JP2006103553A - Compact electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact electric vehicle capable of ensuring the dynamic stability without any size-increased or complicated configuration. <P>SOLUTION: The compact electric vehicle has a seat 112 with an occupant seated therein, a floor 106 provided on a forward lower part of the seat 112, a steering mechanism 200 including a steering shaft 201 erected before the floor 106, right and left front wheels 102 which are rocked in the right-to-left direction by the steering mechanism 200, and rear wheels 103 provided as driving wheels. A steering damper mechanism 217 comprises a cam member 219 which is coaxially arranged with the steering shaft 201 and integrally rotated with the steering shaft 201, a cam support member 220 which is coaxially arranged with the steering shaft 201 and moved in the axial direction along the steering shaft 201 by the effect of a cam 219a when the cam member 219 is rotated, and a damper 221 having the damping effect to the movement in the axial direction of the cam support member 220. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small electric vehicle for use by an elderly person or a person with reduced mobility.

  Small electric vehicles are extremely useful as substitutes for elderly people. In the basic configuration of such a small electric vehicle, for example, a seat on which an occupant sits is installed at the rear of the vehicle body, and a rear wheel as a driving wheel is disposed below the seat. A floor for the occupant to put his / her feet on is provided in the lower front part of the seat, and a steering shaft for steering the front wheels is further provided in front of the floor. A handle is attached to the upper end of the steering shaft, and an occupant is seated on the seat and operates the handle.

  In this type of small electric vehicle, since the target user is an elderly person with weak arm strength, the resistance of the front wheel is reduced so that the steering wheel operation can be performed lightly and the small turn is possible. In general, the cutting angle is increased.

  On the other hand, the structure in which the steering wheel can always be turned lightly may impair dynamic stability, particularly when the vehicle is traveling at a relatively high speed. In view of this point, Patent Document 1 discloses a configuration in which a handle turning angle is regulated at the time of high-speed traveling or reverse traveling using an electric actuator in a small electric vehicle provided for movement of an elderly person or the like. ing.

Japanese Patent Laid-Open No. 10-157647

  However, in the one disclosed in Patent Document 1, since an electric actuator or the like is used, the size and complexity of the device are increased, which causes a cost increase.

  Further, even during high-speed traveling, the steering wheel can be sharply cut until the steering angle is restricted, so it cannot be said that the dynamic stability is improved.

  Furthermore, a means for detecting the vehicle speed and the forward / rearward movement state is required, the configuration becomes complicated, and there is a possibility that the vehicle does not function effectively when the accurate vehicle speed cannot be detected.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a small electric vehicle that can ensure dynamic stability with a configuration that does not increase in size and complexity.

A small electric vehicle according to the present invention includes a seat on which an occupant is seated, a floor provided at a lower front portion of the seat, a steering mechanism including a steering shaft standing in front of the floor, and left and right by the steering mechanism. A small electric vehicle including left and right front wheels that swing and a rear wheel provided as a drive wheel, characterized in that a steering damper mechanism is provided coaxially with the steering shaft.
Another feature of the small electric vehicle of the present invention is that the steering damper mechanism is disposed coaxially with the steering shaft, and is configured to be coaxial with the steering shaft, a cam member that rotates integrally with the steering shaft, and And a cam receiving member that moves axially along the steering shaft when the cam member rotates together with the steering shaft from the straight traveling state to the right or left, and a buffer for the axial movement of the cam receiving member. And a shock absorber having an action. In this case, the steering damper mechanism may further include an urging unit that applies an urging force to the straight movement state of the steering mechanism with respect to the axial movement of the cam receiving member. Further, the shock absorber may have a characteristic that the damping force is small when the axial movement of the cam receiving member is low, and the damping force is large when the cam receiving member is high speed.
Another feature of the small electric vehicle according to the present invention is that the steering shaft is configured such that an upper part and a lower part are connected via a connecting member and the upper part is inclined to the seat side. The damper mechanism is located at a position below the connecting member in the steering shaft.
According to another aspect of the small electric vehicle of the present invention, the steering mechanism is configured such that the steering shaft, a tie rod connecting plate to which rotation of the steering shaft is transmitted, the front wheels are rotatable, and And a front wheel bracket that is supported so as to swing right and left, and a tie rod that connects the tie rod connecting plate and the front wheel brackets to each other. In this case, the tie rod connecting plate, the front wheel bracket, and the tie rod may be disposed below the front portion of the floor.

According to the present invention, since the steering damper mechanism is disposed coaxially with the steering shaft, the installation space for the steering damper mechanism can be reduced, and dynamic stability can be achieved with a configuration that does not increase in size and complexity. Thus, it is possible to provide a small electric vehicle capable of ensuring the above.
In particular, the steering damper mechanism is disposed coaxially with the steering shaft, and is disposed on the same shaft as the steering shaft and the steering shaft. When the cam member rotates, the cam of the cam member causes the steering shaft to rotate. A cam receiving member that moves in the axial direction along with a shock absorber that has a buffering action against the axial movement of the cam receiving member, and the shock absorber has a damping force when the axial movement of the cam receiving member is slow. When the handle is sharply turned, the steering angle is restricted when the handle is suddenly cut, and the handle operation remains light when the handle is turned slowly. A small turn is possible without restricting the turning angle.

(First embodiment)
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing the overall configuration of a small electric vehicle according to the present embodiment, FIG. 2 is a front view, and FIG. 3 is a plan view. In the small electric vehicle 100, a pair of left and right front wheels 102 and a pair of left and right rear wheels 103 are supported by a body frame 101 via a suspension. The body frame 101 is covered with a resin cover including a front cover 104, a leg shield 105, a floor 106, a rear cover 107, and the like, except for a part thereof.

  A substantially box-shaped or box-shaped rear cover 107 projects upward at the rear of the vehicle body, and a drive motor 108 for driving the rear wheel 103 and an output of the drive motor 108 are transmitted to the axle 109 inside the rear cover 107. A power unit including a gear unit 110 (see FIG. 2 and FIG. 3) and a battery and a charger thereof is housed.

  A seat 112 on which an occupant is seated is mounted on the upper side of the rear cover 107 via a bracket 111 that rises from the body frame 101 in a gate shape, for example. The seat 112 includes a seat cushion 113 and a seat back (back) 114, and is supported on the rear cover 107 so as to be pivotable in the horizontal direction. The turning angle is set to 45 degrees and 90 degrees, for example, left and right from the vehicle body center, and can be appropriately turned by operating the operation levers 115 provided on both sides of the seat cushion 113.

  Furthermore, armrests 116 are provided on both sides of the seat back 114, and each armrest 116 is supported so as to be rotatable around a fulcrum 117. A blinker 118 is disposed on each side of each armrest 116. Further, on the back surface of the seat back 114, for example, a grip portion 119 that can be gripped when the small electric vehicle 100 is manually pushed is provided.

  The leg shield 105 protrudes upward at the front of the vehicle body and protects the legs of the occupant seated on the seat 112 from being exposed to wind and the like. A steering shaft 201 constituting a steering mechanism 200 for steering the front wheels 102 is erected inside the leg shield 105, and a handle unit 120 is rotatably attached to the upper end of the steering shaft 201. As shown in FIG. 1, the occupant sits on the seat 112 and operates the handle unit 120. In addition, a pair of left and right rearview mirrors 121 are supported at appropriate positions of the handle unit 120 via a stay 122.

  A storage box or carrier case 123 is mounted on the front surface of the leg shield 105, and the carrier case 123 can be used as a container as appropriate. A headlight is attached at a suitable position below the carrier case 123.

  4 and 5 show the configuration of the steering mechanism 200. FIG. Two left and right steering frames 203 are supported upright at the front end of the body frame 101 (not shown in FIGS. 4 and 5) via a bracket 202. The upper part of each steering frame 203 is appropriately bent toward the seat 112 in accordance with a steering shaft 201 described later.

  A steering shaft 201 is rotatably held inside the steering frame 203 via a holder 204. The steering shaft 201 is configured such that an upper portion and a lower portion are connected via a universal joint 205, and the upper portion is appropriately inclined toward the seat 112 side. As a result, a wide floor space can be secured and the handle unit 120 can be positioned near the passenger. In this case, the steering shaft 201 is preferably tilted toward the seat 112 at a position above the seat 112 (seat surface).

  A handle unit 120 is supported on the upper end of the steering shaft 201. The handle unit 120 includes a loop handle 124, an operation box 125 provided so as to be bridged back and forth in the center of the loop handle 124, a pair of left and right accelerator levers 126 disposed on both sides of the operation box 125, And a brake lever 127 used for parking. The handle unit 120 is disposed at an appropriate inclination from the horizontal to the occupant side, can grasp the desired position of the loop handle 124 without forcibly reaching out, and can operate the handle in a natural posture.

  In the vicinity of the lower end of the steering shaft 201, left and right suspension arms 206 are extended outward from the center in the vehicle width direction. Each suspension arm 206 is supported by a suspension arm bracket 207 (the rear suspension arm bracket is not shown) that is fixed to the vehicle body frame 101 (not shown in FIGS. 4 and 5) so that the suspension arm 206 can swing in the vertical direction. Is done.

  A U-shaped knuckle arm 208 (front wheel bracket) is pivotally supported at the tip of each suspension arm 206 via a king pin 209 so as to be swingable to the left and right. A front wheel is mounted on an axle 210 extending horizontally from the knuckle arm 208. 102 is rotatably supported. A bracket 212 for mounting the suspension spring 211 is fixed to the outer portion of the bracket 202, and the suspension spring 211 is mounted between the bracket 212 and the suspension arm 206.

  A counter shaft 213 is disposed behind the lower end of the steering shaft 201, and a gear 201a provided at the lower end of the steering shaft 201 and a gear 213a of the counter shaft 213 are engaged with each other. The counter shaft 213 is fixed to the tie rod connection plate 214, and when the steering shaft 201 rotates to the right or left, the tie rod connection plate 214 rotates to the right or left via the counter shaft 213. In this case, the rotation limit of the tie rod connecting plate 214 is until it comes into contact with the stopper 215 disposed below the bracket 202.

  The tie rod connecting plate 214 and each knuckle arm 208 are connected to each other via a tie rod 216. Thus, when the steering shaft 201 rotates to the right or left by the steering operation, the front wheel 102 is steered to the right or left via the counter shaft 213, the tie rod connection plate 214, the tie rod 216, and the knuckle arm 208. Note that the steering angle and the steering force can be appropriately set by appropriately selecting the gear ratio between the gear 201a of the steering shaft 201 and the gear 213a of the counter shaft 213.

  As shown in FIG. 1, the vehicle body frame 101 is tilted forward and upward, that is, the floor 106 is also tilted forward and the front portion of the floor 106 extends to the vicinity of the steering shaft 201. In this case, the tie rod coupling plate 214, the knuckle arm 208, the tie rod 216, and the like are disposed below the front portion of the floor 106. With this configuration, the floor 106 can be widened without interfering with the tie rod connecting plate 214, the knuckle arm 208, the tie rod 216, and the like.

  Here, a steering damper mechanism 217 is disposed coaxially with the steering shaft 201 at a position below the universal joint 205.

  A configuration example of the steering damper mechanism 217 will be described with reference to FIG. The steering damper mechanism 217 is disposed coaxially with the steering shaft 201 and has a cylindrical cam bracket 218 that rotates integrally with the steering shaft 201, a cylindrical cam member 219 that is fixed to the cam bracket 218, and the steering shaft 201. A cylindrical cam receiving member (cam follower) 220 that is axially moved along the steering shaft 201 by the action of the cam 219a when the cam member 219 rotates, and the axial movement of the cam receiving member 220. The shock absorber 221 has a shock absorbing action, and the coil spring 222 is disposed around the shock absorber 221 and applies a biasing force to the steering mechanism 200 in a straight traveling state with respect to the axial movement of the cam receiving member 220.

  The cam member 219 is formed in a cylindrical shape, and at least one cam 219a is provided on the upper surface thereof along an arc. The cam receiving member 220 is also formed in a cylindrical shape, and is formed with a cam receiving recess 220a that opens on the inner and outer surfaces and the lower surface thereof, and the cam 219a is positioned in the cam receiving recess 220a. In the example shown in FIG. 6, when the cam member 219 together with the steering shaft 201 rotates in either the left or right direction (arrows l, r) from the straight traveling state of the steering mechanism 200 and exceeds the range X, the cam receiving member 220 is moved to the cam 219a. And is moved in the axial direction along the steering shaft 201 (arrow u).

  Although not specifically shown as the shock absorber 221, for example, a piston linked to the cam receiving member 220 is slidably incorporated in the cylinder tube, and the pressure chambers partitioned by the piston communicate with each other via an orifice. A hydraulically operated type configured as described above may be used. In this case, as shown in FIG. 7, the characteristic that the damping force increases as the movement of the piston (the axial movement of the cam receiving member 220) increases. That is, the damping force is small when the steering shaft 201 rotates slowly, and the damping force is large when it rotates suddenly.

  In the small electric vehicle 100 configured as described above, as shown in FIG. 1, an occupant seated on the seat 112 holds the loop handle 124 of the handle unit 120 (or puts a light hand on it) and operates the accelerator lever 126. The vehicle can be run. Further, when the hand is released from the accelerator lever 126, the accelerator lever 126 returns to the initial position (accelerator fully closed position), and the vehicle can be stopped.

  Here, for example, when the steering wheel 124 is suddenly turned and the torque is input to the steering shaft 201 while the vehicle is traveling, the cam member 219 rotates together with the steering shaft 201. When the cam member 219 rotates beyond the range X shown in FIG. 6, the cam receiving member 220 is pushed up by the cam 219a and tries to move in the axial direction along the steering shaft 201. However, the shock absorber 221 applies a large damping force to the cam receiving member 220 because the cam receiving member 220 moves in the axial direction at high speed. Therefore, a large resistance force acts on the steering operation, and the steering angle is restricted.

  Similarly, when torque is input to the steering shaft 201 due to the disturbance received by the front wheel 102, the cam receiving member 220 is moved at high speed in the axial direction, so that a large damping force is applied and the influence of the disturbance is applied to the steering wheel side. Anti-vibration effect to prevent transmission is demonstrated.

  On the other hand, when the handle 124 is slowly turned, similarly, when the cam member 219 rotates beyond the range X shown in FIG. 6, the cam receiving member 220 is pushed up by the cam 219 a and is moved along the steering shaft 201. In this case, the shock absorber 221 applies only a small damping force to the cam receiving member 221 because the axial movement of the cam receiving member 221 is slow. Therefore, the steering wheel operation remains light, and it is possible to make a small turn without being restricted until the steering angle is maximized.

  As described above, since the steering damper mechanism 217 is disposed coaxially with the steering shaft 201, the installation space for the steering damper mechanism 217 can be reduced. In particular, the steering damper mechanism 217 can be rotated linearly. By adopting a simple configuration that is converted and buffered, it is possible to provide a small electric vehicle that can ensure dynamic stability with a configuration that does not increase in size and complexity.

(Second Embodiment)
As a second embodiment, another configuration example of the steering damper mechanism 217 will be described with reference to FIG. FIG. 8 shows a modified cam receiving recess 220a, and the basic components are the same as those described in the first embodiment.

  In the steering damper mechanism 217 shown in FIG. 6, the damping force is not applied until the range X is exceeded, and the damping force is applied stepwise only when the range X is exceeded, and the damping force is applied to the cam member 219 (that is, The steering shaft 201) is substantially constant regardless of the amount of rotation.

  On the other hand, in the steering damper mechanism 217 shown in FIG. 8, the range X is narrowed, and when the range X is exceeded, the damping force is stepless according to the amount of rotation of the cam member 219 (that is, the steering shaft 201). Is greatly increased. In this case, for example, when the handle 124 is suddenly cut, a larger damping force (resistance force) is applied as the operation amount is larger.

  6 and 8 are merely examples, and desired buffer characteristics can be obtained by appropriately setting the shapes of the cam 219a and the cam receiving recess 220a. For example, if the cam receiving recess 220a has a stepped shape having a plurality of steps, a large damping force is applied in a plurality of steps according to the amount of rotation of the cam member 219 (that is, the steering shaft 201).

  As mentioned above, although this invention was demonstrated with embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention. For example, the shock absorber 221 is not limited, and various structures such as a linear shock absorber, a rotary shock absorber, and a pneumatic shock absorber using bellows can be used.

1 is a side view showing an overall configuration of a small electric vehicle according to an embodiment. 1 is a front view showing an overall configuration of a small electric vehicle according to an embodiment. 1 is a plan view showing an overall configuration of a small electric vehicle according to an embodiment. It is a perspective view which shows the structure of a steering device. It is a perspective view which shows the structure of a steering device. It is a figure which shows the structural example of a steering damper mechanism. It is a characteristic view which shows the characteristic example of the damping force of a shock absorber. It is a figure which shows the other structural example of a steering damper mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Small electric vehicle 102 Front wheel 103 Rear wheel 106 Floor 112 Seat 120 Handle unit 200 Steering mechanism 201 Steering shaft 203 Steering frame 205 Universal joint 206 Suspension arm 208 Knuckle arm 213 Counter shaft 214 Tie rod connection plate 216 Tie rod 217 Steering damper mechanism 218 Cam bracket 219 Cam member 220 Cam receiving member 221 Shock absorber 222 Coil spring

Claims (7)

A seat on which an occupant is seated; a floor provided at a lower front portion of the seat; a steering mechanism including a steering shaft erected in front of the floor; and left and right front wheels swinging left and right by the steering mechanism; A small electric vehicle having a rear wheel provided as a drive wheel,
A small electric vehicle characterized in that a steering damper mechanism is disposed coaxially with the steering shaft.   The steering damper mechanism is arranged coaxially with the steering shaft, and is arranged coaxially with the steering shaft, the cam member rotating integrally with the steering shaft, and the cam member is linearly moved along with the steering shaft. 2. A cam receiving member that moves in an axial direction along the steering shaft when rotated to the right or left from a state, and a shock absorber that has a buffering action against the axial movement of the cam receiving member. The small electric vehicle described in 1.   The small electric vehicle according to claim 2, wherein the steering damper mechanism further includes a biasing unit that applies a biasing force to the straight movement state of the steering mechanism with respect to the axial movement of the cam receiving member.   4. The small electric motor according to claim 2, wherein the shock absorber has a characteristic that a damping force is small when the axial movement of the cam receiving member is low speed and a damping force is large when the cam receiving member is high speed. 5. vehicle.   The steering shaft is configured such that an upper portion and a lower portion are connected via a connecting member, and the upper portion is inclined to the seat side, and the steering damper mechanism is disposed below the connecting member in the steering shaft. The small electric vehicle according to claim 1, wherein the small electric vehicle is provided.   The steering mechanism includes the steering shaft, a tie rod connection plate to which the rotation of the steering shaft is transmitted, a front wheel bracket that rotatably supports the front wheels so as to swing left and right, and the tie rod connection plate. The small electric vehicle according to any one of claims 1 to 5, further comprising a tie rod that connects the front bracket and the front wheel brackets to each other.   The small electric vehicle according to claim 6, wherein the tie rod connecting plate, the front wheel bracket, and the tie rod are disposed below a front portion of the floor.

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