JP2007062669A - Toppling preventive device of small-sized electrically driven vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toppling preventive device for a small-sized electrically driven vehicle capable of preventing the vehicle from toppling without giving an uneasy feeling of toppling to the driver etc. using a simple constitution. <P>SOLUTION: The toppling preventive device has a sub-wheel bracket 42 secured to the lower part of a gear case 35 and extending backward, and on this bracket 42 a sub-wheel arm 43 is borne at one end swingably up and down around a shaft bolt 47. A spring 51 biases the sub-wheel arm 43 to a position abutting to a stopper bolt 49 and holds the arm 43 in this condition. Accordingly a sub-wheel 44 is held in a low position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an overturn prevention device for a small electric vehicle, and more particularly, to an overturn prevention device for a small electric vehicle that contacts the ground and prevents the overturn when the small electric vehicle tilts backward.

  Conventionally, as a fall prevention device for a small electric vehicle such as an electric wheelchair, there is one configured by connecting the other end of a fall prevention bar having a fall prevention wheel attached to one end to a bracket near a drive wheel (for example, Patent Document 1). In this fall prevention device, when the small electric vehicle is in a horizontal state, the fall prevention wheel floats from the grounding surface, and when the small electric vehicle tilts backward, the fall prevention wheel comes into contact with the ground to prevent further rearward tilting. To prevent.

  Here, since wheelchairs generally have large rear wheels and small front wheels, it is easier to get over when stepping over a step and going over from a rear wheel with larger wheels. However, when a small electric vehicle equipped with the above conventional anti-tip device tries to get over the step by going backward, the anti-tip wheel sometimes hits the step and sometimes cannot get over the step.

  In order to solve this problem, as a conventional overturn prevention device for small electric vehicles, the above-mentioned overturn prevention bar can be swung with respect to the bracket, and the overturn prevention bar is held in an upward position. (See, for example, Patent Document 2). In this fall prevention device, when the small electric vehicle moves backward and tries to get over the step, when the fall prevention wheel hits the step, the fall prevention bar is pushed by the step and rotates downward. For this reason, it can prevent that a fall prevention wheel hits a level | step difference and cannot get over a level | step difference.

  In addition, the conventional overturn prevention device for small electric vehicles of Patent Documents 1 and 2 has a problem that the overturn prevention wheel rides on a step and the drive wheel idles, making it impossible for the small electric vehicle to travel. With respect to this problem, in the fall prevention device of Patent Document 1, the mounting angle of the fall prevention bar to the bracket is changed in order to arrange the fall prevention wheel high, and in the fall prevention device of Patent Document 2, the fall prevention device It is conceivable to change the holding position of the fall prevention bar in order to arrange the ring high. However, if the anti-falling wheels are arranged high, the rearward tilt angle of the small electric vehicle when the anti-falling wheel contacts the ground increases, and there is a risk that the small electric vehicle falls.

  In addition, as a conventional overturn prevention device for a small electric vehicle, one end of a first overturn prevention bar is attached to a bracket in the vicinity of a drive wheel, and the second overturn prevention bar is connected to the other end of the first overturn prevention bar. There is one in which one end is rotatably connected and a damper is attached to the first and second fall prevention bars (for example, see Patent Document 3). In this overturn prevention device, the damper is configured such that its supporting force increases as the vehicle inclination angle increases. For this reason, when the inclination angle of the vehicle is small, the support force of the damper is small, the second fall prevention bar can be easily rotated, and the fall prevention device can be prevented from becoming an obstacle when getting over a large step. it can. Therefore, it can be prevented that the fall prevention wheel rides on the step and the drive wheel idles and the small electric vehicle cannot run.

Further, as a conventional overturn prevention device for small electric vehicles, the overturn prevention bar can be rotated in the rotational direction of the drive wheel, and the overturn prevention bar is rotated in the housed state of the overturn prevention device so that the overturn prevention wheel is at a high position. And the rotation range of the fall prevention bar is regulated so that the fall prevention wheel is held at a position lower than the retracted state in a normal traveling state (see, for example, Patent Document 4). ). According to this fall prevention device, the fall prevention wheel is held at a high position in the stored state of the fall prevention device, the fall prevention wheel rides on the step, the driving wheel idles, and the small electric vehicle cannot run. Can be prevented.
JP 2000-333999 A JP 2001-170114 A JP 2001-204767 A JP 2003-000651 A

  However, the fall prevention device for the small electric vehicle of Patent Document 3 has a complicated structure, and increases the cost of the fall prevention device. In addition, the fall prevention device for the small electric vehicle of Patent Document 4 described above is such that the rider holds the fall prevention device every time the rider tries to get over the step so that the fall prevention wheel rides on the step and the drive wheel does not slip. Convenience was low because it had to be moved between normal driving conditions. In addition, if the user forgets to return to the normal running state from the stowed state, there is a risk that the small electric vehicle rolls back, and in addition, the rearward tilt angle of the small electric vehicle when the fall prevention wheel contacts the ground increases. So, the passengers were worried about falling.

  An object of the present invention is to provide an overturn prevention device for a small electric vehicle that can prevent the small electric vehicle from toppling without giving fear of the overturn to a passenger with a simple configuration.

  In order to achieve the above object, the overturn prevention device for a small electric vehicle according to claim 1 includes an auxiliary wheel for preventing overturning that contacts the ground and supports the small electric vehicle when the small electric vehicle tilts backward. In the fall prevention device for a small electric vehicle, one end is pivotally supported so as to be swingable in the vertical direction with respect to the bracket fixed to the vehicle body, and the fall prevention auxiliary wheel is pivotally supported on the other end. And an urging means for urging and holding the arm downward with respect to the bracket.

  The overturn prevention device for a small electric vehicle according to claim 2 is the overturn prevention device for the small electric vehicle according to claim 1, wherein the overturn prevention auxiliary wheel is installed on the ground with respect to the direction of the reaction force received from the ground. The swing center of the arm is arranged in a region on the rear side of the small electric vehicle.

  The overturn prevention device for a small electric vehicle according to claim 3 is the overturn prevention device for the small electric vehicle according to claim 1 or 2, wherein the arm receives an external force from the front side of the small electric vehicle. The arm swings upward with respect to the bracket against the urging force of the urging means.

  The overturn prevention device for a small electric vehicle according to claim 4 is the overturn prevention device for the small electric vehicle according to any one of claims 1 to 3, wherein the small electric vehicle has substantially the front and rear wheel diameters. It is characterized by being the same.

  According to the overturn prevention device for a small electric vehicle according to claim 1, the urging means urges the arm whose one end is pivotally supported so as to be swingable in the vertical direction with respect to the bracket fixed to the vehicle body. And hold. For this reason, the fall prevention auxiliary wheel is arranged at a low position. Thereby, before the small electric vehicle largely tilts backward, the fall prevention auxiliary wheel can contact the ground and prevent the small electric vehicle from falling. In this way, it is possible to prevent the small electric vehicle from falling without giving the user anxiety about falling with a simple configuration. In addition, since the urging means urges and holds the arm in the downward direction, the overturning-preventing auxiliary wheel does not protrude greatly toward the rear of the vehicle. For this reason, it can suppress that the auxiliary wheel for fall prevention contacts obstacles, such as a level | step difference, at the time of reverse drive of a small electric vehicle. As a result, it is possible to prevent the small-sized electric vehicle from becoming unable to travel due to the auxiliary wheels for preventing overturning riding on the obstacle and causing the drive wheels to idle.

  According to the fall prevention device for the small electric vehicle according to claim 2, the arm is disposed in the region on the rear side of the small electric vehicle with respect to the direction of the reaction force received from the ground when the auxiliary wheel for fall prevention contacts the ground. A moving center is arranged. For this reason, when the small electric vehicle tilts backward and the tipping prevention auxiliary wheel comes in contact with the ground, a rotational moment against the urging force is applied to the arm held downward by the urging force of the urging means. Can prevent working. Therefore, when the small electric vehicle tilts rearward and the auxiliary wheel for preventing overturning contacts the ground, it is possible to prevent the arm held downward from swinging upward with respect to the bracket. Thus, the effect of claim 1 can be reliably achieved.

  According to the fall prevention device for the small electric vehicle according to claim 3, when the arm receives an external force from the front side of the small electric vehicle, the arm is directed upward with respect to the bracket against the urging force of the urging means. Fluctuate. For this reason, when the small electric vehicle moves forward, when trying to get over the obstacle, it is possible to prevent the small electric vehicle from being unable to travel due to the auxiliary wheels and arms for preventing the overturn being caught by the obstacle. it can.

  According to the fall prevention device for the small electric vehicle according to the fourth aspect, since the diameters of the front wheels and the rear wheels of the small electric vehicle are substantially the same, when the obstacle is in front of the small electric vehicle, the direction is changed. Even if you do not go back and get over this obstacle, you can go forward and get over this obstacle easily. Therefore, it can be predicted that the passenger tries to get over the obstacle in front of the small electric vehicle, and the effects of claims 1 to 3 can be achieved more reliably.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a left side view of a small electric vehicle including the overturn prevention device according to the embodiment of the present invention, FIG. 2 is a plan view of the small electric vehicle of FIG. 1, and FIG. FIG. 4 is a front view of the small electric vehicle, and FIG. 4 is a rear view of the small electric vehicle of FIG. Hereinafter, the left and right and front and rear directions of the small electric vehicle are referred to based on the passenger.

  This small electric vehicle (hereinafter simply referred to as “vehicle”) 1 is a single-seater and has front suspensions on both the left and right sides of the front end portion of the body frame 11 as shown in FIGS. A pair of left and right front wheels 12 are attached via front wheel suspensions (not shown). A pair of left and right rear wheels 13 are attached to the left and right sides of the rear end portion of the body frame 11 via rear wheel suspension portions (not shown) having rear suspensions 39 (see FIGS. 5A and 5B). ing. The diameters of the front wheel 12 and the rear wheel 13 are substantially the same. A leg shield 15 is erected on the front part of the vehicle body frame 11, and a handle 24 for steering the front wheel 12 left and right is provided on the leg shield 15. A rear body 20 is provided at the rear of the vehicle body frame 11, and a seating seat 16 that is rotatably supported on a horizontal plane is installed on the rear body 20. A low floor type footrest floor 14 is provided between the leg shield 15 and the rear body 20.

  The seat 16 is a single seat and includes a seat 19, a backrest 17, and a pair of left and right armrests 18. The armrest 18 is rotatably supported on a vertical plane (in the direction of the arrow in FIG. 1). In addition, the seating seat 16 can be fixed in a predetermined direction by an angle determination mechanism (not shown), so that passengers can get on and off. On the outer side surfaces of the left and right armrests 18, a pair of left and right turn signals 25 are provided.

  As shown in FIGS. 1 and 3, a front basket 26 for loading luggage is provided on the front surface of the leg shield 15. A headlight 27 is provided below the front basket 26.

  As shown in FIG. 1, the rear body 20 has a front portion covered with a battery cover 22 and a rear portion covered with a rear cover 23. A seat post cover 21 is attached to the rear portion 11 a of the vehicle body frame 11 and covers the middle portion of the rear body 20.

  As shown in FIGS. 2 and 3, the handle 24 includes a base portion 28 and a pair of substantially U-shaped grips 29 attached to the left and right side surfaces of the base portion 28. The grip 29 is of a so-called tiller handle type. The base 28 is equipped with an operation box 30 for performing various operations of the vehicle 1 at the rear. Further, the handle 24 is attached to a parking brake lever 31 attached to the left front portion of the base portion 28, accelerator levers 32 and 33 attached to both left and right side surfaces of the base portion 28, and an upper surface of the base portion 28. A pair of left and right rearview mirrors 34.

  As shown in FIG. 4, a gear case 35 and an electric motor 36 are provided at the lower portion of the rear body 20 so as to correspond to the pair of left and right rear wheels 13. The left and right gear cases 35 accommodate a reduction gear mechanism, a differential gear mechanism, an electromagnetic brake device for braking, a clutch mechanism, and the like (all not shown). The rear wheel 13 is pivotally supported on axles (not shown) protruding outward from the left and right gear cases 35, and the rear wheel 13 is driven by the rotation of the electric motor 36. As shown in FIG. 1, a pair of left and right batteries 37 for supplying electric power to the pair of left and right electric motors 36 are disposed inside the rear body 20.

  The vehicle 1 is provided with a clutch lever 38 on the back surface of the backrest 17 of the seating seat 16 for connecting or disconnecting the electric motor 36 and the rear wheel 13 (see FIGS. 1 and 4). The clutch lever 38 can be used to switch between transmission and non-transmission of power from the electric motor 36 to the rear wheel 13.

  Moreover, as shown in FIGS. 1-4, the vehicle 1 is provided with the left-right paired fall prevention apparatus 40 and 41 which concern on embodiment of this invention in the lower part of the left-right gear case 35, respectively. The fall prevention devices 40 and 41 prevent the vehicle 1 from falling on an uphill road or the like, as will be described later.

  Below, the fall prevention apparatuses 40 and 41 are demonstrated. The pair of left and right fall prevention devices 40 and 41 are formed symmetrically with each other. For this reason, only the right side fall prevention device 41 will be described below.

  5A and 5B are enlarged views of the vicinity of the right-side fall prevention device 41 attached to the vehicle 1, and FIG. 5A is a perspective view of the fall-prevention device 41 from the back and the left side. FIG. 5B is a perspective view of the fall prevention device 41 from the back and right side. 6 is a rear view of the overturn prevention device 41 attached to the gear case 35, FIG. 7 is a left side view of the overturn prevention device 41, and FIG. 8 is taken along line VIII-VIII in FIG. It is sectional drawing of the fall prevention apparatus 41. FIG.

  As shown in FIGS. 5A and 5B, the fall prevention device 41 is attached to the lower part of the gear case 35. The fall prevention device 41 includes a sub-wheel bracket 42 extending substantially horizontally rearward from the lower portion of the gear case 41, a sub-wheel arm 43 attached to the sub-wheel bracket 42, and a sub-wheel attached to the sub-wheel arm 43. 44.

  The sub-wheel bracket 42 is, for example, a bracket having a substantially U-shaped cross section, and is a channel-shaped bracket that extends substantially linearly. One end of the sub-wheel bracket 42 is fixed to a flange 35a formed on the lower surface of the gear case 35 by a fixing bolt 45 (see FIGS. 7 and 8), and the upper surface of the sub-wheel bracket 42 is formed on the rear portion of the gear case 35 by a bolt 46. (See FIGS. 7 and 8), and is fixed to the gear case 35 so as to extend substantially horizontally rearward from the lower portion of the gear case 35. Further, the sub-wheel bracket 42 is formed so that the rear end portion can sandwich the sub-wheel arm 43 so as to be swingable in the vertical direction (see FIGS. 6 and 8).

  One end of the sub wheel arm 43 is fixed to the rear end portion of the sub wheel bracket 42 by the shaft bolt 47 so as to be rotatable about the shaft bolt 47 (see FIGS. 5A to 8). The shaft bolt 47 is mounted substantially horizontally in the left-right direction with respect to the sub-wheel bracket 42 (see FIG. 6), so that the sub-wheel arm 43 is centered on the shaft bolt 47 in the front-rear direction of the vehicle 1. It is rotatable in a substantially parallel vertical plane (in the direction of arrow a in FIG. 7). That is, the sub wheel arm 43 is configured to be able to swing in the vertical direction (arrow a direction) with respect to the sub wheel bracket 42. Further, the sub wheel arm 43 is formed so that the other end portion rotatably holds the sub wheel 44 (see FIG. 6).

  The sub wheel 44 is rotatably fixed to the other end portion of the sub wheel arm 43 by a shaft bolt 48 (see FIGS. 5A to 8). The shaft bolt 48 is attached substantially horizontally in the left-right direction with respect to the sub-wheel bracket 43 (see FIG. 6). The sub-wheel 44 is disposed at a predetermined height that does not contact the ground on a flat surface without an obstacle.

  Moreover, the fall prevention device 41 includes a stopper bolt 49 attached to the sub wheel bracket 42, a cushion 50, and a spring 51, as shown in FIGS.

  The stopper bolt 49 is attached in the vicinity thereof in parallel to the shaft bolt 47, and as shown in FIG. 8, when the sub wheel arm 43 rotates clockwise (in the direction of arrow b) to a predetermined position, The sub wheel arm 43 is disposed at a position in contact with the front surface portion 43 a. That is, the stopper bolt 49 defines the rotation range of the sub wheel 43 in the clockwise direction (arrow b direction). Further, as shown in FIG. 8, when the vehicle 1 is in a horizontal state, the stopper bolt 49 is positioned when the shaft center of the shaft bolt 48 is located slightly ahead of the vertical center (on the line 11) of the shaft bolt 47. In addition, the sub wheel arm 43 is disposed at a position in contact with the front surface portion 43 a.

  The cushion 50 is attached to the upper part of the rear end of the sub-wheel bracket 42, and is disposed at a position where the rear surface portion 43b of the sub-wheel 43 abuts when the sub-wheel 44 reaches a predetermined height. That is, the cushion 50 defines a rotation range of the sub wheel 43 in the counterclockwise direction (the direction of arrow c in FIG. 8). The cushion 50 is formed from an elastic member such as rubber, another resin member, or a metal member.

  As described above, the stopper bolt 49 and the cushion 50 define the rotation range of the sub wheel arm 43 in the directions of the arrows b and c around the shaft bolt 47. That is, the sub-wheel arm 43 is moved up and down between the position where the front surface portion 43a abuts against the stopper bolt 49 in the rearward direction of arrow b and the position where the rear surface portion 43b abuts against the cushion 50 and down between the direction of arrow c. It is configured to be able to swing in the direction.

  The spring 51 is attached so as to urge the sub wheel arm 43 in the direction of arrow b. Specifically, the spring 51 is, for example, a coil spring, and is attached so that the shaft bolt 47 penetrates, one end thereof is fixed to the sub-wheel arm 43, and the other end abuts against the stopper bolt 49. Accordingly, the sub wheel arm 43 is in a state where the front surface portion 43a abuts against the stopper bolt 49 (hereinafter referred to as “normal state”) in a state in which no force other than the urging force of the spring 51 acts on the sub wheel arm 43. ). Thereby, the sub wheel 44 is held at a low position. Further, when a force that rotates the sub wheel arm 43 in the direction of the arrow c against the urging force of the spring 51 acts on the sub wheel arm 43, the sub wheel arm 43 jumps up. The jumping height of the sub wheel arm 43 is a height corresponding to the size of the obstacle, the traveling speed of the vehicle 1 and the like. Note that the height of the sub-wheel arm 43 that springs up is maximized when the sub-wheel arm 43 hits the cushion 50.

  Note that, as described above, the left-side fall prevention device 40 has a symmetrical structure with respect to the right-side fall prevention device 41, and thus detailed description thereof is omitted.

  Hereinafter, the operation of the overturn prevention devices 40 and 41 having the above-described configuration will be described.

  As shown in FIG. 9, while the vehicle 1 is traveling on an uphill road, the operation of the overturn prevention devices 40 and 41 when the front wheel 12 of the vehicle 1 is lifted as shown in FIG. This will be described with reference to FIG. As described above, the left-side fall prevention device 40 has a symmetrical structure with respect to the right-side fall prevention device 41 and operates in the same manner as the right-side fall prevention device 41. Only the operation will be described below. FIG. 11 is an enlarged view showing the operation of the overturn prevention device 41 in the vehicle 1 traveling on the uphill road, and FIG. 12 shows the operation of the overturn prevention device 41 in the state where the front wheel 13 is lifted in the vehicle 1 running on the uphill road. It is an enlarged view which shows operation | movement.

  As shown in FIG. 11, during traveling on an uphill road (see FIG. 9), the sub wheel arm 43 of the fall prevention device 41 is held in a normal state, and the sub wheel 44 is held at a predetermined height from the ground. ing. Next, when the front wheel 12 of the vehicle 1 is lifted for some reason (see FIG. 10), the sub-wheel 44 contacts the ground as shown in FIG. At this time, the reaction force that the sub-wheel 44 receives from the ground is the direction of the arrow d perpendicular to the ground, and the direction in which the reaction force acts (the direction of the arrow d) is the rotation of the sub-wheel therm 43 as shown in FIG. The front side is a line l2 connecting the center p1 of the shaft bolt 47, which is the center, and the grounding point p2 of the sub-wheel 44.

  For this reason, the rotational moment of the sub wheel arm 43 around the shaft bolt 47 due to the reaction force of the ground acts in the direction of the arrow e. Accordingly, the reaction force due to the grounding of the sub wheel 44 tries to rotate the sub wheel arm 43 forward (in the direction of arrow e), and the sub wheel arm 43 is kept in the normal state by the stopper bolt 49.

  As described above, even when the front wheel 13 is lifted and the vehicle 1 is tilted backward, the sub wheel arm 43 continues to maintain the normal state. Therefore, the sub wheel 44 is grounded and the vehicle 1 is fixed by the shaft bolt 47 and the stopper bolt 49. The vehicle 1 can be supported and the vehicle 1 can be prevented from falling.

  As shown in FIG. 8, the overturn prevention device according to the present embodiment has a shaft center of the shaft bolt 48 slightly forward of the shaft 1 just below the shaft center of the shaft bolt 47 (on the line 11) in the horizontal state of the vehicle 1. A stopper bolt 49 is disposed at a position where the front wheel 43 abuts the front surface portion 43 a of the sub wheel arm 43, and the sub wheel arm 43 is held in this normal state by a spring 51. With this configuration, when the vehicle 1 tilts backward and the sub wheel 44 contacts the ground, the reaction force that the sub wheel 44 receives from the ground is always the center p1 of the shaft bolt 47 and the ground point p2 of the sub wheel 44. The rotation moment acting on the sub-wheel arm 43 due to the reaction force of the ground always works forward (in the direction of arrow e), and the sub-wheel The arm 43 continues to be held in the normal state.

  The arrangement position of the stopper bolt 49 is not limited to the above-described position. The stopper bolt 49 abuts against the front surface 43a of the sub wheel arm 43 when the shaft center of the shaft bolt 48 is positioned directly below (on the line 11) in FIG. It is also possible to set the sub wheel arm 43 so that the sub wheel arm 43 is held in the normal state. However, when the vehicle 1 tilts backward and the sub wheel 44 contacts the ground, for example, even if a disturbance such as a road surface condition acts, the sub wheel arm 43 is reliably held in the normal state. The stopper bolt 49 is located at a position where it comes into contact with the front surface portion 43a of the sub-wheel arm 43 when the shaft center of the shaft bolt 48 is located slightly forward of the shaft bolt 47 vertically below the axis (on the line 11). Is preferably arranged.

  Further, as described above, since the sub wheel arm 43 is held in the normal state, the sub wheel 44 is held at a low position. Therefore, the sub-wheel 44 can contact the ground before the vehicle 1 is largely tilted backward, and the vehicle 1 can be prevented from falling. For this reason, it is preferable that the sub wheel 44 is disposed at a low position in the normal state of the sub wheel arm 43.

  Next, the operation of the overturning prevention device 41 when the vehicle 1 travels forward and gets over or passes an obstacle present ahead will be described with reference to FIGS. FIG. 13 is an enlarged view showing the operation of the fall prevention device 41 in the vehicle 1 traveling on a flat road, and FIG. 14 is an enlarged view showing the operation of the fall prevention device 41 when getting over the obstacle of FIG. is there.

  As shown in FIG. 13, while the vehicle 1 is traveling on a flat road, the fall prevention device 41 is held in a normal state by the front portion 43 a of the sub wheel arm 43 abutting against the stopper bolt 49 by the urging force of the spring 51. The Next, when the vehicle 1 further moves forward and the sub wheel 44 hits the rear surface of the obstacle, a reaction force in the backward direction acts on the sub wheel 44 from the obstacle as shown in FIG. Against this, the sub wheel arm 43 jumps backward. For this reason, the fall prevention device 41 is not caught by an obstacle. In addition, when the vehicle 1 gets over or passes an obstacle existing ahead while traveling forward, the sub-wheel 44 positioned at the lowest position among the components of the fall prevention device 41 hits the obstacle. .

  In this way, when the vehicle 1 travels over or passes an obstacle existing ahead during forward travel, if the sub wheel 44 of the sub wheel arm 43 held in the normal state hits the obstacle, the sub wheel As shown in FIG. 14, the arm 43 jumps backward (in the direction of arrow f), so that the sub wheel 44 rides on the obstacle and the rear wheel 13 idles without the obstacle being caught by the sub wheel arm 43 or the sub wheel 44. In addition, the vehicle 1 does not become impossible to travel.

  As described above, in the fall prevention device according to the embodiment of the present invention, the sub wheel arm 43 is vertically moved around the shaft bolt 47 with respect to the sub wheel bracket 42 fixed to the lower portion of the gear case 35 and extending rearward. It is pivotally supported at one end so that it can swing in the direction. Further, the spring 51 urges the sub wheel arm 43 to a position where it abuts against the stopper bolt 49 to hold the sub wheel arm 43 in this state. For this reason, the sub wheel 44 is held at a low position.

  Thus, according to the overturn prevention device according to the present embodiment, the sub-wheel 44 can contact the ground before the vehicle 1 is largely inclined backward, and the overturn of the vehicle 1 can be prevented. For this reason, it is possible to prevent the vehicle 1 from being overturned with a simple configuration without giving the passenger anxiety about overturning. Further, since the spring 51 urges the sub-wheel arm 43 downward and holds it in a normal state, the sub-wheel 44 does not protrude greatly toward the rear of the vehicle 1. For this reason, it is possible to suppress the sub wheel 44 from coming into contact with an obstacle such as a step when the vehicle 1 moves backward. Thereby, it can be prevented that the sub-wheel 44 rides on the obstacle and the rear wheel 13 idles and the vehicle 1 cannot run.

  Further, in the overturn prevention device according to the present embodiment, in the horizontal state of the vehicle 1, the shaft center of the shaft bolt 48 is located on the front side from the vertical directly below the shaft center of the shaft bolt 47 (on the line 11 in FIG. 8). When doing so (see FIG. 8), a stopper bolt 49 is disposed at a position where it abuts against the front surface portion 43a of the sub-wheel arm 43. With this configuration, the sub-wheel arm 43 is held in a normal state in contact with the stopper bolt 49 by the spring 51. Thus, when the vehicle 1 tilts backward and the sub-wheel 44 contacts the ground, the direction of the reaction force that the sub-wheel 44 receives from the ground is always determined based on the center p1 of the shaft bolt 47 and the grounding point of the sub-wheel 44. The rotational moment acting on the sub-wheel arm 43 due to the reaction force of the ground can always be directed forward (in the direction of arrow e in FIG. 12). Can act. Therefore, the sub wheel arm 43 can be kept in the normal state. That is, the shaft bolt 47 that is the pivot center of the sub-wheel arm 43 is disposed in the region on the rear side of the vehicle 1 with respect to the direction of the reaction force received from the ground when the sub-wheel 44 contacts the ground. Become.

  For this reason, according to the fall prevention device according to the present embodiment, when the vehicle 1 is tilted rearward and the sub-wheel 44 contacts the ground, the sub-wheel arm that is held in a normal state by the biasing force of the spring 51. It is possible to prevent the rotational moment against the urging force from acting on 43. Therefore, when the vehicle 1 tilts backward and the sub wheel 43 comes into contact with the ground, the sub wheel arm 43 held in the normal state swings upward (in the direction of arrow c in FIG. 8) with respect to the sub wheel bracket 42. Can be prevented. Thereby, when the vehicle 1 tilts backward, it is possible to reliably prevent the vehicle 1 from falling without giving the passenger a fear of falling.

  Further, in the fall prevention device according to the present embodiment, when the sub wheel 44 hits an obstacle or the like and the sub wheel arm 43 receives an external force from the front side of the vehicle 1, it resists the biasing force of the spring 51. The sub wheel arm 43 swings upward (in the direction of arrow f in FIG. 14) with respect to the sub wheel bracket 42.

  Therefore, according to the overturn prevention device according to the present embodiment, when the vehicle 1 moves forward, when the vehicle 1 tries to get over the obstacle, the sub-wheel 44 and / or the sub-wheel arm 43 are caught by the obstacle and It is possible to prevent the wheel 13 from idling and the vehicle 1 from running impossible.

  In addition, according to the overturn prevention device according to the present embodiment, the front wheel 12 and the rear wheel 13 of the vehicle 1 have substantially the same diameter. Therefore, when there is an obstacle in front of the vehicle 1, Without going backwards and overcoming this obstacle, you can easily move forward and get over this obstacle. Therefore, it can be expected that the passenger tries to get over the obstacle in front of the vehicle 1 and overcome the obstacle, and the effects such as the above-described prevention of overturning and overcoming the obstacle can be surely achieved.

It is a left side view of a small electric vehicle provided with the fall prevention device concerning an embodiment of the invention. It is a top view of the small electric vehicle of FIG. It is a front view of the small electric vehicle of FIG. It is a rear view of the small electric vehicle of FIG. FIG. 5 is an enlarged view of the vicinity of the right-side fall prevention device attached to the small electric vehicle of FIG. 1, FIG. 5 (A) is a perspective view from the back and left side of the fall prevention device, and FIG. It is a perspective view from the back and right side of the fall prevention device. It is a rear view of the fall prevention device attached to the gear case of the small electric vehicle of FIG. FIG. 6 is a left side view of the overturn prevention device of FIG. 5. It is sectional drawing of the fall prevention apparatus in alignment with line VIII-VIII of FIG. It is a figure which shows the mode of the small electric vehicle currently drive | working an uphill road. It is a figure which shows the mode of the small electric vehicle which the front wheel lifted during driving | running | working on an uphill road. It is an enlarged view which shows operation | movement of the fall prevention apparatus in the small electric vehicle currently drive | working an uphill road. It is an enlarged view showing the operation of the overturn prevention device in a state where the front wheels are lifted in a small electric vehicle traveling on an uphill road. It is an enlarged view which shows operation | movement of the fall prevention apparatus in the small electric vehicle which is drive | working a flat road. It is an enlarged view which shows operation | movement of the fall prevention apparatus at the time of getting over the obstacle of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Small electric vehicle 12 Front wheel 13 Rear wheel 35 Gear case 36 Electric motor 40, 41 Fall prevention device 42 Sub wheel bracket 43 Sub wheel arm 44 Sub wheel 45, 46 Fixing bolt 47, 48 Shaft bolt 49 Stopper bolt 50 Cushion 51 Spring

Claims (4)

In the overturn prevention device for a small electric vehicle provided with an auxiliary wheel for preventing overturning that contacts the ground and supports the small electric vehicle when the small electric vehicle tilts backward,
A bracket fixed to the car body,
An arm that is pivotally supported at one end so as to be swingable in the vertical direction with respect to the bracket, and the auxiliary wheel for preventing overturning is pivotally supported at the other end;
And a biasing means for biasing and holding the arm downward with respect to the bracket.   The swing center of the arm is disposed in a region on the rear side of the small electric vehicle with respect to a direction of a reaction force received from the ground when the auxiliary wheel for preventing overturning is installed on the ground. The fall prevention device of the described small electric vehicle.   The arm swings upward with respect to the bracket against the biasing force of the biasing means when the arm receives an external force from the front side of the small electric vehicle. Item 3. The apparatus for preventing overturning of a small electric vehicle according to Item 1 or 2.   The small electric vehicle according to any one of claims 1 to 3, wherein the small electric vehicle has a front wheel and a rear wheel having substantially the same diameter.

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