JP2013237346A - Tire for handcart, wheel for handcart, and handcart - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire for a handcart, a wheel for a handcart, and a handcart having sufficient durability and being capable of exhibiting excellent vibration absorbing performance.SOLUTION: In a tire 30 for a handcart having a ground face 31 and a pair of side faces 32, on at least one of the side faces 32, a plurality of bottomed holes 35 are formed adjacently in the circumferential direction CD of the tire 30. When the plurality of bottomed holes 35 are formed on both the side faces 32, the arrangement of the bottomed holes 35 formed on one of the side faces 32 is formed while deviated from the arrangement of the bottomed holes 35 formed on the other side face 32 in the circumferential direction CD of the tire 30.

Description

  The present invention relates to a tire used for a hand cart, and more particularly to a tire that has sufficient durability and can exhibit excellent vibration absorption. The present invention relates to a wheel for a hand cart having such a tire and a hand cart.

  Wheel carts with wheels are widely available. Examples of the hand cart include a stroller used for moving an infant shown in Patent Document 1, a pet cart used for moving a pet shown in Patent Document 2, a cart used for carrying luggage, and the like. Illustrated. The wheelbarrow tire is made of resin, rubber, foamed plastic, etc., and is designed to have sufficient durability depending on the use of the wheelbarrow cart.

JP2002-220060 JP 2006-254801 A

  However, in carts used for transporting baby carriages, pet carts, and precision instruments, it is preferable that the tires can exhibit not only sufficient durability but also excellent vibration absorption. The present invention has been made in consideration of such points, and provides a tire for a hand cart that has sufficient durability and can exhibit excellent vibration absorption, a wheel having the tire, and a hand cart. For the purpose.

The tire for a hand cart according to the present invention is:
With a ground plane and a pair of sides,
A plurality of bottomed holes are formed side by side in the circumferential direction of the tire on at least one side surface.

  In the tire according to the present invention, the bottomed holes are formed on both one side surface and the other side surface, and the array of bottomed holes formed on the one side surface is formed on the other side surface. The bottomed holes may be displaced from the circumferential direction of the tire.

  In the tire according to the present invention, the bottomed hole is formed on both one side surface and the other side surface, and the inclination angle of the wall surface of the bottomed hole formed on the one side surface is on the other side surface. It may differ from the inclination angle of the wall surface of the formed bottomed hole.

  In the tire according to the present invention, a rib extending around the bottomed hole may be formed on the side surface.

  In the tire according to the present invention, the bottomed hole may have a symmetrical shape about an axis extending in a radial direction from the central axis of the tire (an axis extending in the radial direction).

  In the tire according to the present invention, a recess or a notch may be formed in the ground contact surface.

  In the tire according to the present invention, when bottomed holes are formed on both sides, the center axis of the tire from the bottom of the bottomed hole formed on one side surface to the bottom of the bottomed hole formed on the other side surface The length along the line may be 10 mm or more.

  In the tire according to the present invention, the length from the end on the contact surface side of the side surface to the bottomed hole along the radial direction from the central axis of the tire may be 1 mm or more.

  In the tire according to the present invention, the opening shape on the side surface of the bottomed hole may be a triangular shape or a shape formed by chamfering one or more corners of the triangle.

  In the tire according to the present invention, the triangle in the triangle shape and the shape formed by chamfering one or more corners of the triangle has one side extending in a direction perpendicular to the radial direction from the center axis of the tire, and You may be located on the said side surface so that the angle | corner which opposes one side may be arrange | positioned in the said radial direction rather than the said one side.

  In the tire according to the present invention, the triangle and the triangle in the shape formed by chamfering one or more corners of the triangle have one side extending in a direction perpendicular to the radial direction from the center of the tire, and the one side The corner may be positioned on the side surface so that the corner opposite to is disposed inward in the radial direction from the one side.

  In the tire according to the present invention, the opening shape on the side surface of the bottomed hole may be a circular shape or an elliptical shape.

  In the tire according to the present invention, the opening shape on the side surface of the bottomed hole may be a shape extending in the circumferential direction.

The wheel for a hand cart according to the present invention is:
Any of the tires according to the invention described above;
A wheel for holding the tire.

  The hand cart according to the invention comprises any of the wheels according to the invention described above.

  According to the present invention, excellent vibration absorbability can be imparted to a tire for a hand cart having sufficient durability.

FIG. 1 is a perspective view showing a push cart having wheels for explaining an embodiment of the present invention. FIG. 2 is a side view showing an example of a tire of a hand cart. FIG. 3 is a front view showing the tire of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a partial perspective view showing the tire of FIG. FIG. 6 is a view corresponding to FIG. 2 and showing another example of a tire. FIG. 7 is a view corresponding to FIG. 2 and showing still another example of the tire. FIG. 8 is a view corresponding to FIG. 2 and showing still another example of the tire. FIG. 9 is a view for explaining still another example of the tire, and is a side view showing a wheel including the tire. FIG. 10 is a view corresponding to FIG. 5 and showing the tire of FIG. 9. FIG. 11 is a view for explaining still another example of the tire, and is a side view showing a wheel including the tire. 12 is a view corresponding to FIG. 5 and showing the tire of FIG. FIG. 13 is a diagram for explaining a test method of a vibration impact test.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  In the following, as an example of the hand cart 5, a stroller 10 used when taking out an infant will be described as an example. However, the tires and wheels in the present invention are not limited to the stroller 10, and for example, the hand cart 5 as a pet cart used when moving a pet, or the hand cart as a cart used to transport articles. 5 or the like, and can be widely used for carts configured to be pushed through the operator's hand.

  As shown in FIG. 1, the stroller 10 includes a stroller body 11 having a front leg 12 and a rear leg 14, a front wheel holding mechanism 13 provided at the lower end of the front leg 12 of the stroller body 11, and a rear leg 14 of the stroller body 11. And a rear wheel holding mechanism 15 provided at the lower end. As an example, the front wheel holding mechanism 13 may be configured as a caster that supports the wheel 20 so as to be rotatable and turnable. Further, the rear wheel holding mechanism 15 can be configured as a holding mechanism that supports the wheel 20 in a rotatable and non-turnable manner. Although the front wheel holding mechanism 13 and the rear wheel holding mechanism 15 may hold wheels having different configurations, the following description will be made assuming that the wheels 20 having the same configuration are held.

  As shown in FIG. 1, the wheel 20 includes a tire 30 and a wheel 25 that holds the tire 30. The wheel 25 is made of resin or metal, and is rotatably held by the corresponding front wheel holding mechanism 13 or rear wheel holding mechanism 15. On the other hand, the tire 30 is fitted into the wheel 25 and fixed to the wheel 25.

  As shown in FIGS. 2 to 5, the tire 30 is opposed to the ground contact surface 31 that contacts the ground on which the stroller 10 that is the hand cart 5 travels, the side surface 32 that extends on both sides of the ground contact surface 31, and the ground contact surface 31. And a back surface 33 as a surface to be used. The back surface 33 is a surface that engages with the wheel 25. The pair of side surfaces 32 are surfaces that extend circumferentially around the center axis CA of the tire 30, in other words, the rotation axis of the wheel 20, and generally extend on a surface that is orthogonal to the center axis CA of the tire 30. As can be understood from FIG. 5, the tire 30 extends circumferentially in a shape defined by the ground contact surface 31, the pair of side surfaces 32, and the back surface 33.

  The tire 30 is formed as a solid member, and is formed from resin, rubber, foamed plastic, or the like. The tire 30 is designed to have a predetermined strength and durability according to the use of the hand cart 5. As a typical material used for manufacturing the tire 30, EVA cross-linked foam is exemplified. The EVA cross-linked foam is an ethylene-vinyl acetate copolymer, and is a thermoplastic foam produced by polymerizing ethylene hydrocarbon. The EVA cross-linked foam can be suitably used as a material for the tire 30 for a hand cart in that it has flexibility and elasticity as well as moderate strength. Further, by adding rubbers to the EVA cross-linked foam, the elasticity and heat resistance of the tire 30 can be improved, and the tire 30 can also be colored by adding a pigment.

  A plurality of bottomed holes 35 are formed on at least one side surface 32 of the tire 30. The bottomed hole 35 is a hole having a bottom surface 36 and is distinguished from a through hole. The plurality of bottomed holes 35 are formed side by side in the circumferential direction CD of the tire 30, that is, in the circumferential direction around the rotation axis of the wheel 20. According to such a tire 30, as demonstrated in the description of the test results described later, the tire 30 is further imparted with excellent vibration absorption (shock absorption) while providing sufficient durability. be able to.

  From the viewpoint of uniform vibration absorption and durability at each position along the circumferential direction CD of the tire 30, a plurality of bottomed holes 35 are arranged at a constant pitch in the circumferential direction CD of the tire 30. It is preferable.

  In the illustrated example, a plurality of bottomed holes 35 are formed in the first side surface 32a as one side surface, and a plurality of bottomed holes 35 are formed in the second side surface 32b as the other side surface. As shown in FIGS. 3 to 5, the arrangement of the bottomed holes 35 formed in the first side surface 32 a is along the circumferential direction CD of the tire 30 from the arrangement of the bottomed holes 35 formed in the second side surface 32 b. It ’s out of place. In other words, the bottomed hole 35 formed in the first side surface 32 a is disposed so as to be shifted from the bottomed hole 35 formed in the second side surface 32 b in the circumferential direction CD of the tire 30. Preferably, the bottomed hole 35 formed in the first side surface 32a does not overlap the bottomed hole 35 formed in the second side surface 32b in the direction of the center axis CA of the tire 30, that is, the rotation axis of the wheel 20. It is preferable that they are arranged. According to such an aspect, the vibration absorbability and durability at each position along the circumferential direction CD of the tire 30 can be made uniform.

  As shown in FIG. 4, the inclination angle θa of the wall surface 37 of the bottomed hole 35 formed on the first side surface 32a is equal to the inclination angle θb of the wall surface 37 of the bottomed hole 35 formed on the second side surface 32b. Is different. Specifically, the inclination angle θa of the wall surface 37 of the bottomed hole 35 formed on the first side surface 32a is smaller than the inclination angle θb of the wall surface 37 of the bottomed hole 35 formed on the second side surface 32b. Yes.

  In the production of conventional tires, since a tire can be produced at low cost, a molding method using a pair of dies is widely adopted. In this method, a tire can be obtained in a cavity formed by combining a pair of molds. The first side surface of the manufactured tire is disposed at a position facing one mold, and the second side surface of the fabricated tire is disposed at a position facing the other mold. After the tire is manufactured, the pair of molds are separated from each other, whereby the manufactured tire is released from at least one of the pair of molds.

  And the tire 30 demonstrated here can also be produced cheaply by shaping | molding using a pair of type | mold similarly to the conventional tire. The releasability from the mold of the tire 30 in which the bottomed hole 35 is formed on the side surface 32 depends on the inclination angles θa and θb of the wall surface 37 of the bottomed hole 35. Therefore, when the pair of dies for producing the tire 30 of FIG. 4 are separated from each other, the tire 30 is easily released from the second side surface 32b having a larger inclination angle θa. As described above, when the manufactured tire 30 is released, the tire 30 tends to be supported by a mold on a specific side, so that the tire 30 can be stably produced and the productivity of the tire 30 is increased. Can also be improved.

  In addition, when the bottomed hole 35 is formed in both of a pair of side surfaces 32, the bottomed hole 35 formed in the 2nd side surface 32b from the bottom face 36 of the bottomed hole 35 formed in the 1st side surface 32a. It is preferable that the length la (see FIG. 4) along the central axis CA of the tire 35, that is, the rotation axis of the wheel 20, to the wall surface 37 is 10 mm or more. In this case, deterioration of the strength and durability of the tire 30 due to the provision of the bottomed hole 35 can be extremely effectively prevented.

  Further, the length lb along the radial direction RD from the central axis of the tire 30 from the end of the contact surface side of the side surface 32 to the bottomed hole 35 (see FIG. 4), in other words, in the radial direction of the tire 30. The along length lb is preferably 1 mm or more. In this case, deterioration of the strength and durability of the tire 30 due to the provision of the bottomed hole 35 can be extremely effectively prevented.

  On the other hand, as shown well in FIG. 5, ribs 39 extending around the bottomed hole 35 may be formed on the side surface 32 of the illustrated tire 30. In the example shown in FIGS. 2, 4, and 5, the rib 39 has the side surface 32 of the single bottomed hole 35 so as to define the outer contour of the opening on the side surface 32 of the single bottomed hole 35. The upper opening is surrounded by a circumference. According to such a rib 39, deterioration of the strength and durability of the tire 30 caused by providing the bottomed hole 35 can be extremely effectively prevented. 2, 4, and 5 extend to the ground contact surface 31. For this reason, in the illustrated example, a recess 41 or a notch 41 is formed in the ground contact surface 31.

  Next, the opening shape on the side surface 32 of the bottomed hole 35 will be described. As the opening shape on the side surface 32 of the bottomed hole 35, various shapes that can effectively exhibit vibration absorption can be adopted. Here, some examples of the opening shape on the side surface 32 of the bottomed hole 35 will be described with reference to the drawings.

  In the example shown in FIGS. 2 and 5, and in the examples shown in FIGS. 6 to 12 described later, the opening shape of the bottomed hole 35 extends in the radial direction RD from the center axis CA of the tire 30. The axis is symmetrical about the axis extending in the radial direction of the tire 30. According to such a tire 30, the bottomed hole 35 exhibits the same vibration absorbing function both when rotated clockwise about the rotation axis CA and when rotated counterclockwise. Is possible. That is, a predetermined vibration absorbing performance can be expected regardless of the direction of the traveling direction of the hand cart 5.

  As shown in FIGS. 2 to 5, the opening shape on the side surface 32 of the bottomed hole 35 is a triangular shape or a shape formed by chamfering one or more corners of the triangle. Further, the triangle in the triangle shape and the shape formed by chamfering one or more corners of the triangle has a side perpendicular to the radial direction RD from the center of the tire 30 (in other words, the radial direction of the tire 30). The corners extending and facing the one side are positioned on the side surface 32 so as to be arranged outward in the radial direction RD from the one side.

  By providing such a bottomed hole 35, excellent vibration absorbability can be imparted to the tire 30 while sufficiently maintaining the durability of the tire 30. Here, the result of the test confirmed by the present inventors will be described.

[Study Summary]
We investigated the improvement of vibration absorption by tires by the following method defined by the SG standards of the Japan Product Safety Association.

[Test subject]
The tire shown in FIGS. 2 to 5 described above was manufactured, and the manufactured tire was incorporated into a commercially available baby stroller to prepare a baby stroller for test object 1. On the other hand, a commercially available baby stroller itself was designated as test subject 2. Test object 1 and test object 2 were the same except for the tires. The tire of the test object 1 is different from the tire of the test object 2 in that the bottomed hole 35 and the notch 41 are formed, and is the same in other points. The stroller of the test subject 1 and the stroller of the test subject 2 are reclinable and foldable as in the stroller shown in FIG. 1, and the handle position can be switched between the back position and the facing position. Configured.

〔Test method〕
An accelerometer was attached to the mass dummy abdomen position with the mass dummy placed in the center of the stroller seat. In this state, a vibration impact test was performed on the front wheels and the rear wheels, and vibration acceleration values were measured. As shown in FIG. 13, the vibration impact test was performed by setting a wheel on a steel drum having a diameter of 200 mm having a height difference of 10 mm. The number of revolutions of the drum was 100 revolutions per minute.

〔Test results〕
Both the baby stroller of test subject 1 and the baby stroller of test subject 2 are stipulated by the SG standards of the Japan Product Safety Association, specifically, “vibration acceleration at infant abdominal position is 10 m / s ² or less Was fulfilled. When comparing the test subject 1 stroller and the test subject 2 stroller, the test subject 1 stroller using the tire 30 having the bottomed hole 35 shown in FIGS. 2 to 5 was measured under almost all conditions. The vibration acceleration value was smaller than the vibration acceleration value of the baby stroller of the test object 2 measured under the same conditions. Specifically, the vibration acceleration value measured for the baby stroller of the test subject 1 was approximately 70% to 100% of the vibration acceleration value of the baby stroller of the test subject 2 measured under the same conditions. From this experimental result, it was confirmed that vibration absorption can be improved by providing the tire 30 with the bottomed hole 35 shown in FIGS.

[Evaluation of durability]
The durability of the test subject 1 stroller and the test subject 2 stroller was also investigated by the following method defined by the SG standards of the Japan Product Safety Association. Specifically, the durability test was conducted by the following method. First, a vibration test was performed in a state where a weight was placed on a baby stroller seat, and it was confirmed by visual observation and tactile sensation that there was no abnormality. As shown in FIG. 13, the vibration impact test was performed by setting a wheel on a steel drum having a diameter of 200 mm having a height difference of 10 mm. The number of revolutions of the drum was 100 revolutions per minute. During this vibration test, the back of the seat was in the most tilted state. A weight of 10 kg was placed on the center of the back of the seat, and 25 kg was placed on the center of the seat of the seat. A 20 N force (F) was applied vertically from above to the handle (see FIG. 13). The test time was 3 hours, and it was carried out for each of the front and rear wheels. The stroller folding operation and the steering wheel position switching operation between the back position and the facing position were repeated 20 times each time the vibration test was performed for 1 hour, and it was confirmed that there was no looseness in each part. In addition, after the completion of all tests, a force of 200 N was applied in the direction in which the handle and the like were folded, and it was confirmed that the handle was not folded and the handle was not swung unintentionally. In both the test subject 1 stroller and the test subject 2 stroller, no abnormality was found during and after the test. Moreover, from the test results, the baby stroller of the test subject 1 had the same durability as the baby stroller of the test subject 2.

  Returning to FIGS. 6 to 12 again, the opening shape on the side surface 32 of the bottomed hole 35 will be described. In the example shown in FIG. 6, the triangle shape and the triangle formed by chamfering one or more corners of the triangle are arranged in the opposite direction to the examples shown in FIGS. 2 to 5. That is, the triangle forming the opening shape on the side surface 32 of the bottomed hole 35 extends in a direction perpendicular to the radial direction RD from the center of the tire 30 (in other words, the radial direction of the tire 30). And the corner | angular which faces the said one side is located on the side surface 32 so that it may be arrange | positioned in the radial direction RD rather than the said one side. Providing such a bottomed hole 35 can also impart excellent vibration absorption to the tire 30 while sufficiently maintaining the durability of the tire 30.

  Further, the opening shape in the side surface 32 of the bottomed hole 35 may be a circular shape or an elliptical shape. In the example shown in FIG. 7, the opening shape on the side surface 32 of the bottomed hole 35 is circular. When the opening shape in the side surface 32 of the bottomed hole 35 is an ellipse, the major axis or minor axis of the ellipse extends in the radial direction RD from the center of the tire 30 (in other words, the radial direction of the tire 30). Alternatively, both the major axis and the minor axis of the ellipse may be inclined with respect to the radial direction RD from the center of the tire 30 (in other words, the radial direction of the tire 30). Providing such a bottomed hole 35 can impart excellent vibration absorption to the tire 30 while sufficiently maintaining the durability of the tire 30.

  Further, as in the example shown in FIG. 8, the opening shape on the side surface 32 of the bottomed hole 35 may be a shape extending in the circumferential direction CD. In the example shown in FIG. 8, the opening shape has a shape that extends in the circumferential direction CD while maintaining a certain width along the radial direction RD, and that both ends in the circumferential direction CD are chamfered in a circular shape. doing. As a modification of the tire 30 shown in FIG. 8, the opening shape may extend in a direction perpendicular to the normal direction RD of the tire 30 instead of the circumferential direction CD of the tire 30. Providing such a bottomed hole 35 can also impart excellent vibration absorption to the tire 30 while sufficiently maintaining the durability of the tire 30.

  In the example shown in FIGS. 9 and 10, the opening shape on the side surface 32 of the bottomed hole 35 is a trapezoidal shape or a shape formed by chamfering one or more corners of the trapezoidal shape. In the example shown in FIGS. 9 and 10, the trapezoidal narrow upper base is located outward in the radial direction RA from the center of the tire 30, rather than the trapezoidal wide bottom base. The trapezoidal upper and lower bases extend in a direction orthogonal to the radial direction RA from the center of the tire 30. Further, in the example shown in FIGS. 9 and 10, a recess 41 or a notch 41 is formed in a region serving as a boundary between the ground contact surface 31 and the side surface 32. That is, the recess 41 or the notch 41 is formed across the ground contact surface 31 and the side surface 32. The recess 41 or the notch 41 is formed at a position between the two bottomed holes 35 adjacent to each other along the circumferential direction CD of the tire 30. Such a tire 30 can also exhibit excellent vibration absorption while maintaining sufficient durability.

  In the example shown in FIGS. 11 and 12, the opening shape on the side surface 32 of the bottomed hole 35 is a quadrangular shape, in particular, an isosceles trapezoidal shape. In the example shown in FIGS. 11 and 12, the upper and lower bases of the trapezoidal shape extend in a direction perpendicular to the radial direction RA from the center of the tire 30. The trapezoidal side surface extends in the radial direction RA from the center of the tire 30. Further, in the example shown in FIGS. 11 and 12, a recess 41 or a notch 41 is formed in a region serving as a boundary between the ground contact surface 31 and the side surface 32. That is, the recess 41 or the notch 41 is formed across the ground contact surface 31 and the side surface 32. The recess 41 or the notch 41 is formed at a position adjacent to the bottomed hole 35 in the radial direction RD from the center of the tire 30, and is connected to the bottomed hole 35. Further, a circumferential groove 43 extending in the circumferential direction CD of the tire 30 is formed on each side surface 32. In the illustrated example, the circumferential groove 43 extends across the bottomed hole 35. The depth of the groove 43 is shallower than the depth of the bottomed hole 35. Such a tire 30 can also exhibit excellent vibration absorption while maintaining sufficient durability.

  In addition, although the opening shape in the side surface 32 of the bottomed hole 35 was demonstrated referring drawings, the above description is an illustration, Comprising: The bottomed hole 35 has another shape, for example, polygon, on the side surface 32. It is good also as a shape formed by chamfering one or more corners of a shape or a polygon. Moreover, the opening shape of the bottomed hole 35 formed in the one side surface 32a may be different from the opening shape of the bottomed hole 35 formed in the other side surface 32b. Moreover, you may make it an opening shape differ between the bottomed holes 35 formed in each side surface.

  According to the present embodiment as described above, the plurality of bottomed holes 35 are formed side by side in the circumferential direction CD of the tire 30 on at least one side surface 32 of the tire 30. According to such a tire 30, as demonstrated from the above test results, it is possible to exhibit further excellent vibration absorption while maintaining sufficient durability. Thereby, the riding comfort of the stroller 10 in which the tire 30 is used can be improved. Further, by forming the bottomed hole 35 in the tire 30, it is possible to reduce the weight of the tire 30 and further reduce the weight of the stroller 10 in which the tire 30 is incorporated. Furthermore, the design of the tire 30 can be improved by forming the bottomed hole 35.

  Note that various modifications can be made to the embodiment described above. Hereinafter, an example of modification will be described.

  As an example of the hand cart 5 to which the tire 30 and the wheels 20 are applied, the stroller 10 illustrated in FIG. 1 is illustrated. The stroller 10 shown in FIG. 1 can be folded so as to be miniaturized in the front-rear direction and the height direction. However, the baby stroller is not limited to the example of FIG. 1, for example, a baby stroller that is folded so as to be reduced in the front-rear direction and further folded in the width direction as disclosed in Japanese Patent Application Laid-Open No. 2011-148454. 10 may be configured. Further, the stroller 10 shown in FIG. 1 is configured such that the handle can swing between a back pushing position (rear position) and a facing pushing position (front position). However, the stroller 10 may be configured such that the handle is fixed at the rear position and cannot be swung from the back pushing position.

  Further, as described above, the tire 30 and the wheel 20 described above are not limited to the stroller 10, and for example, a hand cart 5 as a pet cart used when moving a pet, and transportation of an article. It can be used for the hand cart 5 as a cart used in the vehicle.

5 Wheelbarrow Cart 10 Stroller 11 Stroller Body 12 Front Leg 13 Front Wheel Holding Mechanism 14 Rear Leg 15 Rear Wheel Holding Mechanism 20 Wheel 25 Wheel 30 Tire 31 Ground Surface 32 Side 32a First Side 32b Second Side 33 Back 35 Bottomed Hole 36 Bottom 37 Wall 39 Rib 41 Recess, Notch 43 Groove

Claims (11)

In tires for hand carts,
With a ground plane and a pair of sides,
A tire in which a plurality of bottomed holes are formed side by side in the circumferential direction of the tire on at least one side surface. The bottomed hole is formed on both one side surface and the other side surface,
2. The tire according to claim 1, wherein an array of bottomed holes formed on the one side surface is shifted from an array of bottomed holes formed on the other side surface in a circumferential direction of the tire. The bottomed hole is formed on both one side surface and the other side surface,
The tire according to claim 1 or 2, wherein an inclination angle of a wall surface of the bottomed hole formed on the one side surface is different from an inclination angle of a wall surface of the bottomed hole formed on the other side surface.   The tire according to any one of claims 1 to 3, wherein a rib extending around the bottomed hole is formed on the side surface.   The said bottomed hole becomes a symmetrical shape centering | focusing on the axis | shaft (axis extended in radial direction) extended in the radial direction from the center axis line of a tire. tire.   The tire according to any one of claims 1 to 5, wherein the opening shape on the side surface of the bottomed hole is a triangular shape or a shape formed by chamfering one or more corners of a triangle.   The triangle in the triangle shape and the shape formed by chamfering one or more corners of the triangle has one side extending in a direction perpendicular to the radial direction from the central axis of the tire, and an angle facing the one side. The tire according to claim 6, wherein the tire is located on the side surface so as to be disposed outward in the radial direction from the one side.   The tire according to any one of claims 1 to 7, wherein an opening shape on the side surface of the bottomed hole is a circular shape or an elliptical shape.   The tire according to any one of claims 1 to 8, wherein an opening shape on the side surface of the bottomed hole is a shape extending in a circumferential direction. The tire according to any one of claims 1 to 9,
A wheel for a hand cart, comprising a wheel for holding the tire.   A hand cart including the wheel according to claim 10.

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