JP2018094998A - Wheel structure and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel structure and a vehicle capable of improving a traveling property with respect to an irregular ground such as a step, a slope, and a bumpy road while stabilizing a load-carrying platform when the vehicle travels forward and backward.SOLUTION: A wheel structure includes a base member being extended in a forward/backward direction, an extension base part that is fixed to the base member and extended in the vertical direction from the base member, a driving wheel support part connecting the base member and driving wheels such that the driving wheels are relatively movable in the vertical direction with respect to the base member, and a lever member that is extended to intersect with the extension base part and supported to be rotatable with respect to the extension base part. When the driving wheels are relatively moved in the vertical direction with respect to the base member, driven wheels are respectively linked and relatively moved in the vertical direction through the lever member.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wheel structure and a vehicle.

  Matters required for a left-right independent drive type moving mechanism such as a robot having wheels are traversability, agility, and stability. Traversability refers to the ability to move on a road surface of any shape while the wheels are in contact with the ground, while maintaining a stable weight balance of the robot body, without being inoperable during a fall or moving. . Agility is the ability to achieve spatial and temporal efficiencies and diversification of robot work, such as turning around, moving while maintaining posture, and lightness of movement. It is desired to design a moving mechanism having an optimum structure so that each of these performances can be secured in a balanced manner and can be operated at a realistic cost.

A robot having a moving mechanism as described above may have a loading platform so that a load can be carried. Examples of the moving mechanism of the robot having the loading platform include a four-wheel or six-wheel moving mechanism.
As the four-wheel moving mechanism, two driving wheels that are driven separately in the same straight line are arranged in the center, and two caster wheels that can be rotated in a free direction symmetrically in the horizontal plane are arranged before and after that. There is a so-called opposed two-wheel structure mechanism.
Moreover, as a 6-wheel moving mechanism, there is a rocker bogie mechanism having both a rocker link and a bogie link as disclosed in Non-Patent Document 1. In the rocker bogie mechanism, the support member that supports the rear wheel is configured to be rotatable with respect to the support member that supports the front wheel and the middle wheel via a rotation mechanism.

Richard Volpe, “Navigation Results from Desert Field Tests of the Rocky 7 Mars Rover Prototype” The International Journal of Robotics Research Vol. 18, No. 7, July 1999, pp. 669-683

  When using a four-wheel opposed two-wheel structure mechanism as a moving mechanism for a robot having a loading platform, each wheel and its support member are connected by a rigid body, so when overcoming the step, only one front wheel first climbs the step. . For this reason, the entire robot may be tilted, and the entire robot and the loading platform may become unstable. Further, since each wheel and its supporting member are connected by a rigid body, when the robot climbs from the horizontal plane and enters the slope, the two central driving wheels may float and cannot move forward.

In addition, when a six-wheel rocker bogie structure is used as a moving mechanism of a robot having a loading platform, each wheel comes in contact with the road surface and obtains good driving performance even when climbing over a step or traveling on a slope. Accordingly, it is possible to improve the traversability when climbing over a step or going up and down a slope.
On the other hand, since the rocker bogie structure has no symmetry in the front-rear direction, the traverse performance differs between forward travel and reverse travel, and particularly when a heavy load is mounted on the loading platform, it may become unstable during reverse travel. Also, the rocker bogie structure has links from the middle wheel to the center of gravity and from the center of gravity to the rear wheel when the link ratio from the front wheel to the rotating shaft of the rotating mechanism is the same as that of the rotating mechanism to the parking wheel. The ratio is different. For this reason, particularly when a heavy load is loaded on the loading platform, there is a risk that the vehicle may become unstable when climbing over a step.

  The present invention has been made in consideration of such circumstances, and in both forward and reverse travel, a wheel structure that improves the breakthrough of rough terrain such as steps, slopes, and uneven roads while stabilizing the loading platform and The object is to provide a vehicle.

  In order to solve the above problem, a wheel structure according to a first aspect of the present invention includes a base member extending in a first direction, a first passive wheel and a second passive wheel arranged in the first direction, A drive wheel that is disposed between the first passive wheel and the second passive wheel and can be driven independently, and is fixed to the base member, and extends from the base member in a second direction perpendicular to the first direction. Extending first and second extending bases, and an extending end of the first extending base so that the first passive wheel rotates with respect to the first extending base, An extension end of the second extension base so that the second passive wheel rotates with respect to a first passive wheel support part connecting the first passive wheel and the second extension base. And a second passive wheel support portion that connects the second passive wheel to the second passive wheel, and extends in the second direction, the drive wheel being in the second direction relative to the base member A drive wheel support part that connects the base member and the drive wheel so as to be relatively movable in a direction, a drive wheel base part fixed to the drive wheel, and a first rotation mechanism with respect to the drive wheel base part A first link member whose first end is rotatably supported, a second link member whose first end is rotatably supported via a second rotation mechanism with respect to the drive wheel base, The first extending base extends so as to intersect the first extending base, and is supported via a third rotating mechanism so as to be rotatable with respect to the first extending base, and is connected to the first passive wheel support. A first lever member having a first portion and a second portion connected to the second end of the first link member and facing the first portion across the third rotation mechanism; and the second lever member Extending to intersect the extension base and via a fourth rotating mechanism to the second extension base A first part supported rotatably and connected to the second passive wheel support part; connected to a second end of the second link member; and opposed to the first part across the fourth rotation mechanism A second lever member having a second portion, and when the drive wheel moves relative to the base member in the second direction, the first lever member and the second lever member Thus, the first passive wheel and the second passive wheel are configured to move relative to each other in the second direction.

  In the first direction, the distance from the support shaft of the first passive wheel to the rotation shaft of the third rotation mechanism, and the distance from the support shaft of the second passive wheel to the rotation shaft of the fourth rotation mechanism May be in a one-to-one ratio.

  The first link member and the first lever member are connected by a fifth rotating mechanism, the second link member and the second lever member are connected by a sixth rotating mechanism, and the first In a state where one passive wheel, the second passive wheel, and the driving wheel are in contact with a horizontal plane, the distance from the rotation axis of the first rotation mechanism to the rotation axis of the fifth rotation mechanism and the second rotation The distance from the rotation axis of the mechanism to the rotation axis of the sixth rotation mechanism is a one-to-one ratio, the distance from the rotation axis of the fifth rotation mechanism to the center of gravity, and the distance of the sixth rotation mechanism The distance from the rotation axis to the center of gravity may be a ratio of 1: 1.

  There may be a center of gravity of the wheel structure on a virtual extension line in the second direction from the axle of the drive wheel.

  In the first direction, the first rotation mechanism may be disposed closer to the second passive wheel than the second rotation mechanism.

  The first link member and the first lever member are connected by a fifth rotation mechanism whose position can be adjusted in the extending direction of the first lever member, and the second link member and the first lever member are connected to each other. The second lever member may be connected by a sixth rotating mechanism whose position can be adjusted in the extending direction of the second lever member.

  The first passive wheel support part includes a first suspension part that can reduce an impact applied from the first passive wheel, the first suspension part and the first lever member are connected, and The 2nd passive wheel support part may include the 2nd suspension part which can relieve the impact applied from the 2nd passive wheel, and the 2nd suspension part and the 2nd lever member may be connected.

  A vehicle according to a second aspect of the present invention, the vehicle comprising two wheel structures according to the first aspect, wherein the two wheel structures are perpendicular to both the first direction and the second direction. Linked in the direction.

  The vehicle according to the second aspect may further include a cargo bed constituted by the base members of the two wheel structures.

  The vehicle according to the second aspect may further include a load cell installed on the loading platform.

  According to the wheel structure and the vehicle according to the above aspect of the present invention, it is possible to improve the level of stepping on a step, a slope, and an uneven road on a rough road while stabilizing the loading platform.

1 is a top perspective view showing a vehicle according to an embodiment of the present invention. It is a side view which shows the vehicle and wheel structure which concern on embodiment of this invention. It is a top view which shows the vehicle and wheel structure which concern on embodiment of this invention. It is a front view which shows the vehicle and wheel structure which concern on embodiment of this invention. The grounding state of the wheel at the time of the vehicle which concerns on embodiment of this invention climbs a level | step difference is shown. The ground state of the wheel at the time of the vehicle which concerns on embodiment of this invention begins to climb a slope is shown. The wheel grounding state at the time of the vehicle which concerns on embodiment of this invention starts going down a slope is shown.

  Hereinafter, the present invention will be described based on preferred embodiments. In the present embodiment, it is assumed that the platform is stabilized when a step having a height of about 1/3 of the diameter of the wheel is traversed on a slope of about 10 degrees.

[Configuration of Vehicle 1 and Wheel Structure 10]
A vehicle 1 and a wheel structure 10 according to an embodiment of the present invention are shown in FIGS. FIG. 1 is a top perspective view of the vehicle 1. FIG. 2 is a side view of the vehicle 1 and the wheel structure 10. FIG. 3 is a top view of the vehicle 1 and the wheel structure 10. FIG. 4 is a front view of the vehicle 1 and the wheel structure 10. 2 to 4 show a state in which the loading platform and the load cell are removed from the viewpoint of easy viewing of the structure of the wheel structure 10. 1 to 4 is based on the premise that all wheels are in contact with a horizontal plane, and the state of each component may change when climbing over a step or a slope.

  In the drawings, X is the front-rear direction (first direction) of the vehicle 1, Z is the up-down direction (second direction) of the vehicle 1, and Y is the left-right direction (third direction) of the vehicle 1. In the following description, for convenience, the right side in FIG. 2 is the front side of the vehicle 1 (wheel structure 10), and the side on which the ground contact surface is provided is the lower side.

As shown in FIGS. 1 to 4, the vehicle 1 according to the present embodiment is a six-wheel mobile gantry constituted by two wheel structures 10. In the present embodiment, the same components are denoted by the same reference numerals.
The two wheel structures 10 are arranged so that the inner sides of the wheels face each other in the left-right direction Y, and base members 20 provided at the upper part of the wheel structure 10 are connected by a connecting member 13. Thereby, the vehicle 1 is supported in a state where the six wheels are in contact with the ground, and can stably stand on its own even when not being driven.
In addition, a loading platform 11 is provided on the upper part of the two wheel structures 10, and the vehicle 1 can carry a load on the loading platform 11.
In addition, four load cells 12 that are sensors capable of measuring weight are arranged on the loading platform 11 at intervals. Thereby, the weight of the load mounted on the loading platform 11 can be monitored via the load cell 12.

Next, the configuration of the wheel structure 10 will be described.
The wheel structure 10 according to the present embodiment includes a base member 20, passive wheels (first and second passive wheels) 21 and 22, and a drive wheel 23. In addition, the wheel structure 10 has a configuration for connecting the wheels 21 to 23 to the base member 20, extending base portions (first extending base portion, second extending base portion) 24 and 25, and passive wheel support portions. (First passive wheel support portion, second passive wheel support portion) 26 and 27 and a drive wheel support portion 28. Further, the wheel structure 10 includes a drive wheel base 29, link members (first link member, second link member) 30, 31, lever member (first lever) as a configuration for interlocking the wheels 21 to 23. Member, second lever member) 32, 33.

  The base member 20 is disposed on the wheel structure 10 and extends in the front-rear direction X. The base member 20 has a rectangular frame shape in plan view, and the loading platform 11 can be stably fixed on the two base members 20 connected by the connecting member 13.

  The passive wheels 21 and 22 are arranged in parallel with a space in the front-rear direction X. The passive wheels 21 and 22 do not have a drive mechanism, and are configured to rotate so as to face a free direction on a horizontal plane. Examples of the passive wheels 21 and 22 include a caster, a ball caster, and an omni-directional wheel (registered trademark) that is an omnidirectional wheel. Among these, it is particularly preferable to use a caster, and if a caster is used, a structure that is inexpensive and has high running performance can be realized. In addition, since the caster is excellent in load-bearing characteristics, even when a heavy load is mounted on the vehicle, the passive wheels 21 and 22 are damaged and it is difficult to run.

The drive wheel 23 is disposed between the passive wheels 21 and 22. The drive wheels 23 can be driven independently by a motor 34. When the vehicle 1 is moved forward, the two drive wheels 23 are rotated forward at the same speed, and when the vehicle 1 is moved backward, the two drive wheels 23 are rotated reversely at the same speed. Further, the vehicle 1 can be rotated in the horizontal direction by rotating the two drive wheels 23 in opposite directions.
In the present embodiment, the diameter of the drive wheel 23 disposed between the passive wheels 21 and 22 is larger than the diameter of the passive wheels 21 and 22. Thereby, the stability of the vehicle 1 in the front-rear direction X can be further increased.

Each of the extending bases 24 and 25 has a linear shape in which one end is fixed to the base member 20 and extends downward from the base member 20.
The extended base portion 24 extends downward from the front end portion of the base member 20, and the passive wheel support portion 26 is connected to the extended end portion 24 a via a rotation mechanism 56. The extending base 24 is provided with a rotation mechanism (third rotation mechanism) 52 for rotatably supporting the lever member 32. Similarly, the extended base portion 25 extends downward from the rear end portion of the base member 20, and the passive wheel support portion 27 is connected to the extended end portion 25 a via the rotation mechanism 57. The extension base 25 is provided with a rotation mechanism (fourth rotation mechanism) 53 for rotatably supporting the lever member 33.

The passive wheel support portions 26 and 27 are connected to the extended end portions 24a and 25a, respectively, and connect the extended base portions 24 and 25 to the passive wheels 21 and 22, respectively.
The passive wheel support portion 26 includes a passive wheel base portion 35 and a suspension portion 36.
The passive wheel base portion 35 has a V-shape configured by a portion 35 a that extends diagonally forward and downward from the extended end portion 24 a and a portion 35 b that extends downward therefrom and supports the passive wheel 21. The passive wheel support portion 26 is rotatable with a rotation mechanism 56 provided at the extended end portion 24a as a rotation axis. That is, the passive wheel support portion 26 is configured such that the passive wheel 21 is moved relative to the base member 20 in the vertical direction Z when the passive wheel 21 climbs over a step, a slope, or the like.
The suspension portion 36 extends in the up-down direction Z, and the first end 36a is rotatably attached to a substantially central portion of the portion 35a extending in the forward direction of the passive wheel base portion 35, and is opposite to the first end. The second end is rotatably attached to the first end 32 a of the lever member 32. Thereby, when the passive wheel 21 moves relative to the base member 20 in the vertical direction Z, the suspension part 36 can push up or pull down the first end 32 a of the lever member 32. As the suspension part 36, for example, a member including an impact buffering mechanism such as a coil spring or a damper, a bar member, or the like can be used. It is preferable to use an impact buffering member such as a coil spring as the suspension part 36 because the suspension part 36 can mitigate the impact applied to the vehicle 1 from the passive wheel 21 when the passive wheel 21 gets over a step or an obstacle.
Similarly, the passive wheel support portion 27 includes a passive wheel base portion 37 and a suspension portion 38.
The passive wheel base portion 37 has a V-shape that includes a portion 37 a that extends obliquely rearward and downward from the extended end portion 25 a and a portion 37 b that extends downward therefrom and supports the passive wheel 22. The passive wheel support portion 27 can rotate with a rotation mechanism 57 provided at the extended end portion 25a as a rotation axis. That is, the passive wheel support portion 27 is configured such that the passive wheel 22 is moved relative to the base member 20 in the vertical direction Z when the passive wheel 22 climbs over a step or a slope.
The suspension portion 38 extends in the up-down direction Z, the first end 38a is rotatably attached to the approximate center of the portion 37a extending in the forward direction of the passive wheel base portion 37, and the second end 38b is a lever member. A first end 33a of 33 is rotatably mounted. Thereby, when the passive wheel 22 moves relative to the base member 20 in the vertical direction Z, the suspension portion 38 can push up or pull down the first end 33 a of the lever member 33. Other configurations of the suspension portion 38 are the same as those of the suspension portion 36.

The drive wheel support portion 28 extends downward from approximately the center in the front-rear direction X of the base member 20, and connects the base member 20 and the drive wheel 23. The drive wheel support portion 28 is formed of a slide-type or extendable rod-like member, and the length in the vertical direction Z is variable. That is, the drive wheel 23 is configured to move relative to the base member 20 only in the vertical direction Z via the drive wheel support portion 28.
Thereby, for example, when the driving wheel 23 passes through the recess, the driving wheel support portion 28 extends due to the action of gravity, so that the driving wheel 23 can be kept in a grounded state. Therefore, it is possible to avoid the drive wheel 23 from floating and becoming impossible to move forward or backward. Further, for example, when the driving wheel 23 passes through the convex portion, the driving wheel support portion 28 is contracted so that all the wheels including the passive wheels 21 and 22 can be kept in contact with the ground. Therefore, it can be avoided that the passive wheels 21 and 22 float and the vehicle 1 becomes unstable.
Further, the drive wheel support portion 28 connects the base member 20 and the drive wheel 23, so that the drive wheel 23 does not move relative to the base member 20 and the loading platform 11 in the front-rear direction X. Therefore, the state of the loading platform 11 can be stabilized even when traveling on a step or a slope.
Further, the drive wheel support portion 28 may have a coil spring (not shown) that can bias the drive wheel support portion 28 in the expansion / contraction direction (vertical direction Z). In particular, in a state where the passive wheels 21 and 22 and the drive wheel 23 are in contact with the horizontal plane, the coil spring is preferably installed so that the drive wheel support portion 28 is biased in the extending direction. As a result, the impact applied to the vehicle 1 from the drive wheel 23 when the drive wheel 23 gets over a step or an obstacle can be mitigated, and the drive wheel 23 can be pressed against the ground when traveling on a horizontal plane.

  The drive wheel base 29 is fixed to the drive wheel 23. The drive wheel base 29 is a plate material having a substantially inverted triangular shape when viewed from the side. When the drive wheel support portion 28 expands and contracts in the vertical direction Z, the drive wheel base portion 29 moves relative to the base member 20 in the vertical direction Z in conjunction with the drive wheel 23. The drive wheel base 29 is provided with two rotation mechanisms (first rotation mechanism and second rotation mechanism) 50 and 51 spaced in the front-rear direction X. The drive wheel base 29 is connected to the link member 30 via the rotation mechanism 50 and to the link member 31 via the rotation mechanism 51.

One end of the link member 30 is rotatably supported with respect to the drive wheel base 29 via the rotation mechanism 50. The other end of the link member 30 is rotatably supported at a position close to the second end 32 b of the lever member 32 via a rotation mechanism (fifth rotation mechanism) 54.
Similarly, one end of the link member 31 is supported so as to be rotatable with respect to the drive wheel base 29 via the rotation mechanism 51. The other end of the link member 31 is rotatably supported via a rotation mechanism (sixth rotation mechanism) 55 at a position close to the second end 33 b of the lever member 33.

The lever member 32 is a rod-like member extending in the front-rear direction X so as to intersect the extended base portion 24. In a state where each wheel is in contact with the horizontal plane, the lever member 32 is inclined slightly upward toward the front. The lever member 32 is rotatably supported by the extension base 24 via a rotation mechanism 52 at the intersection with the extension base 24. Here, the first end (first portion) 32 a of the lever member 32 is rotatably supported by the second end 36 b of the suspension portion 36 of the passive wheel support portion 26. Further, a rotation mechanism 54 is disposed at a position (second portion) near the second end 32 b of the lever member 32, and is rotatably supported by the end portion of the link member 30 via the rotation mechanism 54. That is, the lever member 32 has a lever structure with the rotation mechanism 52 as a fulcrum. The rotation mechanism 54 may be provided so as to face the first end 33a with the rotation mechanism 52 interposed therebetween.
Therefore, when the passive wheel 21 moves upward with respect to the base member 20, the passive wheel support portion 26, the lever member 32, the link member 30, and the driving wheel base portion 29 are interlocked, and the driving wheel 23 moves relative to the base member 20. To move downward. Therefore, when the passive wheel 21 climbs over a step or uphill, the driving wheel 23 does not float, and the state where all the wheels are in contact with the ground can be stably maintained.
When the passive wheel 21 moves downward with respect to the base member 20, the passive wheel support portion 26, the lever member 32, the link member 30, and the drive wheel base portion 29 are interlocked, and the drive wheel 23 is moved relative to the base member 20. Move up. For example, when the passive wheel 21 gets over a recess or downhill, if the passive wheel 21 moves downward, the driving wheel 23 moves upward, and as long as the driving wheel 23 is grounded, the passive wheel 21 Move further in the direction toward the ground plane. Therefore, when the passive wheel 21 gets over the recess or the downhill, the passive wheel 21 does not float, and the state where all the wheels are grounded can be stably maintained.

  In the present embodiment, the distance from the rotation mechanism 52 to the rotation shaft 54 is set longer than the distance from the rotation mechanism 52 to the first end 32a of the lever member 32. Therefore, when the passive wheel 21 moves over the base member 20 even when the passive wheel 21 climbs over a step or uphill, the passive wheel support portion 26, the lever member 32, the link member 30, and the drive wheel base portion 29 are moved. In conjunction with this, the drive wheel 23 acts strongly to move downward relative to the base member 20. Therefore, the state in which the driving wheel 23 contacts the ground when the passive wheel 21 climbs over a step or uphill can be more stably maintained.

Similarly, the lever member 33 is a rod-shaped member extending in the front-rear direction X so as to intersect the extended base portion 25. In a state where each wheel is in contact with the horizontal plane, the lever member 33 is inclined slightly upward toward the rear. The lever member 33 is rotatably supported by the extension base 25 via a rotation mechanism 53 at the intersection with the extension base 25. Here, the first end (first portion) 33 a of the lever member 33 is rotatably supported by the second end 38 b of the suspension portion 38 of the passive wheel support portion 27. A rotation mechanism 55 is disposed at a position (second portion) near the second end 33 b of the lever member 33, and is rotatably supported by the end portion of the link member 31 via the rotation mechanism 55. That is, the lever member 33 has a lever structure with the rotation mechanism 53 as a fulcrum. The rotation mechanism 55 may be provided so as to face the first end 33a with the rotation mechanism 53 interposed therebetween.
When the passive wheel 22 moves upward with respect to the base member 20, the passive wheel support portion 27, the lever member 33, the link member 31, and the drive wheel base portion 29 are interlocked so that the drive wheel 23 moves downward with respect to the base member 20. Move in the direction. Therefore, even when the passive wheel 22 climbs over a step or an uphill, the state where all the wheels are grounded can be stably maintained without the drive wheel 23 floating.
Further, when the passive wheel 22 moves downward with respect to the base member 20, the passive wheel support portion 27, the lever member 33, the link member 31, and the drive wheel base portion 29 are interlocked so that the drive wheel 23 moves relative to the base member 20. Move up. For example, when the passive wheel 22 gets over a recess or downhill, if the passive wheel 21 moves downward, the driving wheel 23 moves upward, and as long as the driving wheel 23 is grounded, the passive wheel 22 Move further in the direction toward the ground plane. Therefore, even when the passive wheel 22 gets over the recess or the downhill, the passive wheel 22 can be stably kept in a state where all the wheels are grounded without being lifted.

  In the present embodiment, the distance from the rotation mechanism 52 to the rotation shaft 54 is set longer than the distance from the rotation mechanism 52 to the first end 32a of the lever member 32. Therefore, when the passive wheel 21 moves over the base member 20 even when the passive wheel 21 climbs over a step or uphill, the passive wheel support portion 26, the lever member 32, the link member 30, and the drive wheel base portion 29 are moved. In conjunction with this, the drive wheel 23 acts strongly to move downward relative to the base member 20. Therefore, the state in which the driving wheel 23 contacts the ground when the passive wheel 21 climbs over a step or uphill can be more stably maintained.

  That is, in the present embodiment, not only when the vehicle 1 is moving forward but also when moving backward, it is possible to stably maintain a state where all the wheels are in contact with the ground when climbing over a step or a slope.

Further, as an operation opposite to the operation of the lever structure described above, when the driving wheel 23 moves upward with respect to the base member 20, the driving wheel base 29, the link member 30, the lever member 32, and the passive wheel support portion 26 are interlocked. Thus, the passive wheel 21 moves downward with respect to the base member 20. Further, the driving wheel base 29, the link member 31, the lever member 33, and the passive wheel support portion 27 are interlocked to move the passive wheel 22 downward with respect to the base member 20. Therefore, when the driving wheel 23 gets over an obstacle or the like, the passive wheels 21 and 22 do not float, and the state where all the wheels are grounded can be stably maintained.
Further, when the driving wheel 23 moves downward with respect to the base member 20, the driving wheel base 29, the link member 30, the lever member 32, and the passive wheel support portion 26 are interlocked so that the passive wheel 21 moves relative to the base member 20. Move up. Further, the drive wheel base 29, the link member 31, the lever member 33, and the passive wheel support portion 27 are interlocked to move the passive wheel 22 upward with respect to the base member 20. For example, when the driving wheel 23 gets over the recess, if the driving wheel 23 moves downward, the passive wheels 21 and 22 move upward, and as long as the passive wheels 21 and 22 are grounded, the driving wheel 23 Moves further in the direction toward the ground plane. Therefore, when the driving wheel 23 gets over the recess, the driving wheel 23 does not float, and the state where all the wheels are grounded can be stably maintained.

  Further, the lever members 32 and 33 have long holes 32c and 33c each having a long side in a direction parallel to the direction in which the lever members 32 and 33 extend. The position of the rotation mechanism 54 in the lever member 32 can be adjusted by the length of the long hole 32c. Furthermore, the position of the rotation mechanism 55 in the lever member 33 can be adjusted by the length of the long hole 33c. As a result, the vehicle 1 can be run after the rotation mechanisms 54 and 55 are arranged at optimum positions in accordance with the size and shape of the level difference and obstacles assumed. For example, if the rotating mechanisms 54 and 55 are respectively arranged at positions closer to the second ends 32 b and 33 b of the lever members 32 and 33, the distance in which the passive wheel 21 or 22 is separated from the driving wheel 23 in the vertical direction Z. Can move relative to Therefore, even when the vehicle 1 gets over a large step, it is possible to stably maintain a state where all the wheels 21, 22, and 23 are in contact with the ground.

  Further, in the present embodiment, the rotation mechanism 50 is disposed closer to the passive wheel 22 than the rotation mechanism 51 in the front-rear direction X, and accordingly, the rotation mechanism 54 is greater than the rotation mechanism 55 in the front-rear direction X. It is arranged at a position close to the passive wheel 22. By arranging the rotation mechanisms 50, 51, 54, and 55 in this way, the lengths of the lever members 32 and 33 can be configured to be longer. Thereby, the movable range to the up-down direction Z of the passive wheels 21 and 22 can be expanded, and the state which all the wheels contact | ground can be maintained even if it is a bigger level | step difference or a steep slope.

In this embodiment, in the front-rear direction X, the distance from the ground contact position of the passive wheel 21 to the rotation shaft of the rotation mechanism 52 and the distance from the ground contact position of the passive wheel 22 to the rotation shaft of the rotation mechanism 53 are a pair. A ratio of 1 is preferred. Thereby, the difference in leveling performance between forward and reverse travel can be suppressed.
However, when a caster is used as the passive wheels 21 and 22, the relative position of the grounding point of the passive wheels 21 and 22 with respect to the rotation mechanisms 52 and 53 varies depending on the traveling direction by yawing. Therefore, you may design based on the positional relationship with the support shafts L1 and L2 of the passive wheels 21 and 22. FIG. In this case, the distance from the support axis L1 of the passive wheel 21 to the rotation axis of the rotation mechanism 52 and the distance from the support axis L2 of the passive wheel 22 to the rotation axis of the rotation mechanism 53 are in a one-to-one ratio. preferable.
Note that the above-described ratios do not have to be strictly one-to-one, and some errors are allowed as long as the difference in stepping performance between forward and reverse travel can be sufficiently suppressed.

In the present embodiment, the distance from the rotation axis of the rotation mechanism 50 to the rotation axis of the rotation mechanism 54 and the rotation from the rotation axis of the rotation mechanism 51 in a state where the passive wheels 21 and 22 and the drive wheel 23 are in contact with the horizontal plane. The distance from the rotation axis of the mechanism 55 to the center of gravity G is 1: 1, and the distance from the rotation axis of the rotation mechanism 54 to the center of gravity G and the distance from the rotation axis of the rotation mechanism 55 to the center of gravity G are 1: 1. It is preferable that the wheel structure 10 is configured to have a ratio. By configuring the wheel structure 10 in this way, it is possible to further suppress the difference in leveling performance between forward and reverse travel.
In addition, the above-mentioned ratio does not need to be strictly 1: 1, and a slight error is allowed if the difference in stepping performance between forward traveling and backward traveling can be sufficiently suppressed.

  In the present embodiment, the wheel structure 10 is preferably configured so that the center of gravity G is on a virtual extension line in the vertical direction Z from the axle of the drive wheel 23. By configuring the wheel structure 10 in this way, the stability of the vehicle 1 during traveling can be enhanced.

  Moreover, as a material of each element which comprises the vehicle 1, what is necessary is just to use a metal, wood, a resin material, ceramics, etc., and if it has the characteristic suitable for a use, it will not be limited.

  According to the vehicle 1 according to the present embodiment, the other wheels are interlocked according to the vertical movement of each wheel, so that the load can be distributed to each wheel, thereby making it possible to smoothly travel. Therefore, with the vehicle 1 according to the present embodiment, it is possible to improve the level difference, the inclination, and the rough road through the uneven road while stabilizing the loading platform.

[Grounding state of each wheel when the vehicle 1 goes through the steps and slopes]
5 to 7 schematically show the ground contact state of each wheel when the vehicle 1 passes through the steps and the slope. FIG. 5 shows the ground contact state of the wheel when the vehicle 1 climbs the step, FIG. 6 shows the vehicle as it begins to climb the slope, and FIG. 7 shows the wheel when the vehicle 1 begins to descend the slope.

  As shown in FIG. 5, according to the vehicle 1 according to the present embodiment, the wheels 21 to 23 move up and down in conjunction with each other even immediately after the passive wheel 21 climbs the step P, so that sufficient grounding is provided to the drive wheel 23. It is possible to break through without running idle while having power. In addition, even immediately after the drive wheel 23 rides on the step P, each of the wheels 21 to 23 moves up and down in conjunction with each other, so that the passive wheel 22 that is the rear wheel can maintain a grounded state. Therefore, it is possible to stably step through the step P with all the wheels in contact with the ground.

  Further, as shown in FIG. 6, according to the vehicle 1 according to this embodiment, the wheels 21 to 23 move up and down in conjunction with each other even immediately after the passive wheel 21 climbs from the horizontal plane and enters the slope. It is possible to step through the vehicle without idling while maintaining a sufficient grounding force at 23. Further, after that, the grounding state can be maintained until all the wheels climb and completely enter the slope. Therefore, it is possible to stably climb and climb over the slope while all the wheels are in contact with the ground.

  Furthermore, as shown in FIG. 7, according to the vehicle 1 according to the present embodiment, the passive wheels 21 to 23 move up and down in conjunction with the passive wheels 21 immediately after the passive wheels 21 enter the down slope from the horizontal plane. It is possible to pass through the passive wheel 21 without floating and being in an unstable state while maintaining a sufficient grounding force on the wheel 21. Further, after that, the ground contact state can be maintained until all the wheels completely enter the down slope. Therefore, it is possible to stably traverse downhill slopes with all wheels in contact with the ground.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these examples. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the scope of the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 10 ... Wheel structure, 11 ... Loading platform, 12 ... Load cell, 20 ... Base member, 21, 22 ... Passive wheel (1st passive wheel, 2nd passive wheel), 24, 25 ... Extension base (1st 1 extended base, second extended base), 24a, 25a ... extended end, 26, 27 ... passive wheel support (first passive wheel support, second passive wheel support), 28 ... driving wheel support part, 29 ... driving wheel base part, 30, 31 ... link member (first link member, second link member), 32, 33 ... lever member (first lever member, second lever member) ), 50 to 55: Rotating mechanism (first to sixth rotating mechanisms), G: Center of gravity

Claims (10)

A wheel structure,
A base member extending in a first direction;
A first passive wheel and a second passive wheel arranged in the first direction; a drive wheel disposed between the first passive wheel and the second passive wheel and capable of being driven independently;
First and second extending bases fixed to the base member and extending from the base member in a second direction perpendicular to the first direction;
A first passive wheel support portion that connects the extended end portion of the first extension base portion and the first passive wheel so that the first passive wheel rotates relative to the first extension base portion. When,
A second passive wheel support portion that connects the extension end portion of the second extension base portion and the second passive wheel so that the second passive wheel rotates with respect to the second extension base portion. When,
A driving wheel support that extends in the second direction and connects the base member and the driving wheel so that the driving wheel is relatively movable in the second direction with respect to the base member;
A drive wheel base fixed to the drive wheel;
A first link member having a first end supported rotatably with respect to the drive wheel base via a first rotation mechanism;
A second link member having a first end supported rotatably relative to the drive wheel base via a second rotation mechanism;
The first extending base extends so as to intersect the first extending base, and is supported via a third rotating mechanism so as to be rotatable with respect to the first extending base, and is connected to the first passive wheel support. A first lever member connected to the second end of the first link member and facing the first portion across the third rotation mechanism;
The second extending base extends so as to intersect the second extending base, and is rotatably supported via a fourth rotating mechanism with respect to the second extending base, and is connected to the second passive wheel support. And a second lever member connected to the second end of the second link member and having a second portion facing the first portion across the fourth rotation mechanism,
When the driving wheel moves relative to the base member in the second direction, the first passive wheel and the second passive wheel are moved through the first lever member and the second lever member, respectively. A wheel structure configured to move relative to each other in the second direction.   In the first direction, the distance from the support shaft of the first passive wheel to the rotation shaft of the third rotation mechanism, and the distance from the support shaft of the second passive wheel to the rotation shaft of the fourth rotation mechanism The wheel structure according to claim 1, wherein and are in a one-to-one ratio. The first link member and the first lever member are connected by a fifth rotation mechanism, the second link member and the second lever member are connected by a sixth rotation mechanism,
In a state where the first passive wheel, the second passive wheel, and the driving wheel are in contact with a horizontal plane, the distance from the rotation axis of the first rotation mechanism to the rotation axis of the fifth rotation mechanism and the second The distance from the rotation axis of the rotation mechanism to the rotation axis of the sixth rotation mechanism is a 1: 1 ratio, and the distance from the rotation axis to the center of gravity of the fifth rotation mechanism is the sixth rotation. The wheel structure according to claim 1 or 2, wherein the distance from the rotation axis of the mechanism to the center of gravity is a ratio of 1: 1.   The wheel structure as described in any one of Claims 1-3 which has a gravity center on the virtual extension line to the said 2nd direction from the axle shaft of the said driving wheel.   The wheel structure according to any one of claims 1 to 4, wherein in the first direction, the first rotation mechanism is disposed closer to the second passive wheel than the second rotation mechanism. body.   The first link member and the first lever member are connected by a fifth rotation mechanism whose position can be adjusted in the extending direction of the first lever member, and the second link member and the first lever member are connected to each other. The wheel structure according to any one of claims 1 to 5, wherein the second lever member is connected by a sixth rotating mechanism whose position is adjustable in a direction in which the second lever member extends. The first passive wheel support part includes a first suspension part capable of mitigating an impact applied from the first passive wheel, and the first suspension part and the first lever member are connected;
2. The second passive wheel support portion includes a second suspension portion that can reduce an impact applied from the second passive wheel, and the second suspension portion and the second lever member are connected to each other. The wheel structure as described in any one of -6. A vehicle,
Two wheel structures according to any one of claims 1 to 7 are provided,
The vehicle in which the two wheel structures are connected in a third direction perpendicular to both the first direction and the second direction.   The vehicle according to claim 8, further comprising a cargo bed provided on the base member of the two wheel structures.   The vehicle according to claim 9, further comprising a load cell installed on the loading platform.

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