Caster and small-sized mobility

Abstract

To provide a caster and a small-sized mobility excellent in runnability for instance, at direct advancement and change of direction.SOLUTION: A caster 1 includes: a wheel 4; a wheel support part 5 for rotatably supporting the wheel 4 around its central axis O4; a drive part 6 for rotatably driving the wheel support part 5 together with the wheel 4 around a steering axis O1 parallel to a direction orthogonal to the central axis O4 of the wheel 4; and a switching part 7 for switching the wheel support part 5 between a first state in which the central axis O4 of the wheel 4 is positioned on the steering axis O1, and a second state in which the central axis O4 of the wheel 4 is located in a position away from the steering axis O1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to casters and compact mobility. [Background technology]

[0002] Conventionally, a transport cart that is pushed or pulled by an operator has been used to transport luggage and the like. Patent Document 1 (Japanese Patent No. 6839027) discloses a transport cart that includes a flat plate member on which an object to be transported, such as luggage, can be placed, a plurality of casters (free wheels) arranged on the edge of the bottom surface of the flat plate member, an auxiliary wheel (adjustable wheel) arranged in the center of the bottom surface of the flat plate member, and a rotation mechanism (steering motor) that rotates the auxiliary wheel around a vertical axis. In the invention described in Patent Document 1, the auxiliary wheel is switched between a steerable state in which it can be rotated by the rotation mechanism and a fixed state in which the rotation by the rotation mechanism is restricted. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6839027 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the invention described in Patent Document 1, when the transport vehicle is driven, depending on the driving conditions, it may be easy to drive in a steerable state but difficult to drive in a fixed state, or conversely, it may be easy to drive in a fixed state but difficult to drive in a steerable state.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a caster and a small mobility vehicle that have excellent running performance, for example, when traveling straight or when changing direction. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the caster of the present invention is characterized by comprising a wheel, a wheel support part that supports the wheel rotatably around its central axis, a drive part that drives the wheel support part together with the wheel so that it can rotate around a rolling axis parallel to a direction perpendicular to the central axial direction of the wheel, and a switching part that switches the wheel support part between a first state in which the central axis of the wheel is located on the rolling axis and a second state in which the central axis of the wheel is located in a position off of the rolling axis. Effect of the Invention

[0007] According to the present invention, the vehicle has excellent running performance when traveling straight and when changing direction. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of an electric wheelchair according to a first embodiment. [Diagram 2] 2 is a perspective view of a caster (in a first state) that is provided on the electric wheelchair shown in FIG. 1. FIG. [Diagram 3] FIG. 3 is an exploded perspective view of the caster shown in FIG. 2. [Figure 4] 3 is a cross-sectional view taken along line AA in FIG. 2. [Diagram 5] 2 is a perspective view of a caster (in a second state) provided on the electric wheelchair shown in FIG. 1. FIG. [Figure 6] 6 is a cross-sectional view taken along line BB in FIG. 5. [Figure 7] FIG. 11 is a perspective view of a caster (in a first state) that is provided on an electric wheelchair according to a second embodiment. [Figure 8] FIG. 8 is an exploded perspective view of the caster shown in FIG. 7. [Figure 9] FIG. 13 is a perspective view of a caster (in a second state) that is provided on an electric wheelchair according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment of the present invention will be described in detail below with reference to the drawings. However, the configurations described in each of the following embodiments are merely examples, and the scope of the present invention is not limited by the configurations described in each embodiment. For example, each part constituting the present invention can be replaced with any configuration that can exert a similar function. In addition, any configuration may be added. In addition, any two or more configurations (features) of each embodiment can be combined.

[0010] First Embodiment Hereinafter, the first embodiment will be described with reference to Figs. 1 to 6. For convenience of explanation, the upper side in Figs. 1 to 6 will be referred to as "upper" or "upper side", and the lower side will be referred to as "lower" or "lower side" (similarly for Figs. 7 to 9). The up-down direction in Figs. 1 to 6 may be referred to as "vertical direction". The direction perpendicular to the vertical direction may be referred to as "horizontal direction". Fig. 1 is a perspective view of an electric wheelchair according to the first embodiment. The electric wheelchair 10 shown in Fig. 1 is an application of a small mobility that can move by casters 1. Here, "small mobility" refers to a vehicle for one or two people, which is the electric wheelchair 10 in this embodiment. The electric wheelchair 10 includes a chair 2 on which a person can sit, and an electric mechanism unit 3 that supports the chair 2. Chair 2 includes a seat panel 21 having a seat surface 211, a backrest 22 connected to the rear of seat panel 21, a footrest 23 connected to the front of seat panel 21, and a push handle 24 connected to the back of backrest 22. Electric mechanism unit 3 includes four casters 1, a support plate 31 supporting each caster 1, a base unit 32 connecting support plate 31 and seat panel 21 of chair 2, and an electric circuit board 33 and a battery 34 housed within base unit 32.

[0011] Fig. 2 is a perspective view of a caster (first state) provided on the electric wheelchair shown in Fig. 1. Fig. 3 is an exploded perspective view of the caster shown in Fig. 2. Fig. 4 is a cross-sectional view taken along line AA in Fig. 2. Fig. 5 is a perspective view of a caster (second state) provided on the electric wheelchair shown in Fig. 1. Fig. 6 is a cross-sectional view taken along line BB in Fig. 5. As shown in Figs. 2 to 6, the caster 1 includes a wheel 4, a wheel support portion 5, a drive portion 6, a switching portion 7, a connecting portion 8, and a lock portion 9. The wheel 4 has a tire 41 and a wheel (wheelbase) 42 fitted inside the tire 41.

[0012] The wheel support part 5 supports the wheel 4 so as to be rotatable around its central axis O4. In this embodiment, the central axis O4 is parallel to the horizontal direction. As shown in FIG. 2 (as well as FIG. 3 and FIG. 5), the wheel support part 5 has a clamping piece 51 arranged on one side (the front side of the paper) in the direction of the central axis O4 with respect to the wheel 4, and a clamping piece 52 arranged on the other side (the rear side of the paper). As shown in FIG. 4 (as well as FIG. 6), the wheel 4 is clamped between one end of the clamping piece 51 and one end of the clamping piece 52, and is supported rotatably around the central axis O4 via a shaft member 55. In addition, the wheel support part 5 has a connecting part 53 that connects the other end of the clamping piece 51 and the other end of the clamping piece 52, and a protruding part 54 that protrudes upward from the connecting part 53.

[0013] The driving unit 6 drives the wheel support unit 5 together with the wheel 4 so as to be rotatable around the rolling axis O1 parallel to a direction perpendicular to the direction of the central axis O4 of the wheel 4. In this embodiment, the rolling axis O1 is parallel to the vertical direction (up-down direction). As shown in FIG. 3, the driving unit 6 has a first base 61, a second base 62, a motor 63, and a bearing 64. The first base 61 is a plate-shaped member, and an outer ring 641 (see FIG. 4 and FIG. 6) of the bearing 64 is fitted to the inside of the first base 61. A flange portion 611 is formed on the upper part of the first base 61 so as to protrude. The flange portion 611 is fixed to the support plate 31 of the electric mechanism unit 3 by, for example, screwing. The bearing 64 is a thrust bearing that supports the wheel 4 so as to be rotatable around the rolling axis O1. The second base 62 is a ring-shaped member, and an inner ring 642 (see FIG. 4 and FIG. 6) of the bearing 64 is fitted to the outside of the second base 62. In addition, a flange portion 621 is formed protruding from the lower portion of the second base 62. Furthermore, a clamping piece 622 and a clamping piece 623 protruding downward are formed on the flange portion 621. The protruding portion 54 of the wheel support portion 5 is clamped between the clamping piece 622 and the clamping piece 623. A motor 63 is disposed on the upper side of the second base 62. The motor 63 is, for example, a servo motor, and its rotation axis O63 is parallel to the rotation axis O1. In addition, the motor 63 is electrically connected to the battery 34 via the electric circuit board 33. As a result, power is supplied from the battery 34 to the motor 63, and the motor 63 can be driven. This driving force is transmitted to the wheel support portion 5 via the connecting portion 8, and the wheel support portion 5 can be rotated together with the wheel 4 around the rotation axis O1. The method of fixing the motor 63 is not particularly limited, and for example, a method of fixing the motor 63 to the base portion 32 of the electric mechanism portion 3 via a fixing member can be mentioned.

[0014] The switching unit 7 switches the wheel support unit 5 between a first state shown in FIG. 2 (similar to FIGS. 3 and 4) and a second state shown in FIG. 5 (similar to FIG. 6). As shown in FIG. 4, in a side view, that is, when viewed from the direction of the central axis O4, in the first state, the central axis O4 of the wheel 4 is located on the steering axis O1. Also, as shown in FIG. 6, in a side view, that is, when viewed from the direction of the central axis O4, in the second state, the central axis O4 of the wheel 4 is located at a position deviated from the steering axis O1. The switching unit 7 has a shaft member 71 and a lever 72. As described above, the protruding portion 54 of the wheel support unit 5 is clamped between the clamping piece 622 and the clamping piece 623 of the second base 62. The shaft member 71 is disposed in parallel to the central axis O4 at a position different from the central axis O4, and in this embodiment, the shaft member 71 is inserted through the clamping piece 622, the protruding portion 54, and the clamping piece 623 in this order. As a result, the wheel support part 5 together with the wheel 4 is supported rotatably around the shaft member 71, i.e., around a switching rotation axis O71 parallel to the central axis O4 of the wheel 4. The lever 72 is formed to protrude from the protruding part 54 of the wheel support part 5 along the circumferential direction of the wheel 4. When switching the wheel support part 5 from the first state to the second state, or conversely, from the second state to the first state, the lever 72 can be gripped and the switching operation can be performed manually.

[0015] The locking portion 9 maintains the first state and the second state. The locking portion 9 has an engagement piece 91, a shaft member 92, and a biasing member 93. The engagement piece 91 is sandwiched between the clamping piece 622 and the clamping piece 623, similar to the protruding portion 54 of the wheel support portion 5. The shaft member 92 is inserted through the clamping piece 622, the engagement piece 91, and the clamping piece 623 in this order. As a result, the engagement piece 91 is supported rotatably around the shaft member 92. The engagement piece 91 has a convex portion (engagement portion) 911 that protrudes toward the wheel support portion 5. On the other hand, a first recess 541 and a second recess 542 are formed on the edge of the protruding portion 54 of the wheel support portion 5. The first recess 541 and the second recess 542 are arranged around the shaft member 71 with an interval therebetween. The biasing member 93 is a leaf spring that biases the engagement piece 91 toward the protruding portion 54. In the first state, the convex portion 911 of the engagement piece 91 and the first concave portion 541 of the wheel support part 5 engage with each other, and this engaged state can be maintained by the biasing member 93. This maintains the first state. In the second state, the convex portion 911 of the engagement piece 91 and the second concave portion 542 of the wheel support part 5 engage with each other, and this engaged state can be maintained by the biasing member 93. This maintains the second state.

[0016] As shown in Figures 4 and 6, when the wheel support unit 5 rotates around the rolling axis O1, the position of the motor 63 (drive unit 6) with respect to the rolling axis O1 is constant in both the first state and the second state. That is, the rotation axis O63 of the motor 63 overlaps with the rolling axis O1 in both the first state and the second state. This positional relationship can reduce the size of the caster 1 in the horizontal direction, for example, compared to a case in which the rotation axis O63 is horizontally shifted from the rolling axis O1.

[0017] The connecting portion 8 connects the wheel support portion 5 and the driving portion 6 in a first state as shown in FIG. 4, and releases the connection between the wheel support portion 5 and the driving portion 6 in a second state as shown in FIG. 6. As shown in FIG. 3, the connecting portion 8 has a convex portion 81 integrally provided on the protruding portion 54 of the wheel support portion 5, and a recessed portion forming member 82 fixed to the rotor of the motor 63 of the driving portion 6. The convex portion 81 is formed from the protruding portion 54 toward the upper side. The recessed portion forming member 82 has a plurality of recessed portions 83 formed therein. These recessed portions 83 are arranged at equal intervals around the rotation axis O1. In this embodiment, six recessed portions 83 are formed, but this is not limited thereto, and for example, two to five, or seven or more may be formed. Then, as shown in FIG. 4, in the first state, the convex portion 81 can be engaged with one of these recessed portions 83. As a result, the driving force of the drive unit 6 is transmitted to the wheel support unit 5 via the connecting portion 8, and thus the wheel support unit 5 can rotate around the rotation axis O1. Also, as shown in FIG. 6, in the second state, the convex portion 81 can be separated from the concave portion 83 that was engaged in the first state. This allows the wheel support unit 5 to rotate around the rotation axis O1 independent of the drive unit 6, that is, with the driving force of the drive unit 6 released. In this embodiment, the convex portion 81 is provided on the wheel support unit 5 side, and the concave portion 83 is provided on the drive unit 6 side, but this is not limited thereto. For example, the convex portion 81 may be provided on the drive unit 6 side, and the concave portion 83 may be provided on the wheel support unit 5 side.

[0018] In the electric wheelchair 10 having the four casters 1 as described above, by setting each caster 1 in the first state, the center axis O4 of the wheel 4 (grounding point GP4 where the wheel 4 contacts the floor 1000) is located on the steering axis O1 (see FIG. 4). This allows the wheel 4 to rotate around the steering axis O1 while keeping the position of the grounding point GP4 unchanged. This rotation allows the electric wheelchair 10 to turn, that is, change direction, while keeping the position of the seat 211 unchanged. In addition, in the first state, the drive unit 6 and the wheel support unit 5 are connected via the connection unit 8. This allows the direction to be changed by the drive unit 6. Note that even if the wheelchair is pushed while the hand-pushing direction is parallel to the center axis O4 of each wheel 4, it becomes difficult to push the wheelchair by hand, because each wheel 4 is difficult to rotate. Furthermore, if the supply of power to each motor 63 is stopped in the first state, the motor 63 becomes a load, making it difficult to manually change direction. In this way, the first state can be said to be a state suitable for changing direction electrically (by the motor 63).

[0019] Moreover, by putting each caster 1 in the second state, the central axis O4 (grounding point GP4) of the wheel 4 is positioned at a position that is off the steering axis O1. As a result, for example, when the electric wheelchair 10 is pushed while the central axis O4 of each wheel 4 is parallel to the pushing direction, each wheel 4 rotates around the steering axis O1 with this pushing operation, and the direction of each wheel 4 changes, that is, the central axis O4 of each wheel 4 changes to a direction perpendicular to the pushing direction. Then, the electric wheelchair 10 can stably move straight by pushing it by hand. In this way, it can be said that the second state is a state with higher straight-line stability than the first state. Note that, when the electric wheelchair 10 changes direction while stopped in the second state, the position of the seat 211 shifts around one grounding point GP4. Therefore, it can be said that the second state is a state suitable for manual direction changes. As described above, the electric wheelchair 10 can switch one caster 1 between a first state suitable for electric direction changes and a second state suitable for manual direction changes.

[0020] <Second embodiment> Hereinafter, the second embodiment will be described with reference to Figs. 7 to 9, focusing on the differences from the previously described embodiment, and the description of similar matters will be omitted. Fig. 7 is a perspective view of a caster (first state) provided on an electric wheelchair according to the second embodiment. Fig. 8 is an exploded perspective view of the caster shown in Fig. 7. Fig. 9 is a perspective view of a caster (second state) provided on an electric wheelchair according to the second embodiment.

[0021] As shown in FIG. 8 (as well as FIG. 7 and FIG. 9), the wheel support unit 5 has a support unit main body 50 and an auxiliary member 57 that is formed separately from the support unit main body 50 and assists the rotation of the support unit main body 50 around the rotation axis O1. The support unit main body 50 has a clamping piece 51 and a clamping piece 52 that clamp the wheel 4 so as to be rotatable around the central axis O4, a connecting portion 53 that connects the clamping piece 51 and the clamping piece 52, and a protruding portion 56 that protrudes upward from the connecting portion 53. The auxiliary member 57 is a cylindrical member, and its central axis overlaps with the rotation axis O1. The auxiliary member 57 is fixed to the support plate 31 of the electric mechanism unit 3, for example.

[0022] The driving unit 6 has a motor 63, a motor cover 65 that houses the motor 63, a cylindrical portion 66 into which the auxiliary member 57 is inserted, and a connecting portion 67 that connects the motor cover 65 and the cylindrical portion 66. The cylindrical portion 66 is arranged concentrically with the auxiliary member 57 and can rotate around the rotation axis O1 relative to the auxiliary member 57. The connecting portion 67 connects the motor cover 65 together with the motor 63 so that they can rotate around the switching rotation axis O71. The support body 50 of the wheel support unit 5 can also rotate around the switching rotation axis O71, and this rotation allows the support body 50 to be switched between a first state shown in FIG. 7 and a second state shown in FIG. 9. When viewed from the direction of the central axis O4, in the first state, the central axis O4 of the wheel 4 is located on the rotation axis O1. Also, when viewed from the direction of the central axis O4, in the second state, the central axis O4 of the wheel 4 is located at a position deviated from the rotation axis O1.

[0023] As shown in FIG. 8, the connecting portion 8 has a link mechanism 80 made up of a plurality of links.

[0024] In this embodiment, the link mechanism 80 is composed of a pair of links 84 that connect the protruding portion 56 of the support body 50 and the motor cover 65 of the drive unit 6, and a pair of links 85 that connect the protruding portion 56 of the support body 50 and the connecting portion 67 of the drive unit 6. The lock unit 9 also has an active suspension 94. The active suspension 94 also functions as a part of the link mechanism 80, and is connected to the cylindrical portion 66 of the drive unit 6 and the middle of each link 85 in the longitudinal direction. A drive unit (not shown) that drives the active suspension 94 is provided separately.

[0025] The connecting part 8 has a first gear 86 fixed to the rotor of the motor 63 and a second gear 87 fixed to the outer periphery of the auxiliary member 57. The first gear 86 rotates around the rotation axis O63 when the motor 63 is operated. The first gear 86 is engaged with the second gear 87 in the first state shown in FIG. 7, and the first gear 86 is separated from the second gear 87 in the second state shown in FIG. 9. When the motor 63 is operated in the engaged state where the first gear 86 and the second gear 87 are engaged with each other, the driving force of the motor 63 is transmitted to the second gear 87 via the first gear 86. This allows the driving part 6 to rotate around the rotation axis O1 together with the support part main body 50 connected to the driving part 6 via the link mechanism 80. This rotation allows the electric wheelchair 10 to perform a pivot turn, and therefore allows the electric wheelchair 10 to change direction easily and quickly. Furthermore, the active suspension 94 operates to separate the first gear 86 and the second gear 87 from the meshed state. In this separated state, the driving force of the motor 63 is released between the drive unit 6 and the support body 50, allowing them to rotate about the rotation axis O1 independent of the operation of the motor 63. This makes it easier for the electric wheelchair 10 to move straight when pushed by hand.

[0026] As described above, in this embodiment, when the support body 50 rotates around the rotation axis O1, the drive unit 6 rotates around the rotation axis O1 together with the support body 50 in both the first state and the second state. Furthermore, the rotation axis O63 of the motor 63 is located at a position off the rotation axis O1 in both the first state and the second state. This configuration is effective, for example, when it is desired to relatively increase the number of parts and members that rotate around the rotation axis O1. In addition, in this embodiment, the caster 1 has an active suspension 94. This allows each caster 1 to be easily switched between the first state and the second state collectively.

[0027] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. Although the electric wheelchair 10 is used as an application example of a small mobility device in each of the above-mentioned embodiments, it can also be, for example, a transport cart for transporting luggage. In addition, the electric wheelchair 10 is driven by operating the push handle 24 in each of the above-mentioned embodiments, but is not limited thereto, and may be, for example, a device equipped with an electric drive unit such as a motor that drives the wheels 4 and self-propelled by the electric drive unit. [Explanation of symbols]

[0028] 1 Caster 4 wheels 5 Wheel support part 6 Drive unit 7 Switching section 8 Connecting part 9 Locking section 10 Electric wheelchair O1 Snake Axis O4 center axis

Claims

1. Wheels and a wheel support portion that supports the wheel so as to be rotatable around a central axis of the wheel; A drive unit that drives the wheel support unit together with the wheel so as to be rotatable about a rotation axis parallel to a direction perpendicular to a central axis of the wheel; A caster characterized by comprising a switching unit that switches the wheel support portion between a first state in which the center axis of the wheel is located on the steering axis and a second state in which the center axis of the wheel is located at a position off the steering axis.

2. The caster according to claim 1, characterized in that the switching portion is arranged at a position different from the central axis of the wheel, and supports the wheel support portion together with the wheel so as to be rotatable around a switching rotation axis parallel to the central axis of the wheel.

3. The caster according to claim 1, further comprising a connecting portion that connects the wheel support portion and the drive portion in the first state, thereby enabling the wheel support portion to rotate about the rolling axis by the drive portion, and that disconnects the wheel support portion and the drive portion in the second state, thereby enabling the wheel support portion to rotate about the rolling axis independent of the drive portion.

4. The caster described in claim 3, characterized in that the connecting portion has a convex portion protruding from one of the wheel support portion and the drive portion, and a concave portion provided on the other of the wheel support portion and with which the convex portion engages in the first state and which is separated from the other in the second state.

5. The protrusion is provided on the wheel support portion, The caster according to claim 4, characterized in that the recesses are provided in a plurality of equally spaced locations around the rolling axis in the drive portion.

6. The caster according to claim 4, characterized in that when the wheel support portion rotates around the turning axis, the position of the drive portion with respect to the turning axis remains unchanged in both the first state and the second state.

7. The drive unit has a motor, The caster according to claim 6, wherein the rotation shaft of the motor overlaps with the rotation shaft in both the first state and the second state.

8. The caster according to claim 3 , wherein the connecting portion has a link mechanism composed of a plurality of links.

9. The drive unit has a motor, The caster described in claim 3, characterized in that the connecting portion has a first gear provided on one of the wheel support portion and the motor, and a second gear provided on the other, with the first gear meshing with the first gear in the first state and separated from the first gear in the second state.

10. The caster according to claim 9, characterized in that when the wheel support portion rotates around the rolling axis, the drive portion rotates around the rolling axis together with the wheel support portion in both the first state and the second state.

11. The drive unit has a motor, The caster according to claim 10, wherein the rotation shaft of the motor is positioned away from the rotation shaft in both the first state and the second state.

12. The caster according to claim 1, further comprising a locking portion that maintains each of the first state and the second state.

13. The caster according to claim 12, characterized in that the locking portion has an engaging portion that engages with the wheel support portion at a different engaging position in the first state and in the second state.

14. The caster according to claim 12, characterized in that the locking portion has an active suspension.

15. A small mobility vehicle comprising the caster according to claim 1 and capable of moving by means of the caster.

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