JP2019156044A - Simple chassis type four-wheel electric vehicle - Google Patents

Abstract

To provide a simple chassis type electric vehicle capable of floating and climbing over a protruded step in a stable state though having a wheel with a small diameter, realizing a small-turn performance of the vehicle with a simple mechanism, and reducing a vehicle body weight by not using an elastic body for impact absorption.SOLUTION: A skeleton frame structure includes: a main chassis extending in the longitudinal direction; a seat frame placed on and connected to its rear part; right and left side pipes extending to the right and left rear sides with approximately L-shapes from a front part of the main chassis; rear wheel right and left support pipes extending to the right and light rear sides with approximately L-shapes from a front part of the seat frame; a lateral axis pipe horizontally laid in the middles of the rear wheel right and left support pipes; and a pivot part by which rear ends of the right and left side pipes are pivotally supported to the lateral axis pipe. A steering shaft is rotatably protruded diagonally upward from a tip end part of the main chassis. Right and left front wheels are provided on the tip end part through a front wheel steering mechanism interlockingly installed consecutively.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a simple chassis type electric automobile.

  Conventionally, an electric vehicle configured with a simple chassis type such as a pipe has a drive source as a motor and rear wheel drive, and the steering system is configured by interlocking and connecting the front wheel steering mechanism to the handlebar, and the wheels are also small in diameter. It has been devised to reduce the weight of the car body as much as possible.

  For example, Patent Document 1 discloses a small electric vehicle including a steering device having an excellent steering performance by interlockingly connecting a front wheel steering mechanism to a handlebar to increase a steering angle.

JP 2003-261039 A

  However, since the electric vehicle configured in such a conventional simple chassis type has a small diameter, it is difficult to lift the small diameter wheel over when the left and right wheels of the non-driven wheel come into contact with the convex step of the uneven road. Even if the right and left wheels ride on the convex step, a complex structure is required so that the swinging and tilting operation of the front wheel shaft on the convex step is smoothly performed with respect to the horizontal axis of the driven wheel. Also, since the turning angle of the front wheel steering mechanism cannot be maximized, there is a disadvantage that the turning ability of the U-turn is not good.

  The present invention is characterized in that the left and right front wheels are arranged via a main chassis extending in the front-rear direction, a seat frame placed and connected to the rear portion thereof, and a front wheel steering mechanism linked to the front end portion of the main chassis. A simple chassis-type electric automobile.

  In addition, the front wheel steering mechanism has a steering shaft that protrudes obliquely upward from the front end portion of the main chassis, and a knuckle arm via a universal joint for allowing the left and right side portions to move up and down at the front end portion. The tie rod, the king pin, the steering frame, the handle, etc. are mainly constructed in an interlocking manner.

  Also, left and right side pipes extending in a substantially L shape from the front of the main chassis to the left and right rear, a rear wheel left and right support pipe extending from the front of the seat frame to the left and right rear in a substantially L shape, and a rear wheel left and right support pipe A skeleton frame structure is constituted by a horizontal axis pipe horizontally installed in the middle and a pivotal support part in which the rear end of the left and right side pipes is pivotally supported on the horizontal axis pipe.

  Further, a step portion is provided in the middle of the left and right side pipes extending in a substantially L shape from the front portion of the main chassis to the left and right rear.

  Further, the left and right rear wheels are respectively arranged in the middle of the rear wheel left and right support pipes extending in a substantially L shape from the front part of the seat frame to the left and right rear.

According to the present invention, the left and right front wheels are disposed via the main chassis extended in the front-rear direction, the seat frame placed and connected to the rear part thereof, and the front wheel steering mechanism linked to the front end of the main chassis. This reduces the influence of the road surface on the operation handle by conducting the impact received by the left and right front wheels from the road surface to the main chassis, reducing erroneous handle operation due to vibration during driving, and maintaining the straightness of the vehicle In addition, it is possible to reduce the necessity of gripping the handle strongly.
Further, in the conventional vehicle, the steering mechanism and the load absorbing mechanism from the road surface are configured separately, and each of them requires a connecting member for connecting to the front wheel. However, since the front wheel steering mechanism is connected to the main chassis in the present invention, the load that the front wheels receive from the road surface is absorbed by the main chassis while reducing the number of parts that make up the vehicle, reducing the overall weight of the vehicle. Thus, the fuel consumption during driving can be improved as compared with the conventional case.

  In addition, the front wheel steering mechanism has a steering shaft that protrudes obliquely upward from the front end portion of the main chassis, and a knuckle arm via a universal joint for allowing the left and right side portions to move up and down at the front end portion. The tie rod, kingpin, steering frame, steering wheel, etc. are mainly linked together to provide the front wheel steering mechanism necessary for steering as an automobile with a skeleton frame structure. The steering angle of the steering wheel can be made as small as possible, the structure can be made without any obstacles to running and steering, and the front wheel is steered even if either the left or right wheels ride on the convex part on the road surface. Since only the mechanism swings left and right about the steering axis, there is an effect that the convex step can be easily overcome even with a small-diameter front wheel.

  In addition, left and right side pipes extending in a substantially L shape from the front of the main chassis to the left and right rear, a rear wheel left and right support pipe extending in a substantially L shape from the front of the seat frame to the left and right rear, and the rear wheel A skeleton frame structure is configured by a horizontal axis pipe that is installed horizontally in the middle of the left and right support pipes, and a pivot part that pivotally supports the rear ends of the left and right side pipes on the horizontal axis pipe, thereby making it possible to simplify and minimize the skeleton frame. Regardless of the structure, the main chassis and the frame structure such as the seat frame and other various pipes that are connected to the rear part reduce the weight load on the driver and the load stress on the frame when driving. In addition, it has the effect of ensuring safety, and is equipped with various in-vehicle components required for electric automobiles such as left and right front and rear wheels and front wheel steering mechanism. Because the electric automobile can be configured with the minimum required frame configuration, it is lightweight and can exhibit functions that do not hinder traveling as an electric automobile, and the left and right side pipes, The load stress applied to the frame during traveling can be reduced by various constituent pipes with the rear wheel left and right support pipes extending in a substantially L shape from the front part of the seat frame to the left and right rear, and these left and right side pipes and rear wheel left and right The support structure with the support pipe can serve as a shock absorber for the entire vehicle body, and it is not necessary to incorporate a spring mechanism in particular, and it is possible to maintain sufficient strength despite the simple skeleton frame structure. There is an effect that can be secured.

  In addition, a step portion is provided in the middle of the left and right side pipes extending in a substantially L-shape from the front portion of the main chassis to the left and right, thereby providing a structure that can easily get on and off despite the skeleton frame structure. effective.

  In addition, the left and right rear wheels are arranged in the middle of the left and right support pipes after extending from the front part of the seat frame to the left and right rear sides in a substantially L shape, so that the wheels caused by the load load on the left and right rear wheels and the road surface unevenness The impulse can be absorbed by the left and right support pipes of the wheel after extending in an approximately L shape, and the structural strength can be increased by minimizing the load stress on the skeleton frame structure without requiring a shock absorbing mechanism such as a spring. There is an effect that can be enhanced.

It is a side view showing a simple chassis type electric four-wheeled vehicle in an embodiment of the present invention. It is a top view which shows the simple chassis type electric four-wheeled vehicle in embodiment of this invention. It is a perspective view showing a simple chassis type electric four-wheeled vehicle in an embodiment of the present invention. It is a perspective view showing a simple chassis type electric four-wheeled vehicle in an embodiment of the present invention. It is a figure which shows the stress produced in a front wheel at the time of overcoming a convex part. It is a figure which shows the stress which arises in a front wheel when the simple chassis type | mold electric motor vehicle in embodiment of this invention gets over a convex part. It is a figure which shows the stress concerning the frame structure of the seat lower part of the simple chassis type electric four-wheeled vehicle in embodiment of this invention. It is a figure which shows elongation of each pipe which comprises the frame structure of the seat lower part of the simple chassis type | mold electric four-wheeled vehicle in embodiment of this invention.

The gist of the present invention is that the main chassis 10 extended in the front-rear direction, the seat frame 20 placed and connected to the rear part thereof, and the left and right side pipes 30a extended from the front part of the main chassis 10 to the left and right rear in a substantially L shape, 30b, rear wheel left and right support pipes 40a and 40b extending substantially L-shaped from the front of the seat frame 20 to the left and right rear, and a horizontal shaft pipe 50 horizontally placed in the middle of the rear wheel left and right support pipes 40a and 40b, A skeleton frame structure 100 is constituted by a pivotal support portion 51 that pivotally supports the rear ends of the left and right side pipes 30a and 30b on the horizontal shaft pipe 50, and a reinforcing shaft pipe 41 that is horizontally mounted on the rear ends of the rear wheel left and right support pipes 40a and 40b. In addition, the left and right front wheels 80a and 80b are disposed through the front wheel steering mechanism 200 that is linked to the front end of the main chassis 10 in an interlocking manner. There is provided a chassis-type electric four-wheeled vehicle E,
Further, the front wheel steering mechanism 200 projects a steering shaft 60 so as to be rotatable obliquely upward from the front end portion of the main chassis 10, and a universal joint 70 for allowing the left and right side portions to move up and down freely at the front end portion. The knuckle arm 71, the tie rod 72, the king pin 73, the steering frame 74, the handle bar 75, and the like are mainly connected to each other, and are substantially L-shaped from the front of the main chassis 10 to the left and right rear. In the middle of the left and right side pipes 30a and 30b extended in a shape, a step portion 31 is provided, and the rear wheel left and right support pipes 40a extending from the front portion of the seat frame 20 to the left and right rear sides in a substantially L shape. In the middle of 40b, left and right rear wheels 81a and 81b are arranged, respectively.

  An embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 1, 2 and 3 show a side view, a plan view, a perspective view and the like of the simplified chassis type electric four-wheeled vehicle of the present invention.

  As shown in FIG. 3, the basic configuration of the simplified chassis type electric four-wheeled vehicle of the present invention includes a skeleton frame structure 100, which is mounted on a main chassis 10 extending in the front-rear direction and a rear part thereof. The seat frame 20 installed and connected, the left and right side pipes 30a and 30b extending in a substantially L shape from the front of the main chassis 10 to the left and right, and the substantially L shape extending from the front of the seat frame 20 to the left and right rear. Rear wheel left and right support pipes 40a and 40b, rear wheel left and right support pipes 40a and 40b, and a horizontal shaft pipe 50 that is horizontally installed, and a pivot 51 that pivots the rear end of the left and right side pipes 30a and 30b on the horizontal shaft pipe 50. And the rear axle left and right support pipes 40a and 40b and a reinforcing shaft pipe 41 that is horizontally mounted on the rear ends.

  As shown in FIG. 3, the main chassis 10 is formed of a frame having a rigid cross-section extending in the front-rear direction at the center of the vehicle body. The seat frame 20 and other various pipes 30a, 30b, 40a, 40b are the main chassis. 10 is attached.

  The rear end portion of the main chassis 10 rises upward at a certain height to form a seat frame 20 having a rectangular cross section extending rearward from above the rear end portion of the main chassis 10, thereby forming a vehicle body center frame 300 having a stepped side shape as a whole. is doing. Further, a substantially pigeon-shaped seat 21 is erected at the center of the seat frame 20.

  The left and right side pipes 30a and 30b are formed in a substantially L shape that protrudes from the front of the main chassis 10 in the lateral direction, and then bends at a substantially right angle and extends rearward as it is. Or it is comprised from the metal pipe which has rigidity.

The rear ends of the left and right side pipes 30a, 30b extend to the vicinity of the substantially front end edges of the rear wheels 81a, 81b.
The rear wheel left and right support pipes 40a and 40b extend in a substantially L shape from the connecting portion 11 between the rear end portion of the main chassis 10 and the front end portion of the seat frame 20 to the left and right rear sides via the bracket 12, and the rear ends thereof are rear wheels. It extends to the vicinity of the front and rear end edges of 81a and 81b.

As described above, the reinforcing shaft pipe 41 is installed in the middle of the rear wheel left and right support pipes 40a and 40b. In addition, a horizontal axis pipe 50 is installed between the rear wheel left and right support pipes 40a and 40b, in the vicinity of the rear wheel front end edge, and the rear wheel left and right support extending rearward in a substantially L shape on the left and right. The pipes 40 a and 40 b constitute a skeleton frame structure 100 as a whole by forming a substantially rectangular frame firmly by the horizontal axis pipe 50 and the reinforcing axis pipe 41.
In addition, as shown in FIG. 2, the substantially L-shaped rear wheel left and right support pipes 40a and 40b are formed such that the entire rear wheel left and right support pipes 40a and 40b are formed in a substantially rectangular shape by continuously connecting the L-shaped front ends. Further, the strength of the square pipe can be improved.

  Further, the rear ends of the left and right side pipes 30a and 30b are pivotally connected to the horizontal shaft pipe 50, and the pivot support portion 51 allows the horizontal shaft pipe 50 to play in the horizontal boss pipe 52 provided at the rear ends of the left and right side pipes 30a and 30b. It is configured by fitting. That is, the rear portions of the left and right side pipes 30a and 30b are maintained in strength and shape by the support structure of the horizontal pipe 50, and a certain spring constant can be generated by the frame structure. It performs the function of buffering the gravity load on the frame without requiring a frame buffer mechanism such as a mechanism.

  As described above, the vehicle body center frame 300 including the main chassis 10 and the seat frame 20 has a side-stepped vehicle body center frame 300 whose front end position is shifted to the front / rear / up / down position and the front ends of the left / right side pipes 30a, 30b and the rear wheel left / right support pipes 40a, 40b. The parts are connected, further extended rearward, and pivotally intersected at the rear part to form an integrally connected continuous frame.

In FIG. 1, reference numeral 32 denotes a front connection portion 32 between the front ends of the left and right side pipes 30 a and 30 b and the vehicle body center frame 300, and reference numeral 42 denotes a rear connection portion between the rear wheel left and right support pipes 40 a and 40 b and the vehicle body center frame 300. 42 is shown.
With respect to the frame of the skeleton frame structure 100 of the entire vehicle body, as will be described later, by the continuous relationship between the positions of the front and rear connecting portions 32 and 42 and the positions of the pivot portions 51 at the rear ends of the pipes 30a, 30b, 40a, and 40b. Thus, the suspension mechanism can be formed without using a spring. That is, the function of absorbing the impact on the frame of the entire vehicle body during traveling can be achieved.

  Reinforcing shaft pipes 41 are installed horizontally at the rear ends of the rear wheel left and right support pipes 40a and 40b to keep the rear shape of the rear wheel left and right support pipes 40a and 40b, and the rear parts of the rear wheel left and right support pipes 40a and 40b. A wheel support bracket 43 is suspended, a rear axle 44 is installed on the wheel support bracket 43, and left and right rear wheels 81a and 81b are connected to the left and right shaft ends.

  In the space between the left and right rear wheels 81a and 81b, as shown in FIG. 4, a rear wheel drive mechanism case 90 is horizontally placed between the rear wheel left and right support pipes 40a and 40b. Are provided with an electric motor 91 and an interlocking mechanism 92 for transmitting the rear wheels 81a and 81b from the electric motor 91.

  A battery case 93 is mounted on the upper surface of the rear wheel drive mechanism case 90. A wheel brake mechanism 46 is provided via a bracket 45 at a position in front of the rear wheels 81a and 81b in the middle of the rear wheel left and right support pipes 40a and 40b.

  The wheel brake mechanism 46 includes a brake shoe 47 that is press-contactable to the shaft peripheral surfaces of the rear wheels 81a and 81b, and a brake handle 48 for operating the brake shoe 47.

  In the drawing, reference numeral 31 denotes a flat step portion 31 provided in the middle of the left and right side pipes 30a, 30b extending in a substantially L shape from the front of the main chassis 10 to the left and right. The step part 31 can be provided on both sides or one side as required.

Further, a steering shaft 60 is provided so as to be rotatable obliquely above the front end portion of the main chassis 10, and the left and right front wheels 80 a and 80 b are linked to the front end portion of the steering shaft 60 via the front wheel steering mechanism 200. Has been established.
The steering shaft 60 is freely loosely fitted in a cylindrical support case 61 at the tip of the main chassis 10.
In addition, a universal joint 70 is provided at the tip of the steering shaft 60 so as to allow the steering member located on the left and right side portions to move up and down.
The steering member includes a knuckle arm 71, a tie rod 72, a king pin 73, a steering frame 74, a handle bar 75, and the like, and the front wheel steering mechanism 200 is configured by a steering member centered on the steering shaft 60.

The universal joint 70 for interlockingly connecting the steering member to the distal end portion of the steering shaft 60 includes a steering frame 74 integrally connected to the distal end portion of the steering shaft 60, and a free play in the cylindrical steering frame 74. The handle shaft 76 is fitted, and a knuckle arm 71 is integrally connected to the lower end portion of the handle shaft 76 via a bracket 77.
When one of the left and right front wheels 80a and 80b rides on the road surface convex portion, the steering members such as the handle bar 75 and the handle shaft 76 are integrated with the steering shaft 60 around the left and right via the universal joint 70. The swing operation is performed. When the steering member swings, the handle bar 75 also swings left and right, and the lower end of the handle bar 75 moves up and down.

  In order to keep the handlebar 75 in a horizontal position so as not to move up and down, the handlebar 75 is maintained in a horizontal posture with the universal joint 70 interposed between the lower end of the handle shaft 76 and the steering member. 75 steering operations can be configured.

  In the front wheel steering mechanism 200 including the steering member centered on the steering shaft 60, even when one of the left and right front wheels 80a and 80b rides on the convex portion when traveling on the ground, The steering member swings left and right up and down around the steering shaft 60 and easily gets over the road surface convex portion. Since the entire vehicle body constituted by the skeleton frame structure 100 does not tilt left and right, the tilting stress caused by the road surface convex portion can be concentrated on one of the left and right steering members, and it is possible to overcome the small diameter front wheel. .

In the drawing, reference numeral 31 denotes a flat step portion 31 provided in the middle of the left and right side pipes 30a, 30b extending in a substantially L shape from the front of the main chassis 10 to the left and right. The step part 31 can be provided on both sides or one side as required.
The skeleton frame structure 100 of the simple chassis type electric four-wheeled vehicle E configured as described above has characteristic structures in the following two points.

(First characteristic structure)
In the skeleton frame structure 100 of the present invention, a steering shaft 60 projecting obliquely above the tip of the main chassis 10 is configured to be rotatable, and a steering member is linked to the tip of the steering shaft 60. Then, the left and right steering operation of the front wheel is performed by operating the handle bar 75.
Here, in particular, the steering member that performs front wheel steering is left and right around the axial direction of the steering shaft 60, even if one of the left and right front wheels rides on the convex portion of the road traveling surface due to the rotation of the steering shaft 60. By swinging, the entire skeleton frame structure 100 can be kept flat without tilting left and right. Thus, even if one of the left and right front wheels 80a and 80b rides on the convex portion by the rotation of the steering shaft 60, the rear wheels 81a and 81b and the skeleton frame structure 100 can maintain the horizontal state.
In the conventional front wheel steering mechanism in which the steering shaft 60 does not rotate and one of the left and right front wheels 80a and 80b rides on the convex portion, the steering mechanism and the vehicle body frame tilt with the tilt of the front wheel. The front wheel diameter must be increased compared to the steering structure.

A conventional and a dynamic model for overcoming a convex portion of the present invention will be described with reference to FIGS.
In order for the front wheel to get over the convex portion, it is necessary to consider the upward force acting on the tire and the force in the vehicle traveling direction.

  With reference to FIG. 5, a description will be given of the load applied when overcoming a conventional step. First, consider the vertical force to lift the tire. As the vertical force, W is the gravity acting downward, T is the load generated on the front wheel when it collides with the convex part, and θ is the angle between the load T applied to the front wheel and the horizontal plane. The force generated upward on the wheel is Tcosθ. Therefore, in order for the front wheel to lift, Tcos θ> W (Equation 1) may be satisfied.

Next, consider the force acting in the horizontal direction for the tire to move forward over the step.
As the horizontal force, if the forward thrust is F, and the stress generated in the front wheel when it collides with the convex portion is T, the force that inhibits the forward movement is Tsinθ. Therefore, in order for the front wheel to move forward, F> Tsinθ (Formula 2) may be satisfied.

By transforming the above equation 1 with respect to T and substituting it into equation 2,
F ≧ (W / cos θ) × sin θ = W × (sin θ / cos θ) = W tan θ (Formula 3).
Furthermore, (F / W) ≧ tan θ (Expression 4) is established by modifying Expression 3.

Next, with reference to FIG. 6, a dynamic model for overcoming a convex portion when the rotatable steering shaft 60 of the present invention is provided will be considered.
First, as the force in the direction in which the tire moves, the force acting downward is Wcosφ, and the force acting upward is Tcos (θ−φ). Therefore, in order for the tire to lift,
Tcos (θ−φ) ≧ Wcosφ (Formula 5) may be satisfied.

Next, in order for the tire to move forward over the step, consider the force acting in the horizontal direction. As the force in the horizontal direction, if F is the force that the vehicle moves forward, and Tsinθ is the reaction force that is received when the tire collides with the convex portion, Tsinθ.
Therefore, in order for the vehicle to move forward, F ≧ Tsinθ (Formula 6) may be satisfied.

  Further, when Expression 5 is transformed with respect to T, T ≧ W × (cosφ / cos (θ−φ)) (Expression 7). Substituting Equation 7 into Equation 6 and rearranging results in F / W ≧ (cosφ · sinθ) / cos (θ−φ) (Equation 8), which indicates that the smaller the F / W, the easier it is to float. That is, the larger the inclination angle φ due to the rotation of the steering shaft 60 is, the smaller the cos φ is. Therefore, the smaller sin θ is, the easier it is to float, and the smaller the step difference is, the easier it is to float. Therefore, the closer to θ and φ, the closer to the maximum value, and when θ = φ, cos (θ−φ) = 1 and the maximum value is indicated. Preferably, the tilt angle φ due to the rotation of the steering shaft 60 is in the range of 5 ° <φ <45 °, and when the tilt angle φ is 30 °, the step is approximately 1/4 times the propulsive force compared to a normal suspension system. Overcoming is possible.

(Second characteristic structure)
In conventional car body configurations, if the spring mechanism or shock absorbing mechanism for shock absorption is omitted in order to reduce the overall weight of the vehicle and avoid the complexity of the structure, the ride comfort will be reduced accordingly, and an excessive load will be applied to the entire frame. There was a risk that the durability would be reduced. Therefore, in the present invention, the above problem can be solved by configuring based on the following theory. The characteristic structure (second characteristic structure) will be described below with reference to FIGS.

  In the skeleton frame structure 100 of the present invention, the same shock absorbing function as that of the spring can be achieved by using only the skeleton frame structure 100 without using a spring built-in suspension mechanism for absorbing shock.

  That is, the skeleton frame structure 100 of the present invention has a constant spring constant in terms of structure even if no spring is used as calculated below.

The characteristics of the skeleton frame structure 100 of the present invention are considered as follows from the Hooke's law.
In the present invention, an impact absorbing effect equivalent to that of a spring is obtained by expansion and contraction of the rear wheel left and right support pipes 40a and 40b and the left and right side pipes 30a and 30b. The relationship between spring elongation and force follows Hooke's law. That is, if the force applied to the skeleton frame structure 100 due to vibration during traveling of the vehicle is F and the extension of the spring is δL, the relationship of F = K · δL (Equation 9) is established. Here, K is a constant called a spring constant.

  Next, the spring constant [K] of the skeleton frame structure 100 of the present invention is calculated. As shown in FIG. 7, the force applied in the axial direction of the rear wheel left and right support pipes 40a, 40b is F1, the force applied in the axial direction of the left and right side pipes 30a, 30b is F2, and the impact force applied perpendicularly from the road surface is F. Assuming that the angle formed by the rear wheel left and right support pipes 40a and 40b and the left and right side pipes 30a and 30b is θ, F / F1 = sinθ is established, and when this equation is rearranged, F1 = F / sinθ (Equation 10) is established. To do.

  Further, F2 = F1 · cosθ (formula 11) is established from F2 / F1 = cosθ. When F1 of formula 10 is substituted into formula 11, F2 = (F / sinθ) · cosθ = F / tanθ (formula 12) is obtained. To establish.

Further, as shown in FIG. 8, the left and right side pipes 30a and 30b extend rearward by applying an upward force F to the rear wheel left and right support pipes 40a and 40b. The extension is shown in the formula:
δL / S = sin θ≈θ≈tan θ (Formula 13).

  When the entire skeleton frame structure 100 composed of two pipes is considered as a spring, the force applied to the entire skeleton structure is F, and the length of the pipe to be contracted is the stroke S. Therefore, if the spring constant is K, it can be expressed as F = KS according to the equations 10 and 12, and Hook's law. Therefore, it can be expressed as K = F / S (Formula 14).

  Further, as described above, the left and right side pipes 30a and 30b have an elongation of SL and an applied force of F2, so that when the spring constant is K2, it can be expressed as F2 = K2 · SL (Formula 15). Therefore, the extension of the left and right side pipes 30a and 30b can be expressed as SL = F2 / K2 (Formula 16).

Therefore, the spring constant of the skeleton frame structure 100 of the present invention is K = F / (SL / tan θ) by substituting Equation 13 for S of the spring constant equation K = F / S. Is substituted, K = F / ((F2 / K2) · (1 / tanθ)). Substituting Equation 12 into F2 gives K = K2 (tanθ) ² , which can be expressed as a spring constant K = K2. . If θ is 20 °, (tan θ) ² = 0.13, the spring constant of the skeleton frame structure 100 can be reduced to about １ ／ times.

  As described above, in the present invention, the structure of the main chassis 10 and the seat frame 20 is the vehicle body center frame 300, and the left and right side pipes 30a and 30b and the rear wheel left and right support pipes 40a and 40b are connected to the vehicle body center frame 300. In the steering mechanism that constitutes the skeleton frame structure 100 and further includes the left and right front wheels 80a and 80b, the left and right front wheels 80a and 80b are turned by the rotation of the steering shaft 60 connected to the center of the front wheel steering mechanism 200. Even if it rides on the left and right swing and the convex part around the center, only the wheel on which it rides swings and rises, and the other skeleton frame structure 100 is configured to run in a horizontal state with the running surface including the left and right rear wheels 81a and 81b. It has a special feature, and it is a simple chassis-type electric automobile with a small turn. It is possible to provide a driving easy electric four-wheeled vehicle having a buffering function in weighing.

E Simple Chassis Type Electric Automobile 100 Skeleton Frame Structure 300 Car Body Center Frame 10 Main Chassis 11 Connection Part 12 Bracket 20 Seat Frame 21 Seat 30a Left Side Pipe 30b Right Side Pipe 31 Step Part 32 Front Connection Part 40a Rear Wheel Left Support Pipe 40b Rear wheel right support pipe 41 Reinforcing shaft pipe 42 Rear connecting portion 43 Wheel support bracket 44 Rear axle 45 Bracket 46 Wheel brake mechanism 47 Brake shoe 48 Brake handle 50 Horizontal shaft pipe 51 Shaft support 52 Horizontal boss pipe 200 Front wheel steering mechanism 60 Directional axis 61 Support case 70 Universal joint 71 Knuckle arm 72 Tie rod 73 King pin 74 Steering frame 75 Handlebar 76 Handle shaft 80a Left front car 80b right front rear wheel 81a in the rear left wheel 81b right rear wheel 90 wheel drive mechanism case 91 electric motor 92 interlocking mechanism

Claims (5)

A main chassis extending in the front-rear direction;
A seat frame placed and connected to the rear part;
A simple chassis type electric four-wheeled vehicle, wherein left and right front wheels are arranged via a front wheel steering mechanism that is linked to the front end of the main chassis. The front wheel steering mechanism has a steering shaft that protrudes obliquely upward from the front end portion of the main chassis, and a knuckle arm via a universal joint for allowing the left and right side portions to move up and down at the front end portion. 2. A simple chassis type electric automobile according to claim 1, wherein a tie rod, a kingpin, a steering frame, a handle, and the like are mainly linked together. Left and right side pipes extending substantially L-shaped from the front of the main chassis to the left and right rear;
Rear wheel left and right support pipes extending in a substantially L shape from the front part of the seat frame to the left and right rear,
A horizontal axis pipe laid in the middle of the rear wheel left and right support pipe;
A pivot part pivotally supporting the rear end of the left and right side pipes on the horizontal axis pipe;
The skeleton frame structure is constituted by the simple chassis type electric automobile according to claim 1 or 2. The simple chassis according to any one of claims 1 to 3, wherein a step portion is provided in the middle of the left and right side pipes extending in a substantially L shape from the front portion of the main chassis to the left and right rear. Type electric automobile. 5. The left and right rear wheels are respectively arranged in the middle of the rear wheel left and right support pipes extending in a substantially L shape from the front portion of the seat frame to the left and right rear. Simple chassis type electric automobile described.

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