Movable body

Abstract

To provide a movable body capable of dispersing a load applied to a wheel among a plurality of wheels when traveling on an uneven surface.SOLUTION: A movable body according to the present disclosure includes: a vehicle body; at least a pair of drive wheels; a unit rotation shaft connected to the vehicle body along a front and rear direction of the vehicle body; and a rotation unit having a drive wheel holding member that is connected to the vehicle body via the unit rotation shaft, has both end portions connected with the paired drive wheels, and rotates the drive wheels around the unit rotation shaft.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle that uses wheels. [Background technology]

[0002] For example, when a vehicle equipped with wheels travels on an uneven surface, the wheels may come off the surface. In such cases, the detached wheels cannot support the vehicle's own weight and cannot transmit driving force to the surface. For this reason, there is a demand for wheels to always be in contact with the surface, even if the surface is uneven.

[0003] An example of a moving body having a mechanism for grounding wheels on a running surface is the running body disclosed in Patent Document 1. The running body disclosed in Patent Document 1 includes a frame having a left axle holder, a right axle holder, and connecting portions connecting the left and right axle holders, an axle of a left wheel unit rotatably held by the left axle holder, and an axle of a right wheel unit rotatably held by the right axle holder, and further includes a wheel grounding mechanism having, between the left and right axle holders, a protruding member attached to the axle of the left wheel unit, a protruding member attached to the axle of the right wheel unit, an axle provided on the frame disposed between the protruding members, a swinging member whose middle portion in the left-right direction serving as the swing center is supported by the axle, and a link member that links the protruding members and the swinging member.

[0004] The running vehicle disclosed in Patent Document 1 has a wheel ground contact mechanism that allows a pair of diagonally arranged left front and right rear wheels and a pair of left rear and right front wheels to move up and down in opposite directions, so that the wheels of the running vehicle disclosed in Patent Document 1 can contact the ground even on uneven surfaces. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-100539 Summary of the Invention [Problem to be solved by the invention]

[0006] Autonomous controlled robots have been developed as mobile objects. Because autonomous mobile robots must travel along a predetermined path, they are required to have the ability to move in a straight line regardless of the driving environment.

[0007] In a vehicle with a mechanism for grounding its wheels on an uneven surface, the magnitude of the force (ground pressure) exerted on the wheels by the surface may vary significantly depending on the wheel due to changes in the vehicle's posture, etc. In this case, a large load may be placed on the drive mechanism that drives some of the wheels, or the vehicle's ability to move in a straight line may be impaired.

[0008] The present disclosure aims to provide a moving body that can distribute the load acting on a wheel among a plurality of wheels when traveling on an uneven surface. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the mobile body of the present disclosure comprises a vehicle body, at least one pair of drive wheels, a unit rotation shaft connected to the vehicle body along the fore-and-aft direction of the vehicle body, and a rotation unit connected to the vehicle body via the unit rotation shaft, having a pair of drive wheels connected to both ends, and having a drive wheel holding member that rotates the drive wheels around the unit rotation shaft as a rotation center. [Effects of the Invention]

[0010] According to the present disclosure, with a moving body of the present disclosure, when traveling on an uneven surface, the load acting on the wheels can be distributed among a plurality of wheels. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view illustrating an example of the appearance of a moving body according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a diagram illustrating a drive wheel unit. [Figure 3] Side view of drive wheel unit [Figure 4] FIG. 1 is a perspective view illustrating an example of the outer shape of a drive wheel unit rotation shaft; [Figure 5] FIG. 10 is a diagram illustrating an example of rotation of a drive wheel unit including a drive wheel holding member; [Figure 6] FIG. 1 is a diagram illustrating a driven wheel unit; DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, more detailed explanation than necessary, such as detailed explanation of well-known matters or redundant explanation of substantially the same configuration, may be omitted.

[0013] FIG. 1 is a perspective view showing an example of the appearance of a moving body according to an embodiment of the present disclosure. FIG. 1 illustrates a state in which moving body 100 is positioned on a horizontal traveling surface. Moving body 100 according to an embodiment of the present disclosure is a moving body that can move by general means such as autonomous control, remote control, or manual operation. The use of moving body 100 is not limited to a specific use, and may include, for example, a transport vehicle that transports people, objects, etc., a self-propelled cart for cleaning or advertising purposes, etc.

[0014] In the following description, the up-down direction, left-right direction, and front-to-rear direction are directions relative to the moving body 100. That is, as shown in FIG. 1, the up-down direction corresponds to the up-down direction as seen from the moving body 100 when all four wheels (two drive wheels 21 and two driven wheels 31) of the moving body 100 are in contact with a flat running surface (horizontal surface). Furthermore, the front-to-rear direction corresponds to the front-to-rear direction as seen from the moving body 100 when the straight moving direction of the moving body 100 is defined as the front and the opposite direction is defined as the rear. Furthermore, the left-to-right direction corresponds to the left-to-right direction as seen from the moving body 100 when the straight moving direction of the moving body 100 is defined as the forward direction.

[0015] In this specification, the position of each wheel when it is in contact with a horizontal traveling surface may be referred to as the reference position.

[0016] As shown in FIG. 1, the vehicle 100 includes a body 10, a drive wheel unit 20, and a driven wheel unit 30. The drive wheel unit 20, which includes two drive wheels 21, is located in the rear center of the body 10. Two independent driven wheel units 30 are located on the front right and front left sides of the body 10, respectively. Each of the two driven wheel units 30 includes a driven wheel 31 located on the front right and front left sides of the body 10, respectively. The driven wheel unit 30 located on the front right side of the body 10 and the driven wheel unit 30 located on the front left side of the body 10 each have a symmetrical structure.

[0017] The left and right drive wheels 21 can be rotated in unison by the drive wheel unit 20 along a rotation axis parallel to the front-rear direction of the vehicle body 10. As a result, even if a difference in height occurs between the left and right drive wheels 21, for example, when the vehicle 100 travels on an uneven surface and one of the left and right drive wheels 21 rides up on a convex part or gets stuck in a concave part, both drive wheels 21 can maintain a state of contact with the surface.

[0018] In addition, the left and right driven wheels 31 can move in the up and down direction of the vehicle body 10 by the driven wheel units 30.

[0019] This allows all four wheels (two drive wheels 21 and two driven wheels 31) to remain in contact with the traveling surface, even when the traveling object 100 travels on an uneven traveling surface.

[0020] <Body 10> The vehicle body 10 has an upper frame 11 and a lower frame 12. The upper frame 11 is composed of a pair of front and rear frames extending in the front-rear direction and multiple pairs of left and right frames extending in the left-right direction, which are arranged on the same plane. The lower frame 12 is arranged below the upper frame 11. The lower frame 12 is formed so as to avoid the drive wheels 21 and the driven wheels 31. A space is provided between the upper frame 11 and the lower frame 12, and control equipment, a power source, etc. of the vehicle 100 can be placed in this space as needed. The upper surface of the upper frame 11 may also be configured so as to be usable as a cargo bed.

[0021] <Drive wheel unit 20> The drive wheel unit 20 is attached to the upper frame 11 and the lower frame 12.

[0022] Fig. 2 is a diagram for explaining the drive wheel unit 20. Fig. 3 is a side view of the drive wheel unit 20. Note that in Fig. 3, the drive wheel 21 on the near side is made transparent.

[0023] The drive wheel unit 20 includes a drive wheel 21, a rotation unit 22, an elastic unit 23, a mounting member 24, a drive device 25, and a brake device 26.

[0024] The rotation unit 22 is configured to connect the vehicle body 10 (particularly the lower frame 12) and the drive wheels 21. When a difference in height occurs between the left and right drive wheels 21, the rotation unit 22 can rotate the left and right drive wheels 21 in conjunction with each other by rotating a part of the rotation unit 22 about a predetermined center of rotation. Furthermore, even when a part of the rotation unit 22 rotates as the drive wheels 21 move up and down, the remaining part of the rotation unit 22 can maintain its original position (for example, a substantially horizontal position). This allows the vehicle body 10 to maintain a horizontal position even when a difference in height occurs between the left and right drive wheels 21.

[0025] The rotation unit 22 includes a unit rotation shaft 221 , a unit rotation shaft holder 222 , a drive wheel holder 223 , a restoring member 224 , and a rotation suppressing member 225 .

[0026] The unit rotation shaft 221 is a rotation shaft arranged along the front-rear direction of the vehicle body 10. The unit rotation shaft 221 is rotatably held by a unit rotation shaft holder 222 and connected to the vehicle body 10. The unit rotation shaft 221 is also fixed to the left and right central parts of drive wheel holder members 223 arranged along the left and right direction of the vehicle 100.

[0027] The left and right drive wheels 21 are connected to both ends of the drive wheel holding member 223. The drive wheel holding member 223 is, for example, a rod-shaped member extending in the left-right direction of the vehicle body 10. In other words, the distance from the position of the unit rotation shaft 221, which is the rotation center of the drive wheel holding member 223, to the left end of the drive wheel holding member 223, i.e., the left drive wheel 21, is equal to the distance from the right end of the drive wheel holding member 223, i.e., the right drive wheel 21. This allows the drive wheel holding member 223 to rotate the left and right drive wheels 21 around the unit rotation shaft 221.

[0028] The drive wheel holding member 223 does not necessarily have to be a member that extends linearly along the left-right direction of the vehicle body 10, and may include a curved portion.

[0029] A drive device 25 for driving each of the left and right drive wheels 21 and a brake device 26 for stopping the rotation of the drive wheels 21 may be connected to both ends of the drive wheel holding member 223. The drive device 25 is, for example, an electric motor including a gear. It is desirable that the brake device 26 is provided with a lever that can be manually released, but this is not necessary.

[0030] The drive unit 25 can independently control the rotational speeds of the left and right drive wheels 21. As a result, the drive unit 25 can differentially drive the moving body 100 by controlling the rotational speeds of the pair of left and right drive wheels 21.

[0031] With this configuration, the pair of drive wheels 21 arranged on the left and right can rotate in conjunction with each other via the unit rotation shaft 221 and the drive wheel holding member 223. As a result, when at least one of the drive wheels 21 moves upward or downward from the reference position, for example, when the movable body 100 travels on an uneven surface and the drive wheel 21 rides over a convex portion or gets stuck in a concave portion, the drive wheel holding member 223 rotates around the unit rotation shaft 221 as the center of rotation. For example, when one of the drive wheels 21 moves downward, the other drive wheel 21 moves upward.

[0032] As a result, even if the mobile body 100 travels on an uneven surface and one of the drive wheels 21 moves up or down from its reference position due to the unevenness, the other drive wheel 21 moves in the opposite direction in conjunction with the other drive wheel 21, thereby maintaining both drive wheels 21 in contact with the surface. Furthermore, since the load acting on the left and right drive wheels 21 can be evenly distributed between the left and right, it is possible to prevent large ground contact pressure from occurring between some of the drive wheels 21 and the surface, and to prevent a situation in which large ground contact pressure places a heavy burden on the drive unit 25. Furthermore, even when the mobile body 100 travels on an uneven surface, the left and right drive wheels 21 can transmit driving force to the surface without any problems, thereby providing the mobile body 100 with good straight-line performance.

[0033] The restoring member 224 is an elastic body that applies a restoring force to the unit rotation shaft 221 to restore the drive wheel 21 to a reference position when the drive wheel 21 and the drive wheel holding member 223 rotate. The restoring member 224 is disposed between the drive wheel holding member 223 and the unit rotation shaft 221, and is fixed to the unit rotation shaft holding portion 222 and the lower frame 12. As a result, the restoring member 224, together with the unit rotation shaft holding portion 222, holds the unit rotation shaft 221 rotatably relative to the vehicle body 10. In this specification, the restoring force that the restoring member 224 applies to the unit rotation shaft 221 to restore the drive wheel 21 to the reference position is referred to as a first restoring force.

[0034] FIG. 4 is a perspective view illustrating the outer shape of the unit rotation shaft 221. The outer shape of the unit rotation shaft 221 is a shape in which a portion of the side of a cylindrical member is cut off, and includes curved and flat portions. The unit rotation shaft 221 is held by the unit rotation shaft holder 222 at the curved portion. Furthermore, the unit rotation shaft 221 transmits force from the restoring member 224 at the flat portion. This achieves the following functions. That is, the unit rotation shaft 221 has both the function of providing rotational freedom to the drive wheel holding member 223 and the function of receiving a restoring force from the restoring member 224.

[0035] The restoring member 224 is made up of, for example, four pieces of rubber material arranged to form a square hole. When the unit rotation shaft 221 rotates, at least a portion of the rubber material of the restoring member 224 elastically deforms, generating a first restoring force that restores the drive wheel 21 to a reference position relative to the unit rotation shaft 221. Furthermore, the restoring member 224 can also function as a damper against the rotation of the unit rotation shaft 221 due to the friction of the rubber material.

[0036] Even if a difference in height occurs between the left and right drive wheels 21 and causes the drive wheels 21, unit rotation shaft 221, and drive wheel holding member 223 to rotate, the unit rotation shaft holding portion 222 and the restoring member 224 do not rotate, and therefore the lower frame 12 (body 10) connected to the unit rotation shaft holding portion 222 and the restoring member 224 does not rotate either. As a result, even if the left and right drive wheels 21 and drive wheel holding member 223 rotate, the posture of the body 10 is maintained approximately horizontal.

[0037] The rotation suppressing member 225 is a member that suppresses rotation of the drive wheels 21 and the drive wheel holding member 223 beyond a predetermined rotation range. The rotation suppressing member 225 is fixed to the unit rotation shaft holding portion 222. When the drive wheels 21 and the drive wheel holding member 223 rotate to a predetermined position, the drive wheel holding member 223 comes into contact with the rotation suppressing member 225, thereby suppressing further rotation. This makes it possible to prevent an unnecessary difference in the vertical height of the left and right drive wheels 21.

[0038] The elastic body unit 23 is a structure for applying a restoring force to the drive wheel 21 to return the position of the drive wheel 21 to a reference position when the drive wheel 21 moves upward or downward. In this specification, the restoring force applied by the elastic body unit 23 to the drive wheel 21 is referred to as a second restoring force.

[0039] The elastic body unit 23 includes a first elastic body 231, a linear motion suppression member 232, an elastic body holding rotation shaft 233, an elastic body holding shaft 234, an elastic body adjustment jig 235, an elastic body holding bearing 236, and an elastic body unit fixing tool 237. The drive wheel unit 20 has a pair of left and right elastic body units 23, and each of the left and right elastic body units 23 applies a second restoring force to each of the left and right drive wheels 21.

[0040] The first elastic body 231 is a compression spring member that applies a second restoring force to the drive wheel 21 when either the left or right drive wheel 21 moves upward. The first elastic body 231 is arranged substantially along the vertical direction of the movable body 100. The first elastic body 231 may be arranged so as to be inclined in either the front or rear direction from the vertical direction of the movable body. The lower end of the first elastic body 231 is fixed to an elastic body adjustment jig 235 via an elastic body holding rotation shaft 233. On the other hand, the upper end of the first elastic body 231 does not have to be fixed to the elastic body holding bearing 236. The first elastic body 231 is arranged so as to be able to expand and contract between the elastic body adjustment jig 235 and the elastic body holding bearing 236.

[0041] When the drive wheel 21 moves upward, the first elastic body 231 applies a second restoring force to the drive wheel 21 as the compressed spring member expands. On the other hand, when the drive wheel 21 moves downward, the first elastic body 231 does not apply the second restoring force to the drive wheel 21 as the spring member returns to its natural length.

[0042] When the drive wheel holding member 223 rotates, the first elastic body 231 rotates in accordance with the rotation of the drive wheel holding member 223 and expands and contracts along the axial direction due to the elastic body holding rotation shafts 233 provided at the upper and lower ends of the first elastic body 231.

[0043] Since the first elastic bodies 231 are arranged symmetrically on both the left and right sides of the moving body 100, when the moving body 100 is placed on a flat running surface, the drive wheel holding members 223 are substantially parallel to the running surface.

[0044] The elastic body holding shaft 234 is disposed inside the compression spring that constitutes the first elastic body 231. The elastic body holding shaft 234 is held by an elastic body holding bearing 236 so as to be movable along the axial direction of the first elastic body 231. This makes it difficult for the first elastic body 231 to come off even when the drive wheel 21 moves downward. Furthermore, the distance between the elastic body adjusting jig 235 connected to the elastic body holding shaft 234 and the elastic body holding bearing 236 can change only in the direction in which the elastic body holding shaft 234 expands and contracts.

[0045] The elastic body adjustment jig 235 is a member provided with a female screw (screw hole), such as a nut. A male screw provided at the lower end of the elastic body holding shaft 234 is inserted into the screw hole of the elastic body adjustment jig 235. Here, by rotating the elastic body adjustment jig 235, it is possible to adjust the insertion depth of the elastic body holding shaft 234 into the elastic body adjustment jig 235. With this structure, it is possible to adjust the magnitude of the second upward restoring force applied to the drive wheel 21 by the first elastic body 231. Furthermore, by adjusting the left and right elastic body adjustment jigs 235 respectively, it is possible to balance the restoring forces of the left and right first elastic bodies 231.

[0046] The elastic body adjusting jig 235 may use, for example, double nuts to doubly fasten the elastic body holding shaft 234. This makes it possible to prevent the elastic body adjusting jig 235 from shifting position while the moving body 100 is traveling.

[0047] The linear motion suppression member 232 is a member that suppresses upward axial movement of the elastic body holding shaft 234. By arranging the linear motion suppression member 232 for each of the left and right drive wheels 21, it is possible to suppress the range of movement of the left and right drive wheels 21 along the axial direction of the first elastic body 231, i.e., the rotation range of the drive wheels 21 and the drive wheel holding member 223. Furthermore, a shim plate or the like may be inserted when the linear motion suppression member 232 is fixed to the elastic body unit fixing tool 237. If a shim plate or the like is inserted, it is possible to fine-tune the rotation range of the drive wheels 21 and the drive wheel holding member 223.

[0048] It is desirable that the linear motion suppression member 232 has a structure that can withstand a relatively strong force compared to the rotation suppression member 225. It is also desirable that the linear motion suppression member 232 has a performance that is equivalent to or better than the rotation suppression member 225 in suppressing the rotation range of the drive wheel holding member 223.

[0049] The elastic body unit fixing device 237 is fixed to the upper end of the linear motion suppression member 232 and the lower end of the elastic body holding shaft 234 with fixing devices such as bolts. By removing this fixing device, the first elastic body 231, the linear motion suppression member 232, the elastic body holding shaft 234, the elastic body adjusting jig 235, and the elastic body holding bearing 236 can be easily removed integrally from the side of the movable body 100. Consequently, the first elastic body 231 can be easily replaced. With this structure, the magnitude of the restoring force applied to the drive wheel 21 by the first elastic body 231 can be easily changed in accordance with the undulations of the traveling surface on which the movable body 100 is expected to travel.

[0050] Mounting members 24 for mounting the drive wheel unit 20 to the upper frame 11 are provided on the tops of the left and right elastic body units 23, respectively. The mounting members 24 are connected to the elastic body units 23 via elastic body holding rotation shafts 233. As a result, even if the elastic body units 23 rotate from the up-down direction to the left-right direction in conjunction with the rotation of the drive wheel holding member 223, the elastic body holding rotation shafts 233 rotate as a fulcrum, making it difficult for a difference in height to occur between the left and right mounting members 24. As a result, even if a difference in height occurs between the left and right drive wheels 21 when the vehicle 100 is traveling on an uneven surface, for example, the posture of the vehicle body 10 is maintained approximately horizontal.

[0051] 5A is a diagram illustrating an example of rotation of the drive wheel unit 20 including the drive wheel holding member 223. FIG. 5A is a diagram of the drive wheel unit 20 viewed from behind the mobile object 100 when the mobile object 100 is traveling (or stationary) on a level traveling surface. FIG. 5B is a diagram of the drive wheel unit 20 viewed from behind the mobile object 100 when a difference in height occurs between the left and right drive wheels 21 of the mobile object 100, for example, when the mobile object 100 is traveling on an uneven traveling surface. Note that a difference in height between the left and right drive wheels 21 of the mobile object 100 can occur, for example, when one of the left and right drive wheels 21 rides over a convex portion or when one of the drive wheels 21 gets stuck in a concave portion.

[0052] When there is a difference in height between the left and right drive wheels 21 of the movable body 100, the drive wheels 21 and the drive wheel holding members 223 rotate around the unit rotation shaft 221 as the center of rotation. Here, due to the operation of the elastic body units 23, the first elastic bodies 231 of the elastic body units 23 corresponding to the drive wheels 21 that are located relatively high are contracted, while the first elastic bodies 231 of the elastic body units 23 corresponding to the drive wheels 21 that are located relatively high are expanded. Furthermore, in accordance with the rotation of the drive wheel holding members 223, the left and right first elastic bodies 231 each rotate around the drive wheel holding members 223 arranged above and below the first elastic bodies 231 as fulcrums. This makes it less likely that a difference in height will occur between the left and right mounting members 24 fixed to the upper frame 11, regardless of the heights of the left and right drive wheels 21.

[0053] Furthermore, even if the drive wheel holding member 223 rotates as the drive wheel 21 moves up and down, the unit rotation shaft holding portion 222 that holds the unit rotation shaft 221 and the restoring member 224 do not rotate together with the rotation of the drive wheel holding member 223.

[0054] With these configurations, even if a difference in height occurs between the left and right drive wheels 21 when the moving body 100 travels on an uneven surface, the posture of the body 10 can be maintained in its original posture (almost horizontal posture).

[0055] 5B, when there is a difference in height between the left and right drive wheels 21 of the moving body 100, and the height of the drive wheels 21 is relatively high and the ground contact pressure with the running surface is higher than normal, the elastic unit 23 applies a restoring force downward to the drive wheels 21. This prevents a situation in which a large burden is placed on the drive unit due to an increase in the ground contact pressure between the drive wheels 21 and the running surface.

[0056] <Driver wheel unit 30> The pair of left and right driven wheel units 30 are arranged symmetrically on the front right and front left sides of the vehicle body. The pair of left and right driven wheel units 30 are each attached to the lower frame 12. The pair of left and right driven wheel units 30 each have a symmetrical configuration. Figure 6 is a diagram for explaining the driven wheel unit 30.

[0057] The driven wheel unit 30 includes a driven wheel 31, a driven wheel holding member 32, a second elastic body 33, a driven wheel inhibiting member 34, and a rotary joint 35.

[0058] The driven wheels 31 are wheels that can move in all directions, such as omni-wheels, and the driving device 25 generates a difference in rotation speed between the left and right driving wheels 21, allowing the moving body 100 to turn to the left or right.

[0059] The driven wheel holding member 32 is a member that holds the driven wheel 31. The driven wheel holding member 32 is connected to the vehicle body 10 by a rotary joint 35 having a rotation axis that is perpendicular to the front-to-rear direction of the vehicle body 10. As a result, when the vehicle 100 travels on an uneven surface, the driven wheel holding member 32 can rotate the driven wheel 31 relative to the vehicle body 10 around the rotary joint 35 as the center of rotation, thereby keeping the vehicle body 10 approximately horizontal.

[0060] It is desirable that the rotation axis of the rotary joint connecting the driven wheel holding member 32 and the vehicle body 10 is parallel to the running surface. On the other hand, the rotation axis of the rotary joint connecting the driven wheel holding member 32 and the vehicle body 10 does not have to be perpendicular to the fore-and-aft direction of the vehicle body 10. The rotation axis of the rotary joint connecting the driven wheel holding member 32 and the vehicle body 10 may be arranged, for example, in a direction parallel to the fore-and-aft direction of the vehicle body 10 on a plane parallel to the running surface, or in a direction tilted at a predetermined angle from the direction parallel to the fore-and-aft direction of the vehicle body 10. The predetermined angle may be set to, for example, 45 degrees.

[0061] A second elastic body 33 is disposed between the driven wheel holding member 32 and the vehicle body 10. The second elastic body 33 is, for example, a compression spring. The second elastic body 33 functions as a so-called suspension, and the second elastic body 33 allows the entire driven wheel unit 30 to absorb the impact that the driven wheel 31 receives.

[0062] The rotation range of the driven wheel holding member 32 is restricted by a driven wheel restricting member 34 attached to the vehicle body 10. The driven wheel restricting member 34 is preferably made of a soft material such as rubber or a resin block, but is not necessarily so.

[0063] With this structure of the driven wheel unit 30, even if there is a difference in height between the left and right driven wheels 31, the posture of the vehicle body 100 can be kept horizontal.

[0064] <Actions and Effects> As described above, the moving body 100 according to an embodiment of the present disclosure comprises a body 10, at least one pair of drive wheels 21, a unit rotation shaft 221 connected to the body 10 along the fore-and-aft direction of the body 10, and a rotation unit 22 connected to the body 10 via the unit rotation shaft 221, having a pair of drive wheels 21 connected to both ends, and having a drive wheel holding member 223 that rotates the drive wheels 21 around the unit rotation shaft 221 as a rotation center.

[0065] In this way, even if a difference in height occurs between the left and right drive wheels 21 when the vehicle 100 travels on an uneven surface, the drive wheels 21 and the drive wheel holding members 223 rotate around the unit rotation shaft 221 that is aligned in the front-to-rear direction of the vehicle 100. This makes it easier to maintain the pair of drive wheels 21 in contact with the surface, and also makes it possible to distribute the ground contact pressure between the pair of drive wheels 21 and the surface between the left and right. This makes it possible to prevent a situation in which a large load is placed on the drive unit 25 due to a large ground contact pressure being generated between the drive wheels 21 and the surface.

[0066] Furthermore, according to the moving body 100 relating to the embodiment of the present disclosure, the rotation unit 22 further has a restoring member 224 that applies a first restoring force that restores the position of the drive wheel 21 to the reference position relative to the unit rotation shaft 221 when the drive wheel 21 rotates from the reference position with the unit rotation shaft 221 as the center of rotation.

[0067] In this way, when a difference in height occurs between the left and right drive wheels 21 and the ground pressure increases, a first restoring force is applied to return the drive wheels 21 to the reference position, thereby equalizing the load on the left and right drive wheels 21 and making it easier to maintain the posture of the vehicle body 10.

[0068] In addition, the moving body 100 according to the embodiment of the present disclosure further includes an elastic unit 23 that is disposed between the drive wheel 21 and the vehicle body 10 and that applies a second restoring force to the drive wheel 21 to restore the position of the drive wheel 21 to the reference position when the drive wheel 21 rotates from the reference position with the unit rotation axis 221 as the center of rotation.

[0069] As a result, when a difference occurs in the height of the left and right drive wheels 21, a second restoring force is applied to the drive wheel 21 whose ground pressure has increased, so that the load acting on the left and right drive wheels 21 can be made uniform and the posture of the vehicle body 10 can be easily maintained. [Industrial Applicability]

[0070] The present disclosure is useful for a mobile body that can travel on an uneven surface. [Explanation of symbols]

[0071] 100 Mobile 10. Body 11 Upper frame 12 Lower frame 20 Drive wheel unit 21 Drive wheels 22 Rotating Unit 221 Unit rotation axis 222 Unit rotation axis holder 223 Drive wheel holding member 224 Restored parts 225 Rotation suppression member 23 Elastic unit 231 First Elastic Body 232 Linear motion suppression member 233 Elastic body holding rotating shaft 234 Elastic body holding shaft 235 Elastic body adjustment jig 236 Elastic support bearing 237 Elastic unit fixing tool 24 Mounting material 25 Drive unit 26 Brake device 30 Driven wheel unit 31 Driven wheels 32 Driven wheel holding member 33 Second Elastic Body 34 Driven wheel restraining member

Claims

1. The car body and At least one pair of drive wheels; a unit rotation shaft connected to the vehicle body along the front-rear direction of the vehicle body, and a rotation unit having drive wheel holding members connected to the vehicle body via the unit rotation shaft, with the pair of drive wheels connected to both ends thereof, and rotating the drive wheels around the unit rotation shaft; A mobile body comprising:

2. the rotation unit further includes a restoring member that applies a first restoring force to restore a position of the drive wheel to the reference position with respect to the unit rotation shaft when the drive wheel rotates from the reference position around the unit rotation shaft as a rotation center. The moving body according to claim 1 .

3. The restoring member is disposed between the drive wheel holding member and the unit rotation shaft. The moving body according to claim 2 .

4. The rotation unit further includes a rotation suppressing member that suppresses rotation of the drive wheel beyond a predetermined rotation range. The moving body according to claim 1 .

5. an elastic unit disposed between the drive wheel and the vehicle body, which applies a second restoring force to the drive wheel to restore the position of the drive wheel to the reference position when the drive wheel rotates from a reference position around the unit rotation shaft as a rotation center; A moving body according to any one of claims 1 to 4.

6. the elastic unit applies the second restoring force to the drive wheel when the drive wheel moves upward from the reference position, and does not apply the second restoring force to the drive wheel when the drive wheel moves downward from the reference position. The moving body according to claim 5 .

7. A driven wheel, a driven wheel unit that connects the driven wheel to the vehicle body so as to be movable at least in the vertical direction, and that applies a second restoring force to the driven wheel when the driven wheel moves from a reference position, thereby restoring the driven wheel to the reference position; The moving body according to claim 1 further comprising:

8. the driven wheel unit is connected to the vehicle body by a rotary joint having a rotation axis perpendicular to the front-rear direction of the vehicle body, and further includes a driven wheel holding member that holds the driven wheel; The moving body according to claim 7.

9. The driven wheels are wheels that can move in all directions. The moving body according to claim 7.

10. Two or more of the driven wheels are paired together. The moving body according to claim 7.

11. The drive wheels are disposed rearward of the vehicle body relative to the driven wheels. The moving body according to claim 7.

12. a drive device that controls the rotational speed of the pair of drive wheels to differentially drive the moving body; The moving body according to claim 1 .

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