JP4756360B2 - Ball wheel drive mechanism - Google Patents

Description

  The present invention relates to a spherical wheel drive mechanism that travels by driving one spherical wheel.

  Since it has the advantage that it can move smoothly in all directions, spherical wheel drive mechanisms with various structures have been proposed and developed (for example, Patent Documents 1 and 2 and Non-Patent Document 1).

FIG. 7 shows a configuration example of a conventional spherical wheel drive mechanism. As shown in the figure, each of the wheels 1a and 1b is attached to the frames 2a and 2b so as to be rotatable around the A axis. Further, the frames 2a and 2b are each driven to rotate by a motor (not shown) around the C axis, and this rotation is transmitted to the spherical ring 10, whereby the spherical ring 10 rotates. In FIG. 7, the wheels 1 a and 1 b constitute a drive unit that can rotate the spherical wheel 10. By providing three or more drive units having different rotation directions, the spherical ring 10 can be rotated in any direction and can be moved in all directions.
JP 2003-94904 A JP 2005-344777 A “Development of an omnidirectional movement mechanism using basketball” written by Goro Shishido (University of Tokyo) and Yoshihiko Nakamura (University of Tokyo)

  In the conventional spherical wheel drive mechanism as shown in FIG. 7, the wheels 2 a and 2 b that rotatably support the two wheels 1 a and 1 b do not directly contact the spherical wheel 10. , 1b are provided at positions where two opposed surfaces are cut out. Therefore, when the wheels 1a and 1b are rotated by rotating the frames 2a and 2b with a motor, as shown in FIG. 7, there is a state in which the spherical wheel 10 is in contact only at the corners of the wheels 1a and 1b. Can occur. In such a state, the friction between the wheels 1a and 1b and the spherical ring 10 is remarkably reduced, so that the rotational force of the wheels 1a and 1b is hardly transmitted to the spherical ring 10. For this reason, in the conventional spherical wheel drive mechanism driven by two wheels, there is a problem that the frictional change between the wheels 1a and 1b and the spherical wheel 10 becomes large, and the variation in driving force becomes large.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a spherical wheel drive mechanism capable of reliably transmitting the driving force of the wheels to the spherical wheel and realizing stable traveling.

  A spherical wheel driving mechanism according to the present invention is a spherical wheel driving mechanism that drives a spherical wheel by a driving unit, and the driving unit includes three or more driving wheels arranged in series and a frame that supports the driving wheel. And a drive section for rotating the frame, wherein the drive wheel is formed in a spherical shape having a notch surface in part, and the spherical portion is arranged so as to contact the spherical wheel. In addition, the frame supports the drive wheel rotatably on the cut-out surface. According to such a configuration, since three or more wheels are arranged in series, the spherical surface of any one or more wheels can be brought into contact with the spherical wheel. It can be reliably transmitted to the wheel, and stable running can be realized.

  Here, in the frame, the portion that supports the cut-out surface is on the inner side of the outer periphery of the virtual spherical surface including the spherical surface of the wheel.

  The three or more wheels included in the drive unit are rotationally driven so that the spherical surface of at least one wheel is in surface contact with the spherical wheel.

  Furthermore, it is desirable that all the wheels included in the drive unit rotate synchronously in the same direction via a gear by a single motor. Thereby, it can comprise with few motors.

  Moreover, the three or more wheels included in the drive unit may be arranged on a curve so as to follow the outer peripheral curved surface of the spherical wheel. Thereby, a wheel can be contacted with sufficient balance to a spherical ring. The above-described spherical wheel drive mechanism can be mounted on, for example, a moving body or a vehicle.

  ADVANTAGE OF THE INVENTION According to this invention, the driving force of a wheel can be reliably transmitted to a spherical wheel, and the spherical wheel drive mechanism which can implement | achieve the stable driving | running can be provided.

  As shown in FIG. 1, the spherical ring drive mechanism according to the embodiment of the present invention includes a spherical ring 10 and a plurality of drive units 20 (21, 22, 23) as a basic configuration. The spherical wheel drive mechanism can be used for various applications such as mobile robots, vehicles, automatic guided vehicles, and work vehicles. The spherical ring 10 and the drive unit 20 are supported by a support mechanism (not shown) having a shape and function according to the application. In this example, each of the drive units 20 is configured by arranging three or more wheels having parallel rotation axes in series. The drive units 20 are different from each other in the arrangement direction, and in this example, are different from each other by 60 °. Thereby, the spherical ring 10 can be rotationally driven in an arbitrary direction and can travel in all directions on a plane. The drive unit 20 is provided on the outer periphery above the great circle perpendicular to the vertical direction of the spherical ring 10 (the outer periphery of the plane perpendicular to the vertical direction passing through the center of the spherical ring 10).

  The spherical ring 10 is configured by, for example, a sphere made of metal or resin covered with an elastic body such as rubber, or a sphere made of solid elastic rubber. With the spherical wheel 10 having such a structure, vibration, noise, and slipping during traveling can be suppressed.

  FIG. 2 shows a detailed structure of the drive unit 20. FIG. 2A is a plan view of the drive unit 20. FIG. 2B is a front view of the drive unit 20. FIG.2 (c) is sectional drawing in the XX cross section of FIG.2 (b).

  In the conventional spherical wheel drive mechanism, two wheels are provided, but in the spherical wheel drive mechanism according to the embodiment of the present invention, three wheels (rollers) 1a, 1b, and 1c are provided. In this example, the wheels 1 a, 1 b, 1 c are not arranged on a straight line but are arranged in series (in a line) on a curve along the outer periphery of the spherical wheel 10. Each of the wheels 1a to 1c has a spherical shape having a smaller diameter than the spherical wheel 10, two opposed surfaces are cut out, and is configured by a spherical surface and a cut surface. The spherical surface of the wheel 1 is made of a material having a high coefficient of static friction with the spherical wheel 10, and is made of an elastic resin such as rubber, for example. The cut-out surface has a circular shape, and rod-shaped rotary shaft members 3a, 3b, 3c are penetrated at the center thereof and are fixed to the wheels 1a to 1c.

  Each of the rotation shaft members 3a to 3c is attached to two linear members facing each other in the square ring-shaped (ring-band) frames 2a to 2c so as to freely rotate. At this time, the 1st linear member to which rotating shaft member 3a-3c was attached is located inside the outer periphery of the virtual spherical surface containing the spherical surface of wheel 1a-1c in a bearing part, ie, the center side of a wheel. For this reason, even if the wheels 1a to 1c are rotated integrally with the frames 2a to 2c, the spherical portions of the wheels 1a to 1c are in contact with the spherical ring 10, but the frames 2a to 2c are in contact with the spherical ring 10. do not do.

  In the frame 2a, the rod-shaped rotating shaft member 4a is perpendicular to the second linear member in the second linear member extending perpendicularly to the first linear member to which the rotating shaft member 3a is attached. Is attached. The rotating shaft member 4a is attached through a bearing provided in the entire frame 7, and a gear 5a is fixed to the other end. In the frame 2a, the rotation shaft member 41a is also provided on the linear member facing the first linear member to which the rotation shaft member 4a is attached. The rotary shaft member 41a also passes through a bearing provided in the entire frame 7 and is rotatably attached to the entire frame 7.

  The gear 5a meshes with a gear 5d that is rotatably attached to the entire frame 7, and when the gear 5d rotates, the gear 5a also rotates.

  In the frame 2b, the rod-shaped rotating shaft member 4b is perpendicular to the second linear member, in the second linear member extending perpendicularly to the first linear member to which the rotating shaft member 3b is attached. Is attached. The rotating shaft member 4b is attached through a bearing provided in the entire frame 7, and a gear 5b is fixed to the other end. In the frame 2b, the rotation shaft member 41b is also provided on the linear member facing the first linear member to which the rotation shaft member 4b is attached. The rotary shaft member 41b also passes through a bearing provided in the entire frame 7 and is rotatably attached to the entire frame 7.

  The rotating shaft member 4b is fixed to the gear 5b and is also fixed to the rotating shaft of the motor 6. Since the gear 5b attached to the rotation shaft of the motor 6 meshes with the gear 5d, when the gear 5b rotates with the rotation of the motor 6, the rotational force is transmitted to the gear 5d and the gear 5a. Here, the rotation speed of the motor 6 can be adjusted.

  Similarly, in the frame 2c, the rod-shaped rotating shaft member 4c is connected to the second linear member extending perpendicularly to the first linear member to which the rotating shaft member 3c is attached. It is attached perpendicular to. The rotating shaft member 4c is attached through a bearing provided in the entire frame 7, and a gear 5c is fixed to the other end. In the frame 2c, the rotation shaft member 41c is also provided on the linear member facing the first linear member to which the rotation shaft member 4c is attached. The rotating shaft member 41c is also attached to the entire frame 7 so as to freely rotate through a bearing provided on the entire frame 7.

  The gear 5c meshes with a gear 5e that is adjacently attached to the entire frame 7 so as to be freely rotatable. When the gear 5e rotates, the gear 5c also rotates.

  Since the gear 5b attached to the rotation shaft of the motor 6 is also meshed with the gear 5e, when the gear 5b rotates with the rotation of the motor 6, the rotational force is transmitted to the gear 5d and the gear 5a. Here, the gear pitches of the gears 5a to 5e in this example are equal to each other.

  In the drive unit 20 shown in FIG. 2, when the motor 6 rotates, the gears 5a, 5b, and 5c rotate at the same rotational speed in the same rotational direction, so that they are coaxial with the gears 5a, 5b, and 5c. The wheels 1a, 1b, 1c fixed to the same rotate in the same rotational direction at the same rotational speed.

  As can be seen from FIG. 2 (b), the wheels 1a, 1b, 1c are set in a state in which the rotational phase is shifted. Specifically, the rotation phase is set so that any of the wheels 1 a, 1 b, 1 c is in surface contact with the spherical surface of the spherical ring 10. In the example of FIG. 2, when the wheel 1b is used as a reference and the clockwise direction is positive, the wheel 1a is set to −45 degrees and the wheel 1b is rotated to +45 degrees.

  3 to 6 show a state in which the drive unit 20 is in contact with the spherical ring 10, FIG. 3 is a plan view, FIG. 4 is a front view, FIG. 5 is a YY sectional view of FIG. FIG. In the state shown in FIGS. 3 to 6, at least the spherical surface of the wheel 1 b is in surface contact with the spherical ring 10. In such a state, the wheels 1a, 1b, and 1c rotate in the same direction at the same rotational speed, but since the spherical surface of at least one wheel 1 is in surface contact with the spherical wheel 10, the driving force of the wheel 1 is stabilized. Can be transmitted to the spherical wheel 10 to achieve stable running.

  In the above example, the drive unit 20 has three wheels. However, the drive unit 20 is not limited to this, and may have four or more wheels. In addition, although three drive units 20 are provided in the above example, the number is not limited to this, and four or more drive units 20 may be provided.

1 is an overall configuration diagram of a spherical wheel drive mechanism according to the present invention. It is the top view, front view, and sectional drawing of a drive unit in the spherical ring drive mechanism concerning this invention. It is a top view of the spherical-wheel drive mechanism concerning this invention. It is a front view of the spherical-wheel drive mechanism concerning this invention. It is sectional drawing of the spherical-wheel drive mechanism concerning this invention. It is a right view of the spherical-wheel drive mechanism concerning this invention. It is a schematic block diagram of the conventional spherical ring drive mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wheel 2 Frame 3 Rotating shaft member 4 Rotating shaft member 5 Gear 6 Motor 7 Whole frame 10 Spherical ring 20 Drive unit

Claims (6)

A spherical ring drive mechanism for driving a spherical ring by a drive unit,
The drive unit is
Three or more drive wheels arranged in series;
A frame that supports the drive wheel;
A drive unit for rotating the frame,
The drive wheel is configured in a spherical shape having a notch surface in part, and the spherical portion is disposed so as to contact the spherical wheel,
A spherical wheel drive mechanism in which the frame rotatably supports the drive wheel at the cut-out surface.   2. The spherical wheel drive mechanism according to claim 1, wherein a portion of the frame that supports the cut-out surface is located inside an outer periphery of a virtual spherical surface including a spherical surface of the wheel.   The spherical wheel drive mechanism according to claim 1, wherein three or more wheels included in the drive unit are rotationally driven so that a spherical surface of at least one wheel is in surface contact with the spherical wheel.   The spherical wheel drive mechanism according to claim 1, wherein all the wheels included in the drive unit rotate in the same direction through a gear by a single motor.   The spherical wheel drive mechanism according to claim 1, wherein the three or more wheels included in the drive unit are arranged on a curve so as to follow an outer peripheral curved surface of the spherical wheel. A moving body comprising the spherical wheel drive mechanism according to claim 1.

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