JP6169407B2 - Pram wheels and prams - Google Patents

Description

  The present invention relates to a wheel for a baby carriage and a baby carriage.

  For example, as disclosed in Patent Document 1, a baby carriage having wheels is widely used. A wheel of a baby carriage is generally formed by fitting a solid tire formed on a wheel using resin, rubber, foamed plastic, or the like. In many conventional baby carriage wheels, as shown in FIG. 5, the wheel 90 has a pair of support wall portions that protrude radially outward and extend in the circumferential direction at positions that are both outward in the width direction. 91. On the other hand, the tire 95 includes an engaging convex portion 96 that is arranged between the pair of support wall portions 91, and a tire outer portion 97 that is located radially outward of the engaging convex portion. Yes. The tire 95 is attached to the wheel 90 by disposing the engaging convex portion 96 of the tire 95 between the pair of support wall portions 91 of the wheel 90. In addition, the tire outer portion 97 of the tire 95 is supported on the pair of support wall portions 91 to exhibit shock absorption and vibration absorption.

Japanese Patent Laid-Open No. 2002-220060

  As described above, the outer portion of the tire exhibits the shock absorption and vibration absorption inherently expected for the wheel, but the engagement convex portion of the tire is defined by the support wall portion of the wheel. It is located in the space and does not receive a load between the ground on which the baby carriage runs and the wheel. That is, the convex portion for engagement of the tire is merely used as an engaging portion with the wheel without exhibiting shock absorption and vibration absorption. Nevertheless, like the tire outer portion, the tire engaging convex portion is formed thick using a material having a relatively large specific gravity. As a result, the conventional wheels cause problems such as an increase in the weight of the baby carriage and an increase in manufacturing cost. Further, in this type of wheel, since the tire has a thick portion, there are problems such as a long molding time and a decrease in dimensional accuracy.

  On the other hand, the present inventors have developed a wheel different from the conventional one as a result of extensive research. In this wheel, the tire is attached to the wheel by positively utilizing the shrinkage of the tire base portion constituting the ground contact surface of the tire. Therefore, unlike the conventional case, it is possible to eliminate the necessity of providing the tire with a thick portion mainly used as an engaging portion for mounting the tire on the wheel. The present invention is based on such knowledge of the inventors of the present invention, and therefore has a wheel that can cope with various conventional problems caused by the tire having a thick portion, and the wheel. The purpose is to provide a baby carriage.

The wheel according to the invention is
A wheel for a baby carriage held rotatably about a rotation axis,
The annular base portion extending in the circumferential direction around the rotation axis, and the rotation from a position on the base portion that is inward from both ends of the base portion along an axial direction parallel to the rotation axis. A wheel having a pair of annular inner ribs projecting outward in the radial direction about the axis and extending in the circumferential direction;
A tire mounted on the wheel from the outside in the radial direction,
The tire is supported by at least the pair of inner ribs, and has an annular shape that protrudes outward in the radial direction and extends in the circumferential direction in a cross section parallel to both the axial direction and the radial direction. A tire base portion, and an inward protruding portion that protrudes inward in the radial direction from the tire base portion and is engageable with the inner rib,
An outer surface in the radial direction of the tire base portion forms a contact surface.

In the wheel according to the invention,
The wheel protrudes outward in the radial direction from a position on the base portion that is both outward of the pair of annular inner ribs in the axial direction, and extends in the circumferential direction. A rib, and
The outward protrusion height along the radial direction of the inner rib from the base portion is higher than the outward protrusion height along the radial direction of the outer rib from the base portion. May be.

  The wheel by this invention WHEREIN: The said outer side rib may be arrange | positioned in the position used as the edge part of the said base part in the said axial direction.

  In the wheel according to the present invention, the tire base portion of the tire may be separated from the base portion of the wheel between the outer rib and the inner rib in the axial direction.

  In the wheel according to the present invention, the inward protruding portion of the tire may be located between any two ribs adjacent in the axial direction.

  In the wheel according to the present invention, the inward protrusion of the tire is located between the pair of inner ribs, and the inward protrusion of the tire is between the pair of inner ribs in the axial direction. The wheel may be separated from the base portion.

  In the wheel according to the present invention, the tire may be separated from the base portion of the wheel.

  The wheel by this invention WHEREIN: The protrusion height from the said tire base part of the said inward protrusion part may be lower than the thickness of the said tire base part.

  In the wheel according to the present invention, the tire may be subjected to tensile stress in the circumferential direction in the entire region in the axial direction in a state where the tire is mounted on the wheel.

  In the wheel according to the present invention, in a state where the tire is mounted on the wheel, both end portions in the axial direction of the tire base portion are more in the radial direction than inner ends in the radial direction of the inward protruding portions. It may be located inward.

  In the wheel according to the present invention, the end portion of the tire base portion may be located outward of both end portions of the base portion in the axial direction.

  In the wheel according to the present invention, the base portion of the wheel may extend in parallel to the axial direction.

  The baby carriage according to the present invention includes any of the wheels according to the present invention described above.

  According to the present invention, it is possible to eliminate various problems caused by the tire having a thick portion.

FIG. 1 is a perspective view showing a baby carriage having wheels for explaining an embodiment of the present invention. FIG. 2 is a side view showing wheels for the baby carriage. FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view showing the tire before being attached to the wheel, in the same cross section as FIG. 3. FIG. 5 is a cross-sectional view showing a conventional baby carriage wheel in the same cross section as FIG.

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

  As shown in FIG. 1, the baby carriage 10 includes a baby carriage main body 11 having a front leg 12 and a rear leg 14, a front wheel holding unit 13 provided at the lower end of the front leg 12 of the baby carriage main body 11, and a rear leg 14 of the baby carriage main body 11. And a rear wheel holding unit 15 provided at the lower end. As an example, the front wheel holding unit 13 may be configured as a caster that supports the wheel 20 so as to be rotatable and turnable. Further, the rear wheel holding unit 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 unit 13 and the rear wheel holding unit 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 wheel 30 and a tire 40 attached to the wheel 30. The wheel 30 is rotatably held by the corresponding front wheel holding unit 13 or rear wheel holding unit 15. On the other hand, the tire 40 is fitted into the wheel 30 and fixed to the wheel 30.

  The wheel 30 has a rim portion 32 extending annularly in a circumferential direction dc centered on the rotational axis of the wheel 20 and a radial direction da (hereinafter simply referred to as “radial direction”) about the rotational axis of the wheel 20. ), In other words, a plurality of spokes 31 extending radially about the rotation axis of the wheel 20. The plurality of spokes 31 merge at the inner end in the radial direction dr. A through hole 31 a for allowing an axle (not shown) to pass through is formed in the joining portion of the spoke 31. As an example, the wheel 30 can be integrally formed by injection molding a resin material.

  Next, the rim portion 32 of the wheel 30 will be further described in detail with reference mainly to the cross-sectional view shown in FIG. Note that the cross section shown in FIG. 3 is a cross section parallel to both the radial direction da and the axial direction (width direction) da parallel to the rotational axis of the wheel 20.

  The rim portion 32 of the wheel 30 includes a base portion 35, and outer ribs 37 and inner ribs 39 that protrude from the base portion 35 toward the outside in the radial direction dr (side away from the rotation axis). . The base portion 35 extends in the circumferential direction dc, has an annular shape, and has a plate shape in a cross section along the axial direction da. In particular, in the illustrated example, the base portion 35 is formed in a flat plate shape extending in parallel with the axial direction da in the cross section of FIG. Outer ribs 37 are provided at positions corresponding to both ends of the base portion 35 in the axial direction da. A pair of inner ribs 39 are provided from above the base portion 35 between the pair of outer ribs 37 in the axial direction da. That is, the pair of inner ribs 39 are located at positions shifted inward from both ends in the axial direction da of the base portion 35. The pair of inner ribs 39 are disposed on the base portion 35 so as to be separated from each other in the axial direction da.

  The outer rib 37 and the inner rib 39 are provided on the outer surface of the base portion 35 in the radial direction dr, and project outward in the radial direction dr. In particular, in the illustrated example, the outer rib 37 and the inner rib 39 extend from the base portion 35 in parallel with the radial direction dr. The outward projecting height from the base portion 35 along the radial direction dr is the same between the pair of outer ribs 37. Further, the outward projecting height from the base portion 35 along the radial direction dr is the same between the pair of inner ribs 39. Furthermore, the outward protrusion height along the radial direction dr of the inner rib 39 from the base portion 35 is higher than the outward protrusion height along the radial direction dr of the outer rib 37 from the base portion 35. It has become. Each of the outer rib 37 and the inner rib 39 extends in the circumferential direction dc and is formed in an annular shape.

  Next, the tire 40 will be described. As shown in FIGS. 2 and 3, the tire 40 is attached to the wheel 30 from the outside in the radial direction dr. As shown in FIG. 3, the tire 40 includes a plate-shaped tire base portion 45 supported by a pair of outer ribs 37 and a pair of inner ribs 39, and an inward protruding portion 49 provided on the tire base portion 45. Have. The tire base portion 45 has a central portion in the axial direction da having a radius in the cross section shown in FIG. 3 (a cross section parallel to both the axial direction da and the radial direction dr) when the tire 40 is mounted on the wheel 30. It protrudes outward in the direction dr and has a plate shape that is curved in a convex shape toward the outside in the radial direction dr as a whole. The tire base portion 45 extends along the circumferential direction dc and has an annular shape. An outer surface in the radial direction dr of the tire base portion 45 forms a ground contact surface 41 that contacts the ground.

  The inward projecting portion 49 is provided on the inner surface of the tire base portion 45 in the radial direction dr. The inward protruding portion 49 is disposed between the pair of inner ribs 39 of the wheel 30 when the tire 40 is mounted on the wheel 30. In the illustrated example, the inward projecting portion 49 extends along the circumferential direction dc and is formed in an annular shape. In the cross section shown in FIG. 3, the inward protruding portion 49 has a curved outer contour. In particular, in the cross section shown in FIG. 3, the inward protrusion 49 has a shape corresponding to a part of a circle or an ellipse. In the illustrated example, the protruding height of the inward protruding portion 49 along the radial direction dr from the tire base portion 45 is lower than the thickness of the tire base portion 45. Further, the inward protruding portion 49 of the tire 40 is separated from the base portion 35 of the wheel 30 between the pair of inner ribs 39 in the axial direction da.

  The tire 40 is made of a stretchable material such as resin, rubber, foamed plastic or the like. The tire 40 is designed to have a predetermined strength and durability according to the design of the baby carriage. As a typical material used for manufacturing the tire 40, 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 40 for a baby carriage in that it has flexibility and elasticity as well as moderate strength. Further, by adding rubbers to the EVA crosslinked foam, the elasticity and heat resistance of the tire 40 can be improved, and the tire 40 can also be colored by adding a pigment.

  In the wheel 20 in the present embodiment, the tire 40 is disposed on the rim portion 32 of the wheel 30 in a state where the tire 40 is stretched by elastic deformation so that the circumferential length along the circumferential direction dr increases. Through the process, the tire 40 can be attached to the rim portion 32 of the wheel 30 from the outside in the radial direction dr. In FIG. 4, the tire 40 is shown in a state before being attached to the wheel 30. The cross section shown in FIG. 4 shows the same cross section as that in FIG. 3, and shows the molded tire 40 in a state where no external force is applied. In the example shown in FIG. 4, the tire base portion 45 of the tire 40 is formed in a flat plate shape that extends along the axial direction da and is not curved. Further, the tire base portion 45 of the tire 40 has a constant thickness along the axial direction da except for both end portions in the axial direction da.

  In the wheel 20 shown in FIG. 3, the tire 40 is in a state of extending in the circumferential direction dc in the entire region along the axial direction da. In other words, the tire 40 is subjected to tensile stress in the circumferential direction dc over the entire region along the axial direction da. Accordingly, both end portions of the entire width of the tire 40 are subjected to tensile stress while being located in the most inward in the radial direction dr. In particular, in the illustrated example, in a state where the tire 40 is mounted on the wheel 30, both end portions 45 a in the axial direction da of the tire base portion 45 are more than the inner ends 49 a in the radial direction dr of the inward projecting portions 49. It is located inward in the radial direction. Therefore, unless a large external force is applied, the end portion 45a of the tire base 45 subjected to the tensile stress expands against the tensile stress, and thereby the tire 40 is turned off from the end portion 45a and detached from the wheel 30. Can be effectively prevented.

  As described above, the tire base portion 45 of the tire 40 mounted on the wheel 30 is defined by the outer rib 37 and the inner rib 39 protruding outward from the base portion 35 of the wheel 30 in the radial direction dr. It extends along the path and is maintained in a curved shape as shown. Therefore, as shown in FIG. 3, the tire base portion 45 of the tire 40 is separated from the base portion 35 of the wheel 30 in the radial direction dr between the outer rib 37 and the inner rib 39 in the axial direction da. Further, in the illustrated example, the inward protruding portion 49 of the tire 40 is separated from the base portion 35 of the wheel 30 between the pair of inner ribs 39 in the axial direction da. As a result, in the illustrated wheel 20, the tire 40 is separated from the base portion 35 of the wheel 30.

  Next, the operation of the present embodiment will be described.

  In the present embodiment described above, the wheel 30 includes the base portion 35 and the pair of inner ribs 39, and the tire 40 includes the tire base portion 45 and the inward protruding portion 49, and the tire 40 is elastic. The wheel 30 is mounted from the outside in the radial direction dr due to the restoring force. For this reason, the tire base portion 45 of the tire 40 is supported by the inner rib 39 of the wheel 30 and has a plate shape that is convexly curved outward in the radial direction dr in a cross section along the axial direction da. The inward protrusion 49 can engage the inner rib 39.

  According to the wheel 20 of the present embodiment as described above, the displacement of the wheel 30 and the tire 40 in the axial direction da is regulated by the engagement between the inward protruding portion 49 of the tire 40 and the wheel 30. The tire 40 is engaged with the wheel 30 by the contraction of the tire base portion 45. Therefore, unlike the conventional wheel, the tire need not have a thick portion for engagement (engagement convex portion 96 in FIG. 5). In the present embodiment, the manufacturing cost of the wheel 20 can be directly reduced by eliminating the thick portion that cannot exhibit the shock absorption or vibration absorption, which is the original purpose of the tire. Moreover, since the tire 40 is a material having a relatively large specific gravity among the materials used for the baby carriage, the wheels 20 and the baby carriage 10 can be reduced in weight by eliminating the thick portion.

  In addition, the tire 40 of the wheel 20 includes a curved belt-shaped tire base portion 45 and an inward protruding portion 49 protruding from the tire base portion 45, and does not have a thick portion. The molding time of the tire 40 can be shortened and the dimensional accuracy of the tire 40 can be improved. In particular, when the tire 40 is molded using a foamed material such as a general foam rubber as a material used for a tire for a baby carriage wheel, the heating time for foam molding can be greatly shortened.

  Furthermore, since the dimensional accuracy of the tire 40 is improved and the tire 40 is mounted on the wheel 30 by utilizing the contraction of the curved plate-like tire base portion 45 that forms the ground contact surface 41, It is possible to effectively prevent the tire 40 from being lifted, that is, forming a gap between the tire 40 and the wheel 30. As a result, it is possible to effectively prevent the tire 40 from being detached from the wheel 30.

  Further, the wear of the tire 40 proceeds most at a position facing the inner rib 39 in the tire base portion 45. When the tire base portion 45 wears at this position, a streak pattern extending in the circumferential direction dc appears at a position facing the inner rib 39 in the ground contact surface 41 of the tire 40. The user of the baby carriage 10 can determine the presence or absence of wear of the tire 40 based on the presence or absence of the streak pattern, and can replace the wheel 20 at an appropriate time. That is, the wheel 20 according to the present embodiment provides an index related to the replacement time of the wheel 20.

  Further, according to the present embodiment, the wheel 30 protrudes outward in the radial direction dr from the position on the base portion 35 that is both outward of the pair of inner ribs 39 in the axial direction da and is circumferential. It further has a pair of annular outer ribs 37 extending to dc. The height of outward protrusion of the inner rib 39 from the base portion 35 along the radial direction dr is higher than the height of outward protrusion of the outer rib 37 from the base portion 35 along the radial direction dr. It has become. By providing the outer rib 37 in addition to the inner rib 39, the tire base portion 45 is stably supported not only at the position facing the inner rib 39 but also at the position facing the outer rib 37. Thus, the overall contour of the tire base portion 45 that is convex outward in the radial direction dr can be more stably maintained.

  Furthermore, according to the present embodiment, the inward protruding portion 49 is between two ribs adjacent to each other in the axial direction da among the ribs (the outer rib 37 and the inner rib 39) provided on the tire base portion 45. Furthermore, in the illustrated example, it is disposed between the pair of inner ribs 39. Therefore, the displacement of the wheel 30 and the tire 40 in the axial direction da can be effectively regulated by the engagement between the inward projecting portion 49 and the pair of ribs.

  Furthermore, according to the present embodiment, the tire base portion 45 of the tire 40 is separated from the base portion 35 of the wheel 30 between the outer rib 37 and the inner rib 39 in the axial direction da. Further, the inward protruding portion 49 of the tire 40 is also separated from the base portion 35 of the wheel 30. As a result, the tire 40 is separated from the wheel 30 in the radial direction dr as a whole. According to such a wheel 20, the tire base portion 45 of the tire 40 bends between the outer rib 37 and the inner rib 39 of the wheel 30, and the tire base portion 45 and the inward protruding portion 49 become the wheel 30. By bending between the pair of inner ribs 39, and further by bending the inner rib 39 of the wheel 30, sufficient shock absorption and sufficient vibration absorption can be achieved even when the tire base portion 45 is thin. It can be applied to the wheel 20.

  The inward protruding portion 49 prevents the tire 40 from shifting in the axial direction da with respect to the wheel 30 in cooperation with the contraction force of the tire base portion 45. Therefore, in the baby carriage wheel 20, it is not necessary to increase the height of the inward protruding portion 49 until it comes into contact with the base portion 35. Further, the protruding height of the inward protruding portion 49 from the tire base portion 45 can be made lower than the thickness of the tire base portion 45. Thus, if the protrusion amount of the inward protrusion portion 49 from the tire base portion 45 is reduced, the molding time of the tire 40 can be further shortened and the dimensional accuracy of the tire 40 can be further improved.

  Further, in the present embodiment, the tire 40 receives tensile stress in the circumferential direction dc in the entire region in the axial direction da in a state where the tire 40 is mounted on the wheel 30. According to such a wheel 20, the mounting state of the tire 40 on the wheel 30 is stabilized. Thereby, it can prevent more effectively that the tire 40 will remove | deviate from the wheel 30. FIG.

  Further, in the present embodiment, in a state where the tire 40 is mounted on the wheel 30, both end portions 45 a in the axial direction da of the tire base portion 45 are more than the inner ends 49 a in the radial direction dr of the inward protruding portions 49. , Located inward in the radial direction dr. According to such a wheel 20, it is possible to effectively prevent the end portion 45 a in the axial direction da of the tire 40 from being turned over from the wheel 30, thereby stably preventing the tire 40 from coming off the wheel 30. Can be avoided.

  Further, in the present embodiment, as well shown in FIG. 3, the end portion 45a of the tire base portion 45 in the axial direction da is more in the axial direction da than the both end portions 35a of the base portion 35 in the axial direction da. Located outside. Therefore, it is possible for the tire 40 to absorb the impact from the outside in the axial direction da. In particular, in the present embodiment, the outer rib 37 that supports the tire base portion 45 is provided at the end portion 35a of the base portion 35. Therefore, the end portion 45a of the tire base portion 45 and the base portion 35 in the axial direction da are arranged. Such a positional relationship with the end 35a is stably maintained.

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

  For example, in the above-described embodiment, the example in which the outer rib 37 is provided at the positions corresponding to both end portions in the axial direction da of the base portion 35 has been described, but the present invention is not limited thereto. The outer rib 37 may be arranged at a position slightly shifted inward along the axial direction da from both end portions of the base portion 35.

  In the above-described embodiment, the example in which the outer rib 37 and the inner rib 39 extend from the base portion 35 in parallel with the radial direction dr has been described, but the present invention is not limited thereto. One or more of the outer rib 37 and the inner rib 39 may extend from the base portion 35 along a direction inclined with respect to the radial direction dr. Further, the outer rib 37 and the inner rib 39 do not need to protrude linearly from the base portion 35 in the cross section of FIG. 3, and may be curved, for example.

  Further, in the above-described embodiment, the example in which the pair of outer ribs 37 and the pair of inner ribs 39 are provided on the base portion 35 of the wheel 30 is not limited to this. For example, the radial direction dr Further ribs protruding from the base portion 35 toward the outside may be provided. Further ribs may extend annularly in the circumferential direction dc, or may be provided intermittently along the circumferential direction dc.

  Furthermore, although the base part 35 of the wheel 30 was formed in the flat plate shape extended in parallel with the axial direction da in embodiment mentioned above, it is not restricted to this. For example, the base part 35 may be curved.

  Furthermore, in the above-described embodiment, an example in which the tire base portion 45 of the tire 40 has a substantially constant thickness has been shown. However, the present invention is not limited thereto, and for example, the thickness may vary along the axial direction da. Good.

  Furthermore, in the above-described embodiment, the example in which the tire 40 is separated from the base portion 35 of the wheel 30 in the radial direction dr has been described, but the present invention is not limited thereto. For example, the tire 40 may be in contact with the base portion 35 of the wheel 30 only at both end portions 45a.

  Further, in the above-described embodiment, the example in which the inward projecting portion 49 extends annularly along the circumferential direction dc is shown, but the present invention is not limited thereto. For example, the inward protruding portions 49 may be provided intermittently at intervals in the circumferential direction dc.

  Further, in the above-described embodiment, the example in which the inward projecting portion 49 extends between the pair of inner ribs 39 has been described, but the present invention is not limited thereto. For example, the inward protruding portion 49 may be provided on the tire base portion 45 so as to extend between any two adjacent ribs. For example, a pair of inward projecting portions 49 is provided on the tire base portion 45, and one inward projecting portion 49 of the pair of inward projecting portions 49 is located on one side in the axial direction da. 37 and the inner rib 39, and the other inward protruding portion 49 may be disposed between the outer rib 37 and the inner rib 39 located on the other side in the axial direction da. .

  Furthermore, in the above-described embodiment, an example of the cross-sectional shape of the inward projecting portion 49 has been shown. However, the cross-sectional shape of the inward projecting portion 49 can be various shapes such as a triangle and a quadrangle.

  Furthermore, the baby carriage 10 illustrated in FIG. 1 is illustrated as an example of the baby carriage 10 to which the tire 40 and the wheel 20 are applied. The baby carriage 10 shown in FIG. 1 can be folded so as to be downsized in the front-rear direction and the height direction. However, the baby carriage is not limited to the example of FIG. 1, for example, a baby carriage disclosed in Japanese Patent Application Laid-Open No. 2011-148454 can be further folded and further downsized in the width direction after being folded down in the front-rear direction. 10 may be configured. Further, the baby carriage 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 baby carriage 10 may be configured such that the steering wheel is fixed at the rear position and cannot swing from the back pushing position.

DESCRIPTION OF SYMBOLS 10 Stroller 11 Stroller body 12 Front leg 13 Front wheel holding unit 14 Rear leg 15 Rear wheel holding unit 20 Wheel 30 Wheel 31 Spoke 31a Through hole 32 Rim 35 Base part 35a End part 37 Outer rib 39 Inner rib 40 Tire 41 Grounding surface 45 Tire base Part 45a End part 49 Inward protrusion part 49a Inner end da Axial direction dc Circumferential direction dr Radial direction

Claims (13)

A wheel for a baby carriage held rotatably about a rotation axis,
The annular base portion extending in the circumferential direction around the rotation axis, and the rotation from a position on the base portion that is inward from both ends of the base portion along an axial direction parallel to the rotation axis. A wheel having a pair of annular inner ribs projecting outward in the radial direction about the axis and extending in the circumferential direction;
A tire mounted on the wheel from the outside in the radial direction,
The tire is supported by at least the pair of inner ribs, and has an annular shape that protrudes outward in the radial direction and extends in the circumferential direction in a cross section parallel to both the axial direction and the radial direction. A tire base portion, and an inward protruding portion that protrudes inward in the radial direction from the tire base portion and is engageable with the inner rib,
A gap is formed between the tire and the wheel,
A baby carriage wheel, wherein a surface of the tire base portion that is outward in the radial direction forms a contact surface.   A wheel for a baby carriage held rotatably about a rotation axis,
  The annular base portion extending in the circumferential direction around the rotation axis, and the rotation from a position on the base portion that is inward from both ends of the base portion along an axial direction parallel to the rotation axis. A wheel having a pair of annular inner ribs projecting outward in the radial direction about the axis and extending in the circumferential direction;
  A tire mounted on the wheel from the outside in the radial direction,
  The tire is supported by at least the pair of inner ribs, and has an annular shape that protrudes outward in the radial direction and extends in the circumferential direction in a cross section parallel to both the axial direction and the radial direction. A tire base portion, and an inward protruding portion that protrudes inward in the radial direction from the tire base portion and is engageable with the inner rib,
  The outer surface in the radial direction of the tire base portion forms a contact surface,
  The tire is a wheel for a baby carriage that receives tensile stress in the circumferential direction in the entire region in the axial direction when the tire is mounted on the wheel. The wheel protrudes outward in the radial direction from a position on the base portion that is both outward of the pair of annular inner ribs in the axial direction, and extends in the circumferential direction. A rib, and
The height of outward protrusion along the radial direction of the inner rib from the base portion is higher than the height of outward protrusion of the outer rib from the base portion along the radial direction. Item 3. A baby carriage wheel according to item 1 or 2 . 4. The baby carriage wheel according to claim 3 , wherein the outer rib is disposed at a position to be an end portion of the base portion in the axial direction. 5. 5. The baby carriage wheel according to claim 3 , wherein the tire base portion of the tire is separated from the base portion of the wheel between the outer rib and the inner rib in the axial direction. The wheel for a baby carriage according to any one of claims 1 to 5 , wherein the inward protruding portion of the tire is located between any two ribs adjacent to each other in the axial direction. The inward protruding portion of the tire is located between the pair of inner ribs,
In between the pair of inner rib in the axial direction, the inward protrusion of the tire is spaced from the base portion of the wheel, for baby carriage according to any one of claims 1 to 6 the wheels of. The wheel for a baby carriage according to any one of claims 1 to 7 , wherein the tire is separated from the base portion of the wheel. The wheel for the baby carriage according to any one of claims 1 to 8 , wherein a protruding height of the inward protruding portion from the tire base portion is lower than a thickness of the tire base portion. In a state where the tire is mounted on the wheel, both end portions in the axial direction of the tire base portion are positioned inward in the radial direction with respect to an inner end in the radial direction of the inward protruding portion. The baby carriage wheel according to any one of claims 1 to 9.   The wheel for baby carriages as described in any one of Claims 1-10 in which the edge part of the said tire base part is located in the outer side of the both ends of the said base part in the said axial direction.   The baby carriage wheel according to any one of claims 1 to 11, wherein the base portion of the wheel extends in parallel with the axial direction.   A baby carriage provided with the wheel according to any one of claims 1 to 12.

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