Vehicle transport

Abstract

We provide highly practical vehicle transport systems. [Solution] A vehicle transporter is provided with a clamping device 20 having a pair of clamp bars 22. By closing the pair of clamp bars, the vehicle's wheels are clamped front and rear at the bottom of the tire's contact surface, and the vehicle is lifted by raising the wheels while the clamping device is in the closed state. Each of the pair of clamp bars has an inclined surface, and in the closed state, the inclined surface is configured to support the tire's contact surface, and the angle of inclination between the inclined surface and the horizontal plane is 45° or more. When transitioning the clamping device from the clamped state to the unclamped state, the force required to pull the clamp bars out from between the road surface and the tire becomes substantially zero, making it possible to easily transition the clamping device from the clamped state to the unclamped state.

Description

Technical Field

[0001] The present invention relates to a vehicle transporter for transporting vehicles.

Background Art

[0002] For example, there is a vehicle transporter as described in the following patent document. In that vehicle transporter, each wheel of the vehicle to be transported is lifted while being clamped by a clamping device, and is transported in that state.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the vehicle transporter described in the above patent document, the clamping device includes a pair of clamping bars, and in the state of transporting the vehicle, the pair of clamping bars are in a closed state, that is, the clamping device is in a clamped state. In the state where the transportation of the vehicle is completed, the pair of clamping bars are in an open state, that is, the clamping device is in an unclamped state. However, when shifting from the clamped state to the unclamped state, the clamping bar may get caught between the tire and the road surface, and in that case, it becomes difficult to pull out the clamping bar from the wheel. By facilitating the pulling out of the clamping bar when shifting from the clamped state to the unclamped state, the practicality of the vehicle transporter is improved. The present invention has been made in view of such circumstances, and an object thereof is to provide a highly practical vehicle transporter.

Means for Solving the Problems

[0005] In order to solve the above problems, the vehicle transporter of the present invention is A vehicle transport machine equipped with a clamping device having a pair of clamping bars, which, when the pair of clamping bars is closed, clamps the wheels of a vehicle from the front and rear at the bottom of the tire's contact surface, and lifts the wheels while the clamping device is closed, thereby lifting and transporting the vehicle. Each of the pair of clamp bars is characterized in that it has an inclined surface, and in the closed state, the inclined surface is configured to support the contact surface of the tire, and the angle of inclination between the inclined surface and the horizontal plane is 45° or more. [Effects of the Invention]

[0006] According to the vehicle transporter of the present invention, when transitioning the clamping device from the clamped state to the unclamped state, the force required to pull the clamp bar out from between the road surface and the tire, i.e., the pull-out load, becomes substantially zero, making it possible to easily transition the clamping device from the clamped state to the unclamped state.

[0007] Furthermore, as the angle of inclination of the above-mentioned inclined surface increases, the force required to maintain the clamped state increases, so it is desirable to keep the angle of inclination as small as possible. Specifically, for example, it is desirable to keep it at 60° or less, and even more so, at 50° or less. Most preferably, it should be 45°. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the entire vehicle transport machine of the embodiment. [Figure 2] This is a perspective view showing the vehicle transporter of the embodiment in the process of transporting a vehicle. [Figure 3] This is a schematic diagram showing the vehicle transporter of the embodiment in the process of transporting a vehicle, viewed from the side. [Figure 4] This diagram schematically shows the wheels of the vehicle to be transported and the clamp bar when the clamping device is in the clamped state. [Figure 5] This graph shows the relationship between the inclination angle of the clamp bar's inclined surface and the tensile force applied to the clamp bar. [Modes for carrying out the invention]

[0009] Hereinafter, a vehicle transport machine, which is an embodiment of the present invention, will be described in detail with reference to the drawings as an example of how to carry out the present invention. In addition to the embodiments described below, the present invention can be carried out in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Examples]

[0010] [A] Vehicle transporter configuration The vehicle transporter of this embodiment comprises a drive unit 10 and a base 12, as shown in the perspective view in Figure 1. In the diagram, the upper left represents the front, the lower right represents the rear, the lower left represents the left side, and the upper right represents the right side with respect to the vehicle transporter. The drive unit 10 is located on the front side of the base 12. This vehicle transporter transports vehicle C in the state shown in the perspective view in Figure 2. In Figure 2, the orientation is the same as in Figure 1, and in Figure 2, vehicle C is being transported facing backward.

[0011] The drive unit 10, although a detailed explanation of its structure will be omitted, has a pair of front wheels 14 on the left and right sides. These front wheels 14 are both drive wheels and steering wheels. Therefore, the drive unit 10 includes a drive device for rotating the front wheels 14, a braking device for applying braking force to the front wheels 14, a steering device for steering the front wheels 14, and a controller for controlling these drive device, braking device, and steering device. In addition, this vehicle transporter is equipped with an autonomous driving controller for autonomous driving. Autonomous driving is performed by determining its own position and orientation. For this reason, a pair of sensor units 16 are provided on the top, one on the left and one on the right, to monitor the surroundings of the vehicle transporter in order to acquire its own position and orientation. Each sensor unit 16 is composed of one or more sensing devices such as a camera, millimeter-wave radar, or LiDAR.

[0012] The vehicle C to be transported has four wheels W, one at the front and one at the rear. The base 12 is equipped with clamping devices 20, specifically a front clamping device 20f and a rear clamping device 20r, to clamp each of the four wheels W at the bottom of the tires. As can be seen in Figure 2, the front clamping device 20f is a device for clamping the front wheels W of the vehicle C (the rear wheels W of the vehicle C in Figure 2), and the rear clamping device 20r is a device for clamping the rear wheels W of the vehicle C (the front wheels W of the vehicle C in Figure 2). In the following explanation, when it is not necessary to distinguish between the front and rear, they will be collectively referred to as the clamping device 20.

[0013] Each of the front clamping device 20f and the rear clamping device 20r has a pair of front and rear clamping bars 22 on the left and right sides of the base 12, respectively. To distinguish between the clamping bars 20, the front clamping bar 22 of the front clamping device 20f may be called clamping bar 22ff, the rear clamping bar 22 of the front clamping device 20f may be called clamping bar 22fr, the front clamping bar 22 of the rear clamping device 20r may be called clamping bar 22rf, and the rear clamping bar 22 of the rear clamping device 20r may be called clamping bar 22rr. Furthermore, when it is not necessary to distinguish between the front clamping device 20f and the rear clamping device 20r, the front clamping bar 22 may be called clamping bar 22f and the rear clamping bar 22 may be called clamping bar 22r.

[0014] Regarding the front clamping device 20f, the front clamp bar 22f (22ff) is fixed to the base 12 in a position that extends to the left and right. In contrast, the rear clamp bar 22r (22fr) is rotatable around a vertically extending pivot axis 24 between a retracted position that extends forward and backward, and an extended position that extends left and right. Regarding the rear clamping device 20, both the front clamp bar 22f (22rf) and the rear clamp bar 22r (22rr) are rotatable around a vertically extending pivot axis 24 between a retracted position that extends forward and backward, and an extended position that extends left and right. Incidentally, in Figure 1, the clamp bars 22fr, 22rf, and 22rr are all in the retracted position, while in Figure 2, they are all in the extended position. The rotation of the clamp bar 22 between the retracted and deployed positions is performed by a retractable cylinder-type actuator 26, although a detailed explanation of its structure will be omitted.

[0015] The rear clamping device 20r has a slider 28 that can slide back and forth along the base 12, and the clamping bar 22 and actuator 26 are held by the slider 28. The position of the rear clamping device 20r is adjustable according to the wheelbase of the vehicle C to be transported.

[0016] Referring to Figure 3, which schematically shows the vehicle C being transported as viewed from the left, the base 12 is equipped with roller-shaped rear wheels 30. The rear wheels 30 are rotatably held at the rear end of an arm 32, the front end of which is pivotably supported by the base 12. On the other hand, although a detailed explanation will be omitted, the drive unit 10 incorporates a base lifting device 34 that raises and lowers the front end of the base 12. By rotating the arm 32 and raising and lowering the front end of the base 12, the base 12 can be raised and lowered. Incidentally, Figure 3 shows the base 12 in the raised state.

[0017] Regarding the front clamp device 20f, the state where the rear clamp bar 22r is in the stored position is when the pair of clamp bars 22 are in the open state, and the state where the rear clamp bar 22r is in the deployed position is when the pair of clamp bars 22 are in the closed state. Similarly, regarding the rear clamp device 20r, the state where both the front clamp bar 22f and the rear clamp bar 22r are in the stored position is when the pair of clamp bars 22 are in the open state, and the state where both the front clamp bar 22f and the rear clamp bar 22r are in the deployed position is when the pair of clamp bars 22 are in the closed state. Furthermore, when the pair of clamp bars 22 are in the closed state and sandwich the wheels W of the vehicle C front and rear, it is the clamped state, and when the pair of clamp bars 22 are in the open state and the clamping of the wheels W is released, it is the unclamped state. Incidentally, FIG. 3 shows the case where all the clamp devices 20 are in the clamped state. The control of the clamp devices 20, the control of the base lifting device 34, and the rotation of the arm 32 are also performed by the above-mentioned controller.

[0018] Regarding the operation of the vehicle transporter when transporting a vehicle, the vehicle transporter inserts the base 12 under the vehicle C to be transported until the fixed clamp bar 22ff abuts against the front wheel W of the vehicle while retreating straight in the state where the base 12 has descended. Then, both the front clamp device 20f and the rear clamp device 20r are set in the clamped state. In that state, by raising the base 12, the vehicle C is lifted and the vehicle C is transported. When detaching from the transported vehicle C, the base 12 is lowered in the clamped state, and then both the front clamp device 20f and the rear clamp device 20r are set in the unclamped state, and it advances straight to extract the base 12 from the vehicle C.

[0019] [B] Inclined surface of the clamp bar In this vehicle transporter, as shown in Fig. 4(a), the clamping device 20 clamps the wheels W of the vehicle C to be transported front and rear at the lower part of the ground contact surface Gf of the tire T by closing a pair of clamping pump bars 22f and 22r, that is, in the clamped state, and lifts the vehicle C by lifting the wheels W while maintaining the clamped state. More specifically, each of the pair of clamping bars 22f and 22r has inclined surfaces If facing each other, and in the closed state, these inclined surfaces If are configured to support the ground contact surface of the tire T. When lowering the vehicle C after the transportation, as shown in Fig. 4(b), the base 12 is lowered so that the wheels W, that is, the tires T, are brought into contact with the ground. Incidentally, the inclined surface If is a plane parallel to the wheel axis OL, which is the axis of the vehicle W, in the closed state. Note that Fig. 4 is a schematic diagram and is shown such that the entire wheel W including the tire T is a rigid body.

[0020] The clamping bar 22 can have, for example, a square cross-section as described in the above prior art patent document. However, in view of the ease of insertion of the clamping bar 22 between the ground contact surface Gf of the tire T and the road surface GL when shifting from the open state to the closed state, that is, when shifting from the unclamped state to the clamped state, and the efficient clamping of the tire T, the vehicle transporter provides the inclined surface If on the clamping bar 22.

[0021] If we define the angle between the inclined surface If of the clamp bar 22 and the horizontal plane (for example, the road surface GL) as the inclination angle θ (<90°), then the smaller the inclination angle θ, the better the ease of insertion and efficient holding described above. However, if the inclination angle θ is small, it is expected that it will be difficult to detach the clamp bar 22 from the tire T when moving a pair of clamp bars 22 from the closed state to the open state, that is, when moving from the clamped state to the unclamped state, while the tire T is in contact with the ground. In other words, if the inclination angle θ is shallow, it is expected that the clamp bar 22 may become jammed between the contact surface Gf of the tire T and the road surface GL due to variations in various factors such as the unevenness of the road surface GL, how the wheel load (weight per wheel) is applied to the clamp bar 22, and deviations from the appropriate relative position and relative posture of the tire T and the clamp bar 22. Therefore, in this vehicle transport machine, the inclination angle θ of the inclined surface If of the clamp bar 22 is set to 45° or more.

[0022] The inclination angle θ of the inclined surface If will be explained in detail below, referring to Figure 4(c), which shows a mechanical model. Figure 4(c) shows the state in which the tire T is in contact with the ground in the clamped state.

[0023] If F is the wheel load, F1 is the reaction force from the road surface GL to the wheel W, F2 is the reaction force from the clamp bar 22 to the wheel W (reaction force in the direction normal to the inclined surface If), and μ is the coefficient of friction between the inclined surface If and the contact surface Gf of the tire T, then the force balance in the vertical direction of the wheel W is expressed by the following equation. Incidentally, downward forces are represented as + and upward forces as -. F-F1-2 F2 cosθ-2 μ F2 sinθ=0 (1) Regarding the balance of forces in the longitudinal direction (left-right direction in the diagram) of wheel W, since it is symmetrical, that is, the resultant force is 0, so the notation in the equation is omitted here.

[0024] When a force (pulling load) is applied horizontally to a clamp bar 22 in the front-rear direction (left-right direction in the diagram) as a pulling force F4, the vertical force balance of one of the clamp bars 22r can be expressed by the following equation. Incidentally, F3 is the reaction force from the road surface GL to the clamp bar 22. Various forces are represented as + for downward and - for upward in the vertical direction, and as + for backward (rightward in the diagram) and - for forward (leftward in the diagram) in the front-rear direction. F2·cosθ+μ·F2·sinθ-F3=0 ···(2) On the other hand, the force balance in the front-rear direction of the clamp bar 22r can be expressed as follows: F2·sinθ-μ·F2·cosθ+F4=0 ···(3) Incidentally, regarding the force balance of the other clamp bar 22, which is clamp bar 22f, the only difference is that the sign of the force in the front-rear direction (left-right direction in the diagram) of the wheel W is reversed, so the notation in the equation here is omitted.

[0025] By solving the above equations as a system of simultaneous equations, the relationship between the inclination angle θ of the inclined surface If and the tensile force F4 can be derived, and this relationship is represented as shown in the graph in Figure 5. More specifically, as the inclination angle θ increases from 0°, the tensile force F4 decreases, and becomes 0 when the inclination angle θ is 45°. If the inclination angle θ becomes larger than that, the sign of the tensile force F4 reverses. In other words, the tensile force F4 acts as a force that repels the clamp bar 22.

[0026] In light of the above, the inclination angle θ of the inclined surface If of the clamp bar 22 in this vehicle transporter is set to 45° or more. By setting the inclination angle θ to 45° or more, even if the various factors mentioned above, such as the unevenness of the road surface GL, vary to some extent, almost no force is required to transition from the clamped state to the unclamped state, that is, practically no force is required.

[0027] Furthermore, considering that a force is required to maintain the closed state when the inclination angle θ exceeds 45°, it is not desirable to make the inclination angle θ too large. Specifically, it is desirable to keep it at 60° or less, and even more so, at 50° or less. And, to put it extremely, it is desirable to keep the inclination angle θ at 45°.

[0028] [C] Variations of vehicle transport machines This vehicle transporter is designed to transport vehicle C in the reverse direction, but it may also transport it in the forward direction, or it may be capable of transporting in either direction. Furthermore, the vehicle transporter to which this invention applies may lift and transport only one of the front or rear wheels of vehicle C, in which case a clamping device with an inclination angle θ of the inclined surface of the clamp bar of 45° or more should be used with respect to the wheel being lifted. Moreover, although the vehicle transporter is designed to be autonomous, it may also be operated by a human.

[0029] This vehicle transporter employs a clamping device 20r for the front wheels W of vehicle C, which switches between a clamped state and an unclamped state by rotating both of a pair of clamping bars 22. For the rear wheels W of vehicle C, a clamping device 20f is employed, which switches between a clamped state and an unclamped state by rotating one of a pair of clamping bars 22. In other words, a vehicle transporter to which the present invention applies only needs to employ a clamping device that switches between a clamped state and an unclamped state by operating at least one of a pair of clamping bars. [Explanation of Symbols]

[0030] 10: Drive unit 12: Base 20: Clamping device 22: Clamp bar 26: Actuator C: Vehicle W: Wheel T: Tire Gf: Contact surface If: Inclined surface GL: Road surface μ: Coefficient of friction F: Wheel load F1: Reaction force from road surface F2: Reaction force from clamp bar F3: Reaction force from road surface F4: Pull-out force θ: Incline angle of the inclined surface

Claims

1. A vehicle transport machine equipped with a clamping device having a pair of clamping bars, which, when the pair of clamping bars is closed, clamps the wheels of a vehicle from the front and rear at the bottom of the tire's contact surface, and lifts the wheels while the clamping device is closed, thereby lifting and transporting the vehicle. A vehicle transport machine characterized in that each of the pair of clamp bars has an inclined surface, and in the closed state, the inclined surface is configured to support the contact surface of the tire, and the angle of inclination between the inclined surface and the horizontal plane is 45° or more.

2. The vehicle transporter according to claim 1, wherein the inclination angle is 60° or less.

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