JP4524536B2 - Electric wheel drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The electric wheel drive device of the present invention is a four-wheeled vehicle, a two-wheeled vehicle, a golf cart, a three-wheeled or four-wheeled cart for elderly people and persons with disabilities, a hand-held unicycle used in the construction site or the transportation industry, or It is used when various vehicles such as four-wheeled vehicles are electrically driven (including the case where auxiliary power is applied by electricity).
[0002]
[Prior art]
As a driving device for an electric vehicle, an electric wheel driving device that incorporates an electric motor on the inner diameter side of a wheel constituting the wheel and transmits the driving force of the electric motor to the wheel is disclosed in Japanese Patent Laid-Open Nos. 7-131961 and 9 As described in Japanese Patent No. -23631, it is conventionally known. Of these, in the case of the structure described in Japanese Patent Laid-Open No. 7-131961, the wheel is directly rotated by an electric motor (without a speed reducer). In contrast, in the case of the structure described in Japanese Patent Laid-Open No. 9-23631, the driving force of the electric motor is configured to be transmitted to the wheel via a multistage gear type reduction gear.
[0003]
[Problems to be solved by the invention]
Among the conventional electric wheel drive devices as described above, in the case of the structure described in JP-A-7-131961, a large output torque is required for the electric motor. A heavy object must be used. For this reason, not only does the cost increase, but it becomes difficult to sufficiently secure the running performance of the electric vehicle. On the other hand, in the case of the structure described in Japanese Patent Laid-Open No. 9-23631, the noise generated at the meshing portion of the gears constituting the gear type reduction gear tends to be large, which is inconvenient for passengers of electric vehicles. It becomes easy to give pleasure.
In view of such circumstances, the present invention has been invented to realize an electric wheel drive device that can be configured in a small size and light weight, can easily obtain sufficient traveling performance, and has low noise generated during driving at low cost. It is.
[0004]
[Means for Solving the Problems]
  The electric wheel driving device of the present invention includes a wheel formed by supporting a tire around the wheel, and driving means provided on the inner diameter side of the wheel for rotationally driving the wheel.
  The driving means is formed by connecting an electric motor and a friction roller type speed reducer in series with each other in the power transmission direction.
  The electric motor has a motor case, and the tip end portion of the rotary drive shaft projects in the axial direction from the end portion of the motor case.
  or,The friction roller type speed reducer includes an outer ring that is provided around the tip of the rotary drive shaft in an eccentric manner with respect to the rotary drive shaft and is rotatable with the wheel, and an outer peripheral surface of the rotary drive shaft. It is arranged in an annular space that exists between a certain driving side cylindrical surface and a driven side cylindrical surface that is the inner circumferential surface of this outer ring, and whose radial width is not the same in the circumferential direction. A cylindrical surface for power transmission is provided with at least one guide roller and at least one wedge roller.
  Further, the motor case is formed by combining a bottomed cylindrical main body having a bottom plate portion at the base end portion and a cover plate fixedly attached to the distal end opening of the main body, and of these cover plates. Has a through hole for inserting a portion closer to the tip of the intermediate portion of the rotary drive shaft. The motor case includes an outer peripheral surface of the support shaft that protrudes on a side surface opposite to the cover plate at the center of the connecting plate that is coupled and fixed to the cover plate in a state of covering the tip of the rotation drive shaft, and the main body. The wheel is rotatably supported by rolling bearings provided between the outer peripheral surface of the front end portion of the wheel and two positions of the inner peripheral surface of the wheel.
[0005]
[Action]
When a wheel is rotationally driven by the electric wheel drive device of the present invention configured as described above, the rotational drive shaft of the electric motor is rotated by energizing the electric motor. The rotation of the rotation drive shaft is transmitted to the outer ring through the guide roller and the wedge roller, and rotates the wheel together with the outer ring. The power transmission between the rotary drive shaft and the guide roller and wedge roller, and the power transmission between the guide roller and wedge roller and the outer ring are all performed by friction transmission, and thus occur during power transmission. Noise and vibration are low. Further, the wedge roller tends to bite into a narrow portion of the annular space with a force corresponding to the magnitude of torque transmitted from the rotary drive shaft to the outer ring. For this reason, the contact portion between the outer peripheral surface of the rotary drive shaft and the outer peripheral surface of the guide roller and wedge roller, and the contact portion between the outer peripheral surface of the guide roller and wedge roller and the inner peripheral surface of the outer ring The surface pressure increases as the torque increases. In other words, when the torque is small, the surface pressure of each contact portion is low. For this reason, the torque transmission of each of these contact portions can be performed efficiently.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show a first example of an embodiment of the present invention. The electric wheel drive device of the present invention includes a wheel 3 formed by supporting a tire 2 around the wheel 1 and a driving means provided on the inner diameter side of the wheel 1 for rotationally driving the wheel 3. . The drive means is supported by a suspension device (not shown), and the wheel 1 is rotatably supported around the drive means, whereby 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 on the inner end portion of the wheel 1 (the end portion closer to the center in the width direction of the vehicle and the left end portion in FIG. 1). 4 is provided.
[0007]
The drive means is formed by connecting an electric motor 5 and a friction roller type speed reducer 6 in series with each other in the power transmission direction. The electric motor 5 has a bottomed cylindrical motor case 7. The motor case 7 has a bottomed cylindrical main body 9 having a bottom plate portion 8 at a base end portion (left end portion in FIG. 1), and a lid fixedly attached to a front end (right end in FIG. 1) opening portion of the main body 9. It is formed by combining with the plate 10. The central axis of the outer peripheral surface of the peripheral wall 11 of the main body 9 and the central axis of the inner peripheral surface are decentered from each other so that the thickness of the peripheral wall 11 is not the same in the circumferential direction. Screw holes 12 are formed at a plurality of positions on the base end surface of the main body 9, and a plurality of bolts (not shown) through which components of a suspension device (not shown) are inserted are screwed into the screw holes 12. The main body 9 can be coupled and fixed to the suspension device by tightening. Further, an annular protrusion 13 is formed on one surface (left surface in FIG. 1) of the lid plate 10 so that it can be fitted to the tip opening of the main body 9 without rattling. The center of the annular protrusion 13 and the center of the outer peripheral surface of the cover 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 protrusion 13 fitted in the front end opening of the main body 9, and is further attached to the main body 9 by a plurality of screws 14. It is fixed to the connection.
[0008]
In this manner, the main body 9 and the lid plate 10 are coupled and fixed to each other. At both ends of the motor case 7, a support hole 15 and a through hole 16 are concentric with each other and the peripheral wall. It is formed concentrically with the inner peripheral surface of the portion 11. And inside the support hole 15 and the through-hole 16, the base end part (left end part of FIG. 1) and the intermediate part front end part (right side of FIG. 1) of the rotary drive shaft 17 that constitutes the electric motor 5, Each is rotatably supported. Among these, inside the support hole 15 provided in the center portion of the bottom plate portion 8 of the main body 9, the base end portion of the rotary drive shaft 17 is arranged in a radial or axial manner such as a deep groove type or an angular type ball bearing. The load in both directions is rotatably supported by a rolling bearing 18 that can be supported. On the other hand, inside the through hole 16 provided in the central portion of the lid plate 10, a portion near the tip of the intermediate portion of the rotary drive shaft 17 is arranged radially, such as a deep groove type or an angular type ball bearing. Axial bi-directional loads are supported rotatably by a bearing 19 that can be supported.
[0009]
In this way, a rotor 20 composed of a permanent magnet or the like is provided between the pair of rolling bearings 18 and 19 at an intermediate portion of the rotary drive shaft 17 rotatably supported by the motor case 7. The outer drive support is carried out in a state in which the rotation with respect to the rotary drive shaft 17 is prevented. 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 that faces the outer peripheral surface of the rotor 20. And through the lead-out hole 24 formed in a part of the said baseplate part 8, the conducting wires 23 and 23 for electrifying this stator 21 or taking out the signal of the sensor 22 for detecting the phase of the said rotor 20 are taken. Take out to the outside.
[0010]
In addition, an annular convex portion 25 is formed in a portion surrounding the through hole 16 at the central portion of the other surface (right surface in FIG. 1) of the lid plate 10, and a connecting plate 26 is formed on the tip surface of the annular convex portion 25. Is fixed. Of the two side surfaces of the connecting plate 26, the protrusions 27 are disposed at three positions in the circumferential direction on one side (the left surface in FIG. 1) facing the annular convex portion 25, and the same amount toward the annular convex portion 25. It is formed in a protruding state. The connecting plate 26 is fixed to the lid plate 10 by three bolts 28 and 28 in a state where the front end surfaces of the projections 27 and 27 and the front end surface of the annular convex portion 25 abut each other. is doing. In the example shown in the figure, an indicia fitting portion is provided between the outer peripheral edge portion of each of the protrusions 27 and 27 and the outer peripheral edge portion of the annular convex portion 25, so that the connecting plate 26 is connected to the lid plate 10. Positioning in the radial direction is intended. In this manner, with the coupling plate 26 being coupled and fixed to the lid plate 10, the projections 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 is in a state of loosely entering a concave hole 29 formed at the center of one side of the connecting plate 26.
[0011]
Further, a support shaft 30 protrudes from the central portion of the other surface of the connecting plate 26 (the right surface in FIG. 1) so as to protrude to the opposite side of the lid plate 10. 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 end portion of the main body 9 of the motor case 7 and two positions of the inner peripheral surface of the wheel 1. As described above, the wheel 1 is rotatably supported with respect to a suspension device (not shown) by rolling bearings 31a and 31b capable of supporting loads in both radial and axial directions. In this state, the wheel 1 is disposed 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 from each other.
[0012]
The friction roller type speed reducer is provided at a portion of the intermediate portion of the wheel 1 that is rotatably supported with respect to the main body 9 in such a positional relationship and is located around the tip of the rotary drive shaft 17. 6 is supported and fixed. For this reason, in the case of this example, the holding 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 on the inner diameter side of the holding ring 33. The outer ring 32 engaged with the spline is held down to a predetermined position shown in FIG. In this state, the inner peripheral surface of the outer ring 32 is concentric with the wheel 1 and is eccentric from the outer peripheral surface of the rotary drive shaft 17. Accordingly, an annular space 36 is provided between the inner peripheral surface of the outer ring 32 and the outer peripheral surface of the tip end portion of the rotary drive shaft 17. The width in the radial direction is not the same in the circumferential direction.
[0013]
In the annular space 36, two guide rollers 37a and 37b and one wedge roller 38 are installed to constitute the friction roller type speed reducer 6. In order to install these rollers 37a, 37b, 38, three support shafts 39a, 39b are provided in the annular space 36 portion. Of these three support shafts 39a and 39b, the two support shafts 39a and 39a located on the lower right side in FIGS. 1 and 2 and the upper right side in FIG. 2 have both ends at the lid plate 10 and the connecting plate. 26 is press-fitted and fixed in the fitting holes 40, 40 formed in 26. Therefore, the two support shafts 39a and 39a are not displaced in the circumferential direction or the diametrical direction in the annular space 36. On the other hand, of the three support shafts 39a and 39b, the remaining one support shaft 39b located on the upper left side in FIG. 2 has both ends of the outer ring with respect to the lid plate 10 and the connecting plate 26. 32 is supported so as to be slightly displaceable in the circumferential direction and the diametrical direction. For this purpose, a support hole 41 having an inner diameter larger than the outer diameter of the support shaft 39b is formed in a part of the lid plate 10 and the connecting plate 26 that is aligned with both ends of the one support shaft 39b. The both end portions of the support shaft 39b are loosely engaged with the support holes 41.
[0014]
The guide rollers 37a and 37b and the wedge roller 38 are rotatably supported by bearings such as radial needle bearings 42 and 42 around the intermediate portions of the support shafts 39a and 39b supported as described above. is doing. In addition, in order to couple and fix the connecting plate 26 to the lid plate 10, the protrusions 27, 27 projecting from one side of the connecting plate 26 are connected to the guides with respect to the circumferential direction of the connecting plate 26. It exists between the rollers 37a and 37b and the wedge rollers 38. In other words, the protrusions 27 and 27 and the guide rollers 37 a and 37 b or the wedge roller 38 are alternately present in the annular space 36 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 wedge roller 38 and the circumferential side surface of each of the protrusions 27 and 27 do not interfere with each other.
[0015]
In this manner, the power transmission, which is the outer peripheral surface of each of the guide rollers 37a and 37b and the wedge roller 38, rotatably supported between the lid plate 10 and the connecting plate 26 by the support shafts 39a and 39b. The cylindrical surfaces 43 and 43 are in contact with a driving-side cylindrical surface 44 that is the outer peripheral surface of the distal end portion of the rotary drive shaft 17 and a driven-side cylindrical surface 45 that is the inner peripheral surface of the outer ring 32. . As described above, the width in the radial direction of the annular space 36 in which the guide rollers 37a and 37b and the wedge roller 38 are installed is not the same in the circumferential direction. In this manner, the outer diameters of the guide rollers 37a and 37b and the wedge roller 38 are made different from each other by making the width dimension of the annular space 36 the same in the circumferential direction. That is, of the guide rollers 37a and 37b and the wedge roller 38, the wedge roller 38 and the guide roller positioned on the side where the tip of the rotational drive shaft 17 is eccentric with respect to the outer ring 32 (the upper side in FIGS. 1 and 2), respectively. The outer diameters of 37b are the same as each other and are relatively small. On the other hand, the outer diameter of the guide roller 37a located on the opposite side (lower side in FIGS. 1 and 2) from the eccentric end of the rotary drive shaft 17 with respect to the outer ring 32 is set to the wedge roller 38 and the guide. It is larger than the outer diameter of the roller 37b. The power transmission cylindrical surfaces 43 and 43, which are the outer peripheral surfaces of the guide rollers 37a and 37b and the wedge roller 38, are brought into contact with the driving side and driven side cylindrical surfaces 44 and 45, respectively.
[0016]
Of the guide rollers 37a and 37b and the wedge roller 38, both ends of the support shafts 39a and 39a that support the guide rollers 37a and 37b are connected to the lid plate 10 and the connecting plate 26 as described above. It is fixed (in the annular space 36). In contrast, the support shaft 39b supporting the wedge roller 38 is slightly displaced in the circumferential direction and the diametrical direction with respect to the lid plate 10 and the connecting plate 26 (in the annular space 36) as described above. I support it. Accordingly, the wedge roller 38 can also be slightly displaced in the circumferential direction and the diameter direction in the annular space 36. The support shaft 39b that supports the wedge 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 lid plate 10 and the connecting plate 26. In order to move the wedge roller 38 toward the narrow part of the annular space 36, the wedge roller 38 is elastically lightly pressed.
[0017]
When the wheel is driven to rotate by the electric wheel driving device of the present invention configured as described above, the electric motor 5 is energized so that the rotation driving shaft 17 of the electric motor 5 is rotated clockwise in FIG. Rotate. The rotation of the rotary drive shaft 17 is transmitted to the outer ring 32 via the guide rollers 37a and 37b and the wedge roller 38, and rotates the rollers 37a, 37b and 38 in the counterclockwise direction of FIG. Further, the rotation of each of the rollers 37a, 37b, 38 is transmitted to the outer ring 32, and rotates the outer ring 32 together with the wheel 1 in the counterclockwise direction of FIG. The power transmission between the rotary drive shaft 17 and the guide rollers 37a and 37b and the wedge roller 38, and the power transmission between the guide rollers 37a and 37b and the wedge roller 38 and the outer ring 32 are all friction. Since transmission is performed, noise and vibration generated during power transmission are low.
[0018]
Further, the wedge roller 38 tends to bite into a portion where the width of the annular space 36 is narrow (the upper central portion in FIG. 2) with a force corresponding to the magnitude of torque transmitted from the rotary drive shaft 17 to the outer ring 32. It becomes. Therefore, a contact portion between the drive-side cylindrical surface 44 that is the outer peripheral surface of the rotary drive shaft 17 and the power transmission cylindrical surfaces 43 and 43 that are the outer peripheral surfaces of the guide rollers 37a and 37b and the wedge roller 38, and The contact pressure between the power transmission cylindrical surfaces 43 and 43 and the driven cylindrical surface 45 which is the inner peripheral surface of the outer ring 32 increases as the torque increases. In other words, when the torque is small, the surface pressure of each contact portion is low. For this reason, the surface pressure of each contact portion is set to an appropriate value according to the torque to be transmitted, and torque transmission can be performed efficiently.
[0019]
That is, when the distal end portion of the rotational drive shaft 17 rotates clockwise in FIG. 2 and the outer ring 32 is rotated counterclockwise, the wedge roller 38 is attached to the distal end portion of the rotational drive shaft 17. By receiving a force in the same direction as the pressing force by the elastic material 47 from the driving side cylindrical surface 44 that is the outer peripheral surface and the driven side cylindrical surface 45 that is the inner peripheral surface of the outer ring 32, the width of the annular space 36 is increased. It tends to move toward a narrow portion, that is, the upper center of FIG.
[0020]
As a result, the power transmission cylindrical surface 43 which is the outer peripheral surface of the wedge roller 38 strongly presses the drive side cylindrical surface 44 and the driven side cylindrical surface 45. An inner diameter side contact portion 48 that is a contact portion between the power transmission cylindrical surface 43 and the drive side cylindrical surface 44, and a contact between the power transmission cylindrical surface 43 and the driven side cylindrical surface 45. The contact pressure of the outer diameter side contact portion 49 that is the contact portion is increased. In this way, when the contact pressure of both the inner diameter side and outer diameter side contact portions 48 and 49 with respect to the wedge roller 38 is increased, the wedge roller 38 is pressed by the power transmission cylindrical surface 43 which is the outer peripheral surface of the wedge roller 38. The rotary drive shaft 17 and the outer ring 32 are slightly displaced in the diametrical direction due to elastic deformation and an assembly gap. As a result, the contact pressure of both the inner diameter side and outer diameter side contact portions 48 and 49 with respect to the respective guide rollers 37a and 37b is increased. Then, based on the frictional engagement at the inner diameter side and outer diameter side abutting portions 48 and 49, the rotational force of the distal end portion of the rotary drive shaft 17 is passed through the guide rollers 37a and 37b and the wedge roller 38. Thus, transmission to the outer ring 32 is possible.
[0021]
As described above, the force for moving the wedge roller 38 toward the narrow portion of the annular space 36 is the magnitude of the rotational driving force transmitted from the tip of the rotational driving shaft 17 to the outer ring 32. It changes according to the height. As the force increases, the contact pressures of both the inner diameter side and outer diameter side contact portions 48 and 49 increase. 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 friction roller type speed reducer can be ensured. In the case of this example, the rotational speed of the outer ring 32 matches the rotational speed of the rotary drive shaft 17, that is, the rotational speed of the rotary drive shaft 17 is multiplied by the reduction ratio of the friction roller type speed reducer 6. When the speed becomes higher than the above speed, the friction roller type transmission 6 is disconnected. That is, in this case, the wedge roller 38 is displaced to the wide side (lower left side in FIG. 2) of the annular space 36 against the elastic force of the elastic material 47. As a result, the contact pressures of both the inner diameter side and outer diameter side contact portions 48 and 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 an appropriate structure when the wheel 3 is rotationally driven only in one direction.
[0022]
Next, FIG. 3 shows a second example of the embodiment of the present invention. This example shows a structure in which the wheel 3 (see FIG. 1) can be driven to rotate in both directions. Therefore, the structure of this example is implemented in combination with the electric motor 5 (see FIG. 1) that can change the rotation direction. In the case of such a structure of this example, one guide roller 37 and two wedge rollers 38a and 38b are used as three rollers constituting the friction roller type speed reducer 6a. Among these, the roller installed in the widest part of the annular space 36 is a guide roller 37 that has a relatively large diameter and does not change its installation position. On the other hand, a pair of rollers provided with the narrowest part of the annular space 36 sandwiched between them is a wedge roller 38a which has a relatively small diameter and can be slightly displaced in the circumferential direction and the diameter direction. 38b. The support shafts 39b and 39b that support the wedge rollers 38a and 38b are elastically pressed in opposite directions toward the narrowest part of the annular space 36.
[0023]
In the case of the structure of this example configured as described above, when the rotary drive shaft 17 rotates clockwise in FIG. 3, the left wedge roller 38a in FIG. Bite into the part. On the other hand, when the rotary drive shaft 17 rotates counterclockwise in FIG. 3, the right wedge roller 38b in FIG. 3 bites into the narrowed portion of the annular space 36. In the case of this example, in order to support both end portions of the support shafts 39b and 39b that support the wedge rollers 38a and 38b, the support holes 41a formed in the cover plate 10 and the connecting plate 26 (see FIG. 1). 41a, the length of the annular space 36 in the circumferential direction is restricted. Specifically, the position of the end of the support hole 41a, 41a on the side where the width of the annular space 36 is wide (the lower side in FIG. 3) is more annular than in the case of the first example described above. The space 36 is close to the position where the width is narrowest. The wedge rollers 38a and 38b are not excessively retracted to the wide side of the annular space 36.
[0024]
In the case of this example configured as described above, any wedge roller 38a (38b) bites into a narrow portion of the annular space 36, regardless of the direction in which the rotary drive shaft 17 rotates. The contact pressure of the contact portions 48 and 49 on the inner and outer diameter sides of the wedge roller 38a (38b) is increased. On the other hand, the retracting amount of the wedge roller 38b (38a) displaced in the retracting direction from the narrow portion of the annular space 36 is also limited. As a result, with respect to both the wedge rollers 38a, 38b and the guide roller 37, the contact pressures of the contact portions 48, 49 on the inner diameter side and the outer diameter side are sufficiently increased, and from the rotary drive shaft 17 to the outer ring 32, Power can be transmitted efficiently. In the case of the structure of this example, the friction roller type speed reducer 6a transmits rotation in both directions between the rotary drive shaft 17 and the outer ring 32, so that the electric motor 5 has a power generation function. By using the one, it is possible to configure a so-called energy recovery system that generates electric power by transmitting the rotation of the wheel 3 (see FIG. 1) side to the electric motor 5 during braking. As described above, except that the bi-directional power transmission from the rotary drive shaft 17 to the outer ring 32 is enabled, it is the same as in the case of the first example described above.
[0025]
In any of the embodiments, the reduction ratio of the friction roller type reduction gears 6 and 6a is 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. Is possible. When considering the friction roller type reduction gears 6 and 6a incorporated in the electric wheel drive device for an electric vehicle, the reduction ratio can be set in the range of about 3 to 9. Moreover, if a reduction ratio of this level is obtained, it is possible to cope with this problem by reducing the outer diameter of the tip of the rotary drive shaft 17, so the friction roller type is increased as the reduction ratio is increased. The reduction gears 6 and 6a do not increase in size. Therefore, the electric motor 5 can be a high-speed, small and lightweight one, and the electric wheel drive device as a whole can be reduced in size and weight. For this reason, it is possible to facilitate the design of the electric wheel drive device which must be installed in a limited space together with the braking parts such as the disk rotor. In addition, when incorporated in an automobile having a suspension system with a spring, the so-called unsprung load can be reduced, which can contribute to the improvement of the running performance of the electric automobile centered on the ride comfort and running stability.
[0026]
【The invention's effect】
Since the present invention is configured and operates as described above, it is possible to realize an electric wheel drive device that can be configured in a small size and light weight, can easily obtain sufficient traveling performance, and has low noise generated during operation at low cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first example of an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a view similar to FIG. 2, showing a second example of an embodiment of the present invention.
[Explanation of symbols]
1 wheel
2 tires
3 wheels
4 Support tube
5 Electric motor
6, 6a Friction roller reducer
7 Motor case
8 Bottom plate
9 Subject
10 Cover plate
11 Perimeter wall
12 Screw holes
13 Annular protrusion
14 Screw
15 Support hole
16 through holes
17 Rotation drive shaft
18 Rolling bearing
19 Rolling bearing
20 Rotor
21 Stator
22 sensors
23 Conductor
24 Lead hole
25 Annular convex part
26 Connecting plate
27 Protrusion
28 volts
29 concave hole
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 Wedge roller
39a, 39b Support shaft
40 Mating hole
41, 41a Support hole
42 Radial needle bearings
43 Cylindrical surface for power transmission
44 Drive side cylindrical surface
45 Driven cylindrical surface
46 Cylinder hole
47 Elastic material
48 Inner diameter side contact part
49 Outer diameter side contact part

Claims (2)

A wheel formed by supporting a tire around the wheel, and driving means provided on the inner diameter side of the wheel for rotationally driving the wheel;
This drive means is formed by connecting an electric motor and a friction roller type speed reducer in series with respect to the transmission direction of power,
The electric motor has a motor case, and the tip end portion of the rotation drive shaft projects in the axial direction from the end portion of the motor case.
The friction roller type speed reducer includes an outer ring that is provided around the tip of the rotary drive shaft in an eccentric manner with respect to the rotary drive shaft and is rotatable with the wheel, and an outer peripheral surface of the rotary drive shaft. It is arranged in an annular space that exists between a certain driving side cylindrical surface and a driven side cylindrical surface that is the inner circumferential surface of this outer ring, and whose radial width is not the same in the circumferential direction. A cylindrical surface for power transmission, comprising at least one guide roller and at least one wedge roller ;
The motor case is a combination of a bottomed cylindrical main body having a bottom plate portion at the base end portion and a lid plate fixedly attached to the distal end opening of the main body. It has a through-hole for inserting a portion closer to the tip of the intermediate portion of the rotary drive shaft, and the lid at the center of the connecting plate coupled and fixed to the cover plate in a state of covering the tip of the rotary drive shaft The wheel is supported rotatably by a rolling bearing provided between the outer peripheral surface of the support shaft protruding from the opposite side of the plate and the outer peripheral surface of the tip of the main body and the two inner peripheral surfaces of the wheel. Yes,
Electric wheel drive device. The central axis of the central shaft and the inner peripheral surface of the outer peripheral surface of the peripheral wall portion of the motor case is eccentric to each other, the thickness in the radial direction of the peripheral wall portion has gradually changed in the circumferential direction, in claim 1 The described electric wheel drive device.

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