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Title:
SUSPENSION FRICTION DRIVE AND AUTO-BALANCING TRANSPORATION DEVICE HAVING SAME
Document Type and Number:
WIPO Patent Application WO/2019/099042
Kind Code:
A1
Abstract:
A suspension friction drive system and an auto- balancing personal transportation device having same. The suspension friction drive system may include two wheels (at least one of which is a drive wheel) that contact the rim of a wheel to be driven. The wheels preferably contact the rim at a contact angle that increases friction such that wheel driving performance is enhanced. The wheels are also preferably positioned such that some degree of shock absorption is provided and additional absorption may be supported. Various embodiments and features are disclosed including a suspension frame coupled between the two wheels, the use of at least two drive wheels, a suspension bias mechanism, and a drive wheel substantially centered on the rim, among others.

Inventors:
CHEN, Shane (1821 Nw Eighth Avenue, Camas, WA, 98607, US)
Application Number:
US2017/062450
Publication Date:
May 23, 2019
Filing Date:
November 20, 2017
Export Citation:
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Assignee:
CHEN, Shane (1821 Nw Eighth Avenue, Camas, WA, 98607, US)
International Classes:
B62K11/00; B62D61/00; B62K1/00; B62K17/00; B62K19/30
Foreign References:
US20140058600A12014-02-27
US20160325585A12016-11-10
US20110220427A12011-09-15
US20160332690A12016-11-17
Attorney, Agent or Firm:
SULLIVAN, Steven, J (PO Box 5997, Portland, OR, 97228, US)
Download PDF:
Claims:
CLAIMS

1. An auto-balancing personal transportation device, comprising:

at least a first rim having a first tire mounted thereon;

a first wheel configured to contact the rim;

a second wheel configured to contact the rim;

a first drive motor to drive at least one of the first and second wheels, and to thereby drive the rim that is in contact with the driven wheel;

wherein one of the first and second wheels is located forward of a center of the device and the other is located rearward of a center of the device.

2. The device of claim 1, wherein the driven wheel is positioned with the rim such that a line tangent to the contact of the wheel and rim is at an angle between 30 and 90 degrees from horizontal when the device is at rest.

3. The device of claim 2, wherein the driven wheel is positioned with the rim such that the tangent line of contact is between 45 and 85 degrees from horizontal when the device is at rest.

4. The device of claim 2, wherein the driven wheel is positioned with the rim such that the tangent line of contact is between 60 and 80 degrees from horizontal when the device is at rest.

5. The device of claim 1, wherein, at rest on a horizontal surface, a line connecting the axes of rotation of the first and second wheels is substantially horizontal .

6. The device of claim 5, wherein the first and second wheels are preferably arranged substantially symmetrically about a line perpendicular to the line connecting the axis.

7. The device of claim 1, wherein the rim has a degree of flexibility that allows increased vertical movement of at least one of the first and second wheels relative to the rim when the device is subjected to a shock .

8. The device of claim 1, wherein at least one of the drive wheels is substantially centered on the rim.

9. The device of claim 1, further comprising a second drive motor and wherein the first drive motor drives the first wheel and the second drive motor drives the second wheel .

10. The device of claim 1, further comprising a mechanism to bias the first and second wheels into contact with the rim. 11. The device of claim 10, further comprising a frame that holds the first and second wheels at a given spacing from each other and wherein the bias mechanism biases the frame such that the wheels contact the rim. 12. The device of claim 1, further comprising:

first and second foot platforms located on opposite sides of the rim;

a position sensor; a battery; and

a control circuit;

wherein the drive motor drives the wheel to try to auto-balance the device based on position information from the position sensor.

13. The device of claim 12, further comprising a housing that covers a portion of the wheel and is configured to be contacted by the leg of a rider below the knee when a rider is standing on the foot platforms.

14. A suspension friction drive system, comprising: at least a first rim having a first tire mounted thereon;

a first wheel configured to contact the rim;

a second wheel configured to contact the rim; and a first drive motor to drive at least one of the first and second wheels;

wherein the first wheel is located forward of a center of the device and the second wheel is located rearward of a center of the device.

15. The device of claim 14, further comprising a frame to which the first and second wheel are coupled, the frame and wheels being configured with the rim such that downward force on the frame causes the first and second wheels to contact with the rim.

16. The device of claim 14, wherein a line tangent to the contact point of the first wheel with the rim has an angle from horizontal, when the device is at rest on a horizontal surface, of between 45 and 90 degrees.

17. The device of claim 14, wherein a line tangent to the contact point of the first wheel with the rim has an angle from horizontal, when the device is at rest on a horizontal surface, of between 55 and 85 degrees.

18. The device of claim 14, wherein the first and second wheels are arranged in the device forward and rearward of a center in a substantially symmetric manner. 19. The device of claim 14, further comprising a mechanism to bias the first and second wheels into contact with the rim.

20. The device of claim 14, further comprising a second drive motor and wherein the first drive motor drives the first wheel and the second drive motor drives the second wheel .

Description:
SUSPENSION FRICTION DRIVE AND AUTO-BALANCING

TRANSPORATION DEVICE HAVING SAME

FIELD OF THE INVENTION

The present invention relates to suspension friction drive systems and to auto-balancing personal transportation devices (and other devices) having same.

BACKGROUND OF THE INVENTION

The prior art includes U.S. Patent no. 8,807,250, issued to Shane Chen for a Powered Single-Wheeled Self- Balancing Vehicle for Standing User (the '250 patent) . Fig. 1 of this patent shows a friction drive arrangement in a self-balancing personal transportation device. The friction drive arrangement of this figure is positioned such that the "contact angle," the angle of the tangent line where the main force of the drive wheel contacts the rim, is approximately 0 degrees (from horizontal) . This arrangement is prone to slipping, particularly when conditions are adverse, such as wet, or traversing uphill, etc .

Friction drive motors, however, are lightweight and highly efficient. Thus, their inability to work in an auto-balance transportation device of the prior art resulted in the use of heavier, less-efficient (and hence ride-time shortening) motors and heavier batteries to drive the less efficient motors. Thus, the failure of the drives was problematic in multiple ways. A need exists for a friction drive arrangement that has increased friction (and/or less slippage) . A need further exists to provide adequate friction drive while also providing some shock absorption (and a suspension that would allow additional shock absorption) .

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a friction drive system that overcomes the shortcomings of the prior art.

It is another object of the present invention to provide a friction drive system with enhanced friction and drive performance.

It is also an object of the present invention to provide a friction drive system with both enhanced drive performance and a level of shock absorption.

Such a friction drive system would provide enhanced performance in an auto-balancing transportation device and result in auto-balancing transportation devices that are lightweight, easy to use, and more energy efficient, among other benefits.

These and related objects of the present invention are achieved by use of a suspension friction drive system and auto-balancing vehicle having same as described herein .

The attainment of the foregoing and related advantages and features of the invention should be more readily apparent to those skilled in the art, after review of the following more detailed description of the invention taken together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective side view of an auto balancing personal transportation device having a suspension friction drive system in accordance with the present invention.

Figs. 2-3 are perspective views a suspension friction drive system in accordance with the present invention.

Fig. 4 is a side elevation view of the suspensinO friction drive system of Figs. 2-3, while Fig. 5 is a cross sectional plan view thereof.

DETAILED DESCRIPTION

Referring to Fig. 1, a perspective side view of an auto-balancing personal transportation device 10 having a suspension friction drive system 50 in accordance with the present invention is shown. While suspension friction drive system 50 is taught in the context of an auto balancing transportation device, it should be recognized that system 50 or the like may be implemented in a non auto-balancing device without departing from the present invention .

Device 10 may include a wheel structure 11 having a tire 12 and a rim 14. A housing 16 covers a portion of the wheel structure and a handle 18 and user-interface 19 may be coupled to and/or formed on the housing. There are two foot platforms 20,30 located on opposite sides of the wheel structure (only one of which is shown) and these may be pivotally connected for movement between a deployed position and a retracted or stowed position (the deployed position is shown for platform 20) .

Device 10 further includes a position sensor 41, a battery 43 (see Fig. 2) and an electronic control circuit 45. The position sensor may be a gyroscopic sensor or other, and preferably provides an indication of the fore- aft pitch of device 10. The control circuit 45 preferably drives the device toward auto-balancing by controlling a drive mechanism (described below) based on a pitch position detected by the position sensor. The sensor 41 and control circuit 45 are shown representatively in phantom lines, located near a top region of the device (near the user control interface), in Fig. 1. They may, however, be located in other locations including on frame 60 (Fig. 2) or elsewhere. Battery 43 may be provided below frame 60 and/or elsewhere.

Device 10 (other than as provided by the drive system described herein) may function in a manner very similar to that of the auto-balancing personal transportation device described in the '250 patent, which is mentioned above and hereby incorporated by reference.

Referring to Figs. 2-3, perspective views (from the two lateral sides) of wheel structure 11 and friction drive system 50 of device 10 of Fig. 1 (with housing 16 removed) are shown. In Fig. 4, a side elevation view of the suspension friction drive system is shown, while in Fig. 5 a cross sectional plan view thereof is shown.

System 50 may include first and second drive wheels 52,54, first and second motors 56,58, a frame 60, a bias arm 62, arm spring 64 and roller 66. Battery 43 is also shown .

In a preferred embodiment, frame 60 is positioned substantially horizontally so the drive wheels 52,54 contact rim 14 at a point forward and rearward in the device. As can be seen in Fig. 2 and Fig. 4, the outside distance from outer edge of the first to the second drive wheel may be nearly as long as the inner diameter of the rim. Arm spring 64 biases the bias arm 62 and roller 66 toward the rim and pushes the drive wheels 52,54 into contact with rim 14. Further, the foot platforms are preferably either coupled directly to frame 60 or to housing 16 which is in turn coupled to frame 60, such that a user' s weight on the foot platforms may pull the drive wheels down and into contact with the rim (in the fore and rear positions shown in the figures), i.e., maintaining the frame in a substantially horizontal position (at rest on a horizontal surface) .

The motors 56,58 are preferably mounted to frame 60 and have an axle 69 (Fig. 5) that is coupled to and transmits movement to drive wheels 52,54, respectively. Various motors are known in the art and may be used here, including hub motors, non-hub motors and others. Belts, gears or other suitable drive mechanisms may be employed. The rim may have a center ridge or be otherwise configured and the drive wheels complementarily configured with the rim. The drive wheel may be centered with the rim (and/or the rim ridge) or be otherwise configured.

Fig. 4 illustrates a dashed line (used to indicate a cross-sectional view) that intersects the axis of rotation of both drive wheels 52,54 (termed the "axis line") . A line perpendicular to this dashed line and in the central vertical plane may represent the general position of a standing human (termed the "standing line") . At rest on a horizontal surface, the axis line is substantially horizontal and the standing line is substantially vertical. When a rider leans forward to commence forward propulsion of the device, the platforms, axis line and standing line all pitch in a similar manner. Wheels 52,54 are preferably arranged in device 10 such that one of wheels 52,54 is always forward of the standing line and one of wheels 54 is always rearward of the standing line. More preferably, wheels 52 and 54 are arranged substantially symmetrically forward and aft of the standing line.

When positioning the drive wheels as shown (i.e., countering one another and rather steeply on the rim) , several benefits are realized. Fig. 4 illustrates an angle, a, of the tangent line of contact of drive wheel 52 with rim 14 (i.e., a line perpendicular to the tangent line of contact traverses the axis of rotation of wheel 52) . When this "contact angle" is approximately 70-80 degrees (from horizontal), the vertically of the contact increases friction over that of the prior art embodiment discussed above (0 degree contact angle) . In addition, there is still a small about of vertical play in the position of the frame, i.e., the contact angle is not 90 degrees, and thus the frame and drive motor have some vertical play thereby allowing movement of the frame (and wheels) and some degree of shock absorption. Arm spring 64 may contribute to shock absorption and additional shock absorbing material (spring, foam, hydraulic, etc.) may be added. In addition, since the drive wheels may be made of rubber or another material with some elasticity, this elasticity could participate in shock absorption.

This contact angle of improved friction yet maintaining shock absorption may be from 45 to nearly 90 degrees, or 60-85 degrees or, more preferably in the 70-80 degree range discussed above. It can also be less than 45 degrees, but the increase in friction will be less. For example, the contact angle may be between 30 and nearly 90 degrees .

While two drive wheels and drive motors are shown (and would provide some redundancy) , it should be realized that one of these wheels could be a non-motorized guide wheel or the like. Whether implemented with one or two drive wheels, it is important that one wheel is positioned forward and the other aft so that the weight of a rider is asserted on both wheels forcing them into high friction content with the rim. The frame coupling the wheels, in this position, also serves as part of the suspension. It should also be recognized that while two motors are shown, a single drive motor driving two drive wheel may be employed .

The surface of the drive wheel and rim may be smooth or roughed depending on the materials used to make the wheel or rim as is known in the art. For example, if a natural rubber is used, the rim may be smooth, yet if a synthetic rubber is used a somewhat abraded rim surface may be helpful . While a single rim and tire are shown, the term single wheel structure as used herein is intended to cover the use of two tires on a single rim or other structures that approximate a single wheel their function.

It should be recognized that the wheel may be made of a slightly flexible material (such as certain metals or alloys thereof or fiberglass) to allow for additional movement of the frame within the wheel (substantially vertically, shock absorption) , and the configurations disclosed herein permit the motors to be higher in the wheel envelope, giving device designers latitude in arranging components and allowing foot platforms (and the position of a user' s foot while riding the device) to be closer to the vertical centerline of the wheel (closer to the center of gravity) .

While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.