JP2012101590A - Wheel for running - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel with improved traveling performance on soft ground such as sandy or muddy ground.
[Solution]
A robot used for lunar exploration or the like includes a body 1 and a wheel 2 provided on the left and right sides of the body 1 so as to be separated from each other. Each wheel 2 includes a loop assembly 10 and a pair of guide plates 20. The loop assembly 10 includes a hub 11, a plurality of inner elastic loops 12 fixed to the outer periphery of the hub 11 at equal intervals, and an outer elastic loop 13 fixedly circumscribed to the inner elastic loop 12. The elastic loops 12 and 13 are made of steel belts and have spring elasticity. The pair of guide plates 20 are elongated in the horizontal direction and are fitted to both side edges of the outer elastic loop 13, thereby elastically deforming the outer elastic loop 13 into a vertically crushed shape.
[Selection] Figure 1

Description

  The present invention relates to a wheel suitable for running on soft ground such as sandy or muddy ground, particularly for a celestial body with a small attractive force such as the moon or underwater sandy or muddy ground where buoyancy is applied.

  Robots (running devices) using wheels are well known. Although this robot is suitable for traveling on a leveled road surface, it is not suitable for traveling on soft ground such as sand or muddy ground. This is because the ground contact area of the wheel is small and the ground contact pressure is large, so that the wheel digs sand and mud and becomes unable to travel or winds up dust and the like.

  Robots using crawlers instead of wheels are also well known. This crawler is constructed by suspending belts on the front and back sprockets, and because it has a large ground contact area and low ground pressure, it is suitable for running on soft ground without digging sand or mud, Or a large load of power required to drive the belt, and is not suitable for a small traveling device such as a robot.

In particular, robots that travel on sandy bodies with low gravitational force or deep sea sandy or swampy areas with buoyancy need to be extremely lightweight due to transport restrictions, and can only be remotely operated, so it is a simple structure that is difficult to break. And it is necessary not to be able to run by digging sand and mud.
The wheel described in Patent Document 1 includes a hub and an endless belt disposed so as to surround the hub. A number of rod-shaped first supports extend radially from the hub toward the belt, and a number of rod-shaped first supports extend from the inner periphery of the belt toward the hub. The first support and the second support are connected by a spring, and the second support is urged in the radial direction and the outward direction by the spring, thereby maintaining the belt in a circular shape concentric with the hub. .

  In the wheel having the above configuration, the second support fixed to the grounded portion moves in the hub direction against the spring in a state where the belt is grounded. Can be secured. As a result, although it is a wheel, it can drive | work without digging the soft ground of a celestial body.

JP 2009-214612 A

  However, since the wheel disclosed in Patent Document 1 requires a large number of rod-shaped supports and springs, the structure is complicated, the risk of failure is high, and traveling on a celestial body such as the lunar surface that cannot be repaired in particular. Not suitable for. Also, because of its complicated structure, it is expensive and cannot reduce its weight.

The present invention has been made to solve the above-described problem. In a traveling wheel, a hub, a plurality of inner elastic loops fixed to the outer periphery of the hub at equal intervals, and the plurality of inner elastic loops. And an outer elastic loop that is circumscribed and fixed to each inner elastic loop, and the outer elastic loop is grounded.
According to the above configuration, in the ground contact state, the outer elastic loop and the inner elastic loop are elastically deformed into a shape crushed up and down. You can travel.
In addition, since the number of parts is small and the structure is simple, it is lightweight and inexpensive, and the risk of failure is extremely small. Because it is extremely light and has a low risk of failure, it can also be applied to celestial bodies such as the moon that cannot be repaired and traveling on the deep sea.

Preferably, it further includes a pair of guide plates that are orthogonal to the axis of the hub and extend long in the horizontal direction, the hub is rotatably supported by the guide plates, and the inner elastic loop is disposed between the guide plates. The outer elastic loop rotates in a state in which both side edges in the axial direction of the hub are elastically deformed so as to circumscribe the horizontal ends of the pair of guide plates and become longer in the horizontal direction.
According to this configuration, since the outer elastic loop is forcibly crushed up and down by the guide plate, the ground contact area of the outer elastic loop can be reliably increased. Therefore, even when the traveling device such as a robot to which the wheel is attached is lightweight, or when traveling on a celestial body such as a moon with small gravity, a sufficient ground contact area can be secured.
Further, since the twist of the outer elastic loop can be restricted by the pair of guide plates and the twist of the inner elastic loop can be restricted, the stable running is possible.
Furthermore, since the outer elastic loop is elastically deformed into a shape crushed up and down by the pair of guide plates, the load-bearing rigidity due to preloading is improved, and fluctuations in the height of the traveling device during traveling can be suppressed.

Preferably, the outer elastic loop and the inner elastic loop are made of elastic strips, the outer elastic loop is wider than the inner elastic loop, and both side edges protrude from the inner elastic loop in the axial direction of the hub.
According to this, an inner side elastic loop and an outer side elastic loop can be made into a simple structure.

Preferably, the elastic band plate is made of a metal band plate.
According to this, it can endure the environment where the temperature changes drastically such as the desert or the moon surface.

Preferably, lugs are provided at intervals on the outer periphery of the outer elastic loop.
According to this, the traction force at the ground contact portion can be secured in the soft ground, and the running can be further stabilized.

  According to the wheel of the present invention, it is possible to stably travel on a soft ground such as a sandy or swampy land underwater where a small gravitational force such as the moon that can only be operated remotely or under buoyancy, and the structure is simple, Lightweight and inexpensive, with few failures.

1A and 1B show a wheel of a lunar surface exploration robot according to an embodiment of the present invention, in which FIG. 1A is a side view and FIG. 1B is a longitudinal sectional view at the center of the wheel. FIG. 2 is a longitudinal sectional view showing the upper half of the wheel in an enlarged manner and exaggerating the thickness of the elastic loop. FIG. 3 shows the loop assembly of the wheel in an unloaded state before the guide plate is assembled, (A) is a side view, and (B) is a longitudinal sectional view at the center of the loop assembly. FIG. 4 is a longitudinal sectional view showing the upper half of the loop assembly in an enlarged manner and exaggerating the thickness of the elastic loop.

A light and small robot (traveling device) for lunar exploration according to a first embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1B, the robot includes a body 1 that is elongated in the front-rear direction, and a total of four wheels 2 (only one is shown) that are spaced apart from each other on the left and right sides of the body 1. ing.

  The body 1 is equipped with a video camera, a communication device, and the like. Further, the body 1 may be equipped with various attachments such as a robot arm and sensors according to the role required of the robot.

  Each of the wheels 2 includes a loop assembly 10 and a pair of guide plates 20 incorporated in the loop assembly 10.

  First, the loop assembly 10 will be described with reference to FIGS. The loop assembly 10 surrounds a central cylindrical hub 11, a plurality of, for example, four inner elastic loops 12 fixed to the outer periphery of the hub 11 at equal intervals, and the inner elastic loops 12. The outer elastic loop 13 is circumscribed and fixed to the loop 12.

  In the present embodiment, each of the inner elastic loop 12 and the outer elastic loop 13 is welded (fixed) at both longitudinal ends of a strip having a uniform thickness, for example, a steel belt (metal strip), over the entire circumference. It is configured. In this embodiment, the outer elastic loop 13 is about 1.0 mm thick, and the inner elastic loop 12 is thinner than this and 0.5 mm thick. However, the thickness of these loops 12 and 13 is the weight of the body 1, the usage environment, etc. It can be appropriately selected depending on the situation.

  Since the elastic loops 12 and 13 have spring elasticity, the elastic loops 12 and 13 are circular in an unconstrained and unloaded state (natural state), elastically deformed into a non-circular shape when a load is applied, and the original circular shape when a load is removed. Return to elasticity.

  The inner elastic loop 12 is in contact with the outer periphery of the hub 11 at one location and fixed by the contact 12a, and is in contact with the inner periphery of the outer elastic loop 13 at another location separated by 180 ° and is fixed by the contact 12b. . A line connecting the fixed points 12a and 12b of the inner elastic loop 12 passes through the central axis L of the hub 11 (hereinafter referred to as a hub axis).

As shown in FIG. 4, the inner elastic loop 12 is fixed to the outer periphery of the hub 11 by a plurality of bolts 14 arranged in the direction of the hub axis L at the fixing point 12a.
The outer elastic loop 13 and the inner elastic loop 12 are fixed to each other by a plurality of bolts 15 and nuts 16 arranged in the direction of the hub axis L at the fixing point 12b.

In the loop assembly 10, the adjacent inner elastic loops 12 are not fixed.
The inner elastic loop 12 and the outer elastic loop 13 are arranged on a plane orthogonal to the hub axis L.

  The outer elastic loop 13 is wider than the inner elastic loop 12, and the inner elastic loop 12 is fixed at the center in the width direction (the hub axis L direction). Both side edges 13 a of the outer elastic loop 13 protrude in the width direction from the inner elastic loop 12.

  Grounding lugs 18 are provided at equal intervals on the outer periphery of the outer elastic loop 13. The ground lug 18 is made of, for example, a sheet metal having an L-shaped cross section and a length substantially equal to the width of the outer elastic loop 13, extends along the width direction of the outer elastic loop 13, and one side is welded to the outer periphery of the outer elastic loop 13. The other side is erected so as to be orthogonal to the outer periphery of the outer elastic loop 13.

  As shown in FIG. 3A, when the loop assembly 10 is in an unconstrained and unloaded state (natural state), the outer elastic loop 13 is substantially circular, and the inner elastic loop 12 is slightly in contact with each other. It is almost circular.

  As shown in FIG. 1, the pair of guide plates 20 have the same shape and are formed horizontally long, and at the periphery thereof, an upper portion 21 and front and rear end portions 22 and 23 form a convex curved surface, and a lower portion 24 forms a concave curved surface. The portions 25 and 26 between the upper portion 21 and the front and rear end portions 22 and 23 are also concave curved surfaces.

Next, the incorporation of the pair of guide plates 20 into the loop assembly 10 will be described in detail.
As best shown in FIG. 2, a circular hole 20 a is formed at the center of each guide plate 20, and a bearing 30 is attached in advance to the inner periphery of the hole 20 a by a bearing holder 31.

  In a state where the outer elastic loop 13 is elastically deformed, the bearings 30 of the pair of guide plates 20 are fitted into both axial ends forming a small diameter of the hub 11, and the peripheral portions of the pair of guide plates 20 are connected to the outer elastic loops. The guide plate 20 is temporarily assembled to the hub 11 by being fitted into the both side edges 13 a of 13.

  Next, fixing the pair of disk-shaped bearing retainers 32 to both end surfaces in the axial direction of the hub 11 completes the incorporation of the guide plate 20 into the loop assembly 10.

  In a state where the pair of guide plates 20 are incorporated in the loop assembly 10 as described above, these guide plates 20 are orthogonal to the hub axis L. The hub 11 is rotatably supported on the guide plate 20 by a bearing 30. The inner elastic loop 12 is disposed between the pair of guide plates 20 and is separated from the guide plate 20 in the hub axis L direction.

  The outer elastic loop 13 has both side edges 13a in contact with the outer periphery of the upper portion 21 and the front and rear end portions 22 and 23 of the guide plate 20, and is elastically deformed into a shape that is horizontally crushed vertically. Accordingly, the inner elastic loop 12 is also elastically deformed into an elliptical shape crushed up and down.

When the wheel having the above configuration is a driven wheel, one guide plate 20 is fixed to the body 1 to be attached to the body 1.
When the robot has four wheels, at least one of the front and rear wheels 2 is a driving wheel, but when the wheel 2 is a driving wheel, the output shaft of the driving source including the motor mounted on the body 1 is one of the wheels. It is connected to the bearing holder 32 or penetrates the bearing holder 32 and is connected to the inner periphery of the hub 11. As another mode, one end of the hub 11 may be extended and protruded into the body 1, and the extended end may be connected to the output shaft of the drive source.

  In the above configuration, when the motor on the body 1 side is driven, the hub 11 rotates, and the rotation of the hub 11 is transmitted to the outer elastic loop 13 via the inner elastic loop 12. The outer elastic loop 13 is grounded and rotates while being in contact with and rubbing the upper portion 21 of the peripheral portion of the guide plate 20 and the outer circumferences of the front and rear end portions 22 and 23, whereby the robot runs. The lug 18 bites into the ground plane and provides traction.

  The outer elastic loop 13 is maintained in a substantially elliptical shape that is crushed up and down by a pair of guide plates 20. Therefore, the ground contact area is large, and it is possible to travel stably without digging soft ground such as sand on the moon surface, and it is possible to suppress the dust from being rolled up.

  Even if the outer elastic loop 13 is not easily crushed by the weight of the robot alone because the robot is light or the gravity is small like the moon surface, the outer elastic loop 13 is forcibly forced by the guide plate 20 as described above. Since it is pulled horizontally and crushed up and down, a sufficient ground contact area can be secured.

  As described above, the outer elastic loop 13 is elastically deformed by the guide plate 20 so as to be crushed up and down, and the inner elastic loop 12 is also elastically deformed accordingly, so that the loop assembly 13 has a so-called preload. Is hanging. Therefore, the rigidity against load is high, the elastic deformation of the elastic loops 12 and 13 is small with respect to the fluctuation of the load during running, the fluctuation of the height of the robot can be suppressed, and a more stable running is possible. It is.

  When running, each inner elastic loop 12 is such that the line connecting the fixing points 12a and 12b forms a short axis when it is positioned up and down, and the line forms a long axis when it is positioned back and forth. Repeat elastic deformation.

  The guide plate 20 maintains the elastic loops 12 and 13 in parallel with the hub axis L and also serves to prevent the loop assembly 10 from being twisted. By preventing the twisting, more stable traveling is possible.

The present invention is not limited to the above embodiment, and various aspects can be adopted. For example, the wheel 2 having the above-described configuration can be used even on soft ground such as deep sea sandy or swampy land where buoyancy on the earth is applied.
The ground lug 18 may be omitted.
The guide plate 20 may be omitted. In this case, since the loop assembly 10 is elastically deformed by the weight of the body 1 or the like, the ground contact area can be increased as compared with a normal wheel. In this case, the elastic loops 12 and 13 may have the same width.
The outer elastic loop 13 may not contact the upper part of the guide plate 20.
The number of the inner elastic loops 12 is not limited to four, and may be three or five or more.
When used with a celestial body, the inner elastic loop 12 and the outer elastic loop may use polyimide thin plates that are resistant to cosmic rays. When used on the seabed, non-water-soluble resins and rubbers, or composites with metals may be used.

  The wheel of the present invention can be used for running on soft ground such as sand, and can also be used for running on celestial bodies such as the moon.

DESCRIPTION OF SYMBOLS 10 Loop assembly 11 Hub 12 Inner elastic loop 13 Outer elastic loop 18 Grounding lug 20 Guide plates 22, 23 Front and rear end portions 30 Bearing

Claims (5)

  A hub, a plurality of inner elastic loops fixed at equal intervals on the outer periphery of the hub, and an outer elastic loop that surrounds the plurality of inner elastic loops and is fixed to be in contact with each inner elastic loop. A traveling wheel characterized in that an elastic loop is grounded. And a pair of guide plates that are orthogonal to the axis of the hub and extend in the horizontal direction.
The hub is rotatably supported by the guide plates, and the inner elastic loop is disposed between the guide plates,
The outer elastic loop rotates in a state in which both side edges in the axial direction of the hub are elastically deformed so as to circumscribe the horizontal ends of the pair of guide plates and become longer in the horizontal direction. The traveling wheel according to claim 1.   The outer elastic loop and the inner elastic loop are made of elastic strips, the outer elastic loop is wider than the inner elastic loop, and both side edges protrude from the inner elastic loop in the axial direction of the hub. Item 3. The traveling wheel according to Item 2.   The traveling wheel according to claim 3, wherein the elastic band plate is made of a metal band plate.   The traveling wheel according to any one of claims 1 to 4, wherein a lug is provided on the outer periphery of the outer elastic loop with an interval.