JP6558983B2 - Wheel structure - Google Patents

Description

  The present invention relates to a wheel structure having a simple and compact structure that can be attached to a vehicle or the like and used to push and pull the vehicle in the front-rear direction, and can reduce the effort required to get over obstacles such as steps.

  Wheels attached to vehicles such as wheelchairs, strollers, and trolleys require a great deal of force and difficulty when climbing over obstacles such as steps of about several centimeters in height on the road or building. There are many things. In addition, when a wheel reaches a level difference (collision), an impact force is generated due to an instantaneous change from horizontal movement to vertical movement, and this impact force makes the user uncomfortable. In the worst case, the vehicle There is a risk of falling. For this reason, the development of a mechanism that allows wheels to easily get over obstacles such as steps is an important issue.

  Therefore, for example, as a technique for facilitating overcoming a step using an auxiliary wheel or the like, Patent Document 1 provides a front bearing in front of the bearing of the leg ring, A three-pronged body with three arms protruding radially is pivotally attached, and a small wheel is provided near the tip of each arm, and a biasing means for position regulation is attached to the three-way body. Then, one small wheel always has a tendency to be located obliquely downward at the front, and the other one is inclined obliquely downward at the rear, and the lower end surface of the rear small wheel is legged when viewed from the side. There is disclosed a stepped traveling wheel device characterized in that it coincides with the circumferential surface of the wheel obliquely downward. According to this technique, the chassis can be easily lifted by exerting the action of the “lever”, and further, since the small wheels are attached, the step portion can be easily climbed.

  In Patent Document 2, as a step-over mechanism, a rotating shaft is attached to the main body so as to extend in the left-right direction, and a front wheel is attached to a front end of a link fixed to the rotating shaft in the center. A step climbing mechanism is disclosed in which a rear wheel is rotatably attached and a pair of stoppers are provided on the main body at different upper and lower front and rear positions above the link.

  Furthermore, as a technique for facilitating overstepping by temporarily increasing the diameter of the wheel using a frame, an arm, or the like, Patent Document 3 discloses that the upper part of the top plate is taken out from the main shaft of the front wheel. The support column is provided with a shaft tube and a base shaft, and the semicircular arms located on both sides of the front wheel are connected to the shaft tube by the base shaft inside the support bracket, and are reinforced with connecting rods on the front and back sides of the semicircular arm. A pendulum type automatic level difference canceller is disclosed, in which a rubber plate is attached to the bottom surface of the semicircular arm and a return spring is provided to connect the support column and the semicircular arm.

  Patent Document 4 discloses a mounting base attached to a lower portion of a main body, a main frame that is pivotally attached to the mounting base by a turning shaft, and that can turn horizontally around the turning shaft, and both sides of the main frame. A caster having both leg portions extending downward from the vehicle and a traveling wheel supported by an axle suspended in a horizontal direction between the two leg portions, has a turning radius larger than that of the traveling wheel, and travels normally. In the set state at the time, one of the contact portions located in front of the traveling wheel is provided at two equal intervals in the rotation direction, and has a long hole through which the axle is inserted. By inserting the, the axle moves in the long hole, and the rideover frame is supported by the main frame in a state where it can rotate while being eccentric with respect to the axle, and between the main frame and the rideover frame. In addition, the transit frame is set to the set state. Casters, characterized in that interposed a link mechanism having a return means for lifting is disclosed.

  According to this technique, it is easy to get over relatively low obstacles such as slight steps on the road surface and pebbles while maintaining the turning performance. In addition, by providing two abutments at equal intervals with respect to the rotation direction of the crossover frame, when overcoming obstacles, the crossover frame can be returned to the set state by half rotation. The distance that the caster travels after getting over the step and returning to the set state is shortened, and even if obstacles etc. are continuous at narrow intervals, it is possible to get over continuously, Since it is supported by a link mechanism interposed between the climbing frame and the main frame and is not supported by an axle or the like, the load on the main body when climbing over an obstacle is on the climbing frame side. It is said that it is not necessary to improve the strength of the existing caster components.

  Furthermore, as a technique for facilitating overstepping by providing a groove in the wheel support part or inside the wheel and moving the axle along the groove, for example, Patent Document 5 discloses a technique of grounding while supporting the vehicle body. A rotating wheel, and a rotating body that can rotate only in a direction opposite to the rotating direction of the wheel as the vehicle travels, wherein the rotating shaft of the wheel and the rotating shaft of the rotating body are arranged substantially in parallel, and the rotation The rotation axis of the body is arranged behind and above the rotation axis of the wheel with respect to the traveling direction of the vehicle body, and the rotation axis of the wheel is a position where the wheel and the rotation body are not linked while the wheel and the rotation body are linked. From the reference position moved forward in the direction of travel of the vehicle body to the interlocking position where the wheel and the rotating body are interlocked, it is arcuate around the rotational axis of the rotating body toward the rear with respect to the traveling direction of the vehicle body. Can move along the trajectory of And comprises a plate-shaped member on either side of the wheel, each comprise a guide groove on the plate-support structure of the wheels to move the rotation axis of the wheel at the guide groove is disclosed. And according to this technique, it is said that a wheel can be smoothly run on obstacles, such as a level difference.

  And in patent document 6, the wheel which consists of a cyclic | annular tire member and the supporting member which supports it is attached to the lower end of the bracket supported so that turning with respect to the support shaft via a shaft member, In a caster that advances forward by rotation, the tire member is provided so as to be rotatable with respect to the support member, and a long hole extending forward from the rotation center of the tire member is provided in the support member, and a shaft member is provided in the long hole. The shaft member is inserted and supported to be non-rotatable with respect to the bracket and the shaft member, and the shaft member is configured to allow the shaft member to be eccentric by sliding forward in the elongated hole. The caster is disclosed, and it is said that the steps can be easily overcome with a light force.

  Further, in Patent Document 7, a wheel support part, an axle to which at least one wheel provided at a part of the wheel support part is attached, and a vehicle body part provided at an upper part of the wheel support part are joined. A sliding piece provided on the vehicle body joint and the wheel support, the sliding piece provided on a lower edge of the wheel support that faces the moving surface on which the wheel moves. And has a curved lower surface contour that is convex with respect to the moving surface, and the sliding piece portion is perpendicular to the axle through the lower portion of the axle. In addition, the sliding piece portion that is configured to be movable so as to exhibit a curved trajectory that exhibits a convex shape with respect to the moving surface and the wheel support portion are provided. The sliding piece part is held at the front end position in the traveling direction of the wheel support part. The shock absorber is disposed at least in the longitudinal direction tip portion of the sliding piece portion opposite to the tip position in the traveling direction of the wheel support portion. The sliding structure provided in front of the wheel moves along the guide surface in the wheel support portion and pushes up the axle to facilitate overcoming the step. .

Japanese Patent Laid-Open No. 10-234783 JP 2008-230387 A JP-A-10-297206 JP 2005-119576 A JP 2005-186920 A JP 2001-334804 A JP 2006-131203 A

  However, the techniques described in Patent Documents 1 to 4 require an auxiliary wheel, a frame, and a supporting structure thereof, so that the structure is complicated and the weight is increased. In addition, there is no provision for impact force, which may cause discomfort to the user and may cause the vehicle to fall.

  In addition, in the techniques described in Patent Documents 5 and 6, the structure for moving the axle is complicated, and the movement of the axle depends on the push-up by the operator and the push-down by the own weight, so that smooth movement can be achieved. Therefore, there is a possibility that an appropriate effect cannot be exhibited. And in the technique of the said patent document 7, there is a problem that it has to make a twin-wheel structure, causes an increase in weight, and lacks compactness.

  SUMMARY OF THE INVENTION The problem to be solved by the present invention is to solve the above-mentioned problem, and it is possible to reduce the effort required to get over obstacles such as steps having a predetermined height, and the wheel structure has a simple and compact structure. To provide a body.

In order to solve the above-described problems, the present invention takes the following technical means.
That is, the invention according to claim 1 is a wheel support member in which a pair of opposing leg portions are formed with a predetermined gap, an axle horizontally installed between the leg portions of the wheel support member, A wheel disposed between the leg portions of the wheel support member by being supported by the axle, and by attaching the wheel support member at an arbitrary position of the object, the object is moved forward or backward by the wheel. A wheel structure that enables push-pull movement in a direction, wherein the wheel includes at least an outer ring and an inner ring that is fitted inside the outer ring, and the wheel is mounted on a flat ground that is a horizontal plane. when being location, wherein the inner ring, with respect to its center point, along with the shaft hole is provided in the eccentric position, the shaft hole is, in the forward direction from the lead line passing through the center point, and wherein From the horizontal line passing through the center point In a state where the direction of the position, the being supported on the axle, the inner ring is in a predetermined range, the cutout portion is formed, on the notch, the inner ring, with respect to the forward direction A restoring mechanism that suppresses the rotation of the inner ring in the case of forward rotation, and allows the inner ring to be reversed so as to be rotated backward with respect to the forward direction from the position where the operation of the forward rotation of the inner ring is settled by the suppression ; A rotation restraining portion that restrains a rearward rotation of the inner ring from the predetermined position of the inner ring when the wheel is disposed on the wheel support member is provided at a predetermined position of the inner ring. At least one wheel structure is provided.

Further, an invention according to claim 2, wherein a wheel structure of claim 1, prior Symbol recovery mechanism includes a first member fixed to one side wall of said notch, said first member , in the center point side of the inner ring, while being pivotally connected by a hinge pin, and a second member of the state erected at a predetermined angle, said first member opening and closing side of the first member and the second member and A plate-like spring disposed along the second member , and the second member abuts against the side of the leg portion in the rear direction, thereby suppressing the front rotation of the inner ring with respect to the front direction, The inner ring can be reversed so as to be rotated backward with respect to the forward direction by a repulsive force of the plate spring.

Further, the invention according to claim 3 is the wheel structure according to claim 1 or 2 , wherein the rotation stop portion is formed on one side or both sides of the side surface of the inner ring, and the rotation stop portion is By abutting on the lower side of the leg, the rear rotation of the inner ring with respect to the front direction is stopped from a predetermined position of the inner ring. Still further, the invention according to claim 4 is the wheel structure according to any one of claims 1 to 3 , wherein a predetermined range including a position where the shaft hole is provided is provided on a side surface of the inner ring. A stepped portion produced by digging deeper than the other range is used as the rotation stop portion.

  According to the wheel structure according to the present invention, the axle is decentered forward and upward in the traveling direction with respect to the rotation center of the wheel, and the restoring mechanism is provided between the inner ring and the wheel support portion, so that the step can be overcome. It is possible to reduce the effort and comfortably get over the steps. Further, by providing a cutout in the inner ring and attaching a restoration mechanism inside the inner ring, the wheel structure itself can have a compact structure.

  And, for example, by using a spring structure capable of restoring against tension, compression, bending, and torsional force, the impact force is absorbed and relaxed, and at the same time, the forward direction It is possible to restore the pre-rotated inner ring to the initial position (initial position when it is arranged on the wheel support member).

It is an example figure showing an embodiment of a wheel structure concerning the present invention, (a) shows a side view, (b) shows a perspective view, and (c) shows an exploded perspective view. It is an example figure showing the embodiment of the wheel structure concerning the present invention, (a) is an outer ring, (b) is a state where an inner ring is inserted in an outer ring, (c) is a state where a restoration mechanism is attached to an inner ring, (d ) Represents a state in which the wheel is attached to the wheel support member. BRIEF DESCRIPTION OF THE DRAWINGS It is an example figure which showed the part of the one side which comprises an inner ring | wheel among embodiment of the wheel structure which concerns on this invention, (a) is a top view, (b) is a front view, (c) represents a side view. (D) is a perspective view of the state which assembled parts from both sides as an inner ring. It is an example figure which showed the wheel support member among embodiment of the wheel structure which concerns on this invention, (a) is a top view, (b) is a front view, (c) is a side view. It is an example figure which showed the 1st member of the decompression | restoration mechanism among embodiment of the wheel structure which concerns on this invention, (a) is a top view, (b) is a front view, (c) is a side view. It is an example figure which showed the 2nd member of the decompression | restoration mechanism among embodiment of the wheel structure which concerns on this invention, (a) is a top view, (b) is a front view, (c) is a side view. It is the perspective view which showed an example of the decompression | restoration mechanism among embodiment of the wheel structure which concerns on this invention. In embodiment of the wheel structure which concerns on this invention, it is an example figure which showed the function of the decompression | restoration mechanism, (a) is the state which the 2nd member contact | abutted to the leg part edge, (b) is the 1st member and A state where the space between the second members is narrowed and the bending of the leaf spring is advanced, (c) shows a state where the restoring mechanism is repelled. In the embodiment of the wheel structure according to the present invention, it is an example diagram showing a state at the time of overstepping, (a) when the step is reached, (b) at the start of stepping, (c) at the time of stepping, ( d) represents the end of overstepping. In embodiment of the wheel structure which concerns on this invention, it is the figure which showed an example of the apparatus used for the experiment verified about the effect. It is the graph which showed the result (loading weight 1.98kg) of the experiment verified about the effect of the embodiment of the wheel structure concerning the present invention. It is the graph which showed the result (loading weight 1.48kg) which verified about the effect of the embodiment of the wheel structure concerning the present invention. It is the graph which showed the result (loading weight 0.98 kg) which verified about the effect of the embodiment of the wheel structure concerning the present invention. This figure shows the conditions for overcoming a step when verifying the effectiveness of reducing the thrust by decentering the shaft hole of the inner ring. It is the table | surface which showed the result of the verification experiment about the effectiveness regarding reduction | decrease of the thrust by decentering the axial hole of an inner ring | wheel. It is the graph which showed the result of the verification experiment about the effectiveness regarding the reduction of the propulsion force by decentering the shaft hole of an inner ring. It is the graph which showed the experimental result of the impact relaxation by the restoring mechanism in the embodiment of the wheel structure concerning the present invention, and restoration.

Hereinafter, embodiments of a wheel structure according to the present invention will be described with reference to the drawings.
FIG. 1 is an example showing an embodiment of a wheel structure according to the present invention, where (a) is a side view, (b) is a perspective view, and (c) is an exploded perspective view. FIG. 2 is an example showing an embodiment of a wheel structure according to the present invention, where (a) is an outer ring, (b) is a state in which an inner ring is fitted in the outer ring, and (c) is a restoring mechanism in the inner ring. The attached state (d) represents a state in which the wheel is attached to the wheel support member. Furthermore, FIG. 3 is an example figure which showed the part of the one side which comprises an inner ring | wheel among embodiment of the wheel structure which concerns on this invention, (a) is a top view, (b) is a front view, (c ) Represents a side view, and (d) is a perspective view of a state where parts are assembled from both sides as an inner ring.

  And FIG. 4 is an example figure of a wheel support member among embodiment of the wheel structure which concerns on this invention, (a) was a top view, (b) was a front view, (c) showed the side view. FIG. 5 is an example showing the first member of the restoring mechanism in the embodiment of the wheel structure according to the present invention, where (a) is a plan view, (b) is a front view, and (c). Is a side view. Furthermore, FIG. 6 is an example figure which showed the 2nd member of the decompression | restoration mechanism among embodiment of the wheel structure which concerns on this invention, (a) is a top view, (b) is a front view, (c) is It is a side view.

  FIG. 7 is a perspective view showing an example of the restoration mechanism among the embodiments of the wheel structure according to the present invention, and FIG. 8 shows the function of the restoration mechanism in the embodiment of the wheel structure according to the present invention. (A) is a state where the second member is in contact with the leg end side, (b) is a state where the space between the first member and the second member is narrowed, and the bending of the leaf spring is advanced. (C) shows a state in which the restoring mechanism is repelled. Reference numeral 10 denotes a wheel structure, 12 denotes a wheel support member, 14 denotes a leg portion, 16 denotes an axle, 18 denotes a wheel, 20 denotes an outer ring, 22 denotes an inner ring, 23 denotes a part, 24 denotes a shaft hole, and 26 denotes restoration. The mechanism, 28 is a rotation stop, 30 is a notch, 32 is a first member, 34 is a hinge pin, 36 is a second member, 38 is a leaf spring, 40 is a step, and 42 is a guide.

  As shown in FIGS. 1 and 4, the wheel structure 10 according to the present embodiment includes a wheel support member 12 formed with a pair of leg portions 14 facing each other with a predetermined gap, and the leg portions of the wheel support member 12. 14 is provided with an axle 16 that is installed horizontally, and a wheel 18 that is supported between the legs 14 of the wheel support member 12 by being supported by the axle 16. By attaching to an arbitrary position of the vehicle, for example, the lower side, the object can be pushed and pulled in the forward direction (traveling direction) or the backward direction (retracting direction) by the wheels 18.

  As shown in FIGS. 1 and 2, the wheel 18 includes an outer ring 20 and an inner ring 22 that is fitted inside the outer ring 20 from both sides. Thus, the shaft hole 24 is provided at an eccentric position with respect to the center point. The shaft hole 24 is supported on the axle 16 in a state in which the shaft hole 24 is positioned forward of a vertical line passing through the center point and upward of a horizontal line passing through the center point. The shaft hole 24 provided at a position as far as possible from the center point (decentered) leads to a reduction in propulsive force when the wheel 18 gets over the step.

  As shown in FIGS. 1 and 2, the inner ring 22 absorbs an impact when the inner ring 22 rotates forward with respect to the forward direction (traveling direction), and further suppresses rotation, as shown in FIGS. In addition, a restoring mechanism 26 is provided for reversing (reversing) the forward direction from the position reached by the rotation with a repulsive force. A rotation restraining portion 28 is provided for restraining the rearward rotation of the inner ring 22 from the predetermined position of the inner ring 22 (the initial position where the wheel 18 is disposed on the wheel support member 12) when arranged on the member 12. It has been. In the present embodiment, the rotation restraining portion 28 is a step portion 40 generated by digging a predetermined range including the position where the shaft hole 24 is provided in the side surface of the inner ring 22 deeper than the other ranges. Plays a role.

  Next, this embodiment will be described in detail. As shown in FIGS. 1 and 2, the wheel 18 constituting the wheel structure 10 in the present embodiment is fitted by assembling the outer ring 20 and parts 23 that are mutually symmetrical from both sides of the outer ring 20, and a plurality of bolts. And an inner ring 22 fastened with a nut.

  As shown in FIG. 3, the part 23 constituting the inner ring 22 is provided with a shaft hole 24 at an eccentric position with respect to the center point, and a notch for attaching the restoring mechanism 26. A portion 30 is formed. The shaft hole 24 provided at a position as far as possible from the center point (decentered) leads to a reduction in propulsive force when the wheel 18 gets over the step. Furthermore, a guide portion 42 for smoothly rotating the outer ring 20 without dropping off is formed on the side surface of the inner ring 22 except for the region attached to the wheel support member 12. By assembling the parts 23 having such a configuration and the parts 23 having a symmetrical structure together, the inner ring 22 shown as an example in FIG. 3D is formed. In the present embodiment, the parts 23 are symmetric with each other. However, since the inner ring 22 only needs to be configured by combining parts on both sides, a part may have an asymmetric shape.

  Subsequently, as shown in FIG. 1 and FIG. 2 (c), the restoring mechanism 26 is provided in a notch portion 30 formed in the inner ring 22, and a bolt and a nut are provided on one side wall of the notch portion 30. The first member 32 (see FIG. 5) attached to the first member 32, the second member 36 (see FIG. 6) in a state of being raised at a predetermined angle with respect to the first member 32, and these as the center point of the inner ring 22 On the side, a hinge structure comprising a hinge pin 34 to be pivotally connected (see FIG. 7), and a leaf spring 38 arranged along these members on the open / close side of the first member 32 and the second member 34 (See FIG. 7).

  In this embodiment, as shown in FIG. 7 and the like, the leaf spring 38 is arranged to pass through the inside of the hinge pin 34 in a state bent at a predetermined angle. However, tension, compression, bending, and twisting are performed. Any restoring mechanism having a spring structure may be used as long as it can restore (repel) the force. Moreover, in this embodiment, although attached to the notch part 30, you may attach to the appropriate position (for example, side surface side) of the inner ring | wheel 22 according to a spring structure.

  Next, as shown in FIGS. 1, 2, and 4, the wheel support member 12 has a leg portion 14 having a bifurcated shape, and a wheel 18 is installed between the leg portions 14. The wheel support member 12 and the wheel 18 are fixed by passing the axle 16 through the support holes 15 provided in the vicinity of the lower portions of the leg portions 14 of the wheel support member 12. At this time, the eccentric shaft hole 24 is supported on the axle 16 at a position forward of a vertical line passing through the center point and above a horizontal line passing through the center point.

  Then, when the inner ring 22 reaches a step or the like and receives an impact, when the inner ring 22 rotates forward by a certain amount with respect to the forward direction, first, as shown in FIG. However, the forward rotation of the inner ring 22 is suppressed by absorbing the impact received by the inner ring 22 together with the leaf spring 38 from the state in contact with the rear side edge of the wheel support member 12.

  In this state, when the inner ring 22 further rotates forward, the first member 32 of the restoring mechanism 26 rotates in the direction of the second member 36 as shown in FIG. As a result, the bending of the leaf spring 38 proceeds. Subsequently, when the shock received by the inner ring 22 is absorbed and the pre-rotation operation is stopped, the bending of the leaf spring 38 tries to return to the original state, and the repulsive force is shown in FIG. It is connected to the rear rotation (reverse rotation) toward the front direction of 22 and returns to the state before receiving the impact.

  The lower end side of the wheel support member 12 is in contact with the rotation stop portion 28 provided on the side surface of the inner ring 22, whereby a predetermined position of the inner ring 22 when the wheel 18 is disposed on the wheel support member 12 (the wheel The rear rotation of the inner ring 22 in the forward direction can be stopped from the initial position where the wheels 18 are arranged on the support member 12. In addition, the rotation stop part 28 may be provided in the both sides | surfaces of the inner ring | wheel 22, and may be provided only in one side surface.

  Here, the principle of the wheel structure according to the present invention overcoming the step will be described with reference to the drawings. FIGS. 9A and 9B are an example diagram showing a state of overcoming a step in the first embodiment of the wheel structure according to the present invention, where FIG. 9A is when the step is reached, FIG. ) Indicates when the step is overtaken, and (d) indicates when the step overstep is completed. The reference numerals are the same as those in FIG. 1 and the like except that 56 is a step structure.

  First, while the wheel 18 is traveling on a flat ground, the outer ring 20 rotates about the inner ring 22, whereby the wheel 18 moves forward. Subsequently, as shown in FIG. 9A, when the wheel 18 reaches a step, the restoring mechanism 26 absorbs the impact. At the start of stepping over the step, the inner ring 22 further rotates forward with respect to the front direction due to the horizontal reaction force from the step. At that time, as shown in (b), the first member 32 of the restoring mechanism 26 is pushed and rotated in the direction of the second member 36 around the hinge pin 34, so that the distance between them is reduced. The bending of the leaf spring 38 proceeds. By this operation, the impact force received by the inner ring 22 is absorbed and relaxed by the restoring mechanism 26, and the repulsive force is accumulated.

  Subsequently, when a certain level of overstepping is performed, the forward rotation of the inner ring 22 is stopped as shown in FIG. Thereafter, as shown in (d), due to the repulsive force accumulated by the restoring mechanism 26, the inner ring 22 gradually starts to rotate backward with respect to the forward direction, and finally reaches a predetermined position (the wheel 18 on the wheel support member 12). Is returned to the initial position). After stepping over the step, the outer ring 20 rotates about the inner ring 22, so that the wheel 18 moves forward.

(Verification experiment 1)
Below, the experimental result verified about the effect of the wheel structure which concerns on this invention is demonstrated. FIG. 10 is a diagram showing an example of an apparatus used in this experiment. The reference numerals are the same as those in FIG. 1 except that 50 is a load tester, 52 is a pulley, 54 is a wire, and 56 is a step structure.

  First, in this experiment, as shown in FIG. 10, the wheel structure 10, the step structure 56 that travels and gets over the wheel 18, and the wire 54 that pulls the step structure 56 backward with respect to the wheel 18. In addition, a load tester 50 that winds the wire 54 via the pulley 52 and measures the overcoming force of the wheel 18 received by the step structure 56 is used. That is, the wire 54 pulls the step structure 56 rearward so that the wheel 18 can travel and get over the step structure 56, and the load testing machine 50 measures the propulsive force at the time of getting over. Is possible.

  In this experiment, the step height of the step structure 56 was set to 10 mm, 20 mm, 30 mm, and 40 mm, and the overcoming force when overcoming each step was measured. The outer ring 20 had an outer diameter of 150 mm and an inner diameter of 110 mm, and the axle 16 was supported by the shaft hole 24 at a position eccentric by 30 mm forward and upward in the traveling direction from the center of rotation.

  Further, the torque value necessary to rotate (close) the first member 32 of the restoring mechanism 26 attached to the inner ring 22 by 1 ° in the direction of the second member 36 is 87.1 Nmm. Including a weight of 12, a 1.98 kg weight was mounted. For comparison with the wheel structure 10, the same applies to a general conventional wheel structure that is composed of an outer ring (outer diameter: 150 mm, inner diameter: 110 mm) and an inner ring, and the axle position is at the center of rotation. The experiment was conducted.

  The experimental results are shown in FIG. As shown in FIG. 11, when the height of the step is higher in the wheel structure according to the present invention than in the conventional wheel structure, the maximum force required to get over the step (maximum overriding propulsion). It became clear that power) was low. For example, when the step was 20 mm, a reduction of about 10% was observed, and when the step was 40 mm, a reduction of about 20% was observed. That is, the wheel structure according to the present invention is easier to get over the step than the conventional wheel structure.

(Verification experiment 2)
Subsequently, a similar experiment was performed under other conditions. Specifically, the experiment is performed by mounting a weight of 1.48 kg on the wheel 18 including the weight of the wheel support member 12, and other configurations are the same as those in the verification experiment 1. The experimental results are shown in FIG. Also in this experiment, when the step height of the wheel structure according to the present invention is higher than that of the conventional wheel structure, the maximum force required to get over the step (overriding maximum thrust) is increased. It turns out that it becomes low.

(Verification experiment 3)
Furthermore, similar experiments were performed under different conditions. Specifically, the experiment is performed by mounting a weight of 0.98 kg on the wheel 18 including the weight of the wheel support member 12, and other configurations are the same as those in the verification experiment 1. The experimental results are shown in FIG. In this experiment, when the level difference is 20 mm, the wheel structure according to the present invention has a higher maximum force (maximum overriding propulsive force) required to overcome the level difference compared to the conventional wheel structure. However, after that, when the level difference becomes 30 mm and 40 mm, the wheel structure according to the present invention also overcomes the level difference when the level difference is higher than the conventional wheel structure. It can be seen that the maximum required force (overriding maximum thrust) is low.

Here, the theory of the driving force when overcoming a step is explained. Thrust F _h generated when the wheel reaches the step is intended to be calculated by a calculation formula shown in FIG. 14, and a (forward) is eccentricity, if we value of b (upper) increases The propulsive force _Fh becomes smaller. In other words, the wheel structure in which the axle is in an eccentric position is superior in terms of propulsive force to the conventional wheel structure in which the axle is located at the center of rotation.

(Verification experiment 4)
Subsequently, a verification experiment on the effectiveness of reducing the propulsive force by decentering the shaft hole of the inner ring was conducted. In the experiment, the restoring mechanism 26 is removed, and the position of the wheel axle (that is, the position of the shaft hole) is set on the X (forward) / Y (upward) axis, (0,0) / (15,15) / ( 15,30) / (30,15) / (30,30), respectively (unit is mm), the height of the step is 20 mm, the wheel 18 includes the weight of the wheel support member 12 and is 0.69 kg. Under the condition where the weight is mounted, the maximum propulsive force (maximum load) is measured and the reduction ratio is calculated by the apparatus having the configuration shown in FIG. As a comparison, the theoretical formula of the reduction ratio is shown in the following formula (Formula 1).

  The experimental results are as shown in FIG. As shown in the figure, it can be seen that the more the position of the axle is decentered, the smaller the value of the maximum propulsive force (maximum load). Then, it can be seen that there is a correlation between the actually measured reduction ratio calculated from the result and the reduction ratio calculated by the theoretical formula of Formula 1. Further, as shown in FIG. 16, it can be read that, when the wheel climbs over the step in the elapsed time of 1 to 2 seconds, the wheel with the eccentric axle position has lower traveling propulsion force. .

(Verification experiment 5)
Next, a verification experiment of impact relaxation and restoration (repulsive force) by the restoration mechanism in the embodiment of the present invention was performed. The leaf spring (38) is a CFRP leaf spring having a thickness of 1 mm and a width of 25 mm, and the angle when the first member (32) of the restoring mechanism (26) is rotated in the direction of the second member (36). And the torque value generated thereby was measured. The result is shown in FIG. As the graph shows, it has been concluded that the use of the leaf spring (38) used in the verification experiment for the restoration mechanism (26) is appropriate in the embodiment of the present invention.

  According to the present invention, the axle is decentered forward and upward in the traveling direction with respect to the center of rotation of the wheel, and since the restoration mechanism is provided between the inner ring and the wheel support portion, labor reduction when overcoming the step, It can be suitably used for the pursuit of comfort. Moreover, a compact wheel structure can be provided by providing a notch in the inner ring and attaching a restoring mechanism therein.

DESCRIPTION OF SYMBOLS 10 Wheel structure 12 Wheel support member 14 Leg 15 Support hole 16 Axle 18 Wheel 20 Outer ring 22 Inner ring 23 Parts 24 Axle hole 26 Restoration mechanism 28 Rotation stop part 30 Notch part 32 First member 34 Hinge pin 36 Second member 38 Plate Spring 40 Stepped portion 42 Guide portion 50 Load tester 52 Pulley 54 Wire 56 Stepped structure

Claims (4)

A wheel support member in which a pair of opposing legs are formed with a predetermined gap; and
Between the leg portions of the wheel support member, an axle laid horizontally,
By being supported on the axle, wheels disposed between the leg portions of the wheel support member;
A wheel structure that enables the object to be pushed and pulled forward or backward by the wheel by attaching the wheel support member at an arbitrary position of the object,
The wheel is composed of at least an outer ring and an inner ring fitted inside the outer ring,
When the wheel is placed on a flat surface that is a horizontal plane, the inner ring is provided with a shaft hole at an eccentric position with respect to the center point, and the shaft hole is lead that passes through the center point. It is supported on the axle in a state that is forward of a straight line and above the horizontal line that passes through the center point.
The inner ring is formed with a notch in a predetermined range, and when the inner ring is rotated forward with respect to the front direction in the notch , the rotation is suppressed and the suppression At least one restoring mechanism is provided that allows the inner ring to be reversed so as to be rotated backward with respect to the forward direction from the position where the forward rotation operation of the inner ring falls .
At a predetermined position of the inner ring, at least one rotation stopping portion is provided to stop the rearward rotation of the inner ring from the predetermined position of the inner ring when the wheel is disposed on the wheel support member. A wheel structure characterized by The restoring mechanism includes a first member fixed to one side wall of the cutout portion, and is pivotally connected to the first member by a hinge pin on the center point side of the inner ring and stands at a predetermined angle. A second member in a raised state, and a plate-like spring disposed along the first member and the second member on the opening and closing sides of the first member and the second member , and the second member includes the second member, By abutting against the rear side of the leg, the front rotation of the inner ring is suppressed, and the inner ring is rotated backward with respect to the front direction by the repulsive force of the plate spring. The wheel structure according to claim 1 , wherein the wheel structure is made possible. The rotation restraining part is formed on one side or both sides of the side surface of the inner ring, and the rotation restraining part comes into contact with the lower side of the leg part, so that the front side of the inner ring is moved from a predetermined position of the inner ring. claim 1 or 2 wheel structure according to, characterized in that to restrain the rotation rear relative to the direction. Among the side surfaces of the inner ring, according to claim 1 to 3, characterized in that has a stepped portion caused by digging deeper and the rotary stop portion than other ranges a predetermined range including the position where the shaft hole is provided The wheel structure according to any one of the preceding claims.