Sphere drive type mobile device and caster equipped therewith

Abstract

To provide a sphere driving type movement device capable of suppressing ununiformity of resistance acting on each rotor of a caster, and a caster provided on the same.SOLUTION: There is provided a sphere driving type movement device 10 comprising: casters 12, 13, 14 attached to a base mechanism 11; and drive spheres 18, 19, 20 which receive rotation force of a drive source in a state of being contacted by the casters 12, 13, 14 and rotate, and roll on a travel plane G, the sphere driving type movement device moving on the travel plane G. The casters 12, 13, 14 comprise: a plurality of rotors contacting the drive spheres 18, 19, 20; and a support member for rotatably supporting the plurality of rotors, in a state in which an angle with respect to the base mechanism 11, is variable. By force acting to each rotor from the drive spheres 18, 19, 20 following deviation of the drive spheres 18, 19, 20 from a reference position, the support member is varied in the angle with respect to the base mechanism 11, and a state in which all rotors contact the drive spheres 18, 19, 20, can be maintained.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a sphere drive type mobile device that moves by rotationally driving a sphere supported by a caster, and to a caster thereof.

Background Art

[0002] A sphere drive type mobile device having three or more spheres and three or more drive sources for applying a rotational force to the spheres (see Patent Document 1) can be adopted for electric wheelchairs, self-propelled carts, etc. since it can move in all directions. In the sphere drive type mobile device of Patent Document 1, for one sphere, two rotors for applying the rotational force of the drive source (drive motor) to the sphere are in contact with the sphere from different directions. Each sphere is supported by two rotors, one wheel caster, and one ball caster.

[0003] When the rotor idles, the sphere drive type mobile device cannot move in the desired direction. Therefore, maintaining the state in which the rotor is pressed against the sphere is important for the stable running of the sphere drive type mobile device. For this purpose, it is conceivable to bring the rotor into contact with the sphere at a position higher than the center of the sphere, and press the rotor against the sphere with the load of the members of the sphere drive type mobile device or the load of the load placed on the sphere drive type mobile device. Note that other rotating bodies such as a sphere can be used instead of the rotor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Also, when the ball caster contacts the sphere at a position higher than the center of the sphere as in the sphere drive type moving device of Cited Document 1, the load of the members and the load carried by the sphere drive type moving device is also applied to the ball caster. Since there is a limit to the load-bearing capacity of the ball caster, if a plurality of ball casters are brought into contact with one sphere to disperse the load applied to the ball caster, the sphere drive type moving device can tolerate a larger load compared to the case where one ball caster is brought into contact with one sphere.

[0006] However, in a sphere drive type moving device in which two rotors contact the sphere at a position higher than the center of the sphere, the uniformity of the resistance force (the resistance force from the sphere to the rotor and the resistance force from the sphere to the ball caster) at each contact point is different between the case where the number of ball casters contacting the sphere at a position higher than the center of the sphere is one and the case where the number is two or more. Specifically, as shown in FIG. 12(A), when one ball caster 104 contacts the sphere 103 with which two rotors 101 and 102 are in contact, the sphere 103 is supported at three points by the rotors 101 and 102 and the ball caster 104, so the resistance force at each of the three contact points is substantially equal. In the example shown in FIG. 12(A), all the contact points are at positions higher than the center of the sphere 103, and the magnitude of the resistance force generated at each contact point is represented by the size of the black circle. This is the same in the examples shown in FIGS. 12(B) and (C).

[0007] On the other hand, as shown in FIGS. 12(B) and (C), when two ball casters 104 and 105 contact the sphere 103, the sphere 103 is supported at four points by the rotors 101 and 102 and the ball casters 104 and 105. Therefore, among the resistance forces at each of the four contact points, the resistance force at one contact point may be extremely smaller than the resistance forces at the other three contact points. And if the contact point where the resistance force becomes extremely small corresponds to either of the rotors 101 and 102, there arises a problem that the running of the sphere drive type moving device becomes unstable.

[0008] This is the same when, in addition to two rotors, three or more ball casters are in contact with the sphere, or when wheel casters are employed instead of ball casters. Furthermore, when wheel casters are employed, it has been confirmed that even in a sphere drive type mobile device in which one wheel caster is in contact with the sphere, when the sphere drive type mobile device changes direction with the turning of the wheel caster, a problem occurs in that the movement of the sphere drive type mobile device becomes not smooth.

[0009] Also, when four ball casters (the same applies to wheel casters) are provided on the legs of a chair and made to contact the floor surface, the resistance acting on one ball caster becomes extremely smaller than the resistance acting on the other three ball casters. And when wheel casters are provided on the legs of a chair, a problem occurs in that when the chair changes direction with the turning of the wheel caster, the movement of the chair becomes not smooth.

[0010] As a result of logical verification and experimental verification regarding these problems, it has been found that these problems can be solved by suppressing the non-uniformity of the resistance acting on each rotating body of the caster (each ball of the ball caster or each wheel of the wheel caster). The present invention has been made in view of such circumstances, and an object thereof is to provide a sphere drive type mobile device capable of suppressing the non-uniformity of the resistance acting on each rotating body of the caster.

Means for Solving the Problems

[0011] The sphere drive type mobile device according to the first invention that meets the above object has casters attached to a base mechanism, and drive spheres that are rotated by being given the rotational force of a drive source and roll on a running surface while being in contact with the casters. In the sphere drive type mobile device that moves on the running surface, each of the casters includes a plurality of rotating bodies that are in contact with the drive spheres, and a support member that rotatably supports the plurality of rotating bodies in a state where the angle with respect to the base mechanism is variable. As the drive sphere deviates from the reference position, the force acting on each rotating body from the drive sphere causes the angle of the support member with respect to the base mechanism to change, and all of the plurality of rotating bodies maintain a state of being in contact with the drive sphere.

[0012] The caster according to the second invention that meets the above object is a caster attached to an object to be attached, and includes a plurality of rotating bodies that are each in contact with an external object, and a support member that rotatably supports the plurality of rotating bodies in a state where the angle with respect to the object to be attached is variable. The support member changes the angle with respect to the object to be attached by the force acting on each rotating body from the external object, and all of the plurality of rotating bodies maintain a state of being in contact with the external object.

Advantages of the Invention

[0013] In the sphere drive type mobile device according to the first invention, as the drive sphere deviates from the reference position, the force acting on each rotating body from the drive sphere causes the angle of the support member with respect to the base mechanism to change, and all of the plurality of rotating bodies maintain a state of being in contact with the drive sphere. Therefore, it is possible to suppress the non-uniformity of the resistance force acting on each rotating body of the caster. Further, in the caster according to the second invention, the force acting on each rotating body from an external object causes the angle of the support member with respect to the object to be attached to change, and all of the plurality of rotating bodies maintain a state of being in contact with the external object. Therefore, it is possible to suppress the non-uniformity of the resistance force acting on each rotating body.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0015] Subsequently, with reference to the attached drawings, embodiments embodying the present invention will be described to facilitate understanding of the present invention. As shown in FIGS. 1 and 2, a spherical drive type mobile device 10 according to an embodiment of the present invention includes three casters 12, 13, and 14 attached to a base mechanism 11, and three drive spheres 18, 19, and 20 that are rotated by being given the rotational force of motors 15, 16, and 17, which are examples of drive sources, while being in contact with the respective casters 12, 13, and 14, and roll on a traveling surface G. It is a device that moves on the traveling surface G. Details will be described below.

[0016] As shown in FIGS. 1 and 2, the base mechanism 11 includes a triangular top plate 21 and side plates 23, 24, 25 fixed to the top plate 21 by connecting members 22. The side plates 23, 24, 25 are arranged in parallel to the respective sides near the three sides of the top plate 21. The side plate 23 to which the motor 15 is fixed rotatably supports a tensioner 26, 27, pulleys 28, 29, and a pulley 30 connected to the output shaft of the motor 15, respectively.

[0017] The tensioners 26, 27, pulleys 28, 29, and pulley 30 are arranged outside the side plate 23. Inside the side plate 23, there are provided a rotor 31 that rotates integrally coaxially with the pulley 28 while being in contact with the drive sphere 18, and a rotor 32 that rotates integrally coaxially with the pulley 29 while being in contact with the drive sphere 19. A toothed belt 33 is wound around the tensioners 26, 27, pulleys 28, 29, and pulley 30. Therefore, the rotational force of the motor 15 is applied to the drive sphere 18 via the pulley 30, the toothed belt 33, the pulley 28, and the rotor 31, and is applied to the drive sphere 19 via the pulley 30, the toothed belt 33, the pulley 29, and the rotor 32.

[0018] The side plate 24 to which the motor 16 is fixed rotatably supports a tensioner 36, 37, pulleys 38, 39, and a pulley 40 connected to the output shaft of the motor 16, respectively. The tensioners 36, 37, pulleys 38, 39, and pulley 40 are arranged outside the side plate 24. Inside the side plate 24, there are provided a rotor 41 that rotates integrally coaxially with the pulley 38 while being in contact with the drive sphere 19, and a rotor 42 that rotates integrally coaxially with the pulley 39 while being in contact with the drive sphere 20.

[0019] A toothed belt 43 is wound around the tensioners 36, 37, pulleys 38, 39, and pulley 40. Therefore, the rotational force of the motor 16 is applied to the drive sphere 19 via the pulley 40, the toothed belt 43, the pulley 38, and the rotor 41, and is applied to the drive sphere 20 via the pulley 40, the toothed belt 43, the pulley 39, and the rotor 42.

[0020] The side plate 25 to which the motor 17 is fixed rotatably supports the tensioners 46, 47, the pulleys 48, 49, and the pulley 50 connected to the output shaft of the motor 17, respectively. The tensioners 46, 47, the pulleys 48, 49, and the pulley 50 are arranged outside the side plate 25. Inside the side plate 25, a rotor 51 that rotates integrally coaxially with the pulley 48 while being in contact with the drive sphere 20, and a rotor 52 that rotates integrally with the pulley 49 while being in contact with the drive sphere 18 are provided.

[0021] A toothed belt 53 is wound around the tensioners 46, 47, the pulleys 48, 49, and the pulley 50. Therefore, the rotational force of the motor 17 is applied to the drive sphere 20 via the pulley 50, the toothed belt 53, the pulley 48, and the rotor 51, and is applied to the drive sphere 18 via the pulley 50, the toothed belt 53, the pulley 49, and the rotor 52. The sphere drive type moving device 10 can adjust the rotational speed and direction of rotation of the drive spheres 18, 19, 20 respectively by controlling the rotational speed and direction of rotation of each of the motors 15, 16, 17, and can perform movement, turning, etc. on the traveling surface G.

[0022] In addition, as shown in FIGS. 1 and 3, four ball casters 54 and the caster 12 are in contact with the drive sphere 18. The rotors 31, 52 provided at the same height are in contact with the drive sphere 18 from different directions at a position higher than the center of the drive sphere 18. The caster 12 is in contact with the drive sphere 18 at a position higher than the center of the drive sphere 18 and, in a plan view, at a position where the distance from the contact position of the rotors 31, 52 with the drive sphere 18 to the center of the top plate 21 (base mechanism 11) is longer.

[0023] The four ball casters 54 provided at the same height are in contact with the drive sphere 18 from four directions at a position lower than the center of the drive sphere 18. The drive sphere 18 is arranged at a predetermined position directly below the corner of the top plate 21 (hereinafter, this position is referred to as the "reference position") by the rotors 31, 52, the caster 12, and the four ball casters 54.

[0024] Since the rotors 31, 52 and the caster 12 are in contact with the drive sphere 18 at a position higher than the center of the drive sphere 18, the rotors 31, 52 and the caster 12 are pressed against the drive sphere 18 by the load of the base mechanism 11 etc. (a part of the sphere drive type moving device 10). When a load is placed on the top plate 21 or when an object 66 (for example, a robot having an arm) is attached to the top plate 21 (see Fig. 10), those loads also act as a force pressing the rotors 31, 52 and the caster 12 against the drive sphere 18.

[0025] As shown in Figs. 2, 3, 4, 5(A) and (B), the caster 12 includes a ring 56 fixed to a fixture 55 attached to the top plate 21, a shaft member 57 whose one side end inserted through the ring 56 is fixed by fitting into the fixture 55, a convex member 59 fixed to a sliding bearing 58 rotatably mounted on the shaft member 57, and a swing table (an example of a support member) 62 that rotatably supports wheels (an example of a rotating body) 60, 61 that respectively contact the drive sphere 18. Note that a rolling bearing may be adopted instead of the sliding bearing 58.

[0026] As shown in Fig. 4, the convex member 59 has a V-shaped protruding portion 63. As shown in Figs. 4, 5(A) and (B), the swing table 62 has a shape in which a V-shaped groove 64 along the longitudinal direction is provided in a rectangular parallelepiped, and the protruding portion 63 is inserted into the groove 64. The groove 64 is larger than the protruding portion 63, and in a state where the protruding portion 63 is inserted into the groove 64, the tip of the protruding portion 63 contacts the bottom of the groove 64, and a gap is provided between the region excluding the tip of the protruding portion 63 and the groove 64.

[0027] In the swing table 62, with the side where the groove 64 is formed as one side, as shown in Figs. 5(A) and (B), a through hole 65 is formed in the swing table 62, one end of which communicates with the bottom of the groove 64 and the other end of which opens to the other side of the swing table 62. The shaft member 57 has a circular cross-section, and the other end formed with a larger diameter than other regions is housed in the through hole 65. The through hole 65 has a larger cross-sectional area in a direction perpendicular to the shaft member 57 as compared with a first region that houses the other end of the shaft member 57 and a second region that houses a portion continuous with the other end of the shaft member 57.

[0028] The first region of the through hole 65 has a larger cross-sectional area in the direction perpendicular to the shaft member 57 than the other end portion of the shaft member 57, and a gap is provided on the outer peripheral side of the other end portion of the shaft member 57. The second region of the through hole 65 has a smaller cross-sectional area in the direction perpendicular to the shaft member 57 than the other end portion of the shaft member 57, and has a larger cross-sectional area in the direction perpendicular to the shaft member 57 than the portion continuous with the other end portion of the shaft member 57. Therefore, with the other end portion of the shaft member 57 housed in the swing table 62, the angle of the swing table 62 with respect to the shaft member 57 can be changed, and the other end portion of the shaft member 57 does not come out toward one side of the swing table 62.

[0029] Thus, with the protruding portion 63 inserted into the groove 64 and the other end portion of the shaft member 57 housed in the through hole 65, the swing table 62 can rotate (swing) about the bottom of the groove 64 (as a rotation axis) where the tip of the protruding portion 63 contacts, as shown in FIGS. 6(A) and 6(B), and the angle with respect to the base mechanism 11 is variable. In the present embodiment, the angle of the swing table 62 with respect to the base mechanism 11 is variable within a range of ±10°.

[0030] The axles of the wheels 60 and 61 are non-parallel and arranged on the same virtual plane, as shown in FIGS. 4, 5(A), and 5(B). For the caster 12, only the outer circumferences of the wheels 60 and 61 are in contact with the drive spheres 18 (the swing table 62 and the like are not in contact with the drive spheres 18). By bringing a plurality of wheels 60 and 61 into contact with the drive spheres 18 as in the present embodiment, the load generated on one wheel can be reduced as compared with the case where one wheel is brought into contact with the drive sphere 18.

[0031] For the caster 12, the extension line of the axis of the shaft member 57 does not intersect the straight line passing through each contact point between the wheels 60 and 61 and the drive spheres 18, and together with the sliding bearing 58, the convex member 59, the swing table 62, and the wheels 60 and 61 are rotatable about the shaft member 57. Therefore, according to the magnitude and direction of the resistance force acting on the wheels 60 and 61 respectively from the drive spheres 18 rolling on the running surface G, the sliding bearing 58, the convex member 59, the swing table 62, and the wheels 60 and 61 rotate about the shaft member 57, and the positions of the wheels 60 and 61 with respect to the shaft member 57 change.

[0032] Here, depending on the magnitude and direction of the force received by the drive sphere 18 rolling on the running surface G from the running surface G, the drive sphere 18 may deviate (be displaced) from the reference position. At this time, as the drive sphere 18 deviates from the reference position, due to the force acting on each wheel 60, 61 from the drive sphere 18, the rocking table 62 changes its angle with respect to the convex member 59, the shaft member 57, the base mechanism 11, etc., as shown in FIGS. 6(A) and 6(B), maintaining the state where all of the two (plural) wheels 60, 61 are in contact with the drive sphere 18, and suppressing the non-uniformity of the magnitudes of the resistance forces received by the wheels 60, 61 from the drive sphere 18, respectively.

[0033] The casters 13 and 14 also have the same design as the caster 12, respectively. They include a ring fixed to a fixture attached to the top plate 21, a shaft member fixed by inserting one end portion passing through the ring into the fixture, a convex member fixed to a sliding bearing rotatably mounted on the shaft member, two wheels (an example of a rotating body) respectively in contact with the drive spheres 19, 20, and a rocking table that rotatably supports the two wheels in a state where the angle with respect to the base mechanism 11 is variable.

[0034] And, as the drive sphere 19 of the caster 13 deviates from the reference position, due to the force acting on each rotating body from the drive sphere 19, the angle of the support member with respect to the base mechanism 11 changes, maintaining the state where all of the two (plural) rotating bodies are in contact with the drive sphere 19. Also, as the drive sphere 20 of the caster 14 deviates from the reference position, due to the force acting on each rotating body from the drive sphere 20, the angle of the support member with respect to the base mechanism 11 changes, maintaining the state where all of the two (plural) rotating bodies are in contact with the drive sphere 20.

[0035] As a result, in the caster 12 (the same applies to the casters 13 and 14), the magnitude of the resistance force received by the rotors 31 and 52 from the drive spheres 18 (for the caster 13, the rotors 32 and 41 receive the drive spheres 19 respectively, and for the caster 14, the rotors 42 and 51 receive the drive spheres 20 respectively) is also suppressed from becoming non-uniform. Therefore, the rotation speed and the direction of rotation of each of the drive spheres 18, 19, and 20 can be stably adjusted by the control of each of the motors 15, 16, and 17.

[0036] Furthermore, in the caster 12 (the same applies to the casters 13 and 14), the movement of the ball drive type moving device 10 involving rotation about the sliding bearings 58, the convex members 59, the swing base 62, and the axle members 57 of the wheels 60 and 61 can also be made smooth.

[0037] Here, in the caster 12, the angle of the swing base 62 with respect to the base mechanism 11 and the like can be changed, and the state where both of the two wheels 60 and 61 are in contact with the drive sphere 18 can be maintained because the swing base 62 is provided so as to be rotatable about a virtual axis J that satisfies the following conditions a) and b) as shown in FIGS. 6(A) and 6(B). This is the same for the casters 13 and 14. a) The virtual axis J is non-parallel to the virtual straight line j passing through the two contact points between each of the two wheels 60 and 61 and the drive sphere 18. b) The virtual axis J does not pass through the center of the drive sphere 18.

[0038] In the present embodiment, the virtual axis J is orthogonal to the virtual straight line j when the swing base 62 is viewed from the front (actually, the virtual straight line j and the virtual axis J do not intersect). Further, instead of the casters 12, 13, and 14, a wheel caster having three or more wheels may be adopted, or a ball caster having two or more (i.e., a plurality of) balls may be adopted. For example, instead of the caster 12, the casters 70 and 80 shown in FIGS. 7 and 8 can be adopted respectively.

[0039] As shown in FIG. 7, the caster 70 includes a shaft member 71 whose one end is fitted and fixed to a fixture fixed to the base mechanism, a convex member 72 directly fixed to the shaft member 71, two balls (an example of a rotating body) 73 and 74 each in contact with the drive sphere 18, and a support member 75 that rotatably supports the two balls 73 and 74 in a state where the angle with respect to the convex member 72 and the base mechanism is variable. Note that the convex member 72 may be fixed to a sliding bearing or a rolling bearing rotatably mounted on the shaft member 71. The caster 70 is designed such that the extension line of the axis of the shaft member 71 is orthogonal to the straight line passing through the two contact points between each of the balls 73 and 74 and the drive sphere 18.

[0040] The support member 75 is provided so as to be rotatable about a virtual axis that is non-parallel to the virtual straight line passing through the two contact points between each of the two balls 73 and 74 and the drive sphere 18 and does not pass through the center of the drive sphere 18, by the tip of the protruding portion 77 of the convex member 72 coming into contact with the bottom of the groove 76 formed in the support member 75. As the drive sphere 18 deviates from the reference position, the force acting from the drive sphere 18 on the balls 73 and 74 causes the angle of the support member 75 with respect to the base mechanism to change, maintaining the state where both of the balls 73 and 74 are in contact with the drive sphere 18.

[0041] As shown in FIG. 8, the caster 80 includes a shaft member 81 whose one end is fitted and fixed to a fixture fixed to the base mechanism, three balls (an example of a rotating body) 82, 83, and 84 each in contact with the drive sphere 18, a universal joint 85 connected to the other end of the shaft member 81, and a support member 86 connected to the shaft member 81 via the universal joint 85 and rotatably supporting the three balls 82, 83, and 84. The caster 80 is designed such that the extension line of the axis of the shaft member 81 is orthogonal to the plane passing through the three contact points between each of the balls 82, 83, and 84 and the drive sphere 18.

[0042] The universal joint 85 is configured to vary the angle of the support member 86 with respect to the base mechanism. Examples of the universal joint 85 include those using a ball joint and those using a universal joint. As the driving sphere 18 deviates from the reference position, the force acting on the balls 82, 83, 84 from the driving sphere 18 causes the angle of the support member 86 with respect to the base mechanism to change, while maintaining the state where all of the balls 82, 83, 84 are in contact with the driving sphere 18.

[0043] Here, each contact point between each of the three balls 82, 83, 84 and the driving sphere 18 is not located on the great circle of the driving sphere 18 through which one contact point always passes through the other two contact points (that is, the three balls 82, 83, 84 are arranged such that at least one of the contact points between the balls 82, 83, 84 and the driving sphere 18 is not always located on the same great circle). Therefore, by adopting the universal joint 85, the support member 86 can maintain the state where all of the balls 82, 83, 84 are in contact with the driving sphere 18.

[0044] This is the same for casters having four or more balls or casters having three or more wheels. If it is designed such that at least one of the contact points between each rotating body (ball or wheel) and the driving sphere is not always located on the same great circle, by adopting the universal joint, it is possible to maintain the state where all the rotating bodies are in contact with the driving sphere. For example, in a caster having four wheels, it is designed such that one of the four contact points where the four wheels contact the driving sphere is not always located on the great circle passing through the other three contact points, or two of the four contact points are not always located on the great circle passing through the other two contact points, so that by adopting the universal joint, the state where all the wheels are in contact with the driving sphere can be maintained.

[0045] On the other hand, in a caster having three or more rotating bodies, if each contact point between each rotating body and the driving sphere is located on the same great circle even temporarily, all the rotating bodies cannot maintain the state of contacting the driving sphere depending on the direction in which the driving sphere deviates from the reference position, whether the rotating body is a ball or a wheel. And when the rotating body is a wheel, in addition to the fact that all the wheels may not be able to maintain the state of contacting the driving sphere, depending on the direction of displacement of the driving sphere, the support member may contact the driving sphere.

[0046] Further, instead of bringing one caster 12 into contact with the driving sphere 18, a plurality of casters may be brought into contact with the driving sphere 18. For example, as shown in FIG. 9, two casters 90, 90a can be brought into contact with the driving sphere 18. The casters 90, 90a have the same design as the caster 12, respectively, as shown in FIG. 9. The shaft member 93 of the caster 90 having two wheels 91, 92 in contact with the driving sphere 18 and the shaft member 93a of the caster 90a having two wheels 91a, 92a in contact with the driving sphere 18 are respectively fixed to both sides of the elongated body 94.

[0047] A V-shaped groove 95 is formed at the center of the elongated body 94, and a V-shaped protruding portion 98 of an insert tool 97 connected to a bar 96 fixed to the base mechanism 11 via a fixture is inserted into the groove 95. The tip of the protruding portion 98 contacts the bottom of the groove 95, and a gap is provided between the region excluding the tip of the protruding portion 98 and the groove 95. The elongated body 94 rotates about the bottom of the groove 95 as a fulcrum. By rotatably providing the elongated body 94 connecting the casters 90, 90a in this way, even if the driving sphere 18 deviates from the reference position, all of the wheels 91, 91a, 92, 92a can be maintained in a state of contacting the driving sphere 18.

[0048] Note that depending on the arrangement of the swing table (an example of a support member) 99 of the caster 90 with respect to the elongated body 94 and the arrangement of the swing table (an example of a support member) 99a of the caster 90a with respect to the elongated body 94, all of the wheels 91, 92, 91a, 92a will be located on the same great circle of the driving sphere 18.

[0049] Moreover, the use of the caster is not limited to the spherical drive type mobile device 10, and for example, it can be attached to the legs of a chair (an example of an object to be attached) and used. Generalizing and defining such a caster, it is as follows. That is, a caster attached to an object to be attached, comprising a plurality of rotators each in contact with an external object, and a support member rotatably supporting the plurality of rotators in a state where the angle with respect to the object to be attached is variable. The support member changes the angle with respect to the object to be attached by the force acting on each rotator from the external object, and maintains a state where all of the plurality of rotators are in contact with the external object.

[0050] Specifically, the caster attached to the leg of a chair is, for example, designed such that with respect to the caster 12, the axis center of the axle of one wheel is located on the extension line of the axis center of the axle of the other wheel, and only the two wheels are in contact with the floor surface (an example of an external object). Also, for casters with two rotators and casters with three or more rotators, by adopting the designs shown below, it is possible to maintain a state where all of the plurality of rotators are in contact with the external object.

[0051] For a caster with two rotators, the support member is provided so as to be rotatable about a virtual axis K that is a) non-parallel to a virtual straight line passing through two contact points between each of the two rotators and the external object, and b) non-perpendicular to the external object, with the external object as a plane. For a caster with three rotators, each rotator is arranged such that at least one of the contact points between the rotator and the external object is not always on the same straight line, and is provided with a universal joint that enables the angle of the support member with respect to the base mechanism to be changed.

[0052] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described forms, and all changes and the like that do not depart from the gist are within the scope of application of the present invention. For example, in the spherical drive type mobile device, a sphere can be used as a rotator that applies the rotational force of the drive source to the drive sphere instead of the rotor. Also, the drive spheres of the spherical drive type mobile device may be four or more.

[0053] The casters are not limited to those adopted by the spherical drive type moving device or those attached to the legs of a chair. For example, the casters can be adopted by a robot or a vehicle that travels with the wheels of the casters in contact with the floor surface. In addition, the sizes of the plurality of rotating bodies (wheels or balls) included in the caster may be different.

[0054] In the above embodiment, three drive spheres are provided, but four or more drive spheres may be provided. In particular, if the load of the spherical drive type moving device and the object loaded thereon increases, it is considered that by increasing the number of drive spheres, the adaptability to heavy loads can be improved. Also, for example, in the above embodiment, two pulleys are rotationally driven by one motor, but dedicated motors can also be provided for each pulley. In this case, although the size of the device may increase, the driving force of the pulley can be increased, and it becomes easier to handle heavy loads. For example, in the above spherical drive type moving device having six pulleys, there will be six motors.

[0055] Furthermore, when four drive spheres are provided, there will be eight pulleys and eight motors. When four drive spheres are provided, the control becomes slightly more complicated compared to the case of three drive spheres. However, for the three drive spheres, like the spherical drive type moving device 10, they are driven by three motors, and dedicated motors are respectively attached to the two pulleys in contact with the remaining one drive sphere, and if it is configured with a total of five motors, the control becomes possible.

[0056] Regarding the constituent material of the caster, basically, it is preferable to use metal materials such as stainless steel, titanium alloy, and tungsten alloy, which have high durability. That is, for the resistance to heavy objects. It is preferable to be composed of a material that can withstand friction and extreme stress. Here, not limited to metal materials, durable resin materials or ceramic materials can also be used. Also, basically, the caster is composed of a metal material, and in order to obtain effects such as slipperiness, a part of a member such as resin may be used.

[0057] Further, compared with the example in which two wheels 60 and 61 are provided on one caster 12 described in FIG. 4 or the example in which two balls 73 and 74 are provided on one caster 70 described in FIG. 7, the configuration becomes slightly more complex, but it is also possible to use a hybrid caster in which one rotating body provided on one caster has a wheel configuration and the other rotating body has a ball configuration. Depending on the usage environment, application, etc., such a hybrid configuration can also be adopted.

[0058] In addition, in the above embodiment, a caster attached to one shaft member is used for one driving sphere, but a plurality of casters attached to different shaft members can also be used for one driving sphere. For example, two shaft members are provided, a caster having two wheels is attached to one shaft member, a caster having two balls is attached to the other shaft member, and each caster can be brought into contact with the driving sphere. In this way, by providing a plurality of shaft members, it is possible to easily cope with heavy objects.

[0059] In the above embodiment, a sphere drive type mobile device including a motor and a pulley has been described. However, it may be configured to be connected to another self-propelled device (for example, a forklift, etc.) and moved without including a motor and a pulley. By mounting the caster of the above embodiment even without a self-propelling means (motor or pulley), a mobile device suitable for transporting heavy objects can be provided.

[0060] As shown in FIG. 10, an object 66 such as an arm, other robot, or storage box for storing a load can be mounted on the sphere drive type mobile device 10, and a working device can be configured by including the sphere drive type mobile device 10 and the object 66 mounted thereon. By mounting the object 66 etc. on the sphere drive type mobile device 10, the total weight may exceed 1000 Kg at 100 Kg, 500 Kg, and 700 Kg, but by mounting the caster of the present embodiment, a sphere drive type mobile device 10 capable of stable traveling can be provided.

[0061] When manufacturing the spherical drive type mobile device, the object 66 may be integrally manufactured. However, considering the convenience of the device, it is preferable to separately manufacture the spherical drive type mobile device 10 and the object 66, and attach the necessary object 66 to the spherical drive type mobile device 10. An example of this embodiment will be described with reference to FIG. 10. FIG. 10 shows an example in which a robot arm is mounted as the object 66 on the spherical drive type mobile device 10.

[0062] Hereinafter, the spherical drive type mobile device 10 and the object 66 joined together are referred to as a working device. Inside the working device, various control units and the like composed of a semiconductor substrate or the like are housed. In FIG. 10, the main control unit 200 controls the entire working device, the object control unit 201 controls the object 66, and the mobile device control unit 202 controls the spherical drive type mobile device 10. In this embodiment, each control unit is composed of an individual semiconductor element, but the three control units may be controlled by one semiconductor element or the like.

[0063] The object control unit 201 controls the drive unit group 203. The drive unit group 203 controls a motor or a solenoid (not shown) which is a specific drive device, and measures the amount of movement of an arm or the like using a sensor 204 or the like. The mobile device control unit 202 controls the drive unit group 205. The drive unit group 205 controls the motors 15, 16, and 17 shown in FIG. 1 which are specific drive devices (drive sources), and measures the amount of movement relative to the ground or the like using sensors 206 such as an optical sensor (not shown).

[0064] The data input / output unit 207 acquires data from outside the working device or sends out various data of the working device to the outside. The data input / output unit 207 performs wired communication or wireless communication. The power input unit 208 guides external power into the working device, and may be wired or perform contactless power supply. For example, when the energy storage unit 209 is a storage battery, it is configured to store the power from the power input unit 208. Also, as a form, there may be a case where the working device is driven only by an external power source, and in that case, the energy storage unit 209 becomes unnecessary.

[0065] Also, basically, when the energy storage unit 209 is composed of a lithium-ion battery or the like, there is also a form in which it is attached to the working device after being charged externally. In this case, the power input unit 208 becomes unnecessary. Also, when the energy storage unit 209 is composed of a fuel cell or the like, the power input unit 208 also becomes unnecessary. Although not shown in the figure, the input unit 210 inputs information from buttons, touch panels, etc. on the working device, and inputs information that cannot be input from the data input / output unit 207 or is difficult to input. For example, correction information of the working device or individual adjustment information required can be input. Also, from the input unit 210, it is possible to turn on and off the power of the entire working device. If this input unit 210 can also be performed from the data input / output unit, it becomes unnecessary. Conversely, if all control information can be input by the input unit 210, the data input / output unit 207 becomes unnecessary.

[0066] An example of the operation of the working device configured in this way will be described. Before starting the working device, the power input unit 208 is connected to an external power source, and the main control unit 200 controls the energy storage unit 209 so as not to be overcharged, and is charged from the power input unit 208 to the energy storage unit 209. When the data input / output unit 207 receives data from the outside, the main control unit 200 analyzes the content of the data. At this time, the data is data regarding the movement of the arm, which is the object 66 of the working device. The main control unit 200 first sends a signal to the moving device control unit 202 based on the data sent to the working device, moves the spherical drive type moving device 10, and arranges the working device at a predetermined position.

[0067] When the working device arrives at a predetermined position, the main control unit 200 sends a signal to the object control unit 201 to cause a predetermined operation to be performed. When the operation is completed, the main control unit 200 again sends a signal to the moving device control unit 202 to make it standby at a predetermined position. At this time, if the working device becomes uncontrollable, information is input to the input unit 210 to stop the function of the working device. In this way, by using the caster of the present embodiment in the working device, even when a heavy object is mounted, the rotor and the drive sphere can be surely brought into close contact with each other, so that the working device can be moved accurately and smoothly, and unnecessary movement of the working device can be suppressed.

[0068] Further, as shown in FIGS. 11(A) and 11(B), a caster 220 can be adopted that includes a hook 223 locked to a protruding portion 222 provided on the swing table 221 and stably maintains the state in which the convex member 224 is in contact with the swing table 221. In the caster 220, a shaft member 225 fixed to the convex member 224 is attached to a thrust bearing 226 fixed to the base mechanism using a bolt 227.

Description of Reference Numerals

[0069] 10: Sphere drive type mobile device, 11: Base mechanism, 12, 13, 14: Caster, 15, 16, 17: Motor, 18, 19, 20: Driving sphere, 21: Top plate, 22: Connecting member, 23, 24, 25: Side plate, 26, 27: Tensioner, 28, 29, 30: Pulley, 31, 32: Rotor, 33: Toothed belt, 36, 37: Tensioner, 38, 39, 40: Pulley, 41, 42: Rotor, 43: Toothed belt, 46, 47: Tensioner, 48, 49, 50: Pulley, 51, 52: Rotor, 53: Toothed belt, 54: Ball caster, 55: Fixture, 56: Ring, 57: Axle material, 58: Slide bearing, 59: Convex member, 60, 61: Wheel, 62: Swing table, 63: Protrusion, 64: Groove, 65: Through hole, 66: Object, 70: Caster, 71: Axle material, 72: Convex member, 73, 74: Ball, 75: Support member, 76: Groove, 77: Protrusion, 80: Caster, 81: Axle material, 82, 83, 84: Ball, 85: Universal joint, 86: Support member, 90, 90a: Caster, 91, 91a, 92, 92a: Wheel, 93, 93a: Axle material, 94: Long body, 95: Groove, 96: Rod, 97: Insertion tool, 98: Protrusion, 99, 99a: Swing table, 200: Main control unit, 201: Object control unit, 202: Mobile device control unit, 203: Drive unit group, 204: Sensor, 205: Drive unit group, 206: Sensor, 207: Data input / output unit, 208: Power input unit, 209: Energy storage unit, 210: Input unit, 220: Caster, 221: Swing table, 222: Protrusion, 223: Hook, 224: Convex member, 225: Axle material, 226: Thrust bearing, 227: Bolt, G: Traveling surface, j: Virtual straight line, J: Virtual axis

Claims

1. A sphere drive type mobile device that has casters attached to a base mechanism and drive spheres that are rotated by the rotational force of a drive source and roll on a running surface while being in contact with the casters, and moves on the running surface. Each of the casters includes two rotating bodies that are in contact with the drive spheres, and a support member that rotatably supports the two rotating bodies in a state where the angle with respect to the base mechanism is variable. As the drive spheres deviate from a reference position, the support member changes its angle with respect to the base mechanism due to the force acting from the drive spheres on the respective rotating bodies, and maintains a state where both of the two rotating bodies are in contact with the drive spheres. The support member is provided so as to be rotatable about a virtual axis J that is a) non-parallel to a virtual straight line passing through two contact points between each of the two rotating bodies and the drive spheres, and b) does not pass through the center of the drive spheres. A sphere drive type mobile device characterized by this.

2. A caster attached to an object to be attached, comprising two rotating bodies that each contact an external object, and a support member that rotatably supports the two rotating bodies in a state where the angle with respect to the object to be attached is variable. The support member changes its angle with respect to the object to be attached due to the force acting from the external object on the respective rotating bodies, and maintains a state where both of the two rotating bodies are in contact with the external object. The support member is provided so as to be rotatable about a virtual axis K that is a) non-parallel to a virtual straight line passing through two contact points between each of the two rotating bodies and the external object, and b) non-perpendicular to the external object. A caster characterized by this.

3. A working device characterized by comprising the sphere drive type mobile device according to Claim 1 and an object mounted on the sphere drive type mobile device.

Images