improve the meshing ratio. However, in this case, a thrust load due to the torsion angle is generated, so that the capacity of the bearing must be ensured, and the driving device is correspondingly increased. The size of becomes large. Further, friction loss due to the thrust load increases, and torque transmission efficiency decreases.

The present invention solves the above-mentioned problems of the conventional electric vehicle, improves the meshing ratio between the gears constituting the reduction gear, reduces gear noise, and reduces the capacity of the bearing to drive the vehicle. It is an object of the present invention to provide an electric vehicle in which the size of the device can be reduced and the torque transmission efficiency does not decrease.

[0007]

For this purpose, in the electric vehicle according to the present invention, first and second motors are connected to a motor and a rotor of the motor, respectively, and reduce the rotation of the motor to transmit the rotation to the respective drive wheels. 2 speed reducers. And
Each of the first and second reduction gears is formed by a helical gear. Also, among the respective helical gears, predetermined helical gears corresponding to the first and second reduction gears are set so that the torsion angles are opposite to each other so that the tooth traces are symmetrical. And are connected to each other so as to cancel the applied thrust load. Another electric vehicle according to the present invention includes a motor, and first and second reduction gears respectively connected to a rotor of the motor and configured to reduce the rotation of the motor and transmit the reduced rotation to the respective drive wheels. Each of the first and second reduction gears is formed by a helical gear, and is connected to each other so as to be able to transmit a thrust load. , Second
The predetermined helical gears corresponding to the reduction gears have the twist angles set to be opposite to each other so that the teeth are symmetrical.

[0008]

According to the present invention, as described above, in the electric vehicle, the first motor is connected to the motor and the rotor of the motor, and the rotation of the motor is reduced and transmitted to the respective drive wheels. , A second reduction gear. Each of the first and second reduction gears is formed by a helical gear. Also, among the respective helical gears, predetermined helical gears corresponding to the first and second reduction gears are set so that the torsion angles are opposite to each other so that the tooth traces are symmetrical. And are connected to each other so as to cancel the applied thrust load.

Accordingly, the meshing ratio can be improved, so that gear noise can be reduced. Also, the thrust load generated when driving the driving device is:
Predetermined helical gears that correspond between the first and second reducers are applied in opposite directions and cancel each other. As a result, the capacity of the bearing can be reduced, and the size of the drive device can be reduced. Further, it is possible to dispose the driving device in a limited space.
Further, since the thrust load is canceled, friction loss of the bearing can be reduced, torque transmission efficiency can be improved, and the cruising distance of the electric vehicle can be increased.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram of an electric vehicle driving device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the electric vehicle driving device according to the embodiment of the present invention. In the figure, 1
Reference numeral 0 denotes a drive unit case, 11 denotes a cylindrical first center case, 12 denotes a cylindrical second center case, 13 denotes a dish-shaped first side cover, and 14 denotes a dish-shaped second side cover. The first and second center cases 11 and 12 are formed with partition walls 16 and 17 extending in the center direction, respectively.

Then, the first and second center cases 1
The opposing end faces of the first and second center cases 11, 12 are joined together by bolts 9a.
The first and second side covers 13 and 14 are
b, 9c, the partition walls 16, 17 are fixed.
A differential device chamber 20 is formed therebetween, and motor chambers 21 and 22 are formed between the partition 16 and the first side cover 13 and between the partition 17 and the second side cover 14.
The differential device chamber 20 accommodates a differential device 23, and the motor chambers 21 and 22 accommodate a plurality of, for example, a pair of first and second motors 24 and 25. The bulkheads 16 and 17 have a shape in which the center protrudes toward the drive wheels (the left-right direction in the drawing) in the axial direction of the first and second motors 24 and 25, and the center of the differential device chamber 20. To accommodate the differential device 23.

The stators 27, 28 of the first and second motors 24, 25 are connected to the first and second center cases 11, 1, respectively.
2 is fixed to the inner peripheral wall. That is, the stator 2
7, 28 are armature iron cores 29, 30 and coils 31, 3
2 and the armature cores 29 and 30 are the first
The second center cases 11 and 12 are positioned near the steps 33 and 34 formed on the inner peripheral walls.

On the other hand, the rotors 41, 42 of the first and second motors 24, 25 are provided with permanent magnets 43, 44 rotatably disposed radially inside the armature cores 29, 30;
It comprises rotating shafts 45 and 46 that support the permanent magnets 43 and 44, and the rotating shafts 45 and 46 are supported by the differential device 23. That is, the differential device 23 includes a differential case 51 formed of a material having sufficient rigidity, a pinion shaft 52 disposed in the differential case 51, and a pinion rotatably disposed with respect to the pinion shaft 52. 53, first and second side gears 54 and 55 arranged in mesh with the pinion 53.

The first and second side gears 54 and 55 differentially rotate the rotation transmitted to the differential case 51, and the first and second drive shafts 56 and 55 are connected to left and right drive wheels (not shown) of the electric vehicle. Transfer to 57. The differential case 51 is provided with the first and second drive shafts 5.
A cylindrical portion (shaft) 51a extending around
The rotary shafts 45 and 46 are supported by the tubular portions 51a and 51b.

The outer peripheral surfaces of the cylindrical portions 51a, 51b and the inner peripheral surfaces of the rotary shafts 45, 46 are spline-fitted by splines 61, 62.
a, 51b, the outer peripheral surface of the root portion,
Bearings 63 and 64 are arranged between the 7, and the differential device 23 is rotatably supported. Then, the cylindrical portions 51a, 51b and the first and second drive shafts 56, 57
Have an appropriate amount of clearance between them and are disposed so as to be relatively rotatable.

The differential device room 20
On the outer periphery of the differential case 51 inside
A parking gear 66 is provided. The first and second
Rings 56a, 57a are provided near the distal ends of the drive shafts 56, 57.
Are formed integrally, and thrust bearings 67, 68 are provided between the rings 56a, 57a and the cylindrical portions 51a, 51b.
Is arranged. The cylindrical portions 51a, 51b and the first and second drive shafts 5 are formed by the thrust bearings 67, 68.
A relative rotation between 6,57 is possible. The rotating shafts 45 and 46 are formed at the steps formed at the roots of the cylindrical portions 51 a and 51 b of the differential case 51, the inner races of the bearings 63 and 64, and the thrust bearing 6.
7, 68 and the rings 56a, 57a.

The driving wheels of the rings 56a, 57a
The planetary gear unit as the first and second reduction gears
The cutouts 72 and 73 are provided. The planetary gear unit
The drive 72, 73 drives the first and second drive shafts 56, 57.
Sun gear S integrally formed at the end on the driving wheel side₁,
S_Two, The sun gear S₁, S_TwoPinion P meshing with₁,
P _Two, The pinion P₁, P_TwoSupport pinion shuff
To PS₁, PS_Two, The pinion shaft PS₁, PS_Two
Carrier CR supporting₁, CR_Two, The pinion
P₁, P_TwoRing gear R meshing with₁, R_TwoConsisting of
Sun gear S₁, S_TwoAre the first and second drive shafts 56 and 57
And the ring gear R₁, R_TwoIs the first and second side cover 1
3 and 14 are spline-fitted.

[0018] Then, the the carrier CR _1, the driving wheel side in the axial direction of the CR ₂ is a transmission shaft 75, 76 is connected, the transmission shaft 75 and 76, the yoke flanges 77 and 78
And spline fit. Further, the yoke flange 7
A drive shaft is connected to 7, 78. The transmission shafts 75 and 76 are connected to the first and second side covers 1 via yoke flanges 77 and 78 and bearings 79 and 80, respectively.
3 and 14 are rotatably supported.

The rotation of the first and second drive shafts 56 and 57 is input to the planetary gear units 72 and 73 via the sun gears S ₁ and S ₂ , and is reduced at the planetary gear units 72 and 73 to reduce the carrier CR _1. , CR
_The power is output to the transmission shafts 75 and 76 via the _second transmission line ₂ . Therefore, the first and second drive shafts 56, 57 and the transmission shafts 75, 7
Since relative rotation occurs between the thrust bearings 6, thrust bearings 69 and 70 are disposed between the two.

As described above, in the planetary gear units 72 and 73, rotation is input from the first and second drive shafts 56 and 57 to the sun gears S ₁ and S ₂ , and the carrier CR
₁ and CR ₂ output a reduced rotation. Drive wheels are connected to the yoke flanges 77 and 78 via a drive shaft. When the first and second motors 24 and 25 are driven, the rotor 4
1 and 42 rotate, and the differential case 51 is rotated via splines 61 and 62. And
This rotation is made differential in the differential device 23 and transmitted to the first and second drive shafts 56 and 57 via the first and second side gears 54 and 55.

The rotation transmitted to the first and second drive shafts 56 and 57 is transmitted to the planetary gear units 72 and 73.
Are input to the sun gears S ₁ and S ₂ of the carrier CR ₁ , CR ₂ , and are decelerated by the planetary gear units 72 and 73.
Output from ₂ . The rotation output from the carriers CR ₁ and CR ₂ is transmitted to the transmission shafts 75 and 76 and the yoke flange 7.
The electric power is transmitted to the drive wheels via the wheels 7 and 78 to drive the electric vehicle.

In the driving device having the above-described structure, the planetary gear units 72 and 73 are used to reduce the rotation of the first and second motors 24 and 25.
Therefore, in order to suppress gear noise generated in the planetary gear units 72, 73, a helical gear, for example, a helical gear is used for the planetary gear units 72, 73 to improve the meshing ratio.

9d and 9e are bolts, 81 and 82 are ring gear flanges, and 83 and 84 are nuts. FIG.
FIG. 3 is a view showing a sun gear of the planetary gear unit in the embodiment of the present invention. In the figure, 56 is a first drive shaft, 57 is a second drive shaft, S ₁ is a sun gear formed integrally with the first drive shaft 56, and S ₂ is the second drive shaft 57
The sun gear is formed integrally with the sun gear.

The torsional angles of the sun gears S ₁ and S ₂ are set opposite to each other so that the tooth traces are symmetrical.
Similarly, the pinions P ₁ , P ₂ (FIG. 2) and the ring gears R ₁ , R ₂ are also formed of helical gears, and the torsional angles are set to be opposite to each other so that the teeth are symmetrical. When the rotation is transmitted to the first and second drive shafts 56 and 57 and input to the planetary gear units 72 and 73, a thrust load is generated on the first and second drive shafts 56 and 57 due to the torsion angles of the respective gears. I do.

FIG. 4 is an explanatory view of a thrust load generated in the embodiment of the present invention, FIG. 5 is an explanatory view of a first side cover in the embodiment of the present invention, and FIG. 6 is a second side cover in the embodiment of the present invention. FIG. FIG. 4A shows a state of the electric vehicle when moving forward, and FIG. 4B shows a state of the electric vehicle when moving backward. FIG. 5A shows the first side cover 1.
3 (FIG. 2), and (b) shows the first side cover 13.
6A shows a cross section of the second side cover 14, and FIG. 6B shows a right side surface of the second side cover 14.

In FIG. 4, reference numeral 10 denotes a drive device case,
1 is a differential case, 56 is a first drive shaft, 5
7 is a second drive shaft, 63 and 64 are bearings, 72 and 73
Is a planetary gear unit, 75 and 76 are transmission shafts,
S₁, S_TwoIs sun gear, R₁, R _TwoIs a ring gear,
P₁, P_TwoIs a pinion. As shown in FIG.
When the electric vehicle is moving forward, the planetary gear unit 7
Sun gear S at 2,73₁, S_TwoIs the center of the drive
Side of the ring gear R₁, R_TwoIs biased to the drive wheel side
Is done. As a result, the sun gear S₁The force applied to
Transmitted to the differential case 51 and the bearing
The driving force is transmitted to the drive device case 10 via the control unit 64. on the other hand,
The sun gear S_TwoDifferential Schalke
The driving device is transmitted to
Is transmitted to the storage case 10.

However, in practice, the force applied to the sun gear S ₁ and the force applied to the sun gear S ₂ in the differential case 51 cancel each other, so that the thrust load is hardly applied to the bearings 63 and 64. Further, the pinion P _1, P ₂ includes a sun gear S _1, S ₂ and are the ring gear R _1, R ₂ and meshed, a force as shown in Figure by the twist angle is generated, the pinion P _1, P ₂
Is canceled out, and no thrust load is applied to the carriers CR ₁ and CR ₂ . And the ring gears R ₁ , R ₂
Generates a biasing force toward the drive wheels, and the force is transmitted to the first and second side covers 13 and 14 via the ring gear flanges 81 and 82. Therefore, no thrust load is applied to the bearings 79, 80 and the thrust bearings 69, 70.

On the other hand, as shown in FIG. 4B, when the electric vehicle moves backward, the sun gears S ₁ and S ₂ are urged toward the driving wheels in the planetary gear units 72 and 73, and the ring gears R ₁ and R ₂ are moved. It is biased toward the center of the drive. As a result, the force applied to the sun gear S ₁ is transmitted to the transmission shafts 75 and 76 via thrust bearings 69 and 70, and further transmitted to the first and second side covers 13 and 14 via bearings 79 and 80. Therefore, no thrust load is applied to the bearings 63, 64.

As described above, the thrust load generated when the electric vehicle moves forward can be offset, so that the capacity of the bearings 63 and 64 can be reduced. The thrust bearings 69, 70 and the bearing 7
No. 9 and 80 are not subjected to a thrust load when moving forward and are applied only when moving backward. However, since the traveling frequency at the time of reverse travel is lower than at the time of forward travel, the durability is increased, and the capacity of the thrust bearings 69, 70 and the bearings 79, 80 can be reduced accordingly, and the size of the drive device can be reduced. it can. Therefore, it is possible to dispose the driving device in a limited space.

Further, since the thrust load is canceled or not applied, the bearings 63, 64, 79,
80 and the thrust bearings 69 and 70 can be reduced in friction loss, the torque transmission efficiency can be improved, and the cruising distance of the electric vehicle can be extended. The sun gears S ₁ and S _{2 of} the planetary gear units 72 and 73,
Each of the pinions P ₁ , P ₂ and the ring gears R ₁ , R ₂ is formed of a helical gear, and the torsion angles are set to be opposite to each other so that the tooth traces are symmetrical. Therefore, if the parts of the planetary gear unit 72 and the parts of the planetary gear unit 73 are mixed and assembled,
The thrust load cannot be reduced.

Therefore, the ring gear flanges 81 and 82 supporting the ring gears R ₁ and R ₂ are respectively fixed to the first and second side covers 13 and 14 by bolts 9 d and 9 e.
And the pitch of the bolt holes of the bolts 9d and 9e is unequal at at least one location. That is, as shown in FIGS. 5 and 6, a plurality of bolts 9d to the ring gear flange 81, either a plurality of bolts 9e is the ring gear flange 82 is provided in the circumferential direction, the bolt 9d ₁ of bolts 9d , 9d ₂
However, among the bolts 9e, 9e ₁ and 9e ₂ are brought close to each other. Moreover, in this case, the first side cover 1
Bolt 9d ₁ on the right top of the ring gear flange 81 when the 3 viewed from the left side, 9d ₂ is located, also, bolts 9e on the left top of the ring gear flange 82 when viewed second side cover 14 from the right side ₁ , 9e ₂ are located.

Therefore, the ring gear flanges 81, 8
2 not only prevents the first and second side covers 13 and 14 from being erroneously assembled, but also the planetary gear units 72 and 7.
3 (FIG. 4) can also be prevented from being erroneously assembled to the first and second side covers 13 and 14. By the way, in the electric vehicle having the above configuration, the first and second motors 24 and 25 are provided corresponding to the respective drive wheels, so that the axial dimension of the first and second motors 24 and 25 can be reduced. You can,
As a result, the shape becomes flat, the interval for supporting the rotors 41 and 42 becomes narrow, and the diameter of the rotors 41 and 42 becomes large. Therefore, the rotors 41, 42
, The center axes of the rotors 41 and 42 are easily inclined due to misalignment.

The rotors 41 and 42 and the planetary gear unit
Gear 72, 73₁, S _TwoIs directly connected
The inclination of the central axes of the rotors 41 and 42
Yas ₁, S_TwoOf the planetary gear unit
Gear contact in 72 and 73 deteriorates, causing gear noise
In addition, the durability is reduced. Therefore,
Shafts 45 and 46 of the motors 41 and 42 and the differential
Spline fitting of the cylindrical parts 51a, 51b of the case 51
And the rotors 41 and 42 are
And the cylindrical portions 51a, 51b are
Drive device case 10 through
And support them. Further, the cylindrical portions 51a, 51
b between the first and second drive shafts 56 and 57
First and second side gears 54 and 55 are provided.
Second side gears 54, 55 and first and second drive shafts 56, 5
7 are spline-fitted.

Therefore, the rotors 41 and 42 and the sun gears S ₁ and S ₂ are divided and connected by spline fitting, and the first and second drive shafts 56 and 57 and the cylindrical portions 51 a and 51 b of the differential case 51 are formed. Since the clearance is formed between the inner walls, the inclination of the central axes of the rotors 41 and 42 does not directly become the inclination of the sun gears S ₁ and S ₂ .

The sun gears S ₁ and S ₂ are connected to a rotating shaft 4.
5, 46 and the spline fitting between the cylindrical portions 51a, 51b,
The gears in the planetary gear units 72 and 73 are supported by an automatic centering function. On the other hand, the carriers CR ₁ and CR ₂ receive moments from the transmission shafts 75 and 76. Accordingly, the bearing between the yoke of the carrier CR _1, CR ₂ and the yoke flange 77, 78 79, 80
And fixed by nuts 83 and 84. Further, the ring gears R ₁ and R ₂ are composed of the first and second side covers 13 and 1.
4 and a floating structure by spline fitting.

With such a structure, it is possible to absorb the inclination of the central axes of the rotors 41 and 42 and the planetary gear units 72 and 73, and to increase the arrangement accuracy of the rotors 41 and 42. In addition, the durability of the planetary gear units 72 and 73 can be improved. Another connection example between the rotors 41 and 42 and the planetary gear units 72 and 73 will be described with reference to FIGS.

FIG. 7 shows a second connection example between the rotor and the planetary gear unit, FIG. 8 shows a third connection example between the rotor and the planetary gear unit, and FIG. 9 shows a fourth connection example between the rotor and the planetary gear unit. FIG. 10 is a diagram showing a fifth connection example between the rotor and the planetary gear unit. In the figure, M ₁ , M ₂ ,..., M _n
Is a motor, 23 is a differential device, 72, 73
Is a planetary gear unit.

In FIG. 7, only one motor M ₁ is provided only on one side of the differential device 23.
In FIG. 8, two motors M ₁ and M ₂ are arranged on the driving wheel side with respect to the planetary gear units 72 and 73, respectively. In FIG. 9, the two motors M ₁ and M 2 are provided only on one side of the differential device 23. M ₂ is provided and FIG.
, A plurality of motors M ₁ , M ₂ ,..., M _n are arranged only on one side of the differential device 23.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic view of a driving device for an electric vehicle, showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a driving device for an electric vehicle showing an embodiment of the present invention.

FIG. 3 is a diagram showing a sun gear of the planetary gear unit in the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a thrust load generated in the embodiment of the present invention.

FIG. 5 is an explanatory diagram of a first side cover according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram of a second side cover in the embodiment of the present invention.

FIG. 7 is a diagram illustrating a second connection example between the rotor and the planetary gear unit.

FIG. 8 is a diagram illustrating a third connection example between the rotor and the planetary gear unit.

FIG. 9 is a diagram illustrating a fourth connection example between the rotor and the planetary gear unit.

FIG. 10 is a diagram illustrating a fifth connection example between the rotor and the planetary gear unit.

[Explanation of symbols]

24 the first motor 25 and the second motor 41 and rotor 72, 73 planetary gear unit _{M 1, M 2, ...,} M n motor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yutaka Taga 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Yasuya Yasui 1 Toyota City Toyota Town, Toyota City, Aichi Prefecture Judgment inside Toyota Motor Corporation Government Kiyoshiharu Yamashita (56) References JP-A-3-213749 (JP, A) JP-A-4-150701 (JP, A) JP-A-2-262806 (JP, A) Japanese Utility Model Publication No. 55-18641 (JP, A) U) Shokai 63-77500 (JP, U) Shokai 61-47140 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 7/116

Claims (2)

(57) [Claims] 1. A (a) a motor, (b) are respectively connected to the rotor of the motor, first of each transmitted decelerates the rotation of the motor to the drive wheels, the second
Gear as well as organic and of the reduction gear, (c) first, second reduction gear are both helical
Formed by, (d) of the helical gears each, the first, helical gears of a given that provoking correspondence between the second reduction gear, the twist angle as the tooth trace respectively are symmetrical set in opposite directions from each other
And to offset the applied thrust load.
Electric vehicle according to claim Rukoto coupled are. And (b) a motor connected to the rotor of the motor.
1st and 2nd which reduce rotation and transmit to each drive wheel, respectively
Gear which has a speed reducer, (c) first, second reduction gear are both helical
Formed by and transmit thrust loads to each other
And (d) the first and second reduction gears of each helical gear.
The predetermined helical gears assigned between
The twist angles are set in opposite directions so that the edges are symmetric.
An electric vehicle, characterized in that: