Wheel structure enabling easy step passage

Abstract

To provide a wheel structure that has a simple structure and no need of daily maintenance, and that can reduce a force required for riding over a road surface projection and a step and can reduce an impact force in advancing and retreating of a main body structure loaded with transport objects, etc., or a wheelchair.SOLUTION: There is provided a wheel structure 10 so configured that a plurality of rollers for guiding free rotation of a wheel 20 are fixedly fitted relatively unmovably in a manner of being fixedly fitted between a pair of disk-shaped side plates 50, with a polygonal support shaft 41 being inserted through a polygonal hole bored in the pair of disk-shaped side plates 50 and a polygonal hole bored in a support member leg 40a of a support member 40 for attachment to a main body structure loaded with transport objects, etc. or a wheelchair, with positions of both polygonal holes being aligned with each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wheel structure that is attached to the underside of a main body structure on which transported goods or the like are placed to enable forward and backward movement, and that reduces the force required to overcome bumps or steps in the road surface that can be obstacles during movement. [Background technology]

[0002] Manually operated transport carts and wheelchairs can be difficult to overcome because they require a large amount of force to get over bumps or steps on the road surface. Furthermore, if the cart is moved with too much momentum to get over the bump or step, an impact force is generated the moment it hits the bump or step, which can cause items loaded on the cart to collapse and can cause discomfort to the wheelchair occupant.

[0003] Several proposals have been made to improve this problem. For example, Patent Document 1 discloses a wheel structure in which the wheel structure is formed by a combination of an outer ring and an inner ring, and after the outer ring abuts against the end face of a step, the inner ring is rotated relative to the outer ring, and the axle is offset forward and upward in the direction of travel with respect to the center of rotation of the outer ring, thereby making it possible to reduce the force required to get over the step.

[0004] Patent Document 2 also discloses a wheel for a moving body that is constructed by combining a tire member that serves as an outer wheel and a support member that serves as an inner wheel, with a bearing fitted between the tire member and the support member, allowing the tire member and the support member to rotate relative to each other, and an axle that is positioned on the support member at a position vertically downward from the radial center, so that when the tire abuts against a step, the axle is pushed in the direction of travel, the support member rotates in the direction of travel, and the axle moves upward in the direction of travel, allowing the wheel to easily overcome the step.

[0005] Patent Document 3 also discloses a wheel device that is configured by combining a tire that serves as an outer wheel and a wheel that serves as an inner wheel, with a roller or rolling bearing fitted between the tire and the wheel, allowing the tire and wheel to rotate relative to one another, with the wheel having an arc-shaped hole drilled in it that faces diagonally upward from the radial center toward the direction of travel, allowing the axle to move along the arc-shaped hole, and when the tire comes into contact with a step, the axle moves along the arc-shaped hole in the direction of travel and approaches the center of rotation for getting over the step, thereby reducing the force required to get over the step.

[0006] Furthermore, Patent Document 4 discloses a caster in which the caster is configured by combining an outer ring and an inner ring, the inner diameter of the outer ring being larger than the outer diameter of the inner ring, the inner ring being positioned eccentrically inside the outer ring, an axle passing through the center of the inner ring, and when the outer ring abuts against a step, the inner ring is pushed by the axle and moves upward along the inner diameter of the outer ring, thereby effectively preventing impact and noise generation when the outer ring abuts against a step.

[0007] Furthermore, Patent Document 5 discloses a caster in which the caster is configured by combining a tire member that serves as an outer wheel and a support plate that serves as an inner wheel, an annular bearing is fitted between the tire member and the support plate, and the tire member and the support plate are rotatable relative to each other, and the support member is perforated with a long hole that faces approximately diagonally upward from the radial center toward the direction of travel, and the axle is configured to be movable along the long hole, and when the tire member abuts against a step, the axle rises along the long hole in the direction of travel, making it possible to easily overcome the step with little force.

[0008] Patent Document 6 also discloses a caster in which the caster is configured by combining a wheel that serves as the outer wheel and a wheel hub that serves as the inner wheel, an annular bearing is fitted between the wheel and the wheel hub, the wheel and the wheel hub are rotatable relative to each other, an arc-shaped long hole is drilled below the wheel hub, and a collar with a bolt inserted therethrough is movable along the long hole, and when the wheel hits a step, the wheel hub rotates along the long hole toward the opposite side of the direction of travel, and the tire swings and displaces diagonally upward and rearward in the direction of travel, allowing the caster to smoothly overcome the step. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2017-13632 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-247297 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-40148 [Patent Document 4] Japanese Patent Application Laid-Open No. 2008-13074 [Patent Document 5] Japanese Patent Application Laid-Open No. 2001-334804 [Patent Document 6] Japanese Utility Model Application Publication No. 06-32108 Summary of the Invention [Problem to be solved by the invention]

[0010] However, the technology described in Patent Document 1 has the following problems. Specifically, because the wheel is constructed by combining the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring in surface contact, when the outer ring rotates relative to the inner ring, the rotational friction resistance with the outer ring is large, resulting in a problem of increased operating force when moving on flat roads. There is also a possibility of malfunction due to the ingestion of debris. Furthermore, because the wheel is constructed by combining parts that slide relative to one another, including the inner ring equipped with a restoring mechanism using a leaf spring to return the inner ring to its original position after passing over a step, the structure is complex, making it difficult to keep manufacturing costs low. Furthermore, in the technology described in Patent Document 2, a bearing is fitted between the tire member that forms the outer wheel and the support member that forms the inner wheel, but a large-diameter bearing is required, which increases the mass of the bearing, increases manufacturing costs, and increases the mass of the entire wheel.Furthermore, the axle, which is the point of application of the force pushing the moving body, is located below the horizontal line passing through the center of rotation of the tire member and below the support member, and the distance on the vertical line from the top surface of the step to the force pushing the moving body acting on the horizontal line passing through the center of the axle is short, and the moment lever acting on the force pushing the moving body is short, resulting in a problem that the force pushing the moving body cannot be reduced when passing over a step. Furthermore, the technology described in Patent Document 3 involves fitting rollers or rolling bearings between the tire (which serves as the outer wheel) and the wheel (which serves as the inner wheel). However, in the case of rollers, annular guide rails are required for rolling, increasing mass and costs. Furthermore, in the case of rolling bearings, large-diameter rolling bearings are required, which increases mass, leading to higher manufacturing costs and an increase in the mass of the entire wheel. Furthermore, arc-shaped holes for axle movement are drilled in the wheel, and the axle slides along these arc-shaped holes, which can cause wear on the arc-shaped holes or the axle. Furthermore, the sliding parts require lubrication with oil or the like, which necessitates daily maintenance. Furthermore, with the technology described in Patent Document 4, the amount of lift of the axle after the outer ring contacts the end face of the step is small, the distance on the vertical line from the top of the step to the force pushing the moving body acting on the horizontal line passing through the center of the axle is short, and the moment lever acting on the force pushing the moving body is short, so there are problems in that the force required to pass over the step cannot be reduced much. Furthermore, in the technology described in Patent Document 5, a bearing is fitted between the tire member (outer ring) and the support plate (inner ring), which requires a large-diameter bearing, increasing the mass of the bearing, leading to higher manufacturing costs and a larger mass for the entire wheel. Furthermore, a long hole for the wheel axle to move is drilled in the wheel, and the wheel axle slides along the long hole, which causes wear on the long hole or the wheel axle. Furthermore, the sliding parts need to be lubricated with oil or the like, which necessitates daily maintenance. Furthermore, in the technology described in Patent Document 6, a bearing is fitted between the wheel (outer ring) and the wheel hub (inner ring), but this requires a large-diameter bearing, which increases the mass of the bearing, leading to higher manufacturing costs and an increase in the mass of the entire wheel. Furthermore, the wheel hub has an arc-shaped hole for swinging around the swing axis, and the collar slides through the arc-shaped hole, which causes wear on the collar or the arc-shaped hole. Furthermore, the sliding parts need to be lubricated with oil or the like, which necessitates daily maintenance.

[0011] According to the present invention, it is possible to provide a wheel structure that does not require daily maintenance because there is no sliding between parts, has a simple and compact structure, and makes it easy to overcome protrusions and steps. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the wheel structure 10 of the present invention is configured such that a polygonal support shaft 41 is inserted and fixedly attached to a support member 40 for attaching to a main body structure on which transported objects etc. are placed, and a pair of disc-shaped side plates 50 so that they do not move relative to each other, and the force F that moves the wheel structure 10 is transmitted from the support member 40 to the wheel 20 through the center P of the polygonal support shaft, and rollers A30, B31 and C32 equipped with bearings 70 for guiding the rotation of the wheel 20 are fixedly attached between the pair of disc-shaped side plates 50, so that the wheel 20 can rotate around the wheel rotation center Q.

[0013] That is, the wheel 20 has a wheel step plane 20b on both sides, which is a step of a predetermined depth H in the form of a concentric circle with a diameter D1 that is a predetermined length shorter than the outer diameter, and a hole with a diameter D2 that is a predetermined length shorter than the concentric circle is drilled in the wheel step plane 20b to form a wheel perforation portion 21. A pair of the disc-shaped side plates 50 having a predetermined gap L between them and the wheel step circumferential wall 20c that forms the step of the predetermined depth H are arranged on both sides of the wheel step plane 20b.

[0014] Then, the rollers A30, B31 and C32 are disposed between the pair of disc-shaped side plates 50 so as to come into contact with the inner wall 20a of the wheel drilling portion. Furthermore, roller B31 is positioned at the lowest end of the inner wall 20a of the wheel perforation section vertically below the wheel rotation center Q so as to receive the reaction force from the road surface, and roller A30 is positioned at a predetermined angle θ1 above the horizontal line passing through the wheel rotation center Q, and roller C32 is positioned at a predetermined angle θ2 above the horizontal line passing through the wheel rotation center Q, as a guide for the wheel 20 to rotate around the wheel rotation center Q.

[0015] Then, in order to provide a predetermined gap M between the disc-shaped side plate 50 and the wheel step plane 20b, a spacer 80 is placed between both sides of the bearing inner ring 70a and the pair of disc-shaped side plates 50, and the roller shaft 60 is inserted. Then, the roller shaft threaded portion 60a protruding from the disc-shaped side plate 50 is fastened and fixed with a nut 61 from the outside of the disc-shaped side plate 50. In addition, in order to prevent relative movement between the support member 40 and the disc-shaped side plate 50, a polygonal hole 50a is drilled in the support member leg 40a, and polygonal holes of the same size as the polygonal holes 50a are drilled in the pair of disc-shaped side plates 50 at a height as far away as possible vertically upward from the wheel rotation center Q, at a position that does not interfere with the rollers A30 and C32, and the polygonal support shaft 41 is inserted by aligning it with the polygonal hole in the support member leg 40a. Then, both ends of the polygonal support shaft 41 are fixed to the support member leg portions 40a with bolts 42, with washers 43 sandwiched between them.

[0016] With the above configuration, the wheel 20 is guided by the rollers A30, B31, and C32, and can rotate freely around the wheel rotation center Q, preventing relative movement between the support member 40 and the disc-shaped side plate 50, and the force F that moves the wheel structure 10 is transmitted from the support member 40 to the wheel 20 through the polygonal support axis center P, resulting in the wheel structure 10. [Effects of the Invention]

[0017] According to the wheel structure 10 of the present invention, the polygonal support axis 41 is positioned eccentrically vertically upward from the wheel rotation center Q, and the position of the force F that moves the wheel structure 10, which acts horizontally to the polygonal support axis center P, is moved far away from the top surface of the step. This lengthens the moment lever that acts on the polygonal support axis center P to apply a force to overcome the step, and reduces the moving force F required to overcome the step. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a front view showing a part of a disk-shaped side plate 50 in one embodiment according to the present invention. [Figure 2] 1 is a side view showing one embodiment of the present invention; [Figure 3] Cross section AA in Figure 1 [Figure 4] Cross section B-B in Figure 2 [Figure 5]CC cross section in Figure 2 [Figure 6] DD cross section in Figure 2 [Figure 7] EE cross section in Figure 2 [Figure 8] FIG. 1 is a front view showing a part of a support member 40 in accordance with the present invention in cross section. [Figure 9] 1 is a front view showing a wheel 20 according to the present invention; [Figure 10] FF cross section in Figure 9 [Figure 11] A side view showing a roller shaft 60 according to the present invention. [Figure 12] 12 is a front view showing the direction of arrow G in FIG. 11. [Figure 13] 1 is a side view showing a partial cross section of a polygonal support shaft 41 according to the present invention. [Figure 14] 14 is a front view showing the direction of arrow H in FIG. 13. [Figure 15] A front view showing the disc-shaped side plate 50 of the present invention. [Figure 16] Illustrative diagram of reduction in moving force F due to eccentricity of polygonal support shaft center P DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing one embodiment of a wheel structure 10 according to the present invention, in which a polygonal support shaft 41 that transmits force F to move the wheel structure 10 and a pair of disc-shaped side plates 50 are fixed with bolts 42, with washers 43 sandwiched between, on a support member 40 for mounting on a main body structure on which transported goods or the like are placed. Between the pair of disc-shaped side plates 50, spacers 80 shown in FIG. 3 are placed on both sides of the bearing inner rings 70a provided on rollers A 30, B 31, and C 32, and roller shafts 60 are inserted and fixed with nuts 61, and rollers A 30, B 31, and C 32 are shown in contact with the inner walls 20a of the wheel boreholes of the wheel 20. Also shown is a state in which the roller A 30 and the roller C 32 are positioned at predetermined angles θ1 and θ2 above the horizontal line passing through the wheel rotation center Q, and the roller B 31 is positioned at the vertically lowest end of the wheel rotation center Q. The predetermined angle may be either θ1 = θ2 or θ1 ≠ θ2. Although the drawings of this embodiment show three rollers, as long as rollers are placed in the positions where roller A30, roller B31, and roller C32 should be placed, rollers may be placed in other positions to increase the number of rollers. The bearing 70 may be any of a ball bearing, a roller bearing, a needle bearing, or a plain bearing.

[0020] 2 is a side view showing one embodiment of the wheel structure 10 according to the present invention, in which a pair of disc-shaped side plates 50, to which rollers A 30, B 31, and C 32 are attached, are attached between the support member legs 40a with a predetermined gap M from the wheel step plane 20b of the wheel 20 shown in FIG. 9, and a polygonal support shaft 41 is fitted between the support member legs 40a and the pair of disc-shaped side plates 50, and is fixed to the support member legs 40a with bolts 42 via washers 43. Also, Figure 3 is a cross-sectional view taken along line AA in Figure 1, and shows a state in which spacers 80 are placed between the pair of disc-shaped side plates 50 and both ends of the bearing inner ring 70a in order to attach the pair of disc-shaped side plates 50 to the wheel step plane 20b with a predetermined gap M. 4 is a cross-sectional view taken along line BB in FIG. 2, showing the positional relationship of the polygonal support shaft 41, roller A 30, roller B 31, and roller C 32 relative to the wheel 20 in the front view, and the positional relationship of the support member 40 and polygonal support shaft 41.

[0021] 2, showing the polygonal support shaft 41 inserted through the support member leg 40a and the pair of disc-shaped side plates 50, and fixed with bolts 42 via washers 43. Also shown in a top plan view is the relative positions of the polygonal support shaft 41, roller A 30, and roller C 32. 6 is a cross-sectional view taken along line DD in FIG. 2, showing the positional relationship between roller A 30, roller B 31 and roller C 32 in a top plan view. 7 is an E-E cross-sectional view of FIG. 2, showing a state in which roller B31 is placed between a pair of disc-shaped side plates 50, spacers 80 are placed on both ends of the bearing inner ring 70a of roller B31, a roller shaft 60 is inserted from the outside of disc-shaped side plate 50, and the roller shaft screw portion 60a protruding from the opposite disc-shaped side plate 50 is tightened with a nut 61, thereby fixing roller B31.

[0022] 8 is a partial cross-sectional front view of the support member 40, showing the support member leg 40a and the polygonal hole 50a drilled therein to fit the polygonal support shaft 41. In this figure, the polygon is depicted as a square. 9 is a front view of the wheel 20, showing the positions of the wheel hole inner wall 20a, the wheel step plane 20b, the wheel step circumferential wall 20c, and the wheel hole 21. FIG. 10 is a cross-sectional view taken along the line FF in FIG. 9, showing the positions of the wheel bore hole inner wall 20a, the wheel step plane 20b, and the wheel step circumferential wall 20c. 11 shows a side view of the roller shaft 60, and FIG. 12 shows a front view as seen from the roller shaft screw portion 60a side as seen in the direction of arrow G in FIG. FIG. 13 is a side view of the polygonal support shaft 41 with a portion thereof in cross section.

[0023] 14 is a view taken along the arrow H in FIG. 13, showing a cross section of the polygonal support shaft 41. In this drawing, the polygon is depicted as a square. 15 is a front view of the disk-shaped side plate 50, showing the positions of the holes for fitting the polygonal support shaft 41 and the roller shaft 60. In this drawing, the polygonal holes are depicted as squares.

[0024] Figure 16 is an explanatory diagram showing that by eccentrically positioning the polygonal support axis center P vertically upward from the wheel rotation center Q, the force F that moves the wheel structure 10 when going over a step is reduced compared to when a force is applied to the wheel rotation center Q. [Industrial Applicability]

[0025] According to the wheel structure 10 of the present invention, a force F is applied to move the wheel structure 10 from the wheel rotation center Q to the polygonal support axis center P, which is eccentric vertically upward, thereby reducing the force F that moves the wheel structure 10, reducing the effort required by the operator when climbing over bumps or steps in the road surface, and further reducing the impact on the main body structure on which the transported goods are placed, making it less likely that the cargo will collapse. Furthermore, when used on the front wheels of a wheelchair, it can reduce the force F required to move the wheelchair when going over bumps or steps in the road, thereby reducing the effort required by the caregiver pushing the wheelchair and reducing the discomfort caused by the impact to the wheelchair occupant. Furthermore, the compact structure does not impose any spatial restrictions on the main body structure on which the wheel structure 10 of the present invention is attached and on which transported items are placed. Furthermore, since the support member 40 and the disk-shaped side plate 50 do not move relative to each other and there is no sliding structure, daily maintenance is not required. Furthermore, since the mounting position of the polygonal support shaft 41 does not change, the force required to overcome protrusions and steps can be reduced both when moving forward and backward, and when returning the main body structure or wheelchair carrying items to be transported to the original direction immediately after passing over a step, it can be moved backward as is, eliminating the need to change direction and making it easy to use. [Explanation of symbols]

[0026] 10 wheel structure 20 wheels 20a Wheel perforation inner wall 20b Wheel step plane 20c Wheel step peripheral wall 21 Wheel perforation 30 Roller A 31 Roller B 32 Roller C 40 Support member 40a Support member leg 41 Polygonal support shaft 42 volts 43 Washer 50 Disc-shaped side panel 50a polygonal hole 60 Roller shaft 60a Roller shaft screw 61 Nut 70 bearings 70a bearing inner ring 80 spacer Q Wheel rotation center P Center of polygonal support shaft θ1 predetermined angle θ2 predetermined angle D1: Diameter shorter than the outer diameter by a specified length D2: Diameter shorter than the concentric circle by a specified length H specified depth L specified gap M specified gap F moving force

Claims

1. A wheel structure (10) supports a wheel (20) for relative rotation while being guided by a plurality of rollers fixedly attached to a pair of disc-shaped side plates (50), characterized in that a polygonal hole (50a) is drilled in a support member leg (40a), and a polygonal hole (50a) of the same size as the polygonal hole (50a) is drilled vertically above the wheel rotation center (Q) of the pair of disc-shaped side plates (50), and the support member (40) is positioned between the support member legs (40a), and a polygonal support shaft (41) is inserted in alignment with the polygonal hole (50a) drilled in the support member leg (40a), and the support member (40) and the disc-shaped side plates (50) are fixedly attached so that they do not move relative to each other.

2. A plurality of rollers are arranged between the pair of disc-shaped side plates 50, and are in contact with the inner wall 20a of the wheel drilling section. The roller B31 is arranged at the vertically lowest end of the wheel rotation center Q, and the roller A30 is arranged at a predetermined angle θ from the horizontal line passing through the wheel rotation center Q. １ The roller C32 is placed above the wheel at a predetermined angle θ from the horizontal line passing through the wheel rotation center Q. ２ 2. The wheel structure (10) according to claim 1, wherein the wheel structure (10) is disposed above and fixedly attached to the pair of disc-shaped side plates (50).

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