WO2003091087A1

WO2003091087A1 - Auxiliary wheel apparatus for vehicles

Info

Publication number: WO2003091087A1
Application number: PCT/KR2002/000942
Authority: WO
Inventors: Jung-Jin Ro
Original assignee: Jung-Jin Ro
Priority date: 2002-04-26
Filing date: 2002-05-20
Publication date: 2003-11-06
Also published as: AU2002309286A1; KR200284049Y1

Abstract

The object of this invention is to provide an auxiliary wheel apparatus for vehicles. This apparatus includes a gear box (44), which is installed around the suspension arm (31) of a vehicle such that the auxiliary wheels are extended or retracted as desired. In the apparatus, a bolt rod (45), assembled with the gear box (44) and rotated by the torque of a motor (43), is connected to a movable plate (51). Two support columns (47, 49) extend at both sides of the bolt rod (45), and are connected to the plate (51) so as to be moved in a vertical direction in conjunction with the bolt rod (45). This apparatus allows a driver to easily park the vehicle in a limited parking area, turn the vehicle on a road having a short radius of curvature, and move the vehicle by a predetermined distance even when a tire is punctured.

Description

AUXILIARY WHEEL APPARATUS FOR VEHICLES

Technical Field

The present invention relates, in general, to an auxiliary wheel apparatus for a vehicle and, more particularly, to an auxiliary wheel apparatus for a vehicle, which is simply mounted to a suspension arm of a front or four wheel drive vehicle such that a gear box and a motor can be raised and lowered and an auxiliary wheel can be folded and unfolded and changed in its direction, thereby allowing a driver to easily park the vehicle in a limited parking area, turn the vehicle on a road of a narrow width and move the vehicle to a desired place distance when a tire is punctured.

Background Art

As the number of automobiles increases steadily, an insufficiency of parking space is looming large as a social problem. While dedicated parking buildings and solid parking facilities have been developed in an attempt to solve the parking problem, limitations necessarily exist in completely solving the parking problem. Due to this fact, parking-related disputes are ceaselessly provoked in most alleys or back streets.

The reason why the parking problem is not completely solved resides in that, on the one hand, numbers of parking spaces are basically insufficient when considering the number of automobiles and, on the other hand, the parking spaces are not efficiently utilized.

That is to say, if it were possible to decrease dead spaces existing between parked automobiles, the number of automobiles capable of being parked per unit area could be significantly increased. However, in actual fact, due to limitation of turning radius of automobiles, the automobiles cannot but be parked while leaving substantial spaces therebetween.

In the conventional art, in an effort to reduce the turning radius of automobiles, devices for minimizing a turning radius of the automobiles and allowing direction change to be effected with four wheels of the automobiles raised from the ground are disclosed in Japanese Patent Publication No. Sho42-21689 (published on October 25, 1967) and Sho44-30286 (published on December 6, 1969) and Korean Patent Publication No. 88-562 (published on April 15, 1988).

However, each of these conventional devices inherently suffers from disadvantages in that an undercarriage structure of the existing automobile must be modified and a heavy hydraulic mechanism and separate frame for supporting the mechanism are additionally needed, whereby a weight of the automobile is seriously increased.

Referring to Fig. 1, there is illustrated a conventional auxiliary wheel apparatus for a vehicle as disclosed in Korean Patent Publication No. 95-877

(published on February 3, 1995). The auxiliary wheel apparatus designated by the reference character A comprises a cylinder 11 having attaching means 10 which allows the cylinder 11 to be attached to a support bracket 3 by bolts, etc. A raising and lowering step motor 12 which is provided with a first reduction gear box 12a is fixedly installed at one side of the cylinder 11. A left and right turning step motor 13 which is provided with a second reduction gear box 13a is installed at the other side of the cylinder 11 so that it can be raised and lowered.

A piston 14 is disposed in the cylinder 11 to be extended from and retracted into the cylinder 11. The piston 14 is formed at a center portion thereof with an internal thread 14a. A lead screw 15 is threadedly coupled into the internal thread 14a so that it can be rotated in both directions. A lower end of the lead screw 15 is always held inserted into the internal thread 14a of the piston 14, and an upper end of the lead screw 15 projects out of an upper end of the cylinder 11 such that a first driven sprocket 16 can be fixed to the upper end of the lead screw 15. A first driving sprocket 12c is fixed to an output shaft 12b of the first reduction gear box 12a of the raising and lowering step motor 12, which output shaft 12b extends upward. The first driving and driven sprockets 12c and 16 are operatively connected with each other via a chain 17, such that forward and backward directional output power of the raising and lowering step motor 12 can be transferred to the lead screw 15.

The left and right turning step motor 13 provided to the other side of the cylinder 11 of the auxiliary wheel apparatus A is fixedly attached to a lower end of the piston 14, on which a bearing 18a is installed, to be raised and lowered integrally with the piston 14. An upper support element 19a is fastened to the lower end of the piston 14. The bearing 18a is intervened between the upper support element 19a and a lower support element 19b. A second driven sprocket

20 is fixed to an upper surface of the lower support element 19b. A locking bolt

21 passes through the lower support element 19b and is threadedly coupled into the lower end of the piston 14. The locking bolt 21 functions to separate the upper support element 19a and the second driven sprocket 20 fixed to the upper surface of the lower support element 19b from each other, allow the second driven sprocket 20 to be rotated, and bear a vertical load.

A first hinge piece is fastened adjacent to an edge of the lower support element 19b and a second hinge piece is fastened adjacent to an edge of a bracket

23 for shrouding an auxiliary wheel 22 which performs a direction-changing function. The first and second hinge pieces are coupled to each other by a hinge shaft 24. By this fact, when the bracket 23 is unfolded, an upper surface of the bracket 23 is brought into contact with a lower surface of the lower support element 19b, and when the bracket 23 is folded, the upper surface of the bracket 23 is held perpendicularly with respect to the lower surface of the lower support element 19b.

A second driving sprocket 13c is fastened to an output shaft 13b of the second reduction gear box 13a of the left and right turning step motor 13. The second driving and driven sprockets 13c and 20 are operatively connected with each other via a chain 17', such that forward and backward directional output power of the left and right turning step motor 13 can be transferred to the lower support element 19b and the bracket 23 positioned under the lower support element 19b to change a direction of the auxiliary wheel 22 leftward or rightward as desired. After the rotation of the auxiliary wheel 22 is effected, the auxiliary wheel 22 can be returned to its neutral position.

However, the conventional auxiliary wheel apparatus as described above, which is constructed to employ the existing power source of a front wheel drive vehicle and the conventional vehicle driving mechanism, encounters a problem in that a support bar should be separately mounted to rear wheels of the vehicle. Also, since the direction change can be effected with the auxiliary wheel brought into contact with the ground, the auxiliary wheel cannot be easily rotated, and therefore, the conventional auxiliary wheel apparatus has not been put to practical use so far.

In Korean Utility Model Application No. 2001-40799 filed on December 29, 2001 devised by several inventors including the present applicant, there is disclosed another auxiliary wheel apparatus for a vehicle, in which a motor is disposed in a trunk and supported by a suspension arm. Nevertheless, this apparatus still has a drawback in that an entire size of the apparatus is large, an available space of the trunk is reduced, and lots of labor and working hours are required to install the apparatus.

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an auxiliary wheel apparatus for a vehicle, which is simply mounted to a suspension arm of a front wheel drive vehicle such that a gear box can be raised and lowered and an auxiliary wheel can be folded and unfolded and changed in its direction, thereby allowing a driver to easily park the vehicle in a limited parking area, turn the vehicle on a road of a narrow width and move the vehicle to a desired place when a tire is punctured. In order to accomplish the above object, the present invention provides an auxiliary wheel apparatus for a vehicle, wherein an upper support plate and a lower support plate are fastened to upper and lower surfaces, respectively, of a suspension arm to increase load bearing capability of the suspension arm; a bolt element, which receives through a gear box rotation force of a first step motor, threadedly passes through a nut element which is fitted through the upper support plate, suspension arm and lower support plate, with first and second support rods also passing through the upper support plate, suspension arm and lower support plate; a raising and lowering plate is anchored to lower ends of the bolt element and first and second support rods to be integrally raised and lowered therewith; a locking section, which is threadedly locked to the lower end of the bolt element passing through the raising and lowering plate, has a pair of bolts which are inserted through a pair of holes defined adjacent to both ends of the locking section, a locker is maintained at a locking position by a pin which is biased by a pair of springs, and a locker releasing piece which is integrally formed with a release projection is attached to a lower surface of the lower support plate so that the locking position of the locker can be released only by the release projection; an auxiliary wheel fastening section has a hinge portion which is rotatably coupled to the locking section in a hinge groove defined at a side of the locking section, and is defined on a side surface thereof with a locking groove in which a locking projection of the locker can be engaged to permit a stable unfolded state of the auxiliary wheel fastening section; the locker is elastically biased by a return spring in a direction where the locking projection is engaged into the locking groove of the auxiliary wheel fastening section, such that unintentional rotation and unlocking of the locker are prevented by the pin to allow the auxiliary wheel fastening section to be stably held in a vertically unfolded state; a second step motor is installed on a rear surface of the auxiliary wheel fastening section such that a worm wheel, which is integrally formed on a center portion of an auxiliary wheel section operatively connected to the second step motor through gear meshing, can change a direction of an auxiliary wheel leftward or rightward as desired; and a hinge pin is rotatably installed on a front surface of the auxiliary wheel fastening section such that the hinge pin is connected to a shaft of a third step motor through a pair of links to receive rotation force of the third step motor to thereby fold and unfold the auxiliary wheel fastening section. By the features of the present invention, an auxiliary wheel is unfolded by a third step motor, direction change of the auxiliary wheel is effected by a second step motor, and a first step motor is operated to lower the auxiliary wheel and raise rear wheels of the vehicle from the ground. Consequently, as the vehicle can be moved in a direction-changed state, a vehicle turning radius is minimized. Further, because it is possible to move the vehicle in a substantially diagonal direction, a driver can easily park the vehicle in a limited parking area, and the vehicle can get out of a parking area in a rapid and convenient manner to improve parking-space utilization efficiency.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a front view illustrating the conventional auxiliary wheel apparatus for a vehicle; Fig. 2 is a front view illustrating an auxiliary wheel apparatus for a vehicle in accordance with an embodiment of the present invention;

Fig. 3 is an exploded perspective view illustrating an entire construction of the auxiliary wheel apparatus according to the present invention;

Fig. 4 is a sectional view independently illustrating a locker of a locking section in the auxiliary wheel apparatus according to the present invention;

Fig. 5 is a sectional view illustrating an inner structure of a gear box in the auxiliary wheel apparatus according to the present invention;

Fig. 6 is a perspective view illustrating an auxiliary wheel fastening section and an auxiliary wheel section in the auxiliary wheel apparatus according to the present invention;

Fig. 7 is a block diagram for explaining operations of the auxiliary wheel apparatus according to the present invention; and

Figs. 8a through 8d are plan views illustrating in-use statuses of the auxiliary wheel apparatus according to the present invention.

Best Mode for Carrying Out the Invention

Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

Fig. 2 is a front view illustrating an auxiliary wheel apparatus for a vehicle in accordance with an embodiment of the present invention, Fig. 3 is an exploded perspective view illustrating an entire construction of the auxiliary wheel apparatus according to the present invention, and Fig. 4 is a sectional view independently illustrating a locker of a locking section in the auxiliary wheel apparatus according to the present invention.

In the auxiliary wheel apparatus according to the present invention, an upper support plate 35 is defined at a center and both sides thereof with through- holes 36, 37 and 38, and a lower support plate 39 is defined at a center and both sides thereof with through-holes 40, 41 and 42. A suspension arm 31 is defined at a center and both sides thereof with through-holes 32, 33 and 34. The upper and lower support plates 35 and 39 are fastened to upper and lower surfaces, respectively, of the suspension arm 31 to increase load-bearing capability of the suspension arm 31. A nut element 46 is fitted into the through-holes defined at the centers of the upper support plate 35, suspension arm 31 and lower support plate 39. A bolt element 45 threadedly passes through the nut element 46 to be moved in upward and downward directions through the nut element 46. The bolt element 45 receives through a gear box 44 rotation force of a first step motor 43.

Each of first and second support rods 47 and 49 is anchored at an upper end thereof to a lower surface of the gear box 44 at both sides of the bolt element 45, such that the first and second support rods 47 and 49 can be raised and lowered integrally with the gear box 44. The first and second support rods 47 and 49 pass through a pair of bushings 48 and 50, respectively, which are fitted into the through-holes defined at both sides of the upper support plate 35, suspension arm 31 and lower support plate 39. Lower ends of the bolt element 45 and first and second support rods 47 and 49 pass through the lower support plate 39 and are anchored to a raising and lowering plate 51 to be moved in upward and downward directions integrally with the raising and lowering plate 51.

A locking section 52 is coupled to a lower surface of the raising and lowering plate 51 and is threadedly locked to the lower end of the bolt element 45. The locking section 52 has a pair of bolts 54 and 56 which are inserted through a pair of holes 58 and 59 defined adjacent to both ends of the locking section 52. A locker 60 is maintained at a locking position by a pin 57 which is biased by a pair of springs 53 and 55. A locker releasing piece 62, which is integrally formed with a release projection 63, is attached to a lower surface of the lower support plate 39 so that the locking position of the locker 60 can be released only by the locker releasing piece 62.

The raising and lowering plate 51 is defined with a pair of rectangular holes 51a and 51b in a manner such that the locker releasing piece 62 attached to the lower support plate 39 can pass through the rectangular holes 51a and 51b. By this fact, even when an obstacle exists below the vehicle, it is possible to secure a space in which an auxiliary wheel fastening section 66 can be rotated. The auxiliary wheel fastening section 66 has a hinge portion 65. The hinge portion 65 is rotatably coupled to the locking section 52 in a hinge groove 64 which is defined at a side of the locking section 52. The auxiliary wheel fastening section 66 is defined on one side surface thereof with a locking groove 67 in which a locking projection 61 of the locker 60 can be engaged to permit the auxiliary wheel fastening section 66 to be stably maintained at an unfolded state.

The locker 60 is elastically biased by a return spring (not shown), in a direction where the locking projection 61 is engaged into the locking groove 67 of the auxiliary wheel fastening section 66, such that unintentional rotation and unlocking of the locker 60 are prevented by the pin 57 to allow the auxiliary wheel fastening section 66 to be stably maintained at the vertically unfolded state. A folding sensor 68 is provided on the other side surface of the auxiliary wheel fastening section 66, and a folding signal receiver 69 is provided on the lower surface of the raising and lowering plate 51, in a manner such that a completely folded state of the auxiliary wheel fastening section 66 can be perceived through cooperation of the folding sensor 68 with the folding signal receiver 69. An unfolding sensor 60 is provided on an upper surface of the auxiliary wheel fastening section 66, and an unfolding signal receiver (not shown) is provided on a lower surface of the locking section 52, in a manner such that a completely unfolded state of the auxiliary wheel fastening section 66 can be perceived through cooperation of the unfolding sensor 60 with the unfolding signal receiver.

A second step motor 72 is installed on a rear surface of the auxiliary wheel fastening section 66 such that a worm wheel 74, which is provided on a center portion of an auxiliary wheel section 73 operatively connected to the second step motor 72 through gear meshing, can change a direction of an auxiliary wheel 75 leftward or rightward as desired. A rotation signal receiver (not shown) is provided on the lower surface of the auxiliary wheel fastening section 66. First through third rotation sensors 76, 77 and 78 are provided adjacent to left, front and right edges on an upper surface of the auxiliary wheel section 73 to which the auxiliary wheel 75 is coupled, in a manner such that the first and second rotation sensors 76 and 77 define an angle of 30° when measured between one line connecting the first and second rotation sensors 76 and 77 and the other line connecting the second rotation sensor 77 and a center of the auxiliary wheel section 73, and the second and third rotation sensors 77 and 78 define an angle of 30° when measured between one line connecting the second and third rotation sensors 77 and 78 and the other line connecting the second rotation sensor 77 and the center of the auxiliary wheel section 73. Therefore, by cooperation between the first through third sensors and the rotation signal receiver, it is possible to control a rotation angle of the auxiliary wheel section 73. A hinge pin 79 is rotatably fixed on a front surface of the auxiliary wheel fastening section 66 such that the hinge pin 79 is connected to a shaft 83 of a third step motor 82 through a pair of links 80 and 81 to receive rotation force of the third step motor 82 to thereby fold and unfold the auxiliary wheel fastening section 66.

Fig. 5 is a sectional view illustrating an inner structure of the gear box in the auxiliary wheel apparatus according to the present invention. A shaft 101 which is rotated by rotation force of the first step motor 43 is supported by a pair of bearings 102 and 103 in the gear box 44. Output power of the shaft 101 is increased by a planetary gear 104 and rotates a gear 105. Rotation force is transferred through a gear 106 meshed with the gear 105 to a rotation shaft 107. The rotation shaft 107 is rotated while being supported by a pair of bearings 108 and 109, to thereby rotate a worm wheel 110. A worm gear 111 which is rotatably meshed with the worm wheel 110 is defined with a shaft hole 112. An upper end of the bolt element 45 is fitted into the shaft hole 1 12 to be integrally rotated therewith. By this, noise generation is prevented while the bolt element 45 is rotated.

Fig. 6 is a perspective view illustrating an auxiliary wheel fastening section and an auxiliary wheel section in the auxiliary wheel apparatus according to the present invention. The second step motor 72 is installed on the rear surface of the auxiliary wheel fastening section 66 in a manner such that rotation force is transmitted through a second gear 115 which is meshed with a first gear 1 14 coupled to a shaft 1 13. A worm 1 16, which is provided on a shaft of the second gear 115, is meshed with the worm wheel 74 which is provided on the upper surface of the auxiliary wheel section 73, in a manner such that an angle of the auxiliary wheel 75 is not changed once being determined. An inner surface of the worm wheel 74 of the auxiliary wheel section 73 is integrally formed with an internal thread 117 such that a bolt 119, which extends through an insertion hole

118 defined at a center portion of the auxiliary wheel fastening section 66, can be threadedly coupled into the internal thread 117.

Fig. 7 is a block diagram for explaining operations of the auxiliary wheel apparatus according to the present invention. In a state wherein a driver shifts gears to a first stage gear or a reverse gear, if a left turn key 120, a straight drive key 121 or a right turn key 122 is switched on in order to park the vehicle while moving the vehicle leftward, rightward or straight forward, a first motor driving unit 124 for driving the first step motor 43 is operated under the control of a main controller 123 which receives power from the outside, to lower the bolt element 45 and thereby raise the rear wheels of the vehicle. If the main controller 123, which precisely perceives a rotated state of the auxiliary wheel 75 by the rotation signal receiver 125 and the sensors 76, 77 and 78, controls a second motor driving unit 126 for driving the second step motor 72, the auxiliary wheel section 73 is rotated leftward or rightward or moved straight forward. If the main controller 123, which perceives an unfolded or a folded state of the auxiliary wheel fastening section 66 through the folding signal receiver 69 and the unfolding signal receiver 127, operates a third motor driving unit 128 for driving the third step motor 82, the auxiliary wheel fastening section 66 is folded or unfolded while being hingedly coupled to the locking section 52. If a return key 129 is switched on, under the control of the main controller 123 which perceives the corresponding state, the first through third motor driving units 124, 126 and 128 are returned to their initial positions to allow the vehicle to travel on the road.

In the auxiliary wheel apparatus for a vehicle according to the present invention, constructed as mentioned above, when it is necessary to park the front wheel drive vehicle or move the parked vehicle to the road while changing a direction of the vehicle leftward or rightward, the left turn key 120 or the right turn key 122 is switched on. In this state, since the auxiliary wheel fastening section 66 is held folded, the auxiliary wheel fastening section 66 is vertically unfolded by the third step motor 82, the auxiliary wheel section 73 is rotated leftward or rightward as desired through an angle of 30° by the second step motor 72, and then the bolt element 45 and the raising and lowering plate 51 are lowered by the first step motor 31 to raise a rear part of the vehicle from the ground, whereby it is possible to abruptly change a direction of the vehicle. Hereafter, as an example, the case in which the vehicle is rotated leftward to be parked will be described in detail.

If the left turn key 120 is switched on, as the main controller 123 operates the third motor driving section 128 to drive the third step motor 82, the auxiliary wheel fastening section 66, which is held folded, receives power through the pair of links 80 and 81 connected to the shaft 83 of the third step motor 82. Then, while being hingedly coupled to the locking section 52, the auxiliary wheel fastening section 66 is rotated to be unfolded. As the unfolding signal receiver 127 receives a signal transmitted from the unfolding sensor 70 which is provided on the upper surface of the auxiliary wheel fastening section 66, to perceive a completely unfolded state of the auxiliary wheel fastening section 66, operation of the third step motor 82 is interrupted.

In this state, the locking projection 61 of the locker 60 is engaged into the locking groove 67 of the auxiliary wheel fastening section 66, and the locker 60 is maintained at the locking position by the pin 57 which is elastically biased by the pair of springs 53 and 55.

If the auxiliary wheel fastening section 66 is vertically unfolded, the main controller 123 outputs a control signal to the second motor driving section 126 for driving the second step motor 72. Then, as the second step motor 72 is rotated forward, the worm wheel 74 which is integrally formed at the center portion of the auxiliary wheel section 73 is also rotated forward through the first and second gears 1 14 and 115 and the worm 1 16, whereby the auxiliary wheel 75 is rotated leftward by 30°. If a signal outputted from the first sensor 76, which is provided to be deviated leftward at an angle of 30° from the center portion of the upper surface of the auxiliary wheel section 73, is received by the rotation signal receiver

125, which is provided on the lower surface of the auxiliary wheel fastening section 66, operation of the second step motor 72 is interrupted through the second motor driving unit 126.

Next, as a control signal is outputted to the first motor driving unit 124, rotation force of the first step motor 43 is transferred to the bolt element 45 through the gear box 44. Then, the bolt element 45 is rotated forward such that the bolt element 45 is screwed into the nut element 46 of the suspension arm 41. At this time, due to the fact that the nut element 46 is fixedly maintained, the bolt element 45 is move downward along with the gear box 44 and the first step motor 43.

In the gear box 44, the shaft 101, which is rotated by the rotation force of the first step motor 43, is supported by the pair of bearings 102 and 103 and increased in its output power by the planetary gear 104, and rotates the gear 105. The rotation shaft 107, which receives the rotation force through the gear 106 meshed with the gear 105 and is supported by the pair of bearings 108 and 109, is rotated to rotate the worm wheel 1 10. Due to the fact that the upper end of the bolt element 45 is screwed through the shaft hole 112 of the worm gear 111 which is rotatably meshed with the worm wheel 110, to be integrally rotated therewith, noise generation is prevented while the bolt element 45 is rotated. At the same time, the first and second support rods 47 and 49, which are positioned leftward and rightward of the bolt element 45, respectively, are also moved downward integrally with the bolt element 45 in a state wherein they pass through the upper support plate 35, the suspension arm 31 and the lower support plate 39, whereby upward and downward movements of the bolt element 45 can be stably implemented.

As the raising and lowering plate 51, to which the lower ends of the bolt element 45 and the first and second support rods 47 and 49 are anchored, is also integrally moved downward, the locking section 52 which is coupled to the lower surface of the raising and lowering plate 51 is moved downward. If the locking section 52 is moved downward, the auxiliary wheel fastening section 66 having the hinge portion 65, which is hingedly coupled into the hinge groove 64 of the locking section 52, is also integrally moved downward. At this time, since the auxiliary wheel fastening section 66 is held vertically unfolded, as the auxiliary wheel 75 is brought into contact with the ground, the rear part of the vehicle is raised from the ground.

Therefore, with two front wheels and the auxiliary wheel 75 brought into contact with the ground, power is transferred to the front wheels. Consequently, it is possible to implement abrupt leftward rotation using the auxiliary wheel 75. The auxiliary wheel 75 allows the vehicle to be parked or driven.

After desired movement of the vehicle is completed, if the return key 129 is manipulated by the driver, the main controller 123 outputs a control signal to the first motor driving unit 124 to operate the first step motor 43 of the auxiliary wheel fastening section 66 in a backward direction. By this, the bolt element 45 is reversely rotated and moved upward along with the first and second support rods

47 and 49. Thus, as the raising and lowering plate 51 to which the bolt element 45 and the first and second support rods 47 and 49 are anchored is integrally moved upward, the locking section 52 which is coupled to the lower surface of the raising and lowering plate 51 is also moved upward. While the raising and lowering plate 51 and the locking section 52 are moved upward, in a state wherein the locker 60 of the locking section 52 coupled to the lower surface of the raising and lowering plate 51 is prevented from being returned to its original position by the pin 57 elastically biased by the pair of springs 53 and 55, the release projection 63 of the locker releasing piece 62 which is coupled to the lower surface of the lower support plate 39 pushes the locker 60 downward. Then, as the raising and lowering plate 51 and the locking section 52 are further moved upward, the locker 60 is forced to be rotated by a lower surface of the locker releasing piece 62, whereby the locking projection 61 of the locker 60 is disengaged from the locking groove 67 of the auxiliary wheel fastening section 66.

While releasing the locking state of the locker 62, when the raising and lowering plate 51 reaches its uppermost position, the main controller 123 interrupts the operation of the first step motor 43. Thereupon, the main controller 123 drives, through the second motor driving unit 126, the second step motor 72 which is installed on the rear surface of the auxiliary wheel fastening section 66. By this, as the worm wheel 74, which is provided at the center portion of the auxiliary wheel section 73 connected to the second step motor 72 through gear meshing, is rotated, the auxiliary wheel 75 is returned to its neutral position. As the rotation signal receiver 125 which is provided on the lower surface of the auxiliary wheel fastening section 66 receives a signal outputted from the second sensor 78 which is provided on the upper surface of the auxiliary wheel section 73, the main controller 123 perceives a complete rotation of the auxiliary wheel section 73 toward the neutral position. Then, the main controller 123 interrupts operation of the second step motor 72 through the second motor driving unit 126, to hold the auxiliary wheel section 73 in the neutral position.

Thereafter, as the main controller 123 operates the third step motor 82 through the third motor driving unit 128 such that the third step motor 82 is rotated in the reverse direction, the auxiliary wheel fastening section 66 is rotated by the rotation force transferred through the pair of links 80 and 81 from the shaft 81 of the third step motor 82. That is to say, the auxiliary wheel fastening section 66, which is unlocked by engagement of the locker 60 with the locker releasing piece 62, is rotated in a counterclockwise direction to be completely folded. If the folding signal receiver 69 which is provided on the lower surface of the raising and lowering plate 51 receives a signal outputted from the folding sensor 68 which is provided on the other side surface of the auxiliary wheel fastening section 66, the main controller 123 perceives a complete folding state of the auxiliary wheel fastening section 66 and then interrupts the operation of the third step motor 82, to thereby allow the auxiliary wheel apparatus to be returned to its initial position.

Hereinbelow, comparison between the vehicle having installed thereon the auxiliary wheel apparatus according to the present invention and the conventional vehicle will be made with reference to Figs. 8a, 8b, 8c and 8d. Fig. 8a illustrates a difference of rotation radius. It is to be noted that the conventional vehicle B is rotated with a large rotation radius whereas the vehicle A equipped with the auxiliary wheel apparatus of the present invention is rotated with a small rotation radius.

Fig. 8b illustrates vehicles which are parked to face a forward direction. It is to be noted that the conventional vehicle B must implement several forward and backward movements whereas the present vehicle A can be parked through a single movement due to the small rotation radius.

Fig. 8c illustrates states wherein vehicles are parked between two vehicles arranged in line along their lengthwise direction. In the case of the conventional vehicles Bl and B2, since they are slowly curved forward or backward, a sufficient parking space must be secured whereas in the case of the present vehicle A equipped with the auxiliary wheel apparatus, since it can be abruptly moved between two adjoining vehicles, it is possible to park the present vehicle in a limited parking area. Referring to Fig. 8d, it is to be readily understood that the present vehicle equipped with the auxiliary wheel apparatus can be moved in a diagonal direction while being held directed forward as it was parked.

While the auxiliary wheel apparatus of the present invention can be effectively used upon parking the vehicle, it is to be readily understood that the auxiliary wheel apparatus allows a driver to change a direction of the vehicle in a limited area and move the vehicle to a desired place when a tire is punctured.

Industrial Applicability

As apparent from the above description, the auxiliary wheel apparatus according to the present invention is installed on a suspension arm of a front or four wheel drive vehicle, in a manner such that an auxiliary wheel is unfolded by a third step motor, direction change of the auxiliary wheel is effected by a second step motor, and a first step motor is operated to lower the auxiliary wheel and raise rear wheels of the vehicle from the ground. Consequently, as the vehicle can be moved in a direction-changed state, a vehicle turning radius is minimized.

Further, because it is possible to move the vehicle in a substantially diagonal direction, a driver can easily park the vehicle in a limited parking area, and the vehicle can get out of a parking area in a rapid and convenient manner.

Although the preferred embodiments of the present invention have been disclosed 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.

Claims

1. An auxiliary wheel apparatus for a vehicle, wherein: an upper support plate which is defined at a center and both sides thereof with through-holes and a lower support plate which is defined at a center and both sides thereof with through-holes are fastened to upper and lower surfaces, respectively, of a suspension arm which is defined at a center and both sides thereof with through-holes; a bolt element, which receives through a gear box rotation force of a first step motor, threadedly passes through a nut element which is fitted into the through-holes defined at the centers of the upper support plate, suspension arm and lower support plate to be moved in upward and downward directions; first and second support rods, each of which is anchored at an upper end thereof to a lower end surface of the gear box at both sides of the bolt element, pass through a pair of bushings, respectively, which are fitted into the through- holes defined at both sides of the upper support plate, suspension arm and lower support plate; lower ends of the bolt element and first and second support rods pass through the lower support plate and are anchored to a raising and lowering plate; a locking section, which is threadedly locked to the lower end of the bolt element on a lower surface of the raising and lowering plate, has a pair of bolts which are inserted through a pair of holes defined adjacent to both ends of the locking section, with a locker maintained at a locking position by a pin which is biased by a pair of springs, and a locker releasing piece integrally formed with a release projection and attached to a lower surface of the lower support plate so that it can release the locking position of the locker; an auxiliary wheel fastening section has a hinge portion which is rotatably coupled to the locking section in a hinge groove defined at a side of the locking section, and is defined on a side surface thereof with a locking groove in which a locking projection of the locker can be engaged; the locker is elastically biased by a return spring in a direction where the locking projection is engaged into the locking groove of the auxiliary wheel fastening section; a second step motor is installed on a rear surface of the auxiliary wheel fastening section such that a worm wheel, which is integrally formed on a center portion of an auxiliary wheel section and is rotated by rotation force transmitted through first and second gears and a worm, can change a direction of an auxiliary wheel leftward or rightward as desired; and a hinge pin is rotatably installed on a front surface of the auxiliary wheel fastening section such that the hinge pin is connected to a shaft of a third step motor through a pair of links to receive rotation force of the third step motor to thereby fold and unfold the auxiliary wheel fastening section.