JP3473058B2 - Traveling motor for electric vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As a conventional arrangement of the traveling motors of an electric vehicle, as shown in JP-A-2-133007, a system in which traveling motors are arranged independently for each wheel, a pair of traveling wheels for either the front wheels or the rear wheels 51 is used. Method of arranging the motor 52 (Fig. 1
2), the single traveling motor 52 is connected to the propeller shaft 5
A method of connecting either the front wheel or the rear wheel 51 via the gear 5 and the differential gear 54 (see FIG. 13) has been proposed.

[0003]

In order to put the electric vehicle into practical use, it is necessary to effectively use battery power, and for that reason, it is extremely important to reduce the weight of the vehicle body. However, in the method of individually driving the wheels 51 by the independent traveling motors, many traveling motors and the inverter 53 for controlling the traveling motors are required, and the burden is heavy in terms of weight, space, and cost.

In the traveling drive system shown in FIG. 13, although the traveling motor 52 can be unified, the weight of the propeller shaft 55 and the differential gear 54 and the burden of space are newly generated.
The weight of the vehicle body also increases, and the power consumption of the battery also increases. Further, since the number of bearings in each part increases, an increase in friction loss cannot be ignored in terms of battery power consumption. The present invention has been made in view of the above problems, and an object of the present invention is to provide a traveling motor for an electric vehicle that can realize a traveling drive system that can be significantly reduced in size and weight as compared with the related art.

[0005]

A traveling motor for an electric vehicle according to claim 1 of the present invention includes a stator fixed to a frame and a hollow cylindrical rotor rotatably supported by the frame and rotated by the stator. And is rotatably supported by the frame or the rotor and formed inside the rotor.
A pair of output shafts each one is fitted to made a space to the rotor coaxially protrudes axially opposite direction, the rotor inner
A differential small gear rotatably supported by the rotor about an axis extending in the radial direction of the rotor in a space formed in the space, and the differential small gears arranged at the other ends of the output shaft pairs. The rotor includes a differential gear that meshes with a gear, and the rotor has an outer peripheral portion rotatably supported by the frame via a bearing.

According to a second aspect of the present invention, there is provided a traveling motor for an electric vehicle, which has a cylindrical rotor rotatably supported by a frame and rotated by the stator, and a rotatably supported by the frame or the rotor. A pair of output shafts, each of which is coaxially fitted in the rotor and has one end protruding in the axially opposite direction, and the output is provided on the outer circumference of the other end of one of the pair of output shafts. A pair of planetary gears, which are rotatably supported about an axis in the same direction as the axis of the shaft and mesh with each other, are arranged, and at the other end of the other output shaft of the pair of output shafts, A sun gear, which has the same axial center as the output shaft and is fixed to the output shaft, is arranged to mesh with one of the pair of planetary gears. The other of the planetary gears And gears provided among meshing with the gear, the rotor is characterized in that its outer periphery is rotatably supported on the frame via a bearing.

A traveling motor for an electric vehicle according to claim 3 of the present invention is characterized in that a rotor bearing portion has a small outer diameter. A traveling motor for an electric vehicle according to claim 4 of the present invention is characterized in that the rotor bearing portion is provided separately from the stator facing portion.

[0008]

In the traveling motor according to claim 1 of the present invention, the differential small gear that rotates together with the rotor and is rotatably supported by the rotor meshes with the large differential gear to form a pair of output shafts. To drive. When the load torque between both output shafts becomes different due to the difference in the rotational speeds of the inner and outer wheels as the vehicle turns, the small differential gears rotate, which causes the rotational speeds of the large differential gears, that is, the rotational speeds of both output shafts. Difference occurs.

In the traveling motor according to claim 2 of the present invention, the rotation of the rotor is transmitted to the one output shaft via the internal gear and the other planetary gear, and in addition to the both gears, the one planetary gear and the sun gear. The rotation of the rotor is transmitted to the other output shaft via the gear, and the pair of output shafts are driven. When the load torque between both output shafts differs due to the difference in the rotational speeds of the inner and outer wheels as the vehicle turns, when the torque of one output shaft increases, the revolution force of the planetary gears decreases and the rotation force increases. Then, when the rotational speed difference between the pair of output shafts is absorbed and the torque of the other output shaft increases, the rotation force of the planetary gears decreases,
The revolution force increases and the difference in the number of revolutions between the pair of output shafts is absorbed.

In each of the traveling motors according to claims 1 and 2, since the differential gear is built in the hollow cylindrical rotor, the traveling drive system of the electric vehicle is constituted by a single motor. Therefore, it is possible to realize much smaller size and lighter weight than before, and it is possible to save electric power required for traveling. Also, since the differential gear is housed in the frame of the motor,
Since a bearing such as a propeller shaft is not required, the bearing portion that causes friction loss can be reduced, and the electric power required for traveling can be saved.

Further, since the rotor is rotatably supported by the frame at the outer peripheral portion thereof, the rotor can be formed in a hollow cylindrical shape, the weight can be reduced, and the space formed inside the rotor can be utilized. The differential small gear and the large gear can be easily arranged. In the traveling motor according to claim 3 of the present invention, the diameter of the bearing can be reduced, the peripheral speed thereof can be reduced, heat generation can be suppressed, and a long life can be achieved.

In the traveling motor according to claim 4 of the present invention, since the rotor is composed of the bearing portion and the stator facing portion, each has a simple shape, is easy to mold, and is assembled in the rotor. Easy assembly of differential gears, shafts, bearings, etc.

[0013]

FIG. 1 shows an example of a traveling drive system for an electric vehicle according to the present invention. Reference numeral 50 is a traveling motor with a built-in differential gear, and a rear wheel 51 is attached to an output shaft pair protruding left and right from the motor 50. Reference numeral 53 is an inverter that controls the motor 50.

2 to 4 are sectional views of the motor 50. FIG. 2 is a sectional view taken along the line AA in FIG. 3, and FIG. 3 is a sectional view taken along the line BB in FIG. Fig. 4 and Fig. 4 are C- in Fig. 3.
A sectional view along line C is shown. A description will be given below based on these drawings. The bowl-shaped casings 10 and 11 are put together and fastened with long bolts (not shown) to form a closed cylindrical space inside. A stator core 1 is fitted in the central portion of the inner peripheral surface of the peripheral walls of the casings 10 and 11, and a stator winding is wound around the stator core 1 to form a stator. The end walls of both casings 10 and 11 rotatably support a cylindrical rotor 4 having openings at both ends through a bearing 15. A plurality of rotors 4 have a plurality of magnetic poles facing the stator core 1 on the outer peripheral surface thereof. The permanent magnets 5 are fixed at equal intervals in the circumferential direction and with alternating polarities. A rotation detector 6 for detecting rotation of the rotor 4 is provided on the end wall of the casing 10.
Is provided.

The central portions of the end walls of both casings 10 and 11 are
The output shafts 26 and 27 are individually supported through the bearing 16, and the inner ends of the output shafts 26 and 27 are rotors 4 made of soft iron.
They face each other with a small space inside. A stay 20 is fixed to the inner peripheral surface of the rotor 4 in the axial center by bolts 30. The stay 20 is a bearing member in which four leg portions 20a project outward in the radial direction.
It is fixed to the rotor 4 by 0. A shaft hole 20b provided in the central portion of the stay 20 rotatably hinders the inner end portions of both output shafts 26 and 27 via the bearing metal 18. The stay 20 is formed with a pair of holes 20c that open in the radial direction, and a pair of pins 21 are press-fitted and fixed in both holes 20c. Both pins 21 rotatably and individually support a pair of differential pinion gears 25, which are bevel gears, via a bearing metal 17.

On the other hand, differential gears 28, 29 are formed at the inner ends of both output shafts 26, 27 at a small distance from the stay 20, and the differential gears 28, 29 are differential gears. 25
And forms a differential gear. The operation of this device will be described below. The stator coil 2 (here, a three-phase winding) of this traveling motor 50, which is a permanent field type synchronous motor, is energized from an inverter (not shown). This inverter determines a three-phase stator voltage waveform according to the angular relationship between the permanent magnet 5 and the stator coil 2 based on the angle signal input from the rotation detector 6 which is a rotary encoder, and determines this three-phase stator voltage. Stator coil 2
Apply to. As a result, a rotating magnetic field is generated in the stator coil 2 and the rotor 4 rotates.

The stay 20 and the differential small gear 25 are rotated by the rotation of the rotor 4, and the differential large gears 28 and 29 are also rotated by being driven by the differential small gear 25. The output shafts 26 and 27 are rotated, and the rear wheel pair 51 is rotated. Here, when the load torques applied to the output shafts 26 and 27 are different, such as during turning, the small differential gear 25 rotates on the basis of the difference torque, which causes the rotational speeds of the large differential gears 28 and 29 to change. A difference occurs and the turning performance of the vehicle is improved.

The traveling motor 50 of this embodiment described above
Since the traveling drive system can be configured with a single traveling motor and inverter, the configuration can be simplified, the number of parts can be reduced, and the weight and size can be reduced. It is possible to reduce the number of bearings, reduce the power consumption of the electric vehicle, and extend the mileage.

(Second Embodiment) A second embodiment is shown in FIGS. This embodiment employs a squirrel-cage induction motor type, in which the laminated core 3 is fitted and fixed to the rotor 4, and the conductor rod 35 is fitted in the slot of the laminated core 3 to form the conductor rod 3.
Both ends of 5 are short-circuited by a short-circuit ring 36.

The motor system of the above embodiment can of course be replaced with another system. (Third Embodiment) A third embodiment is shown in FIGS. This embodiment differs from the first and second embodiments in that the rotor 4 has a stepped cylindrical shape having small diameter portions 41 at both ends. The small-diameter portion 41 is formed separately from the portion of the rotor 4 where the permanent magnets are arranged, and these are joined by the bolts 14. These connections are achieved after assembling the stay 20 and the like in the rotor. In the first and second embodiments, the bearings 15 and 16 are fitted to the frames 10 and 11, but in the present embodiment, the bearing 15 is fitted to the frames 10 and 11, and the bearing 16 is fitted to the rotor 4. ing. The same components as those in the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted.

The above-mentioned structure is superior to the first and second embodiments in the following points. That is, according to the present invention, the outer diameter of the rotor 4 is large because the differential gear mechanism is arranged inside the rotor 4. In the first and second embodiments, the outer diameter position is substantially the same as the outer diameter of the rotor 4. Since the bearing 15 is arranged, the bearing 1
The peripheral speed of No. 5 becomes faster, and a problem that heat is easily generated occurs. On the other hand, in the third embodiment, since the bearing 15 is arranged in the small diameter portion 41 of the rotor 4, the outer diameter of the bearing 15 can be reduced and the peripheral speed can be reduced. Further, by disposing the bearing 16 inside the small-diameter portion 41 instead of the frames 10 and 11, there is no possibility of increasing the axial dimension. Further, since the space S1 for housing the differential gear mechanism and the space S2 for housing the stator 1 are separated, it is possible to prevent the lubricating oil of the differential gear mechanism from leaking to the stator 1 side. In particular, the example shown in FIG. 10 and FIG.
Pin (shaft) that rotatably supports the differential small gear 25
The fixing of the differential small gear 25 to the rotor 4 is achieved by the reference numeral 21, and the number of parts is reduced as compared with the other embodiments described above, the arm portion 20b is unnecessary, and the assembling property is excellent. This structure can also be applied to the other embodiments described above.

(Fourth Embodiment) A fourth embodiment will be described with reference to FIGS.
5 shows. The same parts as those in the first to third embodiments are designated by the same reference numerals, and the description thereof will be omitted. The differential gear of the fourth embodiment is an internal gear 4-a and gears 24, 25, 27.
-A. The internal gear 4-a is integrally formed inside the rotor 4. The gears 24 and 25 are rotatably fixed to the output shaft carrier 26-a of the output shaft 26 by pins 20 and 21, respectively. Gears 24 and 25
Are arranged so as to mesh with. The gear 24 meshes with the internal gear 4-a, and the gear 25 meshes with the gear 27-a.

A sun gear 30 is fixed to one ends of the output shafts 26 and 27 via splines 26-b and 27-b, respectively, and the output shafts 26 and 27 are rotated via a planetary gear 31 and an internal gear 32. Is decelerated and transmitted to the vehicle shaft 40. The operation of the differential gear having the above configuration will be described with reference to FIGS. In FIG. 14, a, b ₂ ,
b ₃ and c are internal gear 4-a, gears 24 and 25, respectively.
27-a is shown. Now a is 'receives a reaction force of _1, and b ₂ is f gives the power of f ₃ to b _3' when f turn the b ₂ in f ₂ receives a reaction force of _2, b ₃ is the f ₄ to c It receives a reaction force of f _'3 empowering. At this time, the force that the carrier 26-a receives is the pins 20, 2
It is considered as the total force of the forces applied to 1, and it is shown in FIG.
Here, F ₂ is the resultant force applied to the pin 20, F ₃ is the resultant force applied to the pin 21, and it is the tangential components F _2r and F _3r that contribute to the torque. here,

[0024]

[ _Equation 1] If the sizes of the gears 24, 25, 27-a are set so that F _2r · r ₂ −F _3r · r ₁ = f ₄ · _r , the torques applied to the shafts 26, 27 become equal and the differential Function as. If the rotations of the shafts 26 and 27 are not equal, such as when turning, the gears 24 and 25 can rotate to absorb the difference in rotation speed.

With the above structure, the traveling motor 52 is
Since the traveling drive system can be configured by the traveling motor and the inverter, the configuration can be simplified, the number of parts can be reduced, and the weight and size can be reduced. Further, since the output of the motor is decelerated and transmitted to the vehicle shaft, the torque of the motor can be reduced, the motor can be downsized, and the torque of the differential gear portion can also be reduced. Therefore, the differential gear can be downsized, and an extremely small differential built-in motor can be obtained.

(Fifth Embodiment) A fifth embodiment will be described with reference to FIGS.
8 shows. The same parts as those in the first to fourth embodiments are designated by the same reference numerals, and the description thereof will be omitted. In this fifth embodiment, the planetary gear type speed reduction mechanism shown in the fourth embodiment is applied to the basic structure of the second embodiment.

According to this structure, as described above, an extremely small differential built-in motor can be obtained. Further, FIG. 17 shows an example in which two reduction gears are provided to further reduce the size. In FIG. 18, a constant velocity joint 61 is provided on the output shaft of the reduction mechanism. 6
1-a is the outer race, 61-b is the inner race,
61-c is a steel ball, and 62 is a vehicle shaft.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a traveling drive system of an electric vehicle of the present invention.

FIG. 2 is a cross-sectional view of the traveling motor of the first embodiment.

FIG. 3 is a sectional view of a rotor of the traveling motor according to the first embodiment.

FIG. 4 is a sectional view of the traveling motor of the first embodiment.

FIG. 5 is a sectional view of a traveling motor according to a second embodiment.

FIG. 6 is a sectional view of a rotor of a traveling motor according to a second embodiment.

FIG. 7 is a sectional view of a traveling motor according to a second embodiment.

FIG. 8 is a sectional view of a traveling motor according to a third embodiment.

FIG. 9 is a sectional view of a rotor of a traveling motor according to a third embodiment.

FIG. 10 is a sectional view of a traveling motor according to a third embodiment.

FIG. 11 is a sectional view of a rotor of a traveling motor according to a third embodiment.

FIG. 12 is a sectional view of a traveling motor according to a fourth embodiment.

FIG. 13 is a sectional view of a rotor of a traveling motor according to a fourth embodiment.

FIG. 14 is a diagram for explaining the operation of the fourth embodiment.

FIG. 15 is a diagram for explaining the operation of the fourth embodiment.

FIG. 16 is a sectional view of a traveling motor according to a fifth embodiment.

FIG. 17 is a sectional view of a modified example of the traveling motor of the fifth embodiment.

FIG. 18 is a cross-sectional view of a modified example of the traveling motor of the fifth embodiment.

FIG. 19 is a schematic plan view showing a traveling drive system of a conventional electric vehicle.

FIG. 20 is a schematic plan view showing a traveling drive system of a conventional electric vehicle.

[Explanation of symbols]

1 stator 4 rotor 10, 11 frames 25 differential small gear 26, 27 Output shaft 28, 29 Differential gear.

Claims (4)

(57) [Claims] 1. A a stator fixed to the frame, a hollow cylindrical rotor which is rotated by the rotatably supported by the stator frame, before being rotatably supported on the frame or the rotor
A pair of output shafts that are fitted coaxially with the rotor in the space formed inside the rotor and have one end protruding in the axial opposite direction, and a shaft that extends in the radial direction of the rotor in the space formed inside the rotor. A differential small gear that is rotatably supported by the rotor about its center; and a large differential gear that is disposed at each other end of the output shaft pair and that meshes with the differential small gear. Is a traveling motor of an electric vehicle, the outer peripheral portion of which is rotatably supported by the frame via a bearing. 2. A stator fixed to a frame, a cylindrical rotor rotatably supported by the frame and rotated by the stator, and a rotor rotatably supported by the frame or the rotor in the rotor. And a pair of output shafts each of which is fitted coaxially with each of the output shafts and has one end protruding in a direction opposite to the axial direction, and the output shaft has an axial center on the outer periphery of the other end of one of the pair of output shafts. A pair of planetary gears, which are rotatably supported about an axis in the same direction and mesh with each other, are arranged, and the other end of the other output shaft of the pair of output shafts has the other end of the pair of planetary gears. Among the pair of planetary gears, the sun gear, which meshes with one of the gears, has the same shaft center as the output shaft, and is fixed to the output shaft is arranged. Biting on the other gear And gears provided among fit, the rotor is an electric vehicle travel motor, characterized in that the outer peripheral portion is rotatably supported on the frame via a bearing. 3. The rotor according to claim 1, wherein a portion of the rotor supported by the bearing has a smaller diameter than a portion of the rotor facing the stator. Electric motor drive motor. 4. A portion of the rotor that is supported by the bearing is formed separately from a portion that faces the stator, and both are coupled by a coupling means. 3. A traveling motor for an electric vehicle according to item 3.