JPH08240254A - Power transmission device for electric vehicle - Google Patents

Abstract

PURPOSE: To compactly form an electric vehicle power transmission device having a planetary gear type reduction gear mechanism and a bevel gear type differential mechanism. CONSTITUTION: Each three of the complex planetary gear 30 of a reduction gear mechanism 12 and the driving bevel gear 54 of a differential mechanism 13 are provided at equal angular intervals about one center line O, and arranged, so as to be staggered from each other at equal angular intervals (60-degree intervals) about the center line O. As a result, the mechanisms 12 and 14 can be overlapped on top of each other along the center line O, so as to avoid interference, and approximately a half of the mechanisms 14 are concealed behind the internal surface of a small diameter pinion 26 along the center line O.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for an electric vehicle, and more particularly to a technique for compactly forming a power transmission device having a planetary gear type speed reduction mechanism and a bevel gear type differential mechanism. Is.

[0002]

[Prior art]

(A) It has a carrier in which a plurality of planetary gears are provided around the center line so as to be rotatable about an axis substantially parallel to the center line at substantially equal angular intervals, and reduce the rotation transmitted from the electric motor. Then, the planetary gear type speed reducing mechanism which outputs from the carrier, and (b) the differential case which is concentrically and integrally provided with the carrier are integrally rotated with the carrier, thereby being substantially orthogonal to the one center line. A bevel gear type that rotatably drives a pair of output members arranged on one center line thereof via a plurality of drive-side bevel gears that are rotatably around an axis and are arranged in the differential case at substantially equal angular intervals. There is known a power transmission device for an electric vehicle, which includes the differential mechanism.
"EVS9" held from November 13th to 16th, 1988
Electric Vehicle Asso
"EVS88-P16" in the newsletter of the "ciation of Canada"
The device described in (a) is an example thereof. The (a) planetary gear type speed reducing mechanism includes (a-1) a carrier rotatably arranged around one center line, and (a-2) a large diameter. A plurality of compound planetary gears (stepped pinions) integrally provided with a pinion and a small-diameter pinion in the axial direction and rotatably arranged around the axis substantially parallel to the one center line on the carrier at substantially equal angular intervals. And (a-3) a sun gear rotationally driven around the one center line by an electric motor and meshed with the large diameter pinion, and (a-4) fixed to a housing and meshed with the small diameter pinion. A ring gear is provided, and while the sun gear is rotationally driven, the carrier is decelerated and rotated. On the other hand, (b) a bevel gear type differential mechanism is provided on the small diameter pinion side. The differential case, which is disposed close to the speed reduction mechanism and concentric with the speed reduction mechanism, and which is integrally provided with the carrier is integrally rotated with the carrier, so that the rotation of the differential shaft around the axis substantially orthogonal to the one center line is performed. A pair of output members arranged on one center line are rotatably driven via a plurality of drive-side bevel gears rotatably arranged in the differential case at substantially equal angular intervals.

[0003]

However, since the bevel gear type differential mechanism is disposed adjacent to the planetary gear type speed reducing mechanism in the one centerline direction, the dimension in the one centerline direction is large. Was hindering miniaturization. For example, such a power transmission device is convenient to be disposed in the width direction of the vehicle coaxially with the electric motor in the axial direction.
Since the axial dimension becomes large, there is a problem that the width dimension of the vehicle must be increased.

The present invention has been made in view of the above circumstances, and an object thereof is to compactly configure a power transmission device including a planetary gear type reduction mechanism and a bevel gear type differential mechanism. Especially.

[0005]

In order to achieve the above object, the speed reducing mechanism and the differential mechanism may be arranged so as to overlap each other in the direction of one center line.
The present invention includes (a) a carrier provided with a plurality of planetary gears rotatably around an axis substantially parallel to one center line at substantially equal angular intervals around the one center line and transmitted from an electric motor. A planetary gear type speed reducing mechanism that decelerates the rotation and outputs the decelerated rotation from the carrier; and (b) the differential case that is concentrically and integrally provided with the carrier is integrally rotated with the carrier, so that the one center line A pair of output members arranged on one center line thereof are rotationally driven through a plurality of drive-side bevel gears arranged in the diff case at substantially equal angular intervals so as to be rotatable about an axis substantially orthogonal to In a power transmission device for an electric vehicle, comprising: a bevel gear-type differential mechanism, (c) one of the planet gears and the drive-side bevel gear is a divisor other than one of the other. In addition to the individual Set the installation position so as not to overlap each other in about the one center line, characterized in that the said speed reduction mechanism said differential mechanism is arranged by overlapping on the one center line direction.

Here, the divisors other than 1 are, for example, when one is two, the other is two, when one is three, the other is three, and when one is four, the other is also two. 4 or 2
When one is 5, the other is 5, and so on.

[0007]

In such a power transmission device for an electric vehicle, the number of the planetary gears and the driving-side bevel gears arranged is approximately several other than one of the other, so that It is possible to position the drive-side bevel gear at an intermediate position between adjacent planetary gears around the center line, and make the reduction gear mechanism and the differential mechanism overlap in one center line direction so that they do not interfere. Can be placed.
As a result, the size in the direction of the one center line can be reduced, the size and weight can be reduced, and the mounting space on the vehicle can be reduced.

Incidentally, since the number of planetary gears in the conventional planetary gear type speed reducing mechanism is generally three, and the number of drive side bevel gears in the bevel gear type differential mechanism is two or four, it is one center. It is difficult to arrange them so that they do not interfere around the line, and they cannot be sufficiently overlapped in the direction of one center line. If the plurality of planet gears and the drive-side bevel gear are arranged at unequal intervals around one center line, they can be arranged so as not to interfere with each other, but the rotational balance deteriorates, which is not preferable.

In a preferred aspect of the present invention, (a) a carrier rotatably arranged around a center line, a large-diameter pinion and a small-diameter pinion are integrally provided in the axial direction, and the one central line is provided. And a plurality of compound planetary gears rotatably arranged on the carrier at substantially equal angular intervals about an axis substantially parallel to, and driven to rotate about the one center line by an electric motor and mesh with the large diameter pinion. And a ring gear fixed to the housing and meshed with the small-diameter pinion, and the planetary gear type speed reduction mechanism in which the carrier is decelerated and rotated as the sun gear is driven to rotate, b) A differential case, which is disposed close to the reduction gear mechanism on the side of the small diameter pinion and concentric with the reduction gear mechanism, and which is integrally provided with the carrier, is used as a key. By being integrally rotated with the rear, one center of the differential gear can be rotated about an axis substantially orthogonal to the one center line through a plurality of drive-side bevel gears arranged in the diff case at substantially equal angular intervals. A power transmission device for an electric vehicle, comprising: a bevel gear-type differential mechanism that rotatably drives a pair of output members arranged on a line; (c) a twisting direction of each meshing tooth of the large diameter pinion and the small diameter pinion. And the leads are equalized, (d) the composite planetary gears and the drive-side bevel gears are arranged in the same number, and the arrangement positions of both gears are staggered about the one center line at substantially equal angular intervals. The speed reduction mechanism and the differential mechanism are arranged so as to overlap each other in the one center line direction.

Here, if the meshing teeth of the large diameter pinion and the small diameter pinion have the same twist direction and lead, the sun gear and the ring gear meshing with them are fixed,
The plurality of compound planetary gears can move in the axial direction while independently rotating around the axis. Therefore, when torque is applied during power transmission, etc., so that the compound planetary gears are independently moved within the predetermined clearance (play) positioned by the carrier to the axial position where they are in proper meshing state. It will move and always obtain an appropriate meshing state, and the meshing state will not be impaired due to slight dimensional error of the carrier etc., and gear noise due to poor meshing and deterioration of power transmission efficiency etc. will be prevented. It

On the other hand, if the large-diameter pinion and the small-diameter pinion have the same twisting direction and lead of the meshing teeth as described above, the thrust forces generated in the two pinions due to the twisting are opposite to each other and have substantially the same magnitude. Since the thrust force of the entire compound planetary gear is offset, the strength and rigidity required for the carrier supporting the compound planetary gear are alleviated, and the device can be configured easily and inexpensively. In addition, it is not always necessary to interpose a thrust bearing between the compound planetary gear and the carrier. Further, since the bending deformation of the carrier due to the thrust force is prevented, the parallelism between the compound planetary gear and the sun gear and the ring gear can be maintained well, and those gears can be properly meshed. Therefore, gear noise is reduced and power transmission efficiency is improved. If the twisting direction of the meshing teeth is set so that the thrust forces generated in the large-diameter pinion and the small-diameter pinion during the main traveling (generally, when traveling forward) face each other in the axial direction, the meshing position is determined based on the difference in the meshing position. The moment generated in the compound planetary gear is canceled as a whole in relation to the moment generated based on the pressure angle, which is more effective.

By the way, if the leads of the meshing teeth of the large-diameter pinion and the small-diameter pinion are made equal, the twist angle of the small-diameter pinion becomes smaller than the twist angle of the large-diameter pinion. If so, the axial dimension becomes large. Therefore, when the bevel gear type differential mechanism is disposed adjacent to the planetary gear type speed reducing mechanism, the axial dimension of the entire power transmission device, that is, the dimension in the one center line direction is further increased. However, if the reduction gear mechanism and the differential mechanism are arranged so as to overlap in the direction of one center line with the same number of the composite planetary gears and the drive-side bevel gears being arranged, even if the axial dimension of the small diameter pinion becomes large. The overall size of the device can be kept small. Further, since the composite planetary gears and the driving-side bevel gears are arranged in the same number and are arranged so as to be staggered at substantially equal angular intervals around one centerline, the weight distribution around one centerline is substantially uniform. As a result, the rotation balance is improved, the power transmission efficiency is improved, and the generation of vibration and abnormal noise is suppressed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. Power transmission device 10 for electric vehicle of FIG.
Is configured to include a planetary gear type reduction mechanism 12 and a bevel gear type differential mechanism 14 which are arranged concentrically with the one center line O, and are arranged concentrically with the one center line O on the left side of the drawing. The rotation of the motor shaft 16 of the electric motor (not shown)
After being decelerated by 2, it is transmitted to the pair of output members 18, 20 via the differential mechanism 14, and further transmitted to the left and right drive wheels. The reduction mechanism 12 includes a carrier 22 rotatably arranged around a center line O, a large-diameter pinion 24 and a small-diameter pinion 26 integrally in the axial direction, and is substantially connected to the one center line O via a planetary shaft 28. A plurality of, in this embodiment, three compound planetary gears 30 rotatably arranged around the parallel shaft center at equal angular intervals on the carrier 22, and a spline fit to the motor shaft 16 to rotate about one center line O. And the large diameter pinion 24.
It is provided with a sun gear 32 meshed with and a ring gear 36 fixed to the housing 34 and meshed with the small-diameter pinion 26. The sun gear 32 is driven to rotate by the motor shaft 16 so that the ring gear 36 reacts with the reaction force. As an element, the carrier 22 is decelerated and rotated at a predetermined gear ratio. Each gear of the reduction mechanism 12 is a helical gear having meshed teeth twisted together, and the large-diameter pinion 24,
The meshing teeth 24a, 26a (see FIG. 3) of the small-diameter pinion 26 have the same twisting direction and the same lead.

The carrier 22 is integrally provided with a differential case portion 38 on the small diameter pinion 26 side, and the differential mechanism 14 is provided.
Of the differential case, and a diff cover 40 is integrally fixed to the opening on the side of the diff case 38 so that the carrier 22 and the diff cover 40 are integrated. Both ends are supported by a housing 34 via a pair of bearings 42 and 44 so as to be rotatable about one center line O and not movable in the axial direction. One bearing 42 is the housing 3
4 is supported by a gear cover 46 integrally fixed to the gear 4. In addition, a plurality of compound planetary gears 30
Are rotatably disposed on the planetary shaft 28 via a pair of needle bearings 48, respectively, and are axially positioned by the carrier 22 via two sets of washers 50 disposed at both ends in the axial direction. It is supposed to be regulated. The axial position is determined with a clearance (play) of a predetermined amount, for example, about 1 mm or less, in order to absorb dimensional errors and mounting errors of each part.

On the other hand, the differential mechanism 14 is arranged close to the reduction mechanism 12 on the small diameter pinion 26 side of the compound planetary gear 30, that is, on the right side in FIG.
A plurality of driving-side bevel gears 54, three in this embodiment, are arranged at equal angular intervals in the diff case 38 so as to be rotatable about an axis substantially orthogonal to the one center line O via a diff shaft 52. And a pair of driven-side bevel gears 56 meshed with the pair of output members 18, 20 such that they cannot rotate relative to each other, and are meshed with three drive-side bevel gears 54, respectively. The number of teeth of the driven bevel gear 56 is an integer multiple of 3, and the driven bevel gear 56 can be easily meshed with the three driving bevel gears 54 arranged at equal angular intervals around the one center line O. ing. Also, a pair of output members 1
8 and 20 are arranged concentrically with the one center line O, and the output member 18 is inserted through the cylindrical motor shaft 16 so as to be relatively rotatable and reaches the opposite side of the electric motor. The differential cover 20 is inserted through the differential cover 40 and projects to the outside of the housing 34. The carrier 2
Of the two, a pump driving gear 58 is provided on the outer peripheral portion of the differential case portion 38, and the lubricating oil in the oil sump 62 is sent to each portion by rotationally driving the oil pump 60.

Here, the composite planetary gears 30 and the drive-side bevel gears 54 are provided in three sets at equal angular intervals around one center line O, respectively, and are provided in the carrier 22 integrally having the differential case portion 38. However, as shown in FIG. 2, the arrangement positions of them are determined so that they are staggered at equal angular intervals (60 ° intervals) around one center line O. This ensures that they do not interfere with each other,
It becomes possible to arrange the reduction mechanism 12 and the differential mechanism 14 so as to overlap each other in the one center line O direction. In this embodiment, as is apparent from FIG. The structure is such that approximately half of the differential mechanism 14 is embedded in the inner peripheral side portion of the small diameter pinion 26 so as to overlap with the re-shaft 28.

As described above, in the power transmission device 10 for an electric vehicle of this embodiment, about half of the differential mechanism 14 in the direction of the one center line O is used as the small diameter pinion 26 of the reduction mechanism 12.
Since it has a structure in which it is embedded in the inner peripheral side portion, the size in the direction of one center line O becomes small, and it is possible to achieve size reduction and weight reduction, and also to save the mounting space on the vehicle. Particularly, in the present embodiment, the drive-side bevel gear 54
Since three are arranged, the PV value of each drive-side bevel gear 54, that is, the value of the surface pressure (P) × speed (V), becomes smaller than that in the case of two. It is possible to make the differential mechanism 14 have a small diameter by disposing the position of the power transmission device 10 close to the one center line O, and as a result, the differential mechanism 14 can be greatly sunk into the inner peripheral side portion of the small diameter pinion 26 and the power transmission device 10 It is possible to downsize the entire diameter.

A power transmission device using a planetary gear device as the differential mechanism 14 is known. In this case, the dimension in the direction of one center line O can be made relatively small, but the carrier of the reduction mechanism and the differential mechanism is known. Since it is supported separately in a cantilevered manner, there was a problem in support rigidity. On the other hand, in this embodiment, the carrier 22 of the speed reduction mechanism 12 is integrally formed with the differential case portion 38 of the differential mechanism 14, and the differential cover 40 is integrally fixed to the differential case portion 38. Since it is supported by the housing 34 via the bearings 42 and 44, a high support rigidity can be obtained, and the compact construction can be achieved as described above.

Further, in the present embodiment, the number of compound planetary gears 30 and the number of drive-side bevel gears 54 are the same, and they are arranged at equal angular intervals around one center line O. The weight distribution around the center line O is substantially uniform, the rotation balance is improved, the power transmission efficiency is improved, and the generation of vibrations and abnormal noises is suppressed.

Further, the large diameter pinion 24 and the small diameter pinion 26 of the compound planetary gear 30 in the reduction mechanism 12 of the present embodiment.
Since the meshing teeth 24a and 26a of each of the same have the same twisting direction and the same lead, a thrust force is not generated in the compound planetary gear 30 regardless of the twisting of the meshing teeth 24a and 24b, and a plurality (three in this embodiment) of the compound teeth are combined. There is an advantage that the planetary gear 30 can move independently in the axial direction and a good meshing state can always be obtained. Hereinafter, this point will be specifically described.

FIG. 3 is a motor of the power transmission device 10 of FIG.
When the shaft 16 is moving forward, that is, in the main operating state,
Used when driven to rotate counterclockwise when viewed from the left side of 1.
FIG. 2 is a perspective view showing a compound planetary gear 30 that is used in a large diameter pinion.
24 and the meshing teeth 24a, 26a of the small diameter pinion 26
Are all left-handed and their leads are equal to each other. This
In the case of, the sun gear 32 rotates counterclockwise together with the motor shaft 16.
Large diameter that meshes with the sun gear 32 when rotated to
Due to the twist of the meshing teeth 24a, the pinion 24 shown in FIG.
Thrust force F to the right_SSWhile the ring acts
The small diameter pinion 26 that meshes with the gear 36 has a meshing tooth 26a.
Thrust force F to the left in Fig. 1 due to the twist of_RS
Works. Further, the large-diameter pinion 24 has its meshing teeth.
Depending on the pressure angle of 24a
Force F_SROn the other hand, the small pinion 26
Is a small diameter pinion 2 depending on the pressure angle of the meshing tooth 26a.
Force F in the direction toward the axis of 6_RRWorks. Sun gear 3
2 to the circumference added to the meshing teeth 24a of the large diameter pinion 24
Force in the direction F_S, The pressure angle of the meshing teeth 24a is α_S, Twist angle
Β_SThen, the above force F_SRIs F_Stan α_SIs represented by
Thrust force F_SSIs F_Stan β_SIt is represented by Also small diameter
The meshing teeth 26a of the pinion 26 are received from the ring gear 36.
The reaction force in the circumferential direction is F_R, The pressure angle of the meshing tooth 26a is α
_R, Twist angle β _RThen, the above force F_RRIs F_Rtan α_R
Is represented by the thrust force F_RSIs F_Rtan β _RIt is represented by
3 shows the large diameter pinion 24 and the small diameter pinion 26.
Only one meshing tooth 24a, 26a of each is shown.
Of.

FIG. 4 shows the relationship among the above forces F _SR , F _SS , F _RR , and F _RS. The forces F _SR and F _RR generated by the pressure angle are the same as those of the compound planetary gear 30 shown in FIG. Although acting as a moment to rotate clockwise about the center line perpendicular to the paper surface, the thrust forces F _SS and F _RS generated by the twisting of the meshing teeth 24a and 26a cause the compound planetary gear 30 to move to the center perpendicular to the paper surface of FIG. It acts as a moment to rotate counterclockwise around the line. Therefore, the two moments cancel each other out and the compound planetary gear 3
The total moment acting on 0 becomes small, and uneven wear of the planetary shaft 28 and the planetary shaft 28
The deformation of the carrier 22 that supports the carrier is reduced, and the durability thereof is improved. Further, since the carrier 22 is less deformed, the planetary shaft 28 and the sun gear 32 are
The parallelism with the one center line O of the ring gear 36 is maintained well, the large diameter pinion 24 and the small diameter pinion 26 are properly meshed with the sun gear 32, and the ring gear 36, and gear noise is reduced. In this way, in canceling the moment, it is desirable to set the twisting direction of the meshing teeth 24a and 26a so that the thrust forces F _SS and F _RS generated in the both pinions 24 and 26 during the main running face each other. In FIG. 4, hatching of the cross section is omitted.

Further, the large diameter pinion 24 and the small diameter pinio
The leads of the meshing teeth 24a and 26a of the connector 26 are equal to each other.
Therefore, the thrust force F_SS= F_RSBecomes That is, large
Opposite direction for small diameter pinion 24 and small diameter pinion 26
Since a torque of approximately the same magnitude acts on the
T and radius of both pinions 24 and 26 are r_S, R _R
Then, the torque T is expressed by the following equation (1), and the meshing teeth 24
Supposing that the leads of a and 26a are L, from the relationship of FIG.
Strike force F_SS, F_RSAre expressed by the following equations (2) and (3), respectively.
F,_SS= F_RSIt becomes. This allows the compound planet
The total thrust force generated in the gear 30 is almost zero,
Required for the carrier 22 supporting the compound planetary gear 30.
The strength and rigidity of the reduction mechanism 12 are eased, and the reduction mechanism 12 is simple and secure.
It is possible to configure the value and carry due to the thrust force.
Since the flexural deformation of the a 22 is prevented, the planetary shuffling
28 and one center line O of the sun gear 32 and the ring gear 36
The parallelism of the large pinion 24 and
The small diameter pinion 26, the sun gear 32, and the ring gear 36
The gears will be meshed properly and gear noise will be reduced.
As a result, the power transmission efficiency is improved. Also a compound planet
Between the gear 30 and the carrier 22 (the differential case portion 38)
Does not necessarily need to have thrust bearings
Alternatively, even if the washer 50 is provided as in the present embodiment,
It is good so that the speed reduction mechanism 12 can be constructed at low cost.
Become. Note that FIG. 5 shows the outer peripheral dimensions of each pinion 24, 26.
2πr_S, 2πr_RAnd the twist angle of the meshing teeth 24a, 26a
β_S, Β _RAnd a diagram for explaining the relationship between the lead L and
It does not correspond to the size and angle of each part. T = r_S・ F_S= R_R・ F_R ... (1) F_SS= F_Stan β_S= F_S・ (2πr_S/ L) = T · (2π / L) (2) F_RS= F_Rtan β_R= F_R・ (2πr_R/ L) = T · (2π / L) (3)

Further, since the large-diameter pinion 24 and the small-diameter pinion 26 have the same lead, the plurality of compound planetary gears 30 rotate independently about their respective axes while the sun gear 32 and the ring gear 36 meshing with them are fixed. While it is possible to move in the axial direction. Therefore, when torque is applied during the power transmission or the like to be rotationally driven, each compound planetary gear 30 is independently positioned in a predetermined clearance (play) by the carrier 22 to an axial position in which the compound planet gears 30 are properly meshed. It moves inside and meshes in a proper meshing state without being forced. As a result, the meshing state is not impaired due to a slight dimensional error of the end surface of the carrier 22, and a proper meshing state is always obtained, resulting in deterioration of gear noise, power transmission efficiency, etc. due to poor meshing. To be prevented.

On the other hand, when the twist angles β _S and β _R are determined independently of each other, the thrust force F _SS = F _S tan
β _S and F _RS = F _R tan β _R are not completely offset. For this reason, the compound planetary gear 30 as a whole is pressed in the axial direction by the thrust force, and the carrier 22 in which the compound planetary gear 30 is arranged is required to have high mechanical strength. When the carrier 22 is flexed and deformed, the compound planetary gear 30 and the sun gear 3
2. There is a problem that the parallelism with the ring gear 36 is impaired, an appropriate meshing state cannot be obtained, and gear noise and power transmission efficiency deteriorate. Further, when the specifications of the large-diameter pinion 24 and the small-diameter pinion 26 are independently determined, when one composite planetary gear 30 moves in the axial direction, the sun gear 32 and the ring gear 36 are relatively rotated accordingly. If the plurality of compound planetary gears 30 do not move in the axial direction at the same time at the same time, backlash or twisting occurs between these gears and the meshing state is impaired.
Gear noise, transmission efficiency, and strength are adversely affected. It is difficult to make all the axial clearances of the composite planetary gears 30 the same, and any one composite planetary gear 30 abuts on the end face of the carrier 22 so that the other composite planetary gears 30 can move further. When it disappears, the thrust force is received between the gears, which causes the above problem.

By the way, as described above, the meshing teeth 24 of the large diameter pinion 24 and the small diameter pinion 26 of the compound planetary gear 30.
If the leads of a and 26a are equal, the small diameter pinion 26
Since the twist angle β _R is smaller than the twist angle β _S of the large-diameter pinion 24, the axial dimension becomes large in order to secure the necessary contact ratio and strength. Therefore, the bevel gear type differential mechanism 14 is provided adjacent to the planetary gear type reduction mechanism 12.
However, when the power transmission device 10 as a whole is increased in axial direction, that is, the size in the direction of one center line O, the number of the compound planetary gears 30 and the number of drive-side bevel gears 52 are the same. In the present embodiment in which the speed reduction mechanism 12 and the differential mechanism 14 are arranged so as to overlap each other in the direction of the center line O, the overall size of the power transmission device 10 is kept small even if the axial dimension of the small diameter pinion 26 is increased. it can.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above embodiment, the compound planetary gear 30 of the reduction mechanism 12 and the driving bevel gear 54 of the differential mechanism 14 are used.
The number of each of the three is three, but the number of each of them is two, four, five, or one is four and the other is two, and so on. The other number can be appropriately changed within a range satisfying the relationship of being a divisor other than one.

Further, the reduction mechanism 12 of the above-mentioned embodiment is provided with the compound planetary gear 30, the ring gear 36 functions as a reaction force element, and reduces the rotation input from the motor shaft 16 to the sun gear 32 at a predetermined reduction ratio. However, it is also possible to use a planetary gear type speed reduction mechanism having another structure such as a planetary gear device having a sun gear as a reaction force element.

Further, in the above embodiment, the meshing teeth 24a, 26 are provided.
Although the twisting directions of the meshing teeth 24a and 26a are set in accordance with the main rotation direction of the sun gear 32 so that the thrust forces F _SS and F _RS generated due to the twisting of a face each other, the thrust force F _SS , F _RS may be set outward so that the twisting directions of the meshing teeth 24a and 26a are set.

The compound planetary gear 30 of the above embodiment is
Engaging teeth 24 of large diameter pinion 24 and small diameter pinion 26
Although the twisting directions and leads of a and 26a are made equal to each other, it is also possible to employ a planetary gear type speed reducing mechanism having a compound planetary gear having different twisting directions and leads.

Although not illustrated one by one, the present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a power transmission device for an electric vehicle that is an embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship around a center line O of a compound planetary gear of a reduction mechanism and a drive-side bevel gear of a differential mechanism in the power transmission system of FIG.

FIG. 3 is a diagram illustrating a schematic shape of meshing teeth of a compound planetary gear of a planetary gear type speed reduction mechanism in the power transmission device of FIG. 1.

FIG. 4 is a diagram showing forces acting in a direction toward an axis and an axial direction acting on each pinion of the compound planetary gear of the planetary gear type speed reduction mechanism in the power transmission system of FIG. 1.

5 is a diagram for explaining the relationship between the lead L of each pinion of the compound planetary gear of the planetary gear type reduction mechanism in the power transmission mechanism of FIG. 1, the twist angles β _S , β _R, and the radii r _S , r _R. .

[Explanation of symbols]

 10: Power transmission device for electric vehicle 12: Planetary gear type speed reduction mechanism 14: Bevel gear type differential mechanism 18, 20: Output member 22: Carrier 30: Compound planetary gear (planetary gear) 38: Differential case part (differential case) 54: Drive side bevel gear O: One center line

Front page continued (72) Inventor Takeji Koide 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Yoshihiko Sasaki 10 Takane, Fujii Town, Aichi Prefecture Aisin AW Co., Ltd. Within

Claims (1)

[Claims] 1. A rotation transmitted from an electric motor, comprising a carrier provided with a plurality of planetary gears rotatably around an axis substantially parallel to one center line at substantially equal angular intervals around the one center line. A planetary gear type speed reducing mechanism for decelerating and outputting from the carrier, and a differential case which is concentrically and integrally provided with the carrier and is integrally rotated with the carrier, thereby an axis substantially orthogonal to the one center line. A bevel gear type that rotatably drives a pair of output members arranged on the one center line via a plurality of drive-side bevel gears rotatably arranged around the center in the differential case at substantially equal angular intervals. In a power transmission device for an electric vehicle including a differential mechanism, one of the planetary gears and the drive-side bevel gear is arranged to be about several other than one of the other, and both gears are arranged. Place it up to the center line. Rinioite set so as not to overlap each other, the reduction mechanism and the differential mechanism and the electric vehicle power transmission device, wherein a was placed in overlap on the one center line direction.