Wheel mounting structure

Abstract

The present invention provides a wheel mounting structure that prevents the wheel from falling off the axle even if the inner and outer bearings are damaged. [Solution] The wheel mounting structure comprises an axle, a hub, two bearings consisting of an inner bearing and an outer bearing disposed between the axle and the hub, a spacer disposed between the two bearings, and a nut or both a nut and a washer that tightens the two bearings from the tip to the base of the axle. The hub has an inner projection that protrudes inward. The two bearings are arranged in parallel with a gap between them along the axis of the axle. The inner projection is positioned within the gap to sandwich the spacer between it and the axle. The outer diameter of at least one of the nut and the washer is larger than the inner diameter of the inner projection.

Description

Technical Field

[0001] The present invention relates to a wheel mounting structure.

Background Art

[0002] Patent Document 1 discloses an automobile wheel mounting structure. This wheel mounting structure includes an axle, a hub provided outside the axle, and a wheel attached to the hub. A bearing is disposed between the hub and the axle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the wheel mounting structure as described above, there is a structure including an inner bearing and an outer bearing disposed with a gap along the axis of the axle. Even in such a wheel mounting structure, it is required that the hub does not come off the axle, that is, the wheel does not fall off the axle, even when the inner bearing and the outer bearing are damaged.

[0005] One object of the present invention is to provide a wheel mounting structure capable of preventing the wheel from falling off the axle even when the inner bearing and the outer bearing are damaged.

Means for Solving the Problems

[0006] A wheel mounting structure according to one aspect of the present invention comprises an axle, a hub disposed on the outer circumference of the axle, an inner bearing and an outer bearing disposed between the axle and the hub, a spacer disposed between the inner bearing and the outer bearing, and a nut or both the nut and a washer for tightening the inner bearing and the outer bearing from the tip to the base of the axle. The hub has an inner projection that protrudes inward. The inner bearing and the outer bearing are arranged in parallel with a gap between them in the direction along the axis of the axle. The inner projection is positioned within the gap to sandwich the spacer between it and the axle. The outer diameter of at least one of the nut and the washer is larger than the inner diameter of the inner projection. [Effects of the Invention]

[0007] By ensuring that the outer diameter of at least one of the nut and washer is larger than the inner diameter of the inner projection, the hub can be prevented from detaching from the axle even if the inner and outer bearings are damaged. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view of a personal mobility device equipped with a wheel mounting structure according to an embodiment. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a schematic enlarged view showing the area around the hub in Figure 2. [Modes for carrying out the invention]

[0009] A wheel mounting structure according to an embodiment of the present invention will be described with reference to the drawings. This embodiment is a wheel mounting structure provided on a personal mobility device. Hereinafter, "personal mobility device" may be simply referred to as "vehicle". In each figure, the same or corresponding parts are denoted by the same reference numerals. The sizes and ratios of the components shown in each figure are represented for the purpose of clarifying the explanation and do not necessarily represent the actual dimensions and ratios. In the figures, "FR" indicates the front of the vehicle, "RR" indicates the rear of the vehicle, "LH" indicates the left side of the vehicle, "RH" indicates the right side of the vehicle, "UP" indicates the top of the vehicle, and "LWR" indicates the bottom of the vehicle. In the following description, the direction of each component will be described based on the direction of the vehicle.

[0010] <Personal Mobility> In this specification, "personal mobility" includes all small mobile vehicles equipped with an electric motor as a prime mover and capable of traveling at speeds considered to be those of pedestrians. For example, standard electric wheelchairs, simple electric wheelchairs, and handlebar-type electric wheelchairs are all included in "personal mobility." Simple electric wheelchairs include both switchable types that can switch between electric and manual powered driving, and assist types that can use electric power to assist human power. The wheel mounting structure according to the embodiment is provided on the handlebar-type electric wheelchair (mobility scooter) shown in Figure 1. Handlebar-type electric wheelchairs are sometimes called senior scooters. This vehicle 1 is a single-seater electric vehicle. Below, the outline of vehicle 1 will first be described with reference to Figure 1, and then the wheel mounting structure will be described with reference to Figures 2 and 3.

[0011] <Vehicle Overview> Vehicle 1 comprises a handle 10, a steering column 15, left and right front wheels 20, a front cover 30, a basket 40, a step 50, a rear cover 60, a seat post 70, a seat 80, and left and right rear wheels 90. Vehicle 1 is a four-wheeled vehicle. The occupant sits on the seat 80, which is supported at the upper end of the seat post 70, and places their feet on the step 50 to operate the handle 10. The left and right front wheels 20 are steered by operating the handle 10. Vehicle 1 is driven by a motor (not shown) that drives the rear wheels 90. The motor is located inside the rear cover 60. The motor is driven by power supplied from a battery. The battery is detachably housed in a battery holder 12. The battery holder 12 is fixed to the rear of the steering column 15. A basket 40 may be attached to the front of the steering column 15 if necessary. In this example, the basket 40 is located between the front cover 30 and the handle 10. This vehicle 1 has a maximum speed of, for example, 6 km / h.

[0012] <Wheel mounting structure> The wheel mounting structure according to the embodiment will be described using the mounting structure of the front wheel 20 in the above-described vehicle 1 as an example. Here, the mounting structure of the left front wheel 20 will be described. As shown in Figures 2 and 3, the wheel mounting structure comprises an axle 21, a hub 22, an inner bearing 23 and an outer bearing 24, a spacer 25, a nut 26 and a washer 27. The hub 22 has an inner projection 22i that protrudes inward. One of the features of the wheel mounting structure according to the embodiment is that the outer diameter of at least one of the nut 26 and washer 27 is larger than the inner diameter of the inner projection 22i. The constituent elements will be described below.

[0013] ≪Axle≫ The axle 21 is a component that serves as the axis of rotation for the front wheel 20. In Figures 2 and 3, the right side of the axle 21 is the base end, and the left side is the tip end. In Figure 3, the plate P and head 21h shown in Figure 2 are omitted. This axle 21 has a head 21h and a shaft portion 21a. As shown in Figure 2, the base end of the axle 21 has a head 21h, and the head 21h is located to the right of the plate P that constitutes the steering knuckle. On the other hand, the shaft portion 21a of the axle 21 extends to the left, passing through the plate P. A male thread is formed at the tip of the shaft portion 21a. As will be described later, a washer 27 is fitted to this tip, and a nut 26 is screwed onto the male thread.

[0014] ≪Hub≫ As shown in Figures 2 and 3, the hub 22 is a component that connects the axle 21 to the wheel 100 of the front wheel 20. The hub 22 comprises a cylindrical portion 22c, an inner projection 22i, and an outer projection 22o.

[0015] The cylindrical portion 22c is located on the outer circumference of the inner bearing 23 and the outer bearing 24. Both bearings 23 and 24 are press-fitted inside the cylindrical portion 22c, and the outer races 23o and 24o of each bearing 23 and 24 are integrated with the cylindrical portion 22c.

[0016] The inner projection 22i presses the spacer 25 (described later) from the outside, reducing the radial misalignment of the spacer 25's axis, and consequently the misalignment of each axis between the hub 22 and the axle 21. This inner projection 22i is a projection that protrudes inward from the inner circumferential surface of the cylindrical portion 22c. The inside of the cylindrical portion 22c refers to the direction from the inner circumferential surface of the cylindrical portion 22c toward the axis of the cylindrical portion 22c. In this example, the shape of the inner projection 22i is an annular plate. The shape of the inner projection 22i may also be a plurality of fan-shaped pieces arranged in parallel around the axis of the cylindrical portion 22c. The inner circumferential surface of the inner projection 22i faces the outer circumferential surface of the spacer 25 so as to be in contact with it. In this example, the inner projection 22i is located in the center in the direction along the axis of the cylindrical portion 22c. This inner projection 22i is positioned between the inner bearing 23 and the outer bearing 24. The width of the inner projection 22i is smaller than the width of the gap formed between the inner bearing 23 and the outer bearing 24. These widths refer to the distance along the axis of the cylindrical portion 22c in the inner projection 22i or gap. The distance by which the inner projection 22i protrudes from the inner circumferential surface of the cylindrical portion 22c can be appropriately selected according to the thickness of the spacer 25. The thickness of the spacer 25 is a distance equal to half the difference between the inner and outer diameters of the spacer 25. The sum of the protruding distance of the inner projection 22i and the thickness of the spacer 25 corresponds to half the difference between the inner and outer diameters of the inner bearing 23 and the outer bearing 24, respectively.

[0017] The outer protrusion 22o is used for fixing the wheel 100 described later. This outer protrusion 22o is a protrusion that projects outward from the outer peripheral surface of the cylindrical portion 22c. The shape of the outer protrusion 22o in this example is an annular plate shape. The shape of the outer protrusion 22o may also be a plurality of fan-shaped pieces arranged in parallel around the axis of the cylindrical portion 22c. The outer surface of the outer protrusion 22o, that is, the surface facing the left side of the vehicle 1, is where the wheel 100 is abutted. The outer protrusion 22o in this example is biased toward the inner bearing ring 23 side, that is, the right side of the vehicle 1, from the center in the direction along the axis of the cylindrical portion 22c. In other words, the outer protrusion 22o in this example is arranged on the inner bearing ring 23 side rather than the inner protrusion 22i. The width of the outer protrusion 22o in this example is narrower than the width of the inner protrusion 22i. However, the width of the outer protrusion 22o may be wider than the width of the inner protrusion 22i, or the same. This width refers to the distance along the axis of the cylindrical portion 22c in the outer protrusion 22o. The distance at which the outer protrusion 22o projects from the outer peripheral surface of the cylindrical portion 22c may be appropriately selected to be a dimension suitable for proper fixing of the wheel 100.

[0018] The above-described cylindrical portion 22c, inner protrusion 22i, and outer protrusion 22o are formed of metal. Also, the cylindrical portion 22c, inner protrusion 22i, and outer protrusion 22o are all continuously and integrally configured.

[0019] ≪Inner Bearing Ring and Outer Bearing Ring≫ The inner bearing ring 23 and the outer bearing ring 24 are independent members that support the hub 22 rotatably with respect to the axle 21. Each of the inner bearing ring 23 and the outer bearing ring 24 used in this example is a radial ball bearing. Each of the bearings 23, 24 has an inner race 23i, 24i, an outer race 23o, 24o, and balls 23b, 24b. A plurality of balls 23b, 24b are interposed between the annular inner races 23i, 24i and the annular outer races 23o, 24o. With this configuration, the outer races 23o, 24o are rotated with respect to the inner races 23i, 24i fixed to the axle 21. The outer races 23o, 24o are integrated with the cylindrical portion 22c by being press-fitted inside the cylindrical portion 22c of the hub 22.

[0020] <<Spacer>> The spacer 25 is a member that fills the gap between the inner bearing 23 and the outer bearing 24 and the space between the axle 21 and the inner protrusion 22i. By filling these gaps and spaces, the distance between the two bearings 23, 24 is maintained, and the misalignment of each axis between the hub 22 and the axle 21 is reduced. The spacer 25 in this example has a cylindrical shape. The inner diameter of the spacer 25 corresponds to the outer diameter of the axle 21. The outer diameter of the spacer 25 corresponds to the inner diameter of the inner protrusion 22i. The length of the spacer 25 along the axis corresponds to the value obtained by subtracting the total length along the axes of the two bearings 23, 24 from the length along the axis of the cylindrical portion 22c of the hub 22. The spacer 25 in this example is formed of metal.

[0021] <<Nut and washer>> The nut 26 is a member that tightens the inner bearing 23 and the outer bearing 24 between the base end portion of the axle 21 and the nut 26 by screwing onto the male thread of the axle 21. The washer 27 prevents the female thread of the nut 26 from interfering with the incomplete thread portion of the male thread on the axle 21. The washer 27 may be provided as necessary, and the seating surface of the nut 26 may directly tighten the inner bearing 23 and the outer bearing 24. The outer diameter of the washer 27 is larger than the outer diameter of the axle 21 and smaller than the inner diameter of the outer race 24o of the outer bearing 24. The outer diameter of the washer 27 in this example is smaller than the outer diameter of the inner race 24i. The inner diameter of the washer 27 is larger than the outer diameter of the axle 21. In this example, both the nut 26 and the washer 27 are used. The outer diameter of the seating surface of the nut 26 and the outer diameter of the washer 27 in this example approximately correspond to the outer diameter of the inner race 24i of the outer bearing 24. The outer diameter of the washer 27 used in this example is slightly larger than the outer diameter of the seating surface of the nut 26. However, the outer diameter of the washer 27 may be the same as the outer diameter of the seating surface of the nut 26.

[0022] <<Wheel, tire and wheel cap>> Furthermore, as shown in Figure 2, a wheel 100 is fixed to the hub 22, and a pneumatic tire 150 is attached to the wheel 100. A wheel cap 160 is also attached to the wheel 100 used in this example. The wheel 100 in this example consists of an inner plate 110 and an outer plate 120. The inner plate 110 is formed from an annular metal plate. A through hole is provided in the center of the inner plate 110. The cylindrical portion 22c of the hub 22 is fitted into this through hole, and the inner peripheral edge of the inner plate 110 is fixed in place by contacting the outer projection 22o. The outer plate 120 is also formed from an annular metal plate. However, the inner diameter of the through hole in the outer plate 120 is larger than the inner diameter of the through hole in the inner plate 110. In other words, the outer plate 120 is positioned at a distance from the hub 22 without contacting it. The wheel 100 is constructed by fastening and bonding the inner plate 110 and the outer plate 120 together with bolts 130 and nuts 140. A disc portion is formed on the inner circumference of the wheel 100, and a rim portion is formed on the outer circumference of the wheel 100, i.e., on the outer circumference of the disc portion. In the longitudinal cross-section of the wheel, the disc portion extends radially in a direction perpendicular to the axis of the hub 22. The rim portion extends in a direction perpendicular to the disc portion. A pneumatic tire 150 is attached to the rim portion.

[0023] ≪Relationship between the inner diameter of the inner projection and the outer diameter of the nut or washer≫ Of the nut 26 and washer 27, the outer diameter of the component that contacts the outer bearing 24 is larger than the inner diameter of the inner projection 22i. If the outer diameter of the component that contacts the outer bearing 24 is less than or equal to the inner diameter of the inner projection 22i, the wheel may fall off the axle 21 due to damage to the inner bearing 23 and the outer bearing 24. For example, when an external force acts to separate the inner race 23i and outer race 23o of the inner bearing 23 and the inner race 24i and outer race 24o of the outer bearing 24 in a direction along their respective axes, the inner races 23i, 24i and the outer races 23o, 24o may separate. If the inner races 23i, 24i and the outer races 23o, 24o separate, the inner races 23i, 24i are fixed to the axle 21, and the outer races 23o, 24o are fixed to the hub 22. As a result, the wheel 100, which is integrated with the hub 22, i.e., the front wheel 20, will detach from the axle 21. On the other hand, if the outer diameter of the component of the nut 26 and washer 27 that contacts the outer bearing 24 is larger than the inner diameter of the inner projection 22i, then even if damage occurs that causes the inner races 23i, 24i and the outer races 23o, 24o to separate, the front wheel 20 will not detach from the axle 21.

[0024] The present invention is not limited to these examples, but is intended to include all modifications within the meaning and scope equivalent to the claims as shown by the claims. In the above embodiment, the mounting structure of the left front wheel 20 was described, but the present invention may also be applied to the mounting structure of the right front wheel 20. Furthermore, the present invention can be applied not only to the front wheels 20 but also to the mounting structure of the rear wheels 90. In addition, the wheel mounting structure of the present invention can be applied not only to the wheel mounting structure of personal mobility devices but also to the wheel mounting structure of ordinary passenger cars and medium-sized and large automobiles. [Explanation of symbols]

[0025] 1. Personal mobility (vehicle) 10 handles 12 Battery holder 15. Steering column 20 Front Wheel 21 axles 21h head 21a Shaft part 22 Hubs 22c cylinder part 22i inner projection 22o lateral process 23 Inner bearing 23i Inner Race 23o Outerwear 23b Ball 24 Outer bearings 24i Inner Race 24o Outerwear 24b Ball 25 Spacers 26 nuts 27 Washers 30 Front Cover 40 Basket 50 steps 60 Rear Cover 70 Seatpost 80 seats 90 Rear wheel 100 wheels 110 Inner Plate 120 Outer Plate 130 volts 140 Nut 150 pneumatic tires 160 Wheel Cap P Plate

Claims

[Claim 1] axle and, A hub positioned on the outer circumference of the axle, An inner bearing and an outer bearing are positioned between the axle and the hub, A spacer positioned between the inner bearing and the outer bearing, The axle comprises a nut or both a nut and a washer for tightening the inner bearing and the outer bearing from the tip to the base end, The hub has an inner projection that protrudes inward, The inner bearing and the outer bearing are arranged in parallel with a gap between them in the direction along the axis of the axle. The inner projection is positioned within the gap so as to sandwich the spacer between itself and the axle. The outer diameter of at least one of the nut and the washer is larger than the inner diameter of the inner projection. Wheel mounting structure.

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