JP2003199289A - Motor-driven wheel drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a structure and reduce a cost by eliminating the need for synchronous controls or the like of both wheels by incorporating an electric motor into either of a pair of right and left wheels. <P>SOLUTION: The pair of right and left wheels 51, 52 are installed on both end of an axle 50: the electric motor 5 and a first wedge roller type change gear 6 which has a one-way clutch function are incorporated into the wheel 51; and a second wedge roller type change gear 6a, which is not incorporated with an electric motor, has a one-way clutch function, and has the reverse rotative direction relative to the wedge roller type change gear 6, is incorporated into the other wheel 52. A transmission shaft 53 that transmits a drive force to the second wedge roller type change gear 6a of the other wheel 52 from the electric motor 5 of the wheel 51 is incorporated into the axle 50. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The electric wheel drive system of the present invention is used in four-wheeled vehicles, two-wheeled vehicles, golf carts or three-wheeled or four-wheeled carts for the elderly and disabled, construction sites and the transportation industry. It is used when various vehicles such as a hand-held unicycle or a four-wheeled vehicle are electrically driven (including a case where auxiliary power is electrically applied).

[0002]

2. Description of the Related Art As a drive device for an electric vehicle, there is an electric wheel drive device in which an electric motor is installed on the inner diameter side of a wheel and the driving force of the electric motor is transmitted to the wheel. It is conventionally known as described in Japanese Patent Laid-Open No. 9-23631. In the structure disclosed in Japanese Patent Laid-Open No. 7-131961, the wheel is directly driven by an electric motor (without a transmission). On the other hand, in the case of the structure disclosed in Japanese Patent Laid-Open No. 9-23631, the driving force of the electric motor is transmitted to the wheels via the multi-stage gear type transmission.

[0003]

In the conventional electric wheel drive device as described above, a pair of left and right wheels are equipped with a pair of electric motors, respectively, and a driving force is applied to each wheel.

However, the pair of left and right wheels respectively have
If a pair of electric motors is incorporated, both electric motors must be driven in proper synchronization, and if the synchronization is improper, the vehicle may inadvertently turn. Also, in order to synchronize both electric motors, it is necessary to match the respective rotation speeds and torques,
It is necessary to take measures such as the sensor, the control circuit, the control software wafer, etc., including the individual difference of the electric motor, which may lead to the cost increase. Further, when the vehicle travels on a curve, the rotational speeds of the left and right wheels are different due to the difference in the inner wheels, which may make the control more difficult.

The present invention has been made in view of the above-mentioned circumstances, and by incorporating an electric motor in only one of a pair of left and right wheels, synchronization control and the like are not required, and the structure is improved. It is an object of the present invention to provide an electric wheel drive device that simplifies and reduces costs.

[0006]

In order to achieve the above object, an electric wheel drive device according to the present invention is an electric wheel drive device having a pair of left and right wheels, wherein one wheel has a one-way clutch. A first transmission having a function,
An electric motor for giving a driving force is incorporated, and a second transmission having a one-way clutch function whose rotation direction is opposite to that of the first transmission is incorporated in the other wheel, and the electric motor drives the second transmission. It is characterized by having a transmission means for transmitting the driving force to the machine.

Further, in the electric wheel drive device according to the present invention, the first transmission and the second transmission are provided around the tip of a rotary drive shaft driven by an electric motor. Between the outer ring rotatably provided with the wheel in an eccentric state with respect to the wheel, the drive side cylindrical surface that is the outer peripheral surface of the rotary drive shaft, and the driven side cylindrical surface that is the inner peripheral surface of the outer ring. At least one guide roller and at least one movable roller, each outer peripheral surface of which is present in the annular space whose width in the radial direction is different in the circumferential direction and which is a cylindrical surface for power transmission. Preferably, the friction roller type transmission utilizing the wedge action is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An electric wheel drive device according to an embodiment of the present invention will be described below with reference to the drawings. First, the internal structure of the electric wheel drive device common to the respective embodiments will be described in detail, and then the first embodiment and the second embodiment.
An embodiment will be described.

(Internal Structure of Electric Wheel Drive Device) FIG.
FIG. 3 is a cross-sectional view showing the internal structure of the electric wheel drive device according to the embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA of FIG.

The electric wheel drive system according to the embodiment of the present invention includes a wheel 3 formed by supporting a tire 2 around the wheel 1, and an inner diameter side of the wheel 1 for rotationally driving the wheel 3. And a drive means provided in the. The drive means is supported by a suspension device (not shown), and the wheel 1 is rotatably supported around the drive means, so that the wheel 3 is rotatably supported by the suspension device. In the illustrated example, a support cylinder portion for supporting and fixing a braking rotary member such as a disk rotor to the inner end portion of the wheel 1 (the end portion near the center in the vehicle width direction, which is the left end portion in FIG. 1). 4 is provided.

The drive means comprises an electric motor 5 and a friction roller type transmission 6 utilizing a wedge action (hereinafter referred to as a wedge roller type transmission 6) connected in series in the power transmission direction. Here, the friction roller type transmission utilizing the wedge action is rotatably provided with the wheel around the tip of a rotary drive shaft driven by an electric motor in a state of being eccentric to the rotary drive shaft. Outer ring,
An annular space that exists between the drive-side cylindrical surface that is the outer peripheral surface of the rotary drive shaft and the driven-side cylindrical surface that is the inner peripheral surface of the outer ring, and that has a radial width that is different in the circumferential direction. And at least one guide roller, each outer peripheral surface of which is a cylindrical surface for power transmission,
It refers to a transmission equipped with individual movable rollers. The movable roller is a roller that generates a pressing force by a wedge action, and is a roller that moves in the radial direction and the circumferential direction. The electric motor 5 has a bottomed cylindrical motor case 7. The motor case 7 has a base end (see FIG.
A bottomed cylindrical main body 9 having a bottom plate portion 8 at the left end portion of
The main body 9 is combined with a lid plate 10 which is attached and fixed to the opening (the right end in FIG. 1) of the main body 9. The peripheral wall portion 1 of this main body 9
The central axis of the outer peripheral surface and the central axis of the inner peripheral surface of 1 are made eccentric to each other, and the wall thickness of this peripheral wall portion 11 is made unequal in the circumferential direction. A screw hole (not shown) is formed at a plurality of base end surfaces of the main body 9 as described above, and a plurality of bolts (not shown) through which constituent components of a suspension device (not shown) are inserted are also provided in the screw holes (not shown). ) And further tightening, the main body 9 can be connected and fixed to the suspension device. Further, on one surface (left surface in FIG. 1) of the cover plate 10, there is formed an annular projection 13 which can be fitted into the front end opening of the main body 9 without rattling. The center of the annular projection 13 and the center of the outer peripheral surface of the lid plate 10 are eccentric to each other in accordance with the eccentricity of the outer peripheral surface and the inner peripheral surface of the peripheral wall portion 11. Such a cover plate 10 is attached to the front end opening of the main body 9 with the annular projection 13 fitted in the front end opening of the main body 9 and further attached to the main body 9 by a plurality of screws 14. On the other hand, it is fixed by binding.

In this way, the support hole 15 and the through hole 16 are concentrically provided at both ends of the motor case 7, which is formed by connecting and fixing the main body 9 and the cover plate 10 to each other. It is formed concentrically with the inner peripheral surface of the peripheral wall portion 11. Then, inside the support hole 15 and the through hole 16,
A base end portion (left end portion in FIG. 1) and an intermediate portion front end portion (right side in FIG. 1) of the rotary drive shaft 17 constituting the electric motor 5 are arranged.
Each part is rotatably supported. this house,
Inside the support hole 15 provided in the central portion of the bottom plate portion 8 of the main body 9, the base end portion of the rotary drive shaft 17 is provided with a load in both radial and axial directions such as a deep groove type or angular type ball bearing. Is rotatably supported by a rolling bearing 18 which can be supported. On the other hand, inside the through hole 16 provided in the central portion of the lid plate 10, the portion near the tip of the intermediate portion of the rotary drive shaft 17 is provided with a radial, such as a deep groove type or angular type ball bearing. It is rotatably supported by a rolling bearing 19 which can support loads in both axial directions.

In this way, a permanent magnet or the like is formed between the pair of rolling bearings 18 and 19 at the intermediate portion of the rotary drive shaft 17 rotatably supported by the motor case 7. The rotor 20 is externally fitted and supported while being prevented from rotating with respect to the rotary drive shaft 17. On the other hand, a stator 21 is supported and fixed to a portion of the inner peripheral surface of the peripheral wall portion 11 facing the outer peripheral surface of the rotor 20. Then, conducting wires 23, 23 for energizing the stator 21 and for extracting a signal of the sensor 22 for detecting the phase of the rotor 20 are provided through a lead-out hole 24 formed in a part of the bottom plate portion 8. It is taken out.

An annular convex portion 25 is formed in the central portion of the other surface (right surface in FIG. 1) of the lid plate 10 surrounding the through hole 16, and the tip end surface of the annular convex portion 25 is The connecting plate 26 is coupled and fixed. Of the two side surfaces of the connecting plate 26, projections 27, 27 are provided at three circumferential positions on one surface (left surface in FIG. 1) facing the annular convex portion 25.
It is formed so as to project toward the same amount. The connecting plate 26 is fixed to the cover plate 10 with three bolts 28, 28 in a state where the tip surfaces of the protrusions 27, 27 and the tip surface of the annular convex portion 25 are in contact with each other. is doing. In the illustrated example, a cage fitting portion is provided between the outer peripheral edge portion of each of the protrusions 27, 27 and the outer peripheral edge portion of the annular convex portion 25, so that the connecting plate 26 with respect to the lid plate 10 is connected. Positioning in the radial direction is achieved. In this manner, with the connecting plate 26 fixedly connected to the cover plate 10, the protrusions 27, 27 at the three positions cover the periphery of the tip of the rotary drive shaft 17. Further, the tip of the rotary drive shaft 17 has a recessed hole 2 formed at the center of one surface of the connecting plate 26.
9 is in a loosely invaded state.

The other surface of the connecting plate 26 (right surface in FIG. 1)
A support shaft 30 is provided at the central portion so as to project to the side opposite to the cover plate 10. Further, a deep groove type or angular type ball bearing provided between the outer peripheral surface of the support shaft 30 and the outer peripheral surface of the tip portion of the main body 9 of the motor case 7 and two positions on the inner peripheral surface of the wheel 1. Rolling bearing 3 that can support both radial and axial loads such as
The wheel 1 is rotatably supported by a suspension device (not shown) by 1a and 31b. In this state, the wheel 1 is arranged concentrically with the outer peripheral surface of the main body 9.
Therefore, the wheel 1 and the inner peripheral surface of the main body 9 are eccentric to each other.

The wedge roller is rotatably supported with respect to the main body 9 in such a positional relationship, and is located at a portion of the inner peripheral surface of the intermediate portion of the wheel 1 located around the tip of the rotary drive shaft 17. Outer ring 3 for constituting the variable speed transmission 6
2 are arranged. For this reason, in the case of this example, the retaining ring 33 fitted in the intermediate portion of the wheel 1 is coupled and fixed to the wheel 1 by a plurality of bolts 34, 34, and at the inner diameter side of the retaining ring 33. The spline-engaged outer ring 32 is held at a predetermined position shown in FIG. 1 by a retaining ring 35. The splines that engage the retaining ring 33 and the outer ring 32 are provided with sufficient play so that the outer ring 32 can freely move in the radial direction relative to the retaining ring 33 by the amount of play of the splines. This allows manufacturing errors and deformation of parts during operation. In this state, the inner peripheral surface of the outer ring 32 is substantially concentric with the wheel 1, and is eccentric from the outer peripheral surface of the rotary drive shaft 17. Therefore, between the inner peripheral surface of the outer ring 32 and the outer peripheral surface of the distal end portion of the rotary drive shaft 17, there is provided an annular space 36 having a radial width that is not uniform in the circumferential direction.

The wedge roller type transmission 6 is constructed by installing two guide rollers 37a, 37b and one movable roller 38 in such an annular space 36.
In the figure, the movable roller 38 is partially cut away and is shown. In order to install each of these rollers 37a, 37b, 38, three support shafts 39a,
39a and 39b are provided. These three support shafts 39
Of the a, 39a and 39b, two support shafts 39a and 39a located on the lower right side of FIGS. 1 and 2 and the upper right side of FIG. 2 have both ends formed on the cover plate 10 and the connecting plate 26, respectively. It is press-fitted and fixed in the fitting holes 40, 40. Therefore,
The two support shafts 39a, 39a are connected to each other by the annular space 36.
It does not move in the circumferential or diametrical direction. On the other hand, of the three support shafts 39a, 39a, 39b, the remaining one support shaft 39b located on the upper left side of FIG.
Supports both ends of the outer ring 32 with respect to the cover plate 10 and the connecting plate 26 so as to be slightly displaceable in the circumferential direction and the diametrical direction. For this reason, a support hole 41 having an inner diameter larger than the outer diameter of the support shaft 39b is formed in a portion of the lid plate 10 and a part of the connecting plate 26 aligned with both ends of the one support shaft 39b. The both ends of the support shaft 39b are loosely engaged with the respective support holes 41.

Then, each support shaft 39 supported as described above.
The guide rollers 37a, 37b and the movable roller 38 are rotatably supported by bearings such as radial needle bearings 42, 42 (the bearings of the movable roller are not shown) around the intermediate portions of a, 39a, 39b. is doing. In order to connect and fix the connecting plate 26 to the lid plate 10, each of the protrusions 2 provided on one surface of the connecting plate 26 in a protruding manner.
7, 27 are present between the guide rollers 37a, 37b and the movable rollers 38 in the circumferential direction of the connecting plate 26. In other words, the protrusions 27, 27 and the guide rollers 37a, 3 are provided in the annular space 36.
7b or movable rollers 38 are alternately present in the circumferential direction of the annular space 36. Further, the outer peripheral surface of each of the guide rollers 37a and 37b or the movable roller 38 and the circumferential side surface of each of the protrusions 27 and 27 do not interfere (rub) with each other.

In this way, the support shafts 39a, 39 are formed.
The guide rollers 37a and 37b are rotatably supported between the cover plate 10 and the connecting plate 26 by a and 39b.
And the cylindrical surfaces 43a, 43a, 43b for power transmission, which are the outer peripheral surfaces of the movable roller 38, respectively.
The drive-side cylindrical surface 44, which is the outer peripheral surface of the distal end of the outer ring 7, and the driven-side cylindrical surface 45, which is the inner peripheral surface of the outer ring 32, are in contact with each other. As described above, each of the guide rollers 37a, 37
The radial width of the annular space 36 in which b and the movable roller 38 are installed is not uniform in the circumferential direction. In this way, the outer diameters of the guide rollers 37a, 37b and the movable roller 38 are made different by the amount of making the width of the annular space 36 unequal in the circumferential direction. That is, of the guide rollers 37a, 37b and the movable roller 38, the movable roller 3 located on the side where the tip of the rotary drive shaft 17 is eccentric with respect to the outer ring 32 (upper side in FIGS. 1 and 2).
8 and the guide roller 37b have the same outer diameter and a relatively small outer diameter. On the other hand, the outer ring 3
The guide roller 37a located on the opposite side (lower side in FIGS. 1 and 2) from the tip of the rotary drive shaft 17 being eccentric with respect to 2.
The outer diameter of the movable roller 38 and the guide roller 37b.
Larger than the outer diameter of. The power transmission cylindrical surfaces 43a, 43a, 43b, which are the outer peripheral surfaces of the guide rollers 37a, 37b and the movable roller 38, are brought into contact with the driving-side and driven-side cylindrical surfaces 44, 45, respectively. .

Among the guide rollers 37a, 37b and the movable roller 38, the guide rollers 37a, 37 are used.
Both end portions of the support shafts 39a, 39a supporting the b are connected to the lid plate 10 and the connecting plate 26 (the annular space 3) as described above.
Fixed (in 6). On the other hand, the support shaft 39b supporting the movable roller 38 is slightly displaced in the circumferential direction and the diametrical direction with respect to the cover plate 10 and the connecting plate 26 (in the annular space 36) as described above. Support is possible. Therefore, the movable roller 38 can also be slightly displaced circumferentially and diametrically within the annular space 36. The support shaft 39b supporting the movable roller 38 is rotatably supported by the support shaft 39b by an elastic material 47 such as a compression spring installed in the cylinder hole 46 of the cover plate 10 and the connecting plate 26. Movable roller 38
Is lightly and elastically pressed to move toward the narrow portion of the annular space 36.

When the wheels are rotationally driven by the electric wheel drive device of the present invention configured as described above, the rotary drive shaft 17 of the electric motor 5 is moved by energizing the electric motor 5 as shown in FIG. Rotate clockwise. The rotation of the rotary drive shaft 17 is transmitted to the outer ring 32 via the guide rollers 37a, 37b and the movable roller 38, and causes the rollers 37a, 37b, 38 to rotate counterclockwise in FIG. Further, these rollers 37a, 37b, 38
2 is transmitted to the outer ring 32, and the outer ring 32 is rotated together with the wheel 1 in the counterclockwise direction in FIG. The transmission of power between the rotary drive shaft 17 and the guide rollers 37a, 37b and the movable roller 38, and the transmission of power between the guide rollers 37a, 37b and the movable roller 38 and the outer ring 32 are both frictional. Since it is performed by power transmission, noise and vibration generated during power transmission are low.

The movable roller 38 is a portion where the width of the annular space 36 is narrow (a central portion in the upper portion of FIG. 2) by a force corresponding to the magnitude of the torque transmitted from the rotary drive shaft 17 to the outer ring 32. Tends to cut into. Therefore, a contact portion between the drive side cylindrical surface 44 which is the outer peripheral surface of the rotary drive shaft 17 and the power transmission cylindrical surface 43a, 43a and 43b which is the outer peripheral surface of the guide rollers 37a and 37b and the movable roller 38, Also, these power transmission cylindrical surfaces 43a, 43
The surface pressure of the contact portion between the a and 43b and the driven-side cylindrical surface 45 that is the inner peripheral surface of the outer ring 32 increases as the torque increases. Conversely, when this torque is small, the surface pressure of each of the contact portions is low. Therefore, the surface pressure of each of these contact portions is set to an appropriate value according to the torque to be transmitted, and the torque can be efficiently transmitted.

That is, the tip of the rotary drive shaft 17 is shown in FIG.
When the outer ring 32 is rotated in the counterclockwise direction by rotating the outer ring 32 in the clockwise direction, the movable roller 38 causes the driving side cylindrical surface 44 and the outer ring 32, which are the outer peripheral surfaces of the tip end portion of the rotary drive shaft 17. From the driven-side cylindrical surface 45, which is the inner peripheral surface, of the annular space 36, a force is applied in the same direction as the pressing force of the elastic material 47, and the annular space 36 moves toward the narrow portion, that is, the center of the upper portion of FIG. Tend to do.

As a result, the power transmission cylindrical surface 43b, which is the outer peripheral surface of the movable roller 38, is replaced by the drive side cylindrical surface 44.
And the driven side cylindrical surface 45 are strongly pressed. And
An inner diameter side contact portion 48 which is a contact portion between the power transmission cylindrical surface 43b and the driving side cylindrical surface 44, and a contact portion between the power transmission cylindrical surface 43b and the driven side cylindrical surface 45. The contact pressure of the outer diameter side contact portion 49 is increased. In this way, both the inner diameter side and outer diameter side contact portions 4 of the movable roller 38 are
When the contact pressures of 8 and 49 become high, the diameter of the rotary drive shaft 17 and the outer ring 32, which are pressed by the power transmission cylindrical surface 43b that is the outer peripheral surface of the movable roller 38, due to elastic deformation and assembly clearance, Slightly displaced in the direction. As a result, the contact pressures of the inner diameter side and outer diameter side contact portions 48 and 49 with respect to the guide rollers 37a and 37b are increased.
Then, based on the frictional engagement between the inner diameter side and outer diameter side contact portions 48 and 49, the rotational force of the tip end portion of the rotary drive shaft 17 is transmitted through the guide rollers 37a and 37b and the movable roller 38. Can be transmitted to the outer ring 32.

As described above, the force for moving the movable roller 38 toward the narrow portion of the annular space 36 is applied from the tip of the rotary drive shaft 17 to the outer ring 32.
Changes according to the magnitude of the rotational driving force transmitted to the. Then, as this force increases, the contact pressure between the inner diameter side and outer diameter side contact portions 48, 49 increases. Therefore, based on such an action, the contact pressure corresponding to the transmitted rotational driving force is automatically selected, and the transmission efficiency of the wedge roller type transmission can be secured.

In the case of this example, the wedge roller type transmission 6
Has a one-way clutch function, and the outer ring 3
When the rotation speed of 2 becomes faster than the rotation speed of the rotary drive shaft 17, that is, the rotation speed of the rotary drive shaft 17 multiplied by the speed ratio of the wedge roller type transmission 6, The connection of the wedge roller type transmission 6 is disconnected. That is, in this case, the movable roller 38 is displaced to the wide side of the annular space 36 (lower left side in FIG. 2) against the elastic force of the elastic material 47. As a result, the contact portions of the inner diameter side and outer diameter side contact portions 48, 49 are reduced or lost, and the rotation of the outer ring 32 is not transmitted to the rotary drive shaft 17. Therefore, the structure of this example is suitable when the wheel 3 is rotationally driven only in one direction.

The gear ratio of the wedge roller type transmission 6 is
It can be arbitrarily adjusted by changing the ratio of the outer diameter of the tip of the rotary drive shaft 17 to the inner diameter of the outer ring 32. Considering the wedge roller type transmission 6 incorporated in the electric wheel drive device for an electric vehicle, the above gear ratio can be set within a range of about 3 to 9. In addition, if a gear ratio of this degree can be obtained, it can be sufficiently dealt with by reducing the outer diameter of the tip end portion of the rotary drive shaft 17, and therefore the wedge roller type can be used as the gear ratio is increased. The transmission 6 does not increase in size. Therefore, as the electric motor 5, a high-speed type and a small size
It is possible to use a lightweight one, and it is possible to reduce the size and weight of the electric wheel drive device as a whole. Therefore, it is possible to facilitate the design of the electric wheel drive device that must be installed in a limited space together with the braking component such as the disk rotor. In addition, when incorporated in a vehicle having a suspension device with a spring, the so-called unsprung load can be reduced, which can contribute to improvement of the traveling performance of the electric vehicle centered on riding comfort and traveling stability. In addition, it is possible to realize an electric wheel drive device that can be configured in a small size and a light weight, can easily obtain sufficient running performance, and generate low noise during operation at low cost.

(First Embodiment) FIG. 3 shows a first embodiment of the present invention.
FIG. 3 is a cross-sectional view of the electric wheel drive device according to the embodiment.
FIG. 4 is a sectional view taken along the line BB of FIG.

In the first embodiment, a pair of left and right wheels 51 and 52 are provided at both ends of the axle 50, and one wheel 51 has an electric motor 5 and a first wedge having a one-way clutch function. Incorporating the roller type transmission 6,
Without incorporating an electric motor in the other wheel 52,
A second friction roller type transmission 6a, which has a one-way clutch function and whose rotation direction is opposite to that of the first wedge roller type transmission 6, is incorporated.

A transmission shaft 53 for transmitting a driving force from the electric motor 5 of one wheel 51 to the second wedge roller type transmission 6a of the other wheel 52 is incorporated in the axle 50.

As described above, according to the first embodiment,
By incorporating the electric motor in only one wheel 52 of the pair of left and right wheels 51, 52, it is possible to eliminate the need for synchronous control and to simplify the structure and reduce the cost. That is, the left and right wheels 51, 5 are driven by one electric motor 5.
Since 2 is driven, it is not necessary to synchronize the electric motor, and the vehicle can be made to travel straight when the vehicle is traveling straight without adding special sensors, control circuits, or control software. In addition, since the first and second wedge roller type transmissions 6 and 6a have a one-way clutch function, when the vehicle travels on a curve, the wedge roller type transmissions on the outside of the curve run idle, so that special control is required. You can smoothly turn the curve without doing.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
FIG. 3 is a cross-sectional view of the electric wheel drive device according to the embodiment.

In the second embodiment, when the distance between the left and right wheels is wide and the transmission shaft 53 is long, the bending of the shaft during manufacturing, the whirling of the shaft during traveling, the resonance, etc. become a problem. 5, the transmission shaft 53
A pair of couplings 54, 54 are interposed between the two. Furthermore, it is more preferable to support the transmission shaft 53 with a bearing 55, set the diameter of the transmission shaft appropriately, and raise the resonance point. Other configurations and the like are similar to those of the first embodiment.

The present invention is not limited to the above-described embodiments, but can be modified in various ways.

[0035]

As described above, according to the present invention,
By incorporating the electric motor in only one of the pair of left and right wheels, it is possible to eliminate the need for synchronous control of both wheels, simplify the structure, and reduce the cost.
That is, since the left and right wheels are driven by one electric motor, it is not necessary to synchronize the electric motors, and no special sensor, control circuit, or control software is added.
When the vehicle travels straight, it is possible to drive the vehicle straight. In addition, since the wedge roller type transmission has a one-way clutch function, when the vehicle travels on a curve,
Since the wedge roller type transmission on the outside of the curve runs idle, the curve can be smoothly turned without any special control.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an internal structure of an electric wheel drive device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view of the electric wheel drive device according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG.

FIG. 5 is a sectional view of an electric wheel drive device according to a second embodiment of the present invention.

[Explanation of symbols]

1 wheel 2 tires Three wheels 4 Support cylinder 5 electric motor 6, 6a Wedge roller type transmission 7 motor case 8 Bottom plate 9 subject 10 Lid plate 11 Peripheral wall 13 Annular protrusion 14 screws 15 Support holes 16 through holes 17 rotary drive shaft 18 Rolling bearing 19 Rolling bearing 20 rotor 21 Stator 22 sensors 23 conductors 24 Outlet hole 25 annular protrusion 26 Connecting plate 27 Projection 28 Volts 29 recess 30 support shaft 31a, 31b Rolling bearing 32 outer ring 33 retaining ring 34 Volts 35 retaining ring 36 annular space 37, 37a, 37b Guide roller 38, 38a, 38b Movable roller 39a, 39b Support shaft 40 fitting hole 41, 41a Support hole 42 radial needle bearing 43 Cylindrical surface for power transmission 44 Drive side cylindrical surface 45 Driven side cylindrical surface 46 Cylinder hole 47 Elastic material 48 Inner diameter side contact part 49 Outer diameter side contact part 50 axles 51,52 wheels 53 transmission shaft 54 Coupling 55 bearings

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3D039 AA01 AA03 AA04 AB01 AC21                       AC33 AC65 AC78 AD23 AD36                 3J051 AA01 BA03 BB08 BC03 BD02                       BE03 FA01                 5H115 PA01 PG04 PG06 PG07 PI16                       PU01 SE08                 5H607 AA11 AA12 BB01 BB07 BB09                       BB14 BB26 CC03 DD08 DD17                       EE23 GG07 GG08                 5H621 GA01 HH01 JK07 JK15 JK19

Claims (2)

[Claims] 1. An electric wheel drive device having a pair of left and right wheels, wherein one wheel has a one-way clutch function.
And a second transmission having a one-way clutch function of which the rotation direction is opposite to that of the first transmission are incorporated in the other wheel. An electric wheel drive device having a transmission means for transmitting a driving force to the second transmission. 2. The first transmission and the second transmission rotate together with the wheels around an end of a rotary drive shaft driven by an electric motor in a state of being eccentric to the rotary drive shaft. The outer ring is freely provided, and is present between the drive-side cylindrical surface that is the outer peripheral surface of the rotary drive shaft and the driven-side cylindrical surface that is the inner peripheral surface of the outer ring, and has a width in the radial direction of the circumference. Friction roller type using a wedge action, which has at least one guide roller and at least one movable roller, each outer peripheral surface of which is arranged in an annular space which is unequal in direction, and which has a cylindrical surface for power transmission. The electric wheel drive device according to claim 1, comprising a transmission.