Description

APPARATUS FOR SHIFTING THE CENTER OF GRAVITY OF A VEHICLE HAVING THREE WHEELS OR MORE

Technical Field

[1] The present invention relates to a vehicle having three wheels or more, and more particularly to an apparatus for shifting the center of gravity of a vehicle having three or more wheels by which upon driving, particularly on a curve in the road, the center of gravity of the vehicle is shifted to the left/right side relative to the driving direction so as to secure stability and safe driving. Background Art

[2] In general, a tricar means a vehicle having three wheels, wherein two wheels are mounted after a driver and one wheel is mounted before the driver (generally called a reversed tricar), or otherwise, two wheels are mounted after the drive and one wheel is mounted before the driver (generally called a regular tricar).

[3] To secure the stability and safety of the tricar during driving on a linear road and a curve, it should be configured such that the breadth of the car at a position where two wheels are mounted in parallel is made larger than that of a common 4- wheel car, or that like a motorcycle, the center of gravity is momentarily shifted partially or completely in the direction of the centripetal force opposite to the centrifugal force. The former case causes the vehicle to have a larger size due to an increase in breadth thereof, and the latter case causes the problems of stability and safety thereof upon the momentary shift of the center of gravity. Because of this, development of the tricar has been carried out by excluding the former case but solving the problems of the latter case.

[4] Recently, more particularly in the 1997 Frankfurt motor show, Mercedes-Benz was noted worldwide for an announcement of a new concept reversed tricar named 'F300 Life -jet'. However, such a reversed tricar had a problem in that power beyond a reasonable need was consumed, and power required for a shift itself of the center of gravity of a car body was also consumed because the tricar was designed so that upon shifting the center of gravity, the car body and all wheels were to be tilted in the direction of the driver's manipulation. In addition, such a tricar still had a problem of shaking upon restoration to a regular position after the shift of the center of gravity, upon stopping, and upon boarding.

[5] Furthermore, also in the recent Tokyo motor show, Phiaro, Japan was noted worldwide for an announcement of a regular tricar named "P67b ETERNITY". However, in such a regular tricar, the center point of the shift circle of the center of

gravity is positioned above the ground, so that upon shifting the center of gravity, side- skidding occurs on a wheel, thereby causing severe wearing of a tire thereof. Such a phenomenon will be weighted particularly upon driving on a curve. In addition, such a tricar is designed so that the center of gravity of an engine installed on the side of rear wheels having the largest weight in a car body is not shifted, so that upon driving on a curve, there will be a greater possibility of incurring an accident as compared to the reversed tricar. Disclosure of Invention Technical Problem

[6] Therefore, the present invention has been made in view of the above-mentioned problems, and the present invention provides an apparatus for shifting the center of gravity of a vehicle having three wheels or more requiring the shifting of the center of gravity to the left/right relative to a driving direction, capable of, upon driving of the vehicle, shifting and restoring the center of gravity more easily, effectively, and precisely, and upon stopping, precisely controlling the left/right movement. Technical Solution

[7] In accordance with an aspect of the present invention, there is provided an apparatus for shifting the center of gravity of a vehicle having three wheels or more, including: a movable frame movably fixed, at one side, to a vehicle body in such a manner that a portion or all of the frame is movable to the left/right side relative to the driving direction of the vehicle body, the frame being shaped like an inverse trapezoid, a regular trapezoid, a rectangle, a square, a regular triangle, or an inverse triangle; and a control unit for controlling the left/right movement of the frame to shift the center of gravity of the vehicle body as needed, the control unit including: (i) a ball screw device including a ball screw and a ball nut; and (ii) wires each having opposite ends wherein one end is coupled to the ball nut, and the other end is coupled to the upper portion of the frame substantially and laterally symmetric with the driving direction of the vehicle body.

[8] In a preferred embodiment, one or more elastic support member is coupled between the left/right sides of the frame and the vehicle body under the left/right sides. The elastic support member may be selected from one in type of a common compression spring having the same tension, one in type of a combination of a wire having a different length and a compression spring, or one in type of a combination of a piston having a different size or length and a compression spring. Such an elastic support member serves to allow the frame, upon the curved driving of the vehicle, shifted to one side by the shift of the center of gravity thereof, to remain at that position with minimum power. On the contrary, when the vehicle is switched from the curved

driving into the linear driving, the elastic support member serves to allow the shifted frame to easily return to its original position with minimum power. [9] In the ball screw device, the shuttling motion of the ball nut relative to the ball screw is carried out by an electric motor or a hydraulic actuator. [10] The electric motor or the hydraulic actuator is supplied with power by means of a power switch. [11] The power switch is preferably disposed at a position near a handle of a vehicle or where a driver's hand or foot reaches. [12] The power switch is automatically controlled by an electronic control unit (ECU) according to a combination of a rotation angle of a handle of a vehicle and a combined centrifugal force by a weight of a vehicle or a driver, or a combined weight of the vehicle and the driver. [13] According to a preferred embodiment of the present invention, an anti-curving roller or rail is disposed over the ball nut, and such an anti-curving roller or rail is directly or indirectly fixed to the vehicle body under the ball nut.

Advantageous Effects

[14] As set forth above, according to the apparatus for shifting the center of gravity of a vehicle having three wheels or more requiring the shifting of the center of gravity to the left/right relative to a driving direction, upon driving of the vehicle, the center of gravity is shifted and restored more easily, effectively, and precisely, and upon stopping, the left/right movement is precisely controlled.

Brief Description of the Drawings [15] The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: [16] FIG. 1 is a perspective view illustrating the main part of an apparatus for shifting the center of gravity according to a preferred embodiment of the present invention; [17] FIGS. 2 and 3 are a perspective view illustrating the main part of a control unit for controlling the shift of the center of gravity of the shifting apparatus in FIG. 1, wherein

FIG. 2 is a view illustrating the shifting apparatus during linear driving, and FIG. 3 is a view illustrating the shitting apparatus during curved driving; [18] FIG. 4 is a perspective view illustrating the main part of a control unit for controlling the shift of the center of gravity of the shifting apparatus in FIGS. 1 to 3; [19] FIG. 5 is a partial sectional view of the control unit of the shifting apparatus show in FIGS. 1 to 3;

[20] FIG. 6 is a view illustrating a frame during linear driving;

[21] FIG. 7 is a view illustrating a frame during curved driving;

[22] FIG. 8 is a perspective view illustrating the main part of an apparatus for shifting the center of gravity according to another preferred embodiment of the present invention;

[23] FIG. 9 is a perspective view illustrating the main part of an apparatus for shifting the center of gravity according to a further preferred embodiment of the present invention; and

[24] FIGS. 10 to 12 are views illustrating various vehicles, to which the apparatus for shifting the center of gravity according to the present invention can adapt, wherein FIG. 10 illustrates a reversed tricar, FIG. 11 illustrates a regular tricar, and FIG. 12 illustrates a lozenge- shaped vehicle. Best Mode for Carrying Out the Invention

[25] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. The drawings and description thereof have been provided for illustrative purposes, so the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, within the scope of the invention.

[26] FIGS. 1 to 3 schematically illustrate the main part of an apparatus for shifting the center of gravity (hereinafter also referred to as "the shifting apparatus") adapted to a vehicle having three wheels or more according to a preferred embodiment of the present invention. FIGS. 4 and 5 illustrate a control unit for controlling the shift of the center of gravity in the shifting apparatus. FIGS. 6 and 7 illustrate the operation state of the shifting apparatus according to the preferred embodiment of the invention.

[27] Referring to these drawings, the apparatus 1 for shifting the center of gravity includes a movable frame having a certain shape, and a control unit for controlling the left/right shift of the frame 10 to shift the center of gravity to the left/right side as needed.

[28] The movable frame 10, as shown in FIG. 1, is movably fixed, at its one end, to a vehicle body in such a manner that a portion thereof is movable in the left/right direction relative to the driving direction of the vehicle body. In the present embodiment, while the movable frame 10 is illustrated in an inverse trapezoidal shape, the frame may have another shape such as a regular trapezoid, a square, a rectangle, a regular triangle, an inverse triangle, and others. Particularly, the inverse trapezoidal frame 10 can be moved to the left/right side with lesser force, thereby improving the controllability of the vehicle.

[29] The control unit for shifting the center of gravity, as shown in the drawings, includes a ball screw device 60 and wires 20a, 20b directly driven by the ball screw device. With the primary operation of the wires 20a, 20b by the ball screw device 60,

the center of the movable frame 10 is shifted in a direction as needed. The ball screw device 60 includes a ball screw 62 and a ball nut 64, wherein the ball screw 62 is rotatably fixed to the vehicle body, and the ball nut 64 is coupled to the ball screw 62 such that it linearly reciprocates therealong. As shown in the drawings, the wires 20a, 20b each are connected, at its one end, to the ball nut 64, and at its other end, to the upper portion of the frame 10 laterally symmetric with the driving direction of the vehicle body.

[30] The ball screw device 60 includes a bearing between the ball nut-side inside and the ball screw 62, allowing the precise control of the ball nut 64. Moreover, the ball screw device 60 restricts the left/right movement of the vehicle when the vehicle is stopped or even driven.

[31] Such a rotation operation of the ball screw 62 in the control unit is performed by an electric motor M, which is operated by means of power supply through a power switch S. While the present embodiment illustrates that the ball screw device 60 is operated by the electric motor M, those skilled in the art may appreciate that the ball screw device 60 can be operated even by a hydraulic actuator. The power switch S is preferably disposed at a position near a handle of a vehicle, or where a driver's hand or foot reaches. The power switch s is automatically controlled by an electronic control unit (ECU) according to a combination of a rotation angle of a handle of a vehicle and a combined centrifugal force by a weight of a vehicle or a driver, or a combined weight of the vehicle and the driver.

[32] An anti-curving roller or rail is disposed on the upper portion of the ball nut 64 so as to prevent the ball screw device 60 from being bent. Such an anti-curving roller or rail is directly or indirectly fixed to the vehicle body under the ball nut 64.

[33] Moreover, the control unit of the shifting apparatus 1 of the present invention further includes an elastic support member in addition to the above-mentioned elements. In the present embodiment, compression springs 50 are used as the elastic support member. The springs 50 are disposed between the left side of the frame 10 and the vehicle body under the left side of the frame 10, and between the right side of the frame 10 and the vehicle body under the right side of the frame 10.

[34] Although the center of gravity of the frame 10 is shifted to a specified direction, the spring 50 supports the portion in the counter direction, allowing the center of gravity to be shifted as needed, and allowing the vehicle body to easily return to its original state when there is no need to shift the center of gravity. The springs 50 are disposed between the left side of the frame 10 and the vehicle body under the left side of the frame 10, and between the right side of the frame 10 and the vehicle body under the right side of the frame 10. In this case, it is preferable that the plurality of springs 50 having the same tension is provided as shown in the drawings. As the number of

springs 50 increases, the driving stability of the vehicle is secured more firmly. While the present embodiment employs the plurality of springs 50 having the same tension, it may be configured such that the springs 50 having a different tension or the structure in which the tension is made different are sequentially installed on the left/right sides of the frame. Herein, it is advantageous to control that the respective springs 50 applied to the left/right sides of the frame 10 have the same tension. The reason why the springs on the respective sides have a different tension is for sequentially applying the force to the respective springs with a different amount. Thus, although the primarily forced spring is cut, the secondarily and thirdly forced springs remain, providing a safe operation.

[35] In the shifting apparatus 1 of the present invention according to the preferred embodiment, the ball screw 62 rotates together with the rotation of the electric motor M, so that the ball nut 64 linearly rotates in a specified direction with the rotation of the ball screw 62. Herein, when the ball nut 64 is moved in the right direction (an arrow direction which however is the left direction from the view point of a driver) on the drawing, the wire denoted as 20a is strained to pull the upper portion of the frame 10 to which the wire 20a is connected, and on the contrary, the wire denoted as 20b comes loose not to pull the upper portion any more of the frame 10 to which the wire 20b is connected. Meanwhile, the spring 50 denoted as 50b draws the frame 10 connected to the wire 20b, so that the center of gravity of the frame 10 is shifted toward the right direction as shown in FIG. 2. Herein, the frame 10 is supported by the spring 50a provided opposite to the spring 50b.

[36] FIG. 8 illustrates an apparatus 1 for shifting the center of gravity according to another preferred embodiment of the present invention. The shifting apparatus 1 in FIG. 8 is identical to the shifting apparatus 1 in FIG. 1, excluding that the elastic support member consists of wires and compression springs.

[37] Referring to FIG. 8, the elastic support members 52a, 52b, and 52c used in the shifting apparatus 1 is in combination of the wires (upper portion) and the compression springs (lower portion). In the elastic support members 52a, 52b, and 52c, the compression springs have the same length, but the wires have different lengths. Making the lengths of the wires different is for, upon the movement of the frame 10 in a specified direction, allowing the elastic support members 52a, 52b, and 52c positioned opposite to the movement to sequentially operate. In this case, the elastic support member denoted as 52a first operates, the elastic support member 52b having a loose wire then operates, and the elastic support member 52c having a looser wire finally operates. The number of the elastic support members is dependent upon the selection of those skilled in the art considering the weight of the vehicle body and the like.

[38] FIG. 9 illustrates an apparatus for shifting the center of gravity according to a further preferred embodiment of the present invention. The shifting apparatus 1 in FIG. 9 is identical to the shifting apparatus 1 in FIG. 1, excluding that the elastic support member consists of pistons and compression springs.

[39] Referring to FIG. 9, the elastic support members 54a, 54b, and 54c used in the shifting apparatus 1 is in combination of the pistons (upper portion) and the compression springs (lower portion). In the elastic support members 54a, 54b, and 54c, the lengths or sizes of the pistons and the compression springs are inversely proportional to each other. To make the length or size of the pistons different is for, upon the movement of the frame 10 in a specified direction, allowing the elastic support members 54a, 54b, and 54c positioned opposite to the movement to sequentially operate. In this case, the elastic support member denoted as 54a first operates, the elastic support member 54b having a larger or longer piston then operates, and the elastic support member 54c having the largest or longest piston finally operates. The number of the elastic support members is dependent upon the selection of those skilled in the art considering the weight of the vehicle body and the like.

[40] FIGS. 10 to 12 illustrate various vehicles to which the shifting apparatus of the present invention can be adapted. That is, FIG. 10 illustrates a reversed tricar, FIG. 11 illustrates a regular tricar, and FIG. 12 illustrates a lozenge- shaped vehicle. These vehicles are common with each other in that the center of gravity should be momentarily shifted by the operation manipulation of a driver in order to secure stability of the vehicle as well as the driver.

[41] Although an exemplary embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.