GB2385839A

GB2385839A - Steering arrangement for an electric vehicle

Info

Publication number: GB2385839A
Application number: GB0302923A
Authority: GB
Inventors: Kunihiro Hayashi
Original assignee: Suzuki Motor Corp
Current assignee: Suzuki Motor Corp
Priority date: 2002-02-27
Filing date: 2003-02-10
Publication date: 2003-09-03
Anticipated expiration: 2023-02-10
Also published as: JP3960077B2; JP2003245311A; TW200303189A; TWI282733B; GB0302923D0; GB2385839B

Abstract

A single-seat electric vehicle, e.g. for use by the handicapped or elderly, has driven rear wheels and steerable front wheels 1. Steering is by rotation of a steering shaft 501 by a handle 505, the steering shaft being rotatably supported by a steering frame 102a-102d which is detachably connected to frame members of the vehicle. The bottom of steering shaft 501 is geared to a countershaft 508, attached to a to a tie rod arm 509, rotating this in the opposite direction to that of shaft 501 to steer the wheels 1 through tie rods 511. The steering shaft 501 incorporates a universal joint to allow the handle 505 to incline towards the rider.

Description

SMALL ELECTRIC VEHICLE The present invention relates to four-wheel small electric vehicles, in particular, for the use of aged persons and persons handicapped in leg.

Small electric vehicles of this kind are called senior cars (R) for example, which are very useful as means of locomotion for aged persons and so on. In the basic construction of such a small electric vehicle, a seat is disposed in a rear portion of the vehicle body for a rider to sit on the seat. A floor is disposed in front of the seat for the rider to put his or her feet on the floor. A steering shaft stands in front of the floor for the rider to operate front wheels. A handle is attached to the upper end of the steering shaft. The rider who is sitting on the seat manipulates the handle.

In recent years, the market of senior car type small electric vehicles has broadened and they are getting used in various applications. Conventionally, such a small electric vehicle was bought and used in case that the receiving space had a relatively wide margin. It is, however, expected that the demand in cities may increase in future with an increase in the aged population. In cities, such a receiving space is apt to be limited. Besides, occasions of entering conveyances such as elevators may increase.

If such a small electric vehicle has its whole length of the upper limit according to a conventional dimensional standard, the vehicle cannot enter an elevator. If the whole length is simply shortened as a countermeasure, problems may arise. In the basic construction of a recent senior car, the steering shaft is disposed in line with the shaft of the handle. Thus, if the whole length of the vehicle is shortened without changing that feature, the distance between the rider and the handle is too narrow. Otherwise, a sufficient space must be ensured by shifting the seat backward accordingly. If the seat is shifted backward and no measure is taken, it may harm the static stability of the rear portion of the vehicle.

The static stability of the vehicle will be additionally discussed. In the vehicle of this kind, to reduce the size, a power unit with an electric motor, a battery for supplying power to the power unit, and further the rider seat are disposed around rear wheels as drive wheels, while only a steering system is disposed around the front wheels. Thus, the vehicle has a construction in which the load on the front wheels is heavier. If no

measure is taken, it is a construction disadvantageous in stability against backward overturn around the rear wheel shaft.

Besides, the conventional steering system extends almost linearly in the upper rear direction in order to improve the feeling of handle manipulation. In case of this construction, however, even if the floor for foot rest of the rider has the same area, the space for the rider's legs is narrowed in accordance with the inclination of the steering shaft.

Besides, the conventional four-wheel senior car type small electric vehicle includes supporting members for supporting the steering shaft for steering the front wheels and the handle shaft attached in an extension of the steering shaft. These are made of pipe materials, shaft holders, or the like, and the height of them is held relatively low.

Recently in many cases, a cowling (leg shield) is attached around the handle, and braces or the like are required for attaching the cowling. Because of manufacture or a figure to an assembling factory, it is no good that such braces are constructed integrally, so they are formed separately in general.

An object of the present invention is to provide a small electric vehicle particularly in which an effective space is ensured with intending to be substantially compact and which has a construction advantageous on manufacture and assembling.

The present invention provides a small electric vehicle according to comprising a floor laid on a vehicle frame in a lower front portion of a single seat supported on the vehicle frame ; left and right front wheels in a pair provided in front of the floor as steering control wheels swingable or pivotable in left and right directions in accordance with handle manipulation, and left and right rear wheels in a pair provided in a lower rear portion of the single seat as drive wheels driven by a power unit, for the vehicle to run with the front and rear wheels; and a battery unit for supplying electric power to the power unit, wherein the vehicle further comprises a steering system in which a steering shaft supporting at its upper end a handle so as to be rotatable in the left and right directions and protruding upward from a front end portion of the floor, and a front-wheel steering knuckle supported in an outer end portion of a suspension arm extending outward in the left and right directions through

a king pin so as to be swingable in the left and right directions, are connected with each other through a tie rod arm and a knuckle arm, and the steering system is disposed in a front end portion of the vehicle frame extending in the front and rear directions of the vehicle under the floor, and a steering frame for supporting the steering shaft so as to be freely rotatable is attached to the vehicle frame so as to be detachable.

Preferably in the vehicle according to the present invention, the floor comprises a main floor portion positioned rearward of the front wheels and having substantially the same width as the interval between the left and right front wheels, and a front floor portion having a width narrower than the interval between the left and right front wheels and narrower than the main floor portion and extending in front of the main floor portion, and the vehicle frame comprises a centre frame portion having substantially the same width as the inside interval between the left and right front wheels and extending in the front and rear directions along both of left and right edge portions of the main floor portion to form the main floor portion, front frame portions extending in front of the centre frame portion at an interval smaller than the interval between the left and right front wheels, supporting the front wheels and the steering system for steering the front wheels, and forming the front floor portion, and a rear frame extending rearward from the centre frame portion and supporting the single seat, the power unit, and the rear wheels.

Preferably in the vehicle according to the present invention, the centre frame portion, the front frame portions, and the rear frame are made of left and right main frame members in a pair, and the vehicle comprises a side carrying handle protruding outward from the centre frame portion on a side face of the main frame portion, and a rear carrying handle protruding rearward of the single seat, interconnecting rear end portions of the left and right main frame members in a pair.

Preferably in the vehicle according to the present invention, the steering shaft is divided into upper and lower half portions substantially in the middle of an upper end portion with which the handle is connected and a lower portion with which the tie rod arm is connected, the upper and lower half portions are interconnected by joint means

freely bendable, the lower half portion stands substantially vertically, and the upper end portion inclines rearward toward the single seat.

Preferably in the vehicle according to the present invention, the steering frame is bent to incline rearward in the vicinity of the joint means, protrudes upward from the front frame portion in the same width, and is attached so as to be detachable.

Preferably in the vehicle according to the present invention, the steering frame is attached to the vehicle frame by a cramp device so as to be detachable.

By constructing the vehicle frame and the steering frame separably, the figure can be small and compact. Thus, the handling can be improved and the assembling efficiency can be improved. Besides, by bending a portion around the steering shaft, the floor space is enlarged and a utility space around feet can be ensured. Besides, the weight centre of the vehicle is not deviated rearward of the vehicle and it can be set at an adequate position, so the static stability of the vehicle is improved.

Further features and advantages of the present invention will become apparent upon a perusal of the appended claims to which the reader is referred, and upon a consideration of the following more detailed description of an embodiment of the invention made with reference to the accompanying drawings, in which: FIG. 1 is a perspective front view illustrating a basic construction of a small electric vehicle according to an embodiment of the present invention; FIG. 2 is a perspective rear view illustrating the basic construction of the small electric vehicle according to the embodiment of the present invention; FIG. 3 is a side view illustrating the basic construction of the small electric vehicle according to the embodiment of the present invention; FIG. 4 is a plane view illustrating the basic construction of the small electric vehicle according to the embodiment of the present invention; FIG. 5 is a front view illustrating the basic construction of the small electric vehicle according to the embodiment of the present invention; FIG. 6 is a perspective view illustrating the vicinity of a frame unit and a battery unit of the small electric vehicle according to the embodiment of the present invention;

FIG. 7 is a side view illustrating the vicinity of the frame unit of the small electric vehicle according to the embodiment of the present invention; FIG. 8 is a plane view illustrating the vicinity of the frame unit of the small electric vehicle according to the embodiment of the present invention; FIG. 9 is a perspective view illustrating the vicinity of a front-wheel supporting mechanism of the small electric vehicle according to the embodiment of the present invention; FIG. 10 is a perspective view illustrating the vicinity of a rotating mechanism for a single seat of the small electric vehicle according to the embodiment of the present invention; FIG. 11 is a perspective view illustrating the battery unit of the small electric vehicle according to the embodiment of the present invention; FIG. 12 is an exploded perspective view illustrating the battery unit of the small electric vehicle according to the embodiment of the present invention; FIG. 13 is a side view illustrating the battery unit of the small electric vehicle according to the embodiment of the present invention; FIG. 14 is a perspective view illustrating the vicinity of a vehicle frame and a steering frame of the small electric vehicle according to the embodiment of the present invention; FIGS. 15A and 15B are front and side views illustrating the steering frame of the small electric vehicle according to the embodiment of the present invention; FIG. 16 is a perspective view illustrating the steering frame and a cramp unit of the small electric vehicle according to the embodiment of the present invention; and FIG. 17 is a side view illustrating the vicinity of the steering shaft and the steering frame of the small electric vehicle according to the embodiment of the present invention.

FIGS. 1 to 5 illustrate the whole construction of the small electric vehicle according to this embodiment. Referring to these drawings, left and right front wheels 1 in a pair and left and right rear wheels 2 in a pair are supported by front and rear portions of a frame unit 100 including a vehicle frame, respectively. The front wheels 1 are supported by a front-wheel supporting mechanism 200. The rear wheels 2 are supported by a rear-wheel supporting mechanism 300. On the rear side of the frame

unit 100, a seat unit 400 forming a single seat for one rider sitting on is supported. In lower front of the single seat, a floor panel 3 forming a low foot-rest floor laid on the vehicle frame is provided. In a front portion of the frame unit 100, a steering mechanism 500 for steering the front wheels 1, which are steering control wheels to swing laterally in accordance with handle manipulation, is provided.

In this example, the rear wheels 2 are drive wheels, which are driven by a power unit 600 including an electric motor provided in a lower rear portion of the single seat. In the present invention, on the lower side of the floor panel 3, a battery unit 700 provided with secondary batteries for supplying electric power to the power unit 600 is disposed.

Also referring to FIGS. 6 to 8, the frame unit 100 is made up of the vehicle frame 101 constructing a chassis portion and a steering frame 102 for supporting a steering handle and so on. The vehicle frame 101 includes a main frame 103 and a rear frame 104. The main frame 103 is made up of a centre frame portion 105 and a front frame portion 106 extending in front of the centre frame portion 105.

The main frame 103 includes a pair of main frame members 107 disposed in the front and rear directions on both of the left and right sides. The main frame members 107 have a shape which is so shrank that the tip is narrowed, in the vicinity of the border between the centre and front frame portions 105 and 106, as illustrated in FIG. 8 and so on. Each main frame member 107 is suitably made of a rectangular pipe material though it is not limitative. For example, it may be made of a C-channel material, a circular pipe material, or the like. In any case, the main frame member 107 has a certain height (vertical thickness). To each main frame member 107, a carrying handle 111 laterally protruding outward and made of, for example, a circular pipe material is added.

In this example, in the main frame members 107, three bridge members 108,109, and 110 are laterally suspended at the front end portion, in the vicinity of the border of the centre and front frame portions 105 and 106, and the rear end portion, respectively. A high rigidity of the main frame 103 is ensured thereby. As illustrated in FIG. 7, the bridge members 108 and 109 are curved so as to protrude downward. A base member

of the front-wheel supporting mechanism as described later is disposed on the bridge members 108 and 109. In an actual vehicle, as illustrated in FIG. 7, the main frame 103 is in a state that it is properly inclined in a front-up manner. At this time, the base member of the front-wheel supporting mechanism is supported in a front-up inclination state so that a rotation axis of a suspension arm as described later is perpendicular to the rear inclination angle (caster angle) of a king pin.

Also as illustrated in FIG. 9, the steering frame 102 is constructed in the manner that four pipe materials 102a to 102d are integrally supported to stand inside of the front end portion of the front frame portion 106. The steering frame 102 stands vertically from the front frame portion 106 (main frame member 107). As described above, since the main frame 103 inclines in a front-up manner, the steering frame 102 is properly inclined to the single seat side. The steering frame 102 is suitably made of a rectangular pipe material.

The rear frame 104 is disposed to incline in an upper rear direction from the vicinity of the rear end portion of each main frame member 107. The rear frames 104 are interconnected by the carrying handle 112 at their respective rear end portions. In the middle in the front and rear directions of the rear frame 104, a bridge member 113 of a nearly arch or trapezoid shape is laterally suspended. To the upper portion of the bridge member 113, a seat post 114 is attached for supporting the seat unit 400. Each of the rear frame 104 and the bridge member 113 is suitably made of a rectangular pipe material though it is not limitative. For example, it may be made of a C-channel material, a circular pipe material, or the like. At the rear end portion of the rear frame 104, a bridge member 115 is laterally suspended that is formed in a curved shape to protrude downward.

The front-wheel supporting mechanism 200 supports the front wheels 1 so as to be freely rotatable and swingable. The front-wheel supporting mechanism 200 includes a base member 201 as a supporting portion held below the front frame portion 106, a

suspension arm bracket 202 fixed on the base member 201, and a suspension arm 203 supported by a suspension arm bracket 202 so as to be freely swingable vertically. The suspension arm 203 extends outward from the centre portion in the left and right

directions of the vehicle and the outer end portion thereof supports the front wheels 1 so as to be freely rotatable.

Mainly by this front-wheel supporting mechanism 200, a protrusion structure is formed that is made of a rigid member extending in the left and right directions between the interval of the left and right front wheels 1 in front of a battery case as described later, and protruding under the battery case. As illustrated in FIGS. 1 to 5, FIG. 7, and so on, the protrusion structure is made up of the base member 201, suspension arm bracket 202, suspension arm 203, and so on, disposed to protrude under the front frame portion 106. By the provision of such a protrusion structure in front of and under the battery case, barrier or protective means is constructed for the battery case that has an important function as a power unit for the vehicle. The delicate power unit can effectively be protected thereby. Even though the vehicle has such a protrusion structure protruding under the front frame portion 106, since the floor 3 is inclined in a front-up manner in the actual vehicle (see FIG. 7), the protrusion structure does not so protrude downward. Thus, the ground clearance of undercarriage can effectively be ensured.

Also referring to FIG. 9, in the front-wheel supporting mechanism 200, on the base member 201 disposed on the bridge members of the main frame 103, two front and rear suspension arm brackets 202 are provided for the respective left and right suspension arms 203. Each suspension arm 203 has a fork shape branching in the front and rear directions. Two branched base ends (inner ends) are pivoted by the two front and rear suspension arm brackets 202 so as to be freely rotatable vertically. At the tip end of the suspension arm 203, a U-shaped knuckle 204 (front-wheel steering knuckle) is pivoted through a king pin 208 so as to be freely rotatable in the left and right directions. To the knuckle 204, a wheel shaft 205 extending horizontally is attached. The front wheels 1 are supported by the wheel shaft 205 so as to be freely rotatable.

To the outer side of the front frame portion 106, a bracket 207 is fixed for suspending a suspension spring 206. The suspension spring 206 is fitted between the bracket 207 and the suspension arm 203 (the front side of the branched fork shape).

The rear-wheel supporting mechanism 300 supports the rear wheels 2 by incorporating with a power unit 600. In this case, the power unit 600 includes an electric motor and reduction gears connected with the output axis of the motor. The support shaft of the final stage gear is constructed as the wheel shaft 301 of the rear wheels 2. The front side of the power unit 600 is pivoted through a bracket 302 (see FIGS. 1 to 3) fixed to the rear end of the main frame member 107. The rear side of the power unit 600 is connected with the lower end of a shock absorber 303. The upper end of the shock absorber 303 is pivoted through a bracket 304 fixed to the rear end of the rear frame 104. The shock absorber 303 can use a compression coil spring, oil pressure, or the like.

In the seat unit 400, a seat cushion frame 401 and a seat back frame 402 each made of a rectangular pipe material or the like are connected into a nearly L-shape to be united. They are supported on a seat post 114 so that the seat cushion frame 401 may be substantially horizontal. In this case, the seat unit 400 is supported so as to be rotatable in the left and right directions and be able to be selectively fixed at plural angular positions in the course of rotation.

To the seat cushion frame 401, a seat cushion 403 is attached as an elastic body. To the seat back frame 402, a seat back 404 is attached as an elastic body. At a proper vertical position of the seat back frame 402, arm rests 405 are supported so as to be rotatable. The rider who is sitting on the seat unit 400 supported on the seat post 114 as illustrated in FIG. 3 can put his or her feet on the floor panel 3. At this time, he or she can step on a foot brake 4 disposed in the vicinity of the front portion of the floor panel 3.

An example of construction of a rotation supporting mechanism of the single seat will be described. Referring to FIG. 10, a base bracket 406 is connected under the seat cushion frame 401. A seat pipe 407 is hung down from the base bracket 406. A pipe holder 408 is fitted in the seat post 114. The seat pipe 407 is fitted in the pipe holder 408 so as to be rotatable. By this construction, the seat cushion frame 401, i. e. , the single seat is rotatable in the left and right directions. The pipe holder 408 may be attached to the seat post 114 so as to be detachable.

To the base bracket 406, a lever holder 410 having a bearing 409 in the front portion thereof is fixed. A rotation shaft 411 is inserted in the bearing 409. The rotation shaft 411 extends outward and is properly bent as illustrated to form a lever portion 412.

To the rotation shaft 411, a nail piece 414 protruding downward from an opening 413 opened in the base bracket 406 is fixed. The nail piece 414 can be rotated by manipulating the lever portion 412. The nail piece 414 has a hole 414a engageable with a tooth of a stopper plate as described later. A stopper plate is fixed to the upper end of the pipe holder 408. Teeth 416 are provided on the outer circumference of the stopper plate 415 at proper angular intervals. Each tooth 416 is cut off at its both sides for clearance. This enables the tooth 416 to engage with the nail piece 414.

By inserting the seat pipe 407 into the pipe holder 408, the single seat is supported on the seat post 114. In this case, by engaging the nail piece 414 with a desired tooth 416 by manipulating the lever portion 412, the single seat can be selectively fixed at a desired angular position.

Referring to FIG. 5 or 9, in the steering mechanism 500, a steering shaft 501 is held inside the steering frame 102 through holders 502 so as to be freely rotatable. The steering shaft 501 is bent so as to incline to the single seat side, in the middle portion of a longitudinal direction through a universal joint 503. A steering handle 505 is supported on the upper end portion of the steering shaft 501 through a bracket 504.

The steering handle 505 has a deformed U-shape whose front portion has been cut off. The rider who is grasping a proper portion of the steering handle 505 can operate to rotate an accelerator lever 506.

A bracket 507 is attached inside the front end portion of each main frame member 107 of the front frame portion 106. On the bracket 507, a boss is provided for supporting the lower end of the steering shaft 501 so as to be freely rotatable. On the rear side of the steering shaft 501 on the bracket 507, a counter shaft 508 is disposed that having a gear to engage with a gear provided on the lower end of the steering

shaft 501. A tie rod arm 509 is fixed to the counter shaft 508. When the steering shaft is rotated rightward or leftward, the tie rod arm 509 is rotated rightward or leftward through the counter shaft 508.

In each front wheel 1, a knuckle arm 510 fixed to the knuckle 204 and the tie rod arm 509 are interconnected through a tie rod 511. By rotating the steering handle 505 rightward or leftward, the front wheels 1 are steered rightward or leftward through the steering shaft 501, counter shaft 508, tie rod arm 509, and tie rod 511. By thus providing the counter shaft 508, the front wheels 1 can be steered in the same direction as the rotation of the steering handle 505. In this case, by properly selecting the gear ratio between the gear on the steering shaft 501 side and the gear on the counter shaft 508 side, the steering angle and force can suitably be set.

As described above, the power unit 600 supports the rear wheels 2 by incorporating with the rear-wheel supporting mechanism 300. A battery unit 700 as described later supplies electric power to the power unit 600 to drive the electric motor 601 therein.

In the battery unit 700 of the present invention, as illustrated in FIG. 8, in a principal area of the floor (or referred to as floor panel) 3, between the frames disposed along the both side edges thereof, a battery case 701 is received that has substantially the same height as the frames. Secondary batteries 702 are arranged in the battery case 701. In the illustrated example, the secondary batteries 702 are arranged in two of front and rear lines within a plane.

The floor 3 is made up of a main floor portion 5 positioned rearward of the front wheels I and having substantially the same width as the interval between the left and right front wheels 1, and a front floor portion 6 having a width narrower than the interval between the left and right front wheels 1 and narrower than the main floor portion 5 and extending frontward of the main floor portion 5. The principal area of the floor 3 is formed by the main floor portion 5, where the battery case 701 is disposed.

The centre frame portion 105 of the main frame 103 as described above extends in the front and rear directions along both of the left and right side edges of the main floor portion 5. The front frame portion 106 extend in front of the centre frame portion 105 at an interval narrower than the interval between the left and right front wheels 1. In this example, the battery case 701 is disposed in between main frame member 107 constructing the centre frame portion 105.

As illustrated in FIG. 11, the battery case 701 has a generally thin box shape. It is formed at substantially the same level as the main frame members 107. This battery case 701 is disposed under the main floor portion 5 in between the main frame members 107. As the dry-type secondary battery 702 used in the present invention, a lithium ion battery is typically used. As the dry-type secondary battery of this kind, a number of cells are combined and packed. In such a case, in many cases, they are piled in a trefoil formation in order to increase the density of the large-size cell module. This is bulky. In this embodiment, however, since the left and right front wheels 1 in a pair are provided as described above and the main floor portion 5 can be formed into a large area having substantially the same width as the interval between the left and right front wheels 1, the total eight secondary batteries 702 can be arranged in two of the front and rear lines within a plane. By holding down the width (diameter) of each secondary battery 702 into one equal to or slightly higher than the height of the main frame member 107, a very thin battery receiving space can be set.

As illustrated in FIG. 12, the battery case 701 is provided on its bottom portion with a holding portion having plural recesses formed so as to correspond to the outer shape of each secondary battery 702. In this embodiment, plural semicircular ribs 701a are formed. Since the secondary batteries 702 are arranged within a plane as described above, the secondary batteries 702 must be fixed so as not to move in the battery case 701 due to vibration. By providing the semicircular ribs 701 a, the secondary batteries 702 are suitably fixed so as not to interfere with each other.

The battery case 701 is provided on the left and right sides with flange-shaped attachment portions 701b. In a state that the flange-shaped attachment portions 701b are put on the respective main frame members 107, the battery case 701 is attached to the main frame members 107 with screws or the like. In this case, an insertion hole 701c is provided for each attachment screw. In the front portion of the battery case 701, that is, on the front side of the secondary batteries 702 in the front line, a cell controller (substrate) 703 is disposed with a holder 701d being interposed.

The cell controller 703 makes a control so that the secondary batteries 702 (cells) may have no capacity and potential differences from each other. The cell controller 703 is perpendicular to the bottom portion of the battery case 701. By thus providing the

cell controller 703 perpendicularly between the parts around the front suspension and the secondary batteries 702, the space in the front and rear directions can effectively be utilized. Even though the cell controller 703 is provided vertically, since the floor is inclined in a front-up manner in the actual vehicle, the cell controller 703 does not so protrude downward. Thus, the ground clearance of undercarriage can effectively be ensured.

As illustrated in FIG. 12 or 13, the upper portion of the battery case 701 is covered with a flat cover 704. The cover 704 has a shape matching the upper opening of the battery case 701. Nail pieces 704a are hung down from the periphery of the lower surface of the cover 704. By engaging the nail pieces 704a with engagement portions 701e, the cover 704 is fixed. In the interface between the battery case 701 and the cover 704, a gasket is fitted so that water, dust, and so on may not enter the battery case 701. By fixing the cover 704 to cover the battery case 701 having received the secondary batteries, a battery pack is constructed.

Also as illustrated in FIG. 13, on the upper side of the battery pack, that is, on the upper side of the cover 704, the floor panel 3 is disposed. The floor panel 3 is put on

the attachment portions 701b of the battery case 701 with spacers being interposed, and attached to the attachment portions 701b with screws or the like. In this case, insertion holes 3a for the attachment screws are provided in the peripheral portion of the floor panel 3. Also, insertion holes 701f are provided in the attachment portions 701b to correspond to the respective insertion holes 3a.

On the lower side of the battery pack, that is, on the lower side of the battery case 701, a generally flat underguard 705 is disposed. The underguard 705 is attached to the bridge members 109 and 110 (see FIG. 6) with screws or the like so as to cover the lower portion of the battery case 701. In this case, insertion holes 705a and 705b for the attachment screws are provided in the front and rear edge portions of the underguard 705, respectively (FIG. 12).

In the small electric vehicle of the present invention, referring to each drawing as above, in the lower front half portion of the single seat disposed rearward of the floor 3, as illustrated in FIG. 3 and so on, a main controller 7 for electronically controlling

electric power to be supplied to an electric motor 601 of the power unit 600 and a charging device 8 for charging the secondary batteries 702 of the battery unit 700 are disposed. The main controller 7 and the charging device 8 are covered with a vehicle cover (not illustrated) formed integrally with and from the floor 3. Thus, they are not exposed outside.

In the space between the left and right rear wheels 2 in a pair disposed rearward of the main controller 7 and so on, a box-or basket-like load receiving device 9 is disposed.

In the upper portion of the load receiving device 9, an opening 9a is opened for enabling load to be taken in and out. As described above, the single seat is supported at a near position above the seat post 114 so as to be rotatable around the seat post 114. By properly rotating the single seat, a part or the whole of the opening 9a of the load receiving device 9 positioned above it can be covered with the single seat from above to be able to be opened and closed.

In the upper portion of the steering frame 102, a switch box (operation panel) 10 is attached at a near position in front of the steering handle 505. As illustrated in FIG. 7 for example, the switch box 10 is supported through a nearly key-shaped bracket 11 fixed to the upper end of the steering frame 102. The switch box 10 carries various switches and the like. For example, switches such as a front/back changeover knob, a speed set knob, a battery residual indicator, and a charge lamp, and further a right/left winker switch and a horn button are disposed.

The switch box 10 is disposed to properly incline at a near position in front of the steering handle 505. Thus, a rider's hand can easily reach the switches and so on necessary for driving operation and the display contents of the display lamp and so on are easily observed. Therefore, the rider who is sitting on the single seat can easily and adequately operate the switches and so on of the switch box 10. At that time, he or she can properly operate the accelerator lever 506 at need.

At a near position under the switch box 10, a cord reel case 12 in which a cord reel is incorporated is attached to the steering frame 102. On the cord real, a charging cord biased to the take-up direction is wound so as to be able to be freely fed. The charging cord is connected with the charging device 8. When the secondary batteries

702 of the battery unit 700 are charged, the charging cord is fed from the cord reel case 12 and the charging device 8 is connected with an external power source through the charging cord.

To the upper portion of the steering frame 102, a main key 13 is attached using a holder 502 for example. The main key 13 is disposed at a position where the rider who sitting on the single seat can easily see. In the lower portion of the main key 13, a box-or basket-like load receiving device 14 is mounted on the steering frame 102.

In the upper portion of the load receiving device 14, an opening is opened for enabling load to be taken in and out.

In case of the above, each unit is covered with a vehicle cover made of a plastic or synthetic resin or the like. It is designed so that a predetermined external design can be obtained as the whole vehicle. In this case, a leg shield and so on are mounted around the steering frame 102. Front and rear fenders may be mounted around the front and rear wheels 1 and 2, respectively.

In an actual vehicle, safety or reservation parts and so on necessary in run are provided. The parts of this kind include a headlamp, a winker, a stop lamp, a side mirror, a horn, and so on. Further, if necessary, other parts are provided.

Also as illustrated in FIG. 14, the steering frame 102 protrudes upward in the same width from the front frame portion 106. Particularly in the present invention, the steering frame 102 is detachably attached to the vehicle frame 101 by a cramp device as described later. In this case, as illustrated in FIGS. 15A and 15B, on the lower end of the steering frame 102, for example, a gull-wing bracket 507 is welded. Both of them are united. In a recess of the bracket 507, a steering shaft attachment boss 512 and a counter shaft attachment boss 513 are disposed.

The cramp device cramps the front frame portion 106 from above and below so that the steering frame 102 may be cramped and fixed to the front frame portion 106. In this case, as illustrated in FIG. 16, a cramp portion 507a of the bracket 507 and a cramp member 514 formed separately sandwich vertically the front frame portion 106. By fastening the cramp portion 507a and the cramp member 514 with a bolt

515, steering frame 102 can be attached. Thus, the vehicle frame 101 and the steering frame 102 are formed separately. They are detachably united by the cramp device.

In the present invention, as illustrated in FIG. 17, the steering shaft 501 is divided into an upper half portion 501A and a lower half portion 501B substantially in the middle of the upper end portion with which the steering handle 505 is connected and the lower end portion with which the tie rod arm 509 is connected. The upper and lower half portions 501A and 501B are connected through a universal joint 503 as interconnecting means freely bendable. In this case, the lower half portion 501B substantially vertically stands from the front frame portion 106, and the upper half portion 501A is disposed to incline rearward toward the single seat.

As described above, the steering frame 102 protrudes upward from the front frame portion 106. Also as apparent from FIG. 17 and so on, it bends to incline backward in the vicinity of the universal joint 503 of the steering shaft 501. In this case, the pipe materials 102a and 102b on the front side of the steering frame 102 are bent so as to be substantially in parallel with the upper half portion 501A of the steering shaft 501.

In actual use of the small electric vehicle of the present invention, the rider who sitting on the single seat can run the vehicle by grasping the steering handle 505, pulling the accelerator lever, or stepping on the foot brake 4 at need. In this case, electric power is supplied to the power unit 600 from the battery unit 700 received under the floor panel 3. The electric motor 601 of the power unit 600 drives the rear wheels 2. By this, the rider can smoothly and adequately drive the small electric vehicle.

Particularly in the small electric vehicle of the present invention, the vehicle frame 101 and the steering frame 102 are constructed separately, and the steering frame 102 is detachably provided by the cramp device. By thus separately constructed, the figure can be small and compact. This considerably improves handling when shipping to an assembling factory or the like for example. Besides, parts around the steering system can partially be assembled. By delivery in a partially assembled form, the assembling efficiency is improved.

Since the steering frame 102 is attached to the vehicle frame 101 by the cramp device, the vehicle frame need not be particularly processed. Labor is not so necessary for assembling. Assembling with high accuracy without a play or the like can be performed.

Besides, in the principal area of the floor panel 3, between the frames disposed along both side edge portions of the floor panel 3, the battery case 701 having substantially the same height as the frames is received. The secondary batteries 702 are disposed in lines within the battery case 701. By arranging the secondary batteries 702 in a plane, the battery receiving space is set to be very thin. By this, with ensuring a ground clearance of undercarriage, the floor having a wide flat face is realized, and a utility space can be ensured around feet. Besides, since the battery unit 700 is disposed in the lowermost portion of the vehicle, the weight centre is lowered so the static and running stability is improved.

Further in this case, the upper half portion 501 A of the steering shaft 501 is disposed to incline rearward toward the single seat, and the steering frame 102 supporting it is also bent to be substantially in parallel with the upper half portion 501A. By thus bending the portion around the steering shaft, the steering frame 102 can be disposed in the most front portion of the vehicle frame 101. This incorporates with the arrangement of the battery unit 700 to enlarge the floor space. Thus, a utility space can be ensured around feet. Besides, the weight centre of the vehicle is not deviated backward of the vehicle and it can be set at an adequate position. Therefore, the static stability of the vehicle is improved.

Since a space is formed between the steering frame 102 and the rider's legs (around knee) as described above, the load receiving device 14 can naturally adequately be disposed. In a conventional vehicle, a front basket is disposed in front of a cowling or steering shaft. The rider who is riding could not take a load in or out of the front basket. In the present invention, since it is disposed at a near portion to the rider, the load receiving device 14 is superior in use, and further troubles such as theft of a load can be prevented in advance.

Further, since the steering frame 102 stands straightly upward in the same width from the front frame portion 106 without spreading in the vehicle width directions, the steering frame 102 can be disposed at the centre and a utility space can be ensured on both the left and right sides. This utility space may be utilized as foot rest or for constructing a load carrier or the like.

Besides, the side and rear carrying handles 111 and 112 are provided on side and rear portions of the vehicle frame 101, respectively. These carrying handles may work more than their original functions. For example, the side carrying handle 111 can function as a getting-on/off step. Besides, the rear carrying handle 112 is expected to function as a rear bumper for example.

Hereinbefore, the present invention has been described with an embodiment. But, the present invention is not limited to these embodiments and it can be changed within the scope of the present invention.

For example, the inclination angle or the like of the steering shaft 501 or steering frame 102 is not limited to one of the illustrated example. It can properly be set at need.

As described above, according to the present invention, in a small electric vehicle of this kind, by separating constructing the vehicle frame and steering frame, the figure can be small and compact. Thus, the handling can be improved and the assembling efficiency can be improved. Besides, by bending a portion around the steering shaft, the floor space is enlarged and a utility space around feet can be ensured. Besides, the weight centre of the vehicle is not deviated rearward of the vehicle and it can be set at an adequate position, so the static stability of the vehicle is improved.

Claims

CLAIMS: 1. A small electric vehicle comprising a floor laid on a vehicle frame in a lower front portion of a single seat supported on said vehicle frame; left and right front wheels in a pair provided in front of said floor as steering control wheels swingable in left and right directions in accordance with handle manipulation, and left and right rear wheels in a pair provided in a lower rear portion of said single seat as drive wheels driven by a power unit, for said vehicle to run with said front and rear wheels; and a battery unit for supplying electric power to said power unit, wherein said vehicle further comprises a steering system in which a steering shaft supporting at its upper end a handle so as to be rotatable in the left and right directions and protruding upward from a front end portion of said floor, and a front-wheel steering knuckle supported in an outer end portion of a suspension arm extending outward in the left and right directions through a king pin so as to be swingable in the left and right directions, are connected with each other through a tie rod arm and a knuckle arm, and said steering system is disposed in a front end portion of said vehicle frame extending in the front and rear directions of said vehicle under said floor, and a steering frame for supporting said steering shaft so as to be freely rotatable is attached to said vehicle frame so as to be detachable.
2. The vehicle according to claim 1, wherein said floor comprises a main floor portion positioned rearward of said front wheels and having substantially the same width as the interval between said left and right front wheels, and a front floor portion having a width narrower than said interval between said left and right front wheels and narrower than said main floor portion and extending in front of said main floor portion, and said vehicle frame comprises a centre frame portion having substantially the same width as the inside interval between said left and right front wheels and extending in the front and rear directions along both of left and right edge portions of said main floor portion to form said main floor portion, front frame portions extending in front of said centre frame portion at an interval smaller than the interval between said left and right front wheels, supporting said front wheels and said steering system for steering said front wheels, and forming said front floor portion,

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and a rear frame extending rearward from said centre frame portion and supporting said single seat, said power unit, and said rear wheels.
3. The vehicle according to claim 2, wherein said centre frame portion, said front frame portions, and said rear frame are made of left and right main frame members in a pair, and said vehicle comprises a side carrying handle protruding outward from said centre frame portion on a side face of said main frame portion, and a rear carrying handle protruding rearward of said single seat, interconnecting rear end portions of said left and right main frame members in a pair.
4. The vehicle according to any one of claims I to 3, wherein said steering shaft is divided into upper and lower half portions substantially in the middle of an upper end portion with which said handle is connected and a lower portion with which said tie rod arm is connected, said upper and lower half portions are interconnected by joint means freely bendable, said lower half portion stands substantially vertically, and said upper end portion inclines rearward toward said single seat.
5. The vehicle according to any one of claims 2 to 4, wherein said steering frame is bent to incline rearward in the vicinity of said joint means, protrudes upward from said front frame portion in the same width, and is attached so as to be detachable.
6. The vehicle according to any one of claims 1 to 5, wherein said steering frame is attached to said vehicle frame by a cramp device so as to be detachable.