JP7181507B2 - three-row wheeled vehicle - Google Patents

Description

The present invention relates to a three-row wheel vehicle having a front wheel, a center wheel and a rear wheel, at least one of the front wheel, center wheel and rear wheel comprising a pair of laterally spaced wheels.

2. Description of the Related Art As self-propelled vehicles, various special vehicles are known which are excellent in traversing uneven terrain, steps, and the like. In order for a vehicle to run on rough terrain, it is necessary for the wheels to have better performance over bumps and the like than ordinary vehicles such as automobiles. In addition, a vehicle such as a self-propelled trolley for transporting cargo needs to have excellent performance in which the wheels run over a step, as in the case where the vehicle runs on a sidewalk from a public road.

As a means for facilitating the vehicle to climb over a protrusion or step, it is conceivable to raise the front wheel when the front wheel reaches a protrusion or step. For example, Patent Document 1 below describes a vehicle having a front wheel, a center wheel, and a rear wheel, in which the front wheel is adjusted by adjusting the length of a link connecting the front wheel and the center wheel and the lateral offset angle of the link. The vehicle is configured so that the front wheels can easily ride over bumps and bumps.

JP 2012-228996 A

[Problems to be solved by the invention]
In the vehicle described in Patent Document 1, it is possible to make it easier for the front wheels to be lifted when they reach a step or the like. If the height is high, the front wheels cannot go over a step or the like. In addition, adjusting the length of the link connecting the front wheels and the center wheel and the lateral offset angle of the link changes the position of the center of gravity of the vehicle, which tends to deteriorate the running stability of the vehicle.

The main object of the present invention is to move the front wheels upward by effectively utilizing not only the upward force that the front wheels receive from bumps and the like, but also the rearward force, so that the front wheels can easily run over bumps and the like. Another object of the present invention is to provide an improved three-row wheeled vehicle.

[Means for Solving the Problems and Effect of the Invention]
According to the present invention, a three-row wheel vehicle (10) having a front wheel (16), a center wheel (18) and a rear wheel (20) arranged in the longitudinal direction, wherein at least the front wheel, the center wheel and the rear wheel One is provided with a three-row wheeled vehicle including a pair of laterally spaced wheels.

The vehicle (10) comprises a leading arm (22) connected to the vehicle body (14) so as to be vertically pivotable about a first pivot line (28A) at its rear end, and a second pivot line (28A). 30A) between a swing arm (24) connected to the front end of the leading arm and rotatably supporting the front wheel at its lower end, and the leading arm and the swing arm. and a link mechanism (26) disposed thereon.

The linkage (26) comprises a pivot link (34) pivotally supported on the vehicle body (14) about a third laterally extending pivot axis (40A) and a rocker at its front end. a horizontal link pivotally attached to the moving arm (24) and pivotally attached at its rear end to the pivot link (34) at a first pivot point (44A) vertically spaced from a third pivot axis; (36) and pivotally attached to the pivot link (34) at one end at a second pivot point (46A) spaced rearwardly from the third pivot axis and at the other end from the first pivot axis. and an up-and-down link (38) pivotally attached to the leading arm (22) on the front side to convert the rearward force transmitted from the front wheel (16) to the swing arm (24) into an upward force. It is arranged to communicate to the leading arm (22).

According to the above configuration, the vehicle includes a leading arm which is connected to the vehicle body so as to be able to pivot in the vertical direction at the rear end thereof, and a leading arm which is connected to the front end of the leading arm so as to be capable of swinging in the longitudinal direction and is connected to the lower end. and a swing arm that rotatably supports the front wheel, and a link mechanism arranged between these arms. The linkage includes a pivot link pivoted to the vehicle body, a horizontal link pivoted at its front end to the swing arm and pivoted at its rear end to the pivot link, and at one end the pivot link. and an upper and lower link pivotally attached at the other end to the leading arm. Further, the link mechanism is configured to convert a rearward force transmitted from the front wheel to the swing arm into an upward force for transmission to the leading arm.

When the front wheels reach a step or the like, the front wheel receives not only an upward force but also a rearward force from the step or the like. An upward force is transmitted by the swing arm to the leading arm, causing the leading arm to pivot upwardly about the rear end. In addition, the rearward force is converted to an upward force by the linkage and transferred to the leading arm, which also causes the leading arm to pivot upwardly about the rear end.

Thus, the leading arm can be pivoted upwardly about the rear end more efficiently than without the linkage mechanism constructed as described above. The front wheels can be positively moved upward. Therefore, the front wheels can be moved upward by effectively utilizing not only the upward force that the front wheels receive from the steps, but also the rearward forces, so that the front wheels can easily run over the steps.

In particular, as will be described later in detail, when the height of a step becomes equal to or greater than the radius of the front wheel, the upward force becomes zero and only the rearward force is exerted. can move the front wheels upwards. Therefore, even if the height of a step is equal to or greater than the radius of the front wheel, the front wheel can run over the step as long as the height is not excessive.

Even if the leading arm pivots when the front wheels run over a step, the center of gravity of the vehicle does not change in either the longitudinal or lateral direction, so the running stability of the vehicle does not deteriorate. .

In the present application, unless otherwise specified, terms such as "front", "rear", "front and back", "front", "rear", and "lateral direction" that indicate the positional relationship and direction between members refer to the vehicle. Anterior-posterior, anterior-posterior and lateral.

In the above description, in order to facilitate understanding of the present invention, reference numerals used in the embodiments are added in parentheses to configurations of the invention corresponding to the embodiments to be described later. However, each component of the present invention is not limited to the component of the embodiment corresponding to the reference numerals attached in parentheses. Other objects, features and attendant advantages of the present invention will be readily understood from the description of embodiments of the present invention described with reference to the following drawings.

1 is a side view showing a first embodiment of a three-row wheel vehicle according to the present invention as seen in the lateral direction of the vehicle; FIG. 2 is a skeleton diagram showing the positions of a swing arm and the like when front wheels are in a neutral position (solid line), a bound position (one-dot chain line), and a rebound position (broken line) in the three-row wheel vehicle shown in FIG. 1. FIG. FIG. 5 is a diagram illustrating a situation in which an external force Fwf acts on the front wheels and is transmitted to the axles of the front wheels when the vehicle reaches a step and is pressed against the corner of the step; FIG. 4 is a side view showing a second embodiment of a three-row wheel vehicle according to the present invention, viewed in the lateral direction of the vehicle; 5 is a skeleton diagram showing the positions of the swing arm and the like when the front wheels are in the neutral position (solid line), the bound position (one-dot chain line), and the rebound position (broken line) in the three-row wheel vehicle shown in FIG. 4. FIG.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[First embodiment]
A three-row wheeled vehicle 10 according to the first embodiment and a second embodiment described later is configured as a self-propelled carriage, and is in a state where a load (not shown) to be transported is placed. and a vehicle body frame 14 fixed to the lower surface of the support plate 12 . Note that the three-row wheeled vehicle of the present invention may be applied to a vehicle such as an unmanned vehicle in which a person rides and moves.

As shown in FIG. 1, vehicle 10 has a pair of laterally spaced front wheels 16FL and 16FR, a pair of center wheels 18CL and 18CR, and a pair of rear wheels 20RL and 20RR, respectively, which are spaced apart from each other. The wheels respectively form a front wheel train, a center wheel train and a rear wheel train. In this specification, the front wheels 16FL and 16FR, the central wheels 18CL and 18CR, and the rear wheels 20RL and 20RR are collectively referred to as the front wheels 16, the central wheels 18, and the rear wheels 20, respectively, as required. Although not shown in FIGS. 1 and 2, the front wheels 16 and the rear wheels 20 are omni wheels that can move not only in the front-rear direction but also in the lateral direction and oblique front-rear direction. The center wheel 18 may consist of a wheel integral with the axis of rotation and a hollow or solid tire supported on the rim of the wheel. The front wheels 16 and the rear wheels 20 may also consist of wheels and tires, like the center wheel 18, and may be supported so as to change the rolling direction.

In a first embodiment, the vehicle 10 includes a pair of laterally spaced leading arms 22 and a pair of swinging arms 24, respectively, disposed between the corresponding leading and swinging arms. and a pair of link mechanisms 26 . Each leading arm 22 is connected to the body frame 14 by a pivot shaft 28 at its rear end so as to be vertically pivotable about a first pivot axis 28A. Although not shown in FIG. 1, the pivot 28 may be fixed to one of the body frame 14 and the leading arm 22 and supported by the other of the body frame and the leading arm via bearings or bushings.

<Front wheel>
Each swing arm 24 is connected at its upper end to the front end of the leading arm 22 by a pivot 30 so as to be capable of swinging back and forth about a second pivot axis 30A, and rotates the corresponding front wheel 16 at its lower end. support possible. In the illustrated first embodiment, each swing arm 24 consists of a main arm 24A and a sub-arm 24B. The main arm 24A is composed of a yoke-shaped upper portion that opens upward and is positioned on both sides of the front end of the leading arm 22, and a flat plate-shaped lower portion that is integral with the upper portion and extends downward from the upper portion. ing. The pivot 30 may be fixed to one of the front end of the leading arm 22 and the main arm 24A, and supported by the other of the front end of the leading arm 22 and the main arm 24A via bearings or bushings.

The sub-arm 24B has a downwardly open yoke shape positioned on both sides of the corresponding front wheel 16, and is integrally connected to the main arm 24A at its upper end by welding or the like. The front wheel 16 has an axle 32, and the sub-arm 24B supports the axle 32 at its lower end so as to be rotatable around the rotation axis 32A via bearings or bushings. The axis of rotation 32A extends laterally forward and downward with respect to the second pivot axis 30A.

In the illustrated first embodiment, a shock absorber (not shown) is arranged between a point P on the main arm 24A of the swing arm 24 and a point Q on the leading arm 22. As shown in FIG. The shock absorber is, for example, a MacPherson strut, a member in which a shock absorber and a compression coil spring are integrally incorporated, and may be designed to reduce the impact input to the front wheel 16 and dampen vibration. . Note that the shock absorber may be arranged at a location other than between the point P and the point Q.

<Link mechanism>
Each linkage 26 includes a pivot link 34 , a horizontal link 36 and a vertical link 38 to convert rearward force transmitted from the front wheel 16 to the swing arm 24 into upward force to move the leading arm 22 . configured to transmit to Note that this also applies to the second embodiment, which will be described later.

In the first embodiment, the pivot links 34 are pivotally supported to the body frame 14 by pivots 40 about a third laterally extending pivot axis 40A, respectively. It is substantially L-shaped with first and second arms extending downwardly and rearwardly. The pivot 40 may be fixed to one of the body frame 14 and the pivot link 34 and supported by the other of the body frame 14 and the pivot link 34 via bearings or bushings.

Horizontal link 36 is pivotally attached at its front end by pivot 42 to the lower end of sub-arm 24B of swing arm 24 about a laterally extending pivot axis 42A. In addition, the horizontal link 36 is pivoted about a laterally extending pivot axis 44A by a pivot 44 spaced downwardly from the third pivot axis 40A at its rearward end. It is pivotally attached to the lower end of one arm. Pivot axis 44A is thus the first pivot point that pivots the rear end of horizontal link 36 to the lower end of the first arm portion of pivot link 34 .

The pivot 42 is fixed to one of the lower end of the sub-arm 24B of the swing arm 24 and the front end of the horizontal link 36, and is supported by the other of the lower end of the sub-arm 24B and the front end of the horizontal link 36 via a bearing or a bush. It's okay. Similarly, the pivot 44 is fixed to one of the lower end of the first arm portion of the pivot link 34 and the lower end of the horizontal link 36, and is attached to the first arm portion of the pivot link 34 via a bearing or bushing. It may be supported by the other of the lower end and the lower end of the horizontal link 36 .

The upper and lower links 38 are pivotally attached to the second arm of the pivot link 34 about a transversely extending pivot axis 46A by means of a pivot 46 spaced rearwardly from the third pivot axis 40A at its lower end. It is pivotally attached to the rear end of the part. Thus, the pivot line 46A is a second pivot point that pivots the lower end of the vertical link 38 to the rear end of the second arm portion of the pivot link 34. As shown in FIG. Further, the vertical link 38 is pivotally attached to the leading arm 22 at its upper end portion forwardly of the first pivot line 28A by a pivot 48 so as to be capable of pivoting around a pivot axis 48A extending in the lateral direction. .

The pivot 46 is fixed to one of the rear end of the second arm portion of the pivot link 34 and the lower end of the vertical link 38, and is attached to the rear end of the second arm portion of the pivot link 34 via a bearing or a bush. and the lower end of the vertical link 38 . Similarly, the pivot 48 may be fixed to one of the upper ends of the leading arm 22 and the vertical link 38 and supported by the other of the leading arm 22 and the upper end of the vertical link 38 via bearings or bushings.

<First and second force transmission paths>
In FIG. 1, the straight lines connecting the pivots of the leading arms 22 and the like are skeleton diagrams showing the corresponding leading arms 22 and the like replaced by straight links. As can be seen from this skeleton view, the sub-arm 24B of the swing arm 24 cooperates with the main arm 24A to transmit the predominantly upward force that the front wheel 16 receives from the travel path X to the front end of the leading arm 22. composes the force transmission path of

The swing arm 24 , pivot link 34 , horizontal link 36 and vertical link 38 cooperate with each other to convert horizontal displacement of the horizontal link 36 into vertical displacement of the vertical link 38 . Therefore, the swing arm 24 and the link mechanism 26 cooperate with each other to convert the rearward force that the front wheel 16 receives from the travel path X into an upward force, thereby causing the front end portion and the rear end portion of the leading arm 22 to move. It constitutes a second force transmission path that transmits between.

<Central wheel>
Each leading arm 22 is integrally provided with a central wheel support arm 50 extending downwardly from pivot 28 . The center wheel support arm 50 cantilevers at its lower end an axle 52 which supports the center wheel 18 through bearings or bushings for rotation about a laterally extending axis of rotation 52A. ing. The axis of rotation 52A extends laterally below the first pivot axis 28A. The center wheel 18 has a chain sprocket 54 integral with the axle 52 . In the first embodiment and the later-described second embodiment, when the vehicle 10 is on the horizontal travel path X, the rotation axis 52A is positioned directly below the first pivot line 28A.

In the illustrated first embodiment, the heights of the pivot lines 42A and 44A are the heights of the rotation axis 32A of the front wheels 16 and the rotation axis 52A of the center wheels 18 when the vehicle 10 is on the horizontal travel path X. Identical to the height, but may differ from the height of these axes of rotation. Also, the heights of the pivot lines 42A and 44A may be different from each other. Further, pivots 28A, 30A and 48A are collinear, but need not be collinear.

<Rear wheel>
Each rear wheel 20 has an axle 56 which is rotatably supported by rear wheel support casters 58 about a laterally extending rotation axis 56A via bearings or bushings. The rear wheel support caster 58 has a downwardly open yoke shape positioned on both sides of the corresponding rear wheel 20, and is welded to the rear end of the trailing arm 60 at the upper end forward of the axle 56. are integrally connected by The front end of the trailing arm 60 cantilevers an axle 62, which is supported by the vehicle body frame 14 via bearings or bushings about a laterally extending pivot axis 62A so as to be pivotable. there is A shock-absorbing compression coil spring 64 is elastically mounted between the rear end portion of the trailing arm 60 and the body frame 14 . Rear wheel 20 has a chain sprocket 66 integral with axle 58 .

<Driving force>
The body frame 14 is provided with an electric motor 68L for driving the left central wheel 18CL and the left rear wheel 20RL and an electric motor 68R for driving the right central wheel 18CR and the right rear wheel 20RR. A chain sprocket 70C for driving the central wheel 18 and a chain sprocket 70R for driving the rear wheel 20 are attached to the output shaft of each electric motor. A chain 72C is wound around the chain sprocket 54 of each center wheel 18 and the chain sprocket 70C for driving the center wheels. Similarly, a chain 72R is wound around the chain sprocket 66 of each rear wheel 20 and the chain sprocket 70R for driving the rear wheels.

As will be explained in detail later, when the front wheel 16 bounces and rebounds, the axis of rotation 52A of the center wheel 18 swings about the first pivot axis 28A, thus changing the distance between the chain sprockets 54 and 70C. do. Further, when the rear wheel 20 bounces and rebounds, the rotational axis 56A of the rear wheel 20 pivots around the pivot 62A, which is different from the axis of the chain sprocket 70R for driving the rear wheels. and 70R change. Accordingly, although not shown in FIGS. 1 and 2, tensioners are provided on chains 72C and 72R to reduce variations in tension in chains 72C and 72R due to changes in the distance between the chain sprockets. there is

<Braking force>
A braking force may be applied to the central wheel 18 and the rear wheel 20 by generating torque in a direction opposite to the direction of rotation during running by the electric motors 68L and 68R. Furthermore, a braking device not shown in FIGS. 1 and 2 is provided so that a braking force is applied to all or part of the front wheels 16, the central wheels 18 and the rear wheels 20, left and right, by the braking device. may be

<Driving>
As can be seen from the above description, in the first embodiment and the second embodiment described later, the front wheels 16 are driven wheels, and the central wheels 18 and rear wheels 20 are driving wheels. When the outputs of the electric motors 68L and 68R are controlled to be the same, the driving forces of the left and right center wheels 18 and the rear wheels 20 are the same, so the vehicle 10 moves straight forward or backward.

On the other hand, when the output of the left electric motor 68L is controlled to be higher than the output of the right electric motor 68R, the driving force of the left central wheel 18CL and the rear wheel 20RL is applied to the right central wheel 18CR and the rear wheel 20RR. It becomes higher than the driving force, and the vehicle 10 moves forward when turning right or moves backward when turning left. Conversely, when the output of the right electric motor 68R is controlled to be higher than the output of the left electric motor 68L, the driving force of the right central wheel 18CR and the rear wheel 20RR drives the left central wheel 18CL and the rear wheel 20RL. force, and the vehicle 10 moves forward on a left turn or reverses on a right turn.

Further, when the left central wheel 18CL and the rear wheel 20RL are driven forward and the right central wheel 18CR and the rear wheel 20RR are driven backward, the vehicle 10 turns right with a small turning radius or does not substantially move. turn right without Conversely, when the right central wheel 18CR and rear wheel 20RR are driven forward and the left central wheel 18CL and rear wheel 20RL are driven backward, the vehicle 10 turns left with a small turning radius or does not substantially move. turn left without

<Force received by the front wheels from bumps>
As shown in FIG. 3, when the front wheels 16 reach the step Y and are pushed against the step Z, such as when the vehicle 10 is moving from a general road to a sidewalk, the front wheels 16 at the corner Z are pushed. An external force Fwf perpendicular to the normal 80 acts on the front wheels 16 and is transmitted to the axle 32 via the front wheels. Therefore, the vertical component Fwfv of the external force Fwf acts on the axle 32 as an upward force, and the horizontal component Fwfh of the external force Fwf acts as a rearward force. The external force Fwf, that is, the vertical component, namely the upward force Fwfv, and the horizontal component, namely the rearward force Fwfh, increase as the driving force of the vehicle 10 increases. As the height of the step Y increases, the upward force Fwfv decreases and the rearward force Fwfh increases. When the height of the step Y is equal to or greater than the radius of the front wheel 16, the upward force Fwfv becomes 0 and the rearward force Fwfh becomes equal to the external force Fwf.

<Riding the front wheel on a step>
When the front wheels 16 run over the step Y, the axle 32 is subjected to an upward force Fwfv and a rearward force Fwfh as described above. try to move to Accordingly, the upward force Fwfv is transmitted to the front end of the leading arm 22 through the first force transmission path described above, causing the leading arm 22 to pivot upward about the pivot line 28A. In addition, the rearward force Fwfh is transmitted to the intermediate portion of the leading arm 22 through the second force transmission path, which also causes the leading arm 22 to pivot upward about the pivot line 28A. .

As the leading arm 22 pivots upwardly about the pivot axis 28A, the swinging arm 24 is lifted while the height of the central wheel 18 does not change substantially. Therefore, as indicated by the dashed line in FIG. 2, the central wheel 18 and the rear wheel 20 are in contact with the running path X, and the support plate 12 maintains its horizontal position. Since it rises relative to the rear wheel 20, it can easily run over the step Y.

It should be noted that as leading arm 22 pivots upward about pivot 28A, axle 52 moves slightly forward as center wheel support arm 50 pivots forward about pivot 28A. At this time, the center wheel 18 can roll forward about the rotation axis 52A. Therefore, the upward pivotal movement of the leading arm 22 is not hindered due to the fact that the central wheel support arm 50 is provided integrally with the leading arm 22 .

<Central wheels run over steps>
When the vehicle 10 runs and the central wheel 18 runs over the step Y, a rearward force Fwfh acts on the axle 52 of the central wheel 18, and the leading arm 22 and the central wheel support arm 50 move around the pivot line 28A. 1 and 2, it receives a moment in the counterclockwise direction. Therefore, the leading arm 22 tries to push the swing arm 24 and the front wheel 16 downward, but the front wheel 16 has already run over the step Y and does not descend, so the reaction force of the moment lifts the center wheel 18. . Therefore, the central wheel 18 can also easily run over the step Y. Even when the front wheel 16 is at the same height as the center wheel 18 and the rear wheel 20 by getting over a protrusion instead of a step, the center wheel 18 is lifted by the reaction force of the moment because the front wheel does not descend.

<Rear wheels running over bumps>
When the vehicle 10 travels further and the front wheels 16 and the center wheels 18 have already run over the step Y, the center of gravity of the vehicle 10 is on or ahead of the rotation axis 52A of the center wheels 18, and the vehicle 10 is in a horizontal posture. become. Therefore, since the rear wheel 18 is lifted from the running path X, it can run over the step Y easily. A rear wheel support caster 58 that supports the rear wheel 20 is supported by a trailing arm 60 . Therefore, even when the rear wheel 18 is at the same height as the front wheel 16 and the center wheel 18 and rides on a protrusion or the like, the trailing arm 60 pivots upward about the front end of the rear wheel 18. can easily climb over protrusions.

<Riding down a step with the front wheel>
As the front wheels 16 ride down the step Y, the front wheels 16 rebound as shown in dashed lines in FIG. and pivots in a counterclockwise direction as viewed in FIG. However, since the height of the central wheel 18 does not substantially change, the central wheel 18 and the rear wheel 20 remain in contact with the step Y. Therefore, the front wheels 16 can easily ride down the step Y, and the vehicle 10 can continue running while the support plate 12 maintains its horizontal posture.

<Riding down the step of the central wheel>
When the center wheel 18 rides down the step Y, the height of the center wheel 18 gradually decreases, so the support plate 12 tends to move forward. Therefore, the leading arm 22 receives an upward force from the front wheel 16 via the swing arm 24 . However, swinging arm 24 experiences a moment about pivot axis 30A in a clockwise direction as viewed in FIGS. 1 and 2, which exerts a downward force on leading arm 22 via the second force transmission path. Thus, the leading arm 22 does not substantially pivot. Therefore, the central wheel 18 can easily ride down the step Y without the support plate 12 suddenly falling forward.

<Rear wheel going down a step>
When the front wheels 16 and the center wheels 18 have completely ridden down the step and only the rear wheel 20 is on the step Y, the trailing arm 60 is pivoted upward about the pivot line 62A. 20 is in a bound state. Thus, the trailing arm 60 is biased downward about the pivot line 62A by the compression coil spring 64 to return to the position when the vehicle 10 is traveling horizontally. Therefore, when the rear wheel 20 rides down the step Y, the rear wheel 20 rolls down around the corner Z of the step Y, and the trailing arm 60 pivots downward about the pivot line 62A. Therefore, the rear wheel 20 can easily ride down the step Y.

[Second embodiment]
The three-row wheeled vehicle 10 according to the second embodiment shown in FIGS. 4 and 5 also includes a pair of laterally spaced leading arms 22 and a pair of swinging arms 24, and corresponding leading arms. and a pair of link mechanisms 26 disposed between the rocking arm. Also in this embodiment, each leading arm 22 is connected to the vehicle body frame 14 by a pivot 28 at its rear end so as to be vertically pivotable about a first pivot line 28A. 4 and 5, members corresponding to members shown in FIGS. 1 and 2 are denoted by the same reference numerals as those shown in FIGS.

In the second embodiment, each linkage 26 is positioned above the corresponding leading arm 22 . Therefore, the horizontal link 36 of the link mechanism 26 is pivoted to the main arm 24A of the swing arm 24 by a pivot 42 arranged above the pivot 30 . Also, the swing arm 24 of the linkage 26 is substantially L-shaped with first and second arm portions extending upwardly and rearwardly from the pivot 40, respectively. Further, the vertical link 38 of the link mechanism 26 is pivoted at its upper end by a pivot 46 to the rear end of the second arm portion of the pivot link 34 so as to be pivotable about the pivot axis 46A. Further, the vertical link 38 is pivotally attached to the leading arm 22 by a pivot 48 on the front side of the first pivot 28A at its lower end so as to be pivotable about the pivot 48A.

As can be seen from a comparison of FIGS. 4 and 5 with FIGS. 1 and 2, other points of the second embodiment are configured in the same manner as the above-described first embodiment. As described above, since the link mechanism 26 is arranged above the leading arm 22, the height of the support plate 12 in the second embodiment is greater than the height of the support plate in the first embodiment.

Also in the second embodiment, the sub-arm 24B of the swing arm 24 cooperates with the main arm 24A to transmit the upward force that the front wheel 16 receives from the travel path X to the front end of the leading arm 22. constitutes the force transmission path. Also, the swing arm 24 and the link mechanism 26 cooperate with each other to convert the rearward force that the front wheel 16 receives from the travel path X into an upward force, thereby causing the front end portion and the rear end portion of the leading arm 22 to move. It constitutes a second force transmission path that transmits between.

Therefore, according to the second embodiment, the front wheel 16, the center wheel 18 and the rear wheel 20 can easily ride over the step Y and easily move over the step Y in the same manner as in the above-described first embodiment. can climb down. In particular, the front wheels 16 can ride over a step even if the height of the step is the same as or slightly larger than the radius of the front wheel 16 .

<Effects Common to First and Second Embodiments>
As can be seen from the above description, according to the above-described first and second embodiments, the upward force Fwfv that the front wheel 16 receives from the step Y is transferred to the front end of the leading arm 22 via the above-described first force transmission path. is communicated to the department. Also, the rearward force Fwfh that the front wheel 16 receives from the step Y is converted into an upward force through the second force transmission path including the link mechanism 26 and transmitted to the intermediate portion of the leading arm 22 . Thus, the leading arm 22 can be pivoted upwardly about the rear end more efficiently than if the linkage 26 constructed as described above were not provided. , the front wheel 16 can be positively moved upward. Therefore, the front wheels can be moved upward by effectively utilizing not only the upward force that the front wheels receive from the step Y or the like, but also the rearward force, so that the front wheels can easily run over the step or the like. can.

Even if the leading arm 22 or the like pivots when the front wheels 16 run over a step Y or the like, the center of gravity of the vehicle 10 does not substantially change in the longitudinal direction or the lateral direction, so the running stability of the vehicle deteriorates. never do.

Further, as described above, the higher the height of the step Y, the smaller the vertical component, that is, the upward force Fwfv, and the larger the horizontal component, that is, the rearward force Fwfh. Therefore, in a conventional vehicle in which the front wheels are supported by casters, or in which the front wheels are supported in the same manner as the support structure for the rear wheels 20, if the height of the step becomes high, the front wheel cannot run over the step. .

In contrast, according to the first and second embodiments, for example, even if the height of the step Y is the same as or slightly larger than the radius of the front wheel 16, the rearward force Fwfh that the front wheel 16 receives from the step is is transmitted to the intermediate portion of the leading arm 22 through the second force transmission path. Thus, the leading arm 22 is pivoted upward about the pivot line 28A, and the front wheel 16 is lifted upward via the swing arm 24. As shown in FIG. Therefore, even if the height of the step is the same as or slightly larger than the radius of the front wheel 16, the front wheel 16 can run over the step.

Also, according to the first and second embodiments described above, the central wheel support arm 50 that supports the central wheel 18 is integral with the rear end of the leading arm 22 . As described above, when the central wheel 18 runs over the step Y and a rearward force Fwfh acts on the axle 52 of the central wheel 18, the leading arm 22 and the central wheel support arm 50 move around the pivot line 28A. It receives a moment in the counterclockwise direction as viewed in FIGS. Therefore, the leading arm 22 tries to push the swing arm 24 and the front wheel 16 downward, but the front wheel 16 has already run over the step Y and does not descend, so the reaction force of the moment lifts the center wheel 18. . Therefore, the central wheel 18 can easily run over the step Y.

In addition, in the above-described first and second embodiments, when the vehicle 10 is on the horizontal travel path X, the rotation axis 52A is located directly below the first pivot axis 28A. Thus, when the leading arm 22 and the central wheel support arm 50 pivot about the first pivot axis 28A, the center wheel 18 is only slightly taller because the rotation axis 52A moves about the first pivot axis 28A. rises to and does not fall. Therefore, even if the load of the vehicle 10 is high and the ground load of each wheel is high, the force of the center wheel 18 pushing the travel path X downward increases, causing the leading arm 22 and the center wheel support arm 50 to move downward. It is possible to avoid that the pivotal motion is inhibited.

Further, according to the first and second embodiments described above, the electric motor 68L for driving the left central wheel and rear wheel and the electric motor 68R for driving the right central wheel and rear wheel are provided. Therefore, the number of electric motors can be reduced and the control of the electric motors can be facilitated compared to the case where the left and left central wheels and rear wheels are each provided with a dedicated electric motor.

Further, a difference in driving force can be applied between the left and right wheels of the center wheel 18 and the rear wheel 20, and driving force can be applied to one of the left and right wheels and braking force can be applied to the other of the left and right wheels. , the vehicle 10 can be turned. Furthermore, by controlling the driving force difference and the braking/driving force difference, the turning direction and turning radius of the vehicle 10 can be controlled without steering the wheels. Furthermore, since a steering device for steering the wheels is not required, the structure of the vehicle 10 can be simplified as compared with a case where a steering device is provided.

Furthermore, according to the first and second embodiments described above, the two rows of wheels, the central wheels 18 and the rear wheels 20, are driving wheels. Therefore, when one of the front wheel 16, the central wheel 18 and the rear wheel 20 rides on a step, even if one of the central wheel 18 and the rear wheel 20 is lifted off the road X, the other of the central wheel 18 and the rear wheel 20 is Since the driving force is generated, the vehicle 10 can run without any trouble.

Although the present invention has been described in detail with respect to particular embodiments, it should be understood that the present invention is not limited to the embodiments described above and that various other embodiments are possible within the scope of the present invention. will be clear to those skilled in the art.

For example, in the first and second embodiments described above, the front wheels 16, center wheels 18 and rear wheels 20 each comprise a pair of laterally spaced wheels, as previously described. However, it is sufficient that at least one of the front wheels 16, center wheels 18 and rear wheels 20 comprise a pair of wheels spaced laterally of the vehicle 10. As shown in FIG. That is, each of the wheels other than the at least one wheel may be one wheel arranged laterally centrally. Also, although the front wheel 16, center wheel 18 and rear wheel 20 have the same diameter, the diameter of each wheel may be different from each other.

In the first and second embodiments described above, the central wheels 18 and the rear wheels 20 are driven by a common electric motor, but the central wheels 18 and the rear wheels 20 are each driven by a dedicated electric motor. It may be driven. Further, the drive source may be a drive device other than the electric motor, and the drive force transmission may be a drive force transmission means other than the chain. Also, the drive wheels may be in-wheel motor type wheels incorporating an electric motor and a reduction gear. Further, the drive wheels may be at least one of the front wheel 16, center wheel 18 and rear wheel 20, or all of these wheels may be drive wheels.

In the first and second embodiments described above, the driving wheels are the center wheel 18 and the rear wheels 20, and the turning of the vehicle 10 is caused by the driving force difference between the left and right wheels of the center wheel 18 and the rear wheels 20. Also, by applying a driving force to one of the left and right wheels and a braking force to the other of the left and right wheels. However, the turning of the vehicle 10 may be performed by controlling the driving force difference or braking/driving force difference of arbitrary drive wheels. Further, turning of the vehicle 10 may be performed by steering at least one of the front wheels 16 and the rear wheels 20, controlling the driving force difference or the braking/driving force difference of any drive wheels and controlling the front and rear wheels. At least one of the wheels may be steered.

Further, in the first and second embodiments described above, the center wheel 18 is supported by a center wheel support arm 50 integral with the leading arm 22 and extending downwardly from the pivot 24, as described above. In addition, the central wheel 18 can easily run over the step. However, the center wheel support arm 50 may be omitted and the center wheel 18 may be supported by other support structures known in the art, such as the rear wheel 20 support structure.

DESCRIPTION OF SYMBOLS 10... Three-row wheel vehicle, 14... Body frame, 16... Front wheel, 18... Center wheel, 20... Rear wheel, 22... Leading arm, 24... Swing arm, 26... Link mechanism, 34... Pivoting link, 36... Horizontal link 38 Vertical link 50 Center wheel support arm 58 Rear wheel support caster 60 Trailing arm 68L, 68R Electric motor 72C, 72R Chain

Claims (1)

A three-row wheel vehicle having a front wheel, a center wheel and a rear wheel arranged longitudinally, wherein at least one of the front wheel, the center wheel and the rear wheel includes a pair of laterally spaced wheels. In a three-row wheel vehicle, a leading arm is connected to the vehicle body at its rear end so as to be vertically pivotable around a first pivot line, and is pivotable forward and backward around a second pivot line. a swing arm connected to the front end of the leading arm and rotatably supporting the front wheel at the lower end; and a link mechanism disposed between the leading arm and the swing arm. , the link mechanism comprises a pivot link pivotally supported on the vehicle body for pivotal movement about a laterally extending third pivot axis; a horizontal link pivotally attached to said pivot link at a first pivot point vertically spaced from said third pivot at one end; and a horizontal link at one end spaced rearwardly from said third pivot. an upper and lower link pivotally attached to the pivot link at a second pivot point and pivotally attached at the other end to the leading arm on the forward side of the first pivot axis; A three-row wheel vehicle, wherein a rearward force transmitted to the swing arm is converted into an upward force and transmitted to the leading arm.

Images