Small electric vehicle

Abstract

This invention provides a small electric vehicle that can effectively increase the rigidity of the bending section of the main frame. [Solution] A small electric vehicle comprising a pair of main frames arranged side by side from front to rear of the vehicle, and a cross member connecting the pair of main frames, wherein each of the pair of main frames has a bent portion formed between its front and rear parts, and the cross member is arranged to straddle the front and rear of the bent portion.

Description

Technical Field

[0004] , ,

[0001] The present invention relates to a small electric vehicle.

Background Art

[0002] Patent Document 1 discloses a small electric vehicle including front wheels and rear wheels disposed at the front and rear of a vehicle body frame, and a seat installed on the vehicle body frame. The rear wheels are driven by a motor. A body cover is provided below the seat, and a battery and a controller of the motor are built in the body cover. The vehicle body frame has a pair of left and right side bars. The seat is installed on a seat post provided at the upper part of a seat frame connecting between the left and right side bars. The middle part of the left and right side bars is bent, and the rear parts of the left and right side bars extend obliquely upward and rearward. The seat frame is fixed to the rear parts of the left and right side bars. Hereinafter, the side bar of Patent Document 1 is referred to as a "main frame".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In small electric vehicles, if a bend is formed in the middle of the main frame, the main frame is prone to deformation starting from the bend. The rear of a small electric vehicle tends to be heavier than the front because it houses the motor, battery, and controller. Furthermore, the rear of a small electric vehicle is subjected to a large load, including the weight of the occupant, because the seat is installed there. If there is a large difference in load between the front and rear of the main frame, twisting is likely to occur at the bend, and the main frame is prone to deformation. To prevent deformation of the main frame, it is conceivable to increase the rigidity of the main frame by making it thicker or attaching reinforcing members to the main frame, but in that case, the cost, weight, and assembly productivity will worsen.

[0005] One of the objectives of the present invention is to provide a small electric vehicle that can effectively increase the rigidity of the bent portion of the main frame. [Means for solving the problem]

[0006] A small electric vehicle according to one aspect of the present invention comprises a pair of main frames arranged side by side from front to rear of the vehicle, and a cross member connecting the pair of main frames. Each of the pair of main frames has a bent portion formed between its front and rear ends. The cross member is arranged to straddle the front and rear of the bent portion. [Effects of the Invention]

[0007] By positioning the cross members connecting the pair of main frames so as to span both the front and rear of the bend, the rigidity of the bend in the main frame can be effectively increased. Because the main frame is less likely to deform from the bend, the handling stability of the small electric vehicle can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view of a small electric vehicle according to an embodiment. [Figure 2]Figure 2 is a schematic perspective view of the body frame of a small electric vehicle according to an embodiment. [Figure 3] Figure 3 is a schematic side view of the rear section of the vehicle frame shown in Figure 2, viewed from the side. [Figure 4] Figure 4 is a schematic perspective view of the rear section of the vehicle frame shown in Figure 2, viewed from a diagonal rearward angle. [Modes for carrying out the invention]

[0009] A specific example of a small electric vehicle according to an embodiment of the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. The sizes of the components shown in each figure are represented for the purpose of clarifying the explanation and do not necessarily represent the actual dimensions. In the figures, "FR" indicates the front of the vehicle, "RR" indicates the rear of the vehicle, "LH" indicates the left side of the vehicle, "RH" indicates the right side of the vehicle, "UP" indicates the top of the vehicle, and "LWR" indicates the bottom of the vehicle. The direction of each component in the following description will be described with reference to the direction of the vehicle described above.

[0010] <Small electric vehicles> The small electric vehicle 1 according to the embodiment will be described with reference to Figures 1 to 4. The small electric vehicle 1 of the embodiment is a single-seater electric vehicle. The small electric vehicle 1 of the embodiment shown in Figure 1 is a handle-type electric wheelchair (mobility scooter). Handle-type electric wheelchairs are sometimes called senior cars. Hereinafter, "small electric vehicle" will be simply referred to as "vehicle".

[0011] One of the features of the vehicle 1 of this embodiment is the structure of the vehicle frame 2 shown in Figure 2. Specifically, a cross member 25 connecting a pair of main frames 22 is positioned at the bent portion 22c.

[0012] As shown in Figure 1, Vehicle 1 comprises front wheels 11 and rear wheels 12, a steering wheel 15, and a seat 16. The occupant sits on the seat 16 and operates the steering wheel 15. Vehicle 1 in this embodiment is a four-wheeled vehicle having two front wheels 11 and two rear wheels 12. Unlike this embodiment, it may also be a three-wheeled vehicle with one front wheel 11 or one rear wheel 12.

[0013] Vehicle 1 is equipped with a motor 6 as shown in Figure 3, and moves by driving the rear wheels 12 with the motor 6. Power is supplied to the motor 6 from the battery 7 shown in Figure 1.

[0014] ≪Vehicle Frame≫ Vehicle 1 comprises a body frame 2 shown in Figure 2 and a cover 3 shown in Figure 1. The body frame 2 forms the skeleton of vehicle 1. The cover 3 is attached to the body frame 2 so as to cover the body frame 2. The body frame 2 includes a steering column 21, a main frame 22, a seat post 23, and a cross member 25.

[0015] [Mainframe] The main frame 22 is composed of a pair, left and right, as shown in Figure 2. The pair of main frames 22 are arranged side by side from front to rear of the vehicle 1. The pair of main frames 22 extend roughly parallel to each other in the front-rear direction. The right main frame 22 and the left main frame 22 are symmetrical. The main frame 22 in this embodiment is made of round pipe material. The front end 22a of the main frame 22 is connected to the steering column 21. In this embodiment, the front end 22a of the main frame 22 is welded to the steering column 21. In this embodiment, the front end 22a of each of the pair of main frames 22 is inclined diagonally upward toward the front. Except for the front ends 22a, the pair of main frames 22 extend almost horizontally from front to rear.

[0016] Each of the pair of main frames 22 has a bent portion 22c in the middle. The bent portion 22c is formed between the front portion 22f and the rear portion 22r of the main frame 22. The bent portions 22c of each of the pair of main frames 22 are formed symmetrically. In this embodiment, the distance between the main frames 22 narrows from front to rear, with the bent portion 22c in between. The portions located in front of the bent portion 22c have a wider spacing and are arranged almost parallel to each other. The portions located behind the bent portion 22c have a narrower spacing and are arranged almost parallel to each other.

[0017] The front section 22f is the part located in front of the bent section 22c. The front section 22f includes the front end 22a. The front section 22f extends almost horizontally except for the front end 22a. In this embodiment, the front section 22f is the horizontal part located in front of the seat post 23, where the floor cover 32, described later, is positioned. The rear section 22r is the part located behind the bent section 22c. The main frame 22 in this embodiment has a second bent section 22d, separate from the bent section 22c. The second bent section 22d is located behind the bent section 22c. In this embodiment, as shown in Figure 3, the rear section 22r inclines slightly upward diagonally towards the rear from the rear end of the front section 22f, then bends and extends diagonally downward towards the rear. The bent section 22c in this embodiment is formed to narrow the distance between the main frames 22 from front to rear and to bend upward. In other words, the bent section 22c bends in two directions: inward and upward of the vehicle 1.

[0018] [Steering column] The steering column 21 is located at the front of the vehicle 1. The steering column 21 supports a steering wheel 15 that steers the front wheels 11 shown in Figure 1. As shown in Figure 2, the steering column 21 extends generally in a vertical direction so as to intersect with the main frame 22. The steering column 21 is inclined such that its lower end is located forward of its upper end. A steering shaft (not shown) is rotatably inserted through the steering column 21. The steering wheel 15 is attached to the upper end of the steering shaft. The steering shaft transmits the rotational operation of the steering wheel 15 to the front wheels 11.

[0019] [Seat Post] The seat post 23 is provided at the rear part of the vehicle 1. The seat post 23 supports the seat 16 shown in FIG. 1. As shown in FIG. 2, the seat post 23 extends upward from the rear part 22r of the main frame 22. The seat post 23 of the embodiment is inclined such that the lower end is located forward of the upper end. The seat 16 is attached to the upper end portion of the seat post 23. In the embodiment, the seat post 23 is fixed on the cross member 25.

[0020] [Cross Member] As shown in FIG. 2, the cross member 25 connects between the pair of main frames 22. As shown in FIGS. 2 and 3, the cross member 25 is arranged so as to straddle before and after the bent portion 22c. That is, the cross member 25 connects between the bent portions 22c in the pair of main frames 22. The cross member 25 is arranged on the bent portion 22c and fixed to the straight portions before and after the bent portion 22c. The cross member 25 of the embodiment is a plate material having a U-shaped cross section with a front piece 25f, a horizontal piece 25u, and a rear piece 25r. The horizontal piece 25u extends horizontally. The front piece 25f extends vertically from the front end of the horizontal piece 25u. The rear piece 25r extends vertically from the rear end of the horizontal piece 25u. Each of the front piece 25f and the rear piece 25r is provided with a notch corresponding to the outer shape of the main frame 22. The notch in the embodiment is semi-circular. The notches of each of the front piece 25f and the rear piece 25r are fitted into the main frame 22, and the cross member 25 is fixed to the main frame 22. The front piece 25f of the cross member 25 is fixed to the straight portion of the front part 22f located in front of the bent portion 22c. The rear piece 25r of the cross member 25 is fixed to the straight portion of the rear part 22r located behind the bent portion 22c. In the embodiment, the cross member 25 is welded to the straight portions before and after the bent portion 22c. The seat post 23 is fixed to the upper surface of the horizontal piece 25u. [[ID=十二]] [[ID=十三]]

[0021] [[ID=十四]] Since the seatpost 23 is attached on top of the cross member 25, the cross member 25 is subjected to a large downward load. When the cross member 25 is positioned on a pair of main frames 22, the cross member 25 is supported from below by the main frames 22, making it difficult for the cross member 25 to detach from the main frames 22.

[0022] The cross member 25 connects the pair of main frames 22 and is fixed so as to straddle the front and back of the bent portion 22c. This structure effectively increases the rigidity of the bent portion 22c of the main frame 22. Therefore, the main frame 22 is less likely to deform starting from the bent portion 22c. Because the main frame 22 is less likely to deform, the handling stability of the vehicle 1 can be improved. In this embodiment, the cross member 25 also functions as a member that supports the seat post 23. Since one cross member 25 can achieve both improved rigidity of the main frame 22 and the function of supporting the seat post 23, it is advantageous in terms of cost, weight, and assembly productivity.

[0023] Unlike the embodiment, the cross member 25 may be fixed not only to the straight sections before and after the bent portion 22c, but also to the bent portion 22c itself. In that case, the cross member 25 may be an E-shaped member with a front piece 25f, a side piece 25u, a rear piece 25r, and an intermediate piece between the front piece 25f and the rear piece 25r. This configuration can further increase the rigidity of the bent portion 22c. Furthermore, the cross member 25 may also be attached to the second bent portion 22d in the same way as the bent portion 22c.

[0024] As shown in Figure 2, the vehicle frame 2 of the embodiment includes a front cross member 26 and a rear cross member 27. The front cross member 26 is provided on the front end 22a of the main frame 22. The front cross member 26 connects the front ends 22a of a pair of main frames 22. The front cross member 26 of the embodiment is made of pipe material. The front cross member 26 is welded to the front end 22a. The rear cross member 27 is provided on the rear end 22r of the main frame 22. The rear cross member 27 connects the rear ends 22r of a pair of main frames 22. The rear cross member 27 is positioned on the rear end 22r. Specifically, the rear cross member 27 is positioned in the portion of the rear end 22r where the distance between the main frames 22 is narrow and they are aligned parallel to each other. The rear cross member 27 of the embodiment includes a front plate portion 27f and a rear plate portion 27r arranged front and rear, and an upper plate portion 27u that connects the upper ends of the front plate portion 27f and the rear plate portion 27r. The front plate section 27f and the rear plate section 27r are C-shaped plates that open downwards. The upper plate section 27u is a rectangular plate that is long in the front-to-back direction. The front plate section 27f and the rear plate section 27r are welded to the rear section 22r.

[0025] In this embodiment, the vehicle frame 2 is equipped with a rear cross member 27, which increases the rigidity of the rear portion 22r of the main frame 22. Unlike this embodiment, the rear ends of a pair of main frames 22 may be connected to form a loop shape for the main frame 22. The rigidity of the rear portion 22r can be increased by placing the rear cross member 27 on the rear portion 22r of the main frame 22 or by forming the rear end of the main frame 22 in a loop shape. By increasing the rigidity of the rear portion 22r, it becomes easier to place heavy objects on the rear portion 22r. As will be described later, the suspension device 5 and motor 6 shown in Figures 3 and 4 are placed on the rear portion 22r.

[0026] [Upper frame] The vehicle frame 2 of this embodiment further includes an upper frame 4 as shown in Figure 2. The upper frame 4 is located above the rear portion 22r of the main frame 22. The upper frame 4 of this embodiment is positioned on top of the rear cross member 27. The upper frame 4 connects the seat post 23 and the rear cross member 27. The upper frame 4 extends rearward from the middle portion of the seat post 23. As shown in Figure 3, the shape of the upper frame 4 as viewed from the side of the vehicle 1 is generally triangular and tapers towards the rear. The upper surface of the upper frame 4 is inclined diagonally downward toward the rear. The front end of the upper frame 4 is fixed to the rear surface of the seat post 23. The rear part of the upper frame 4 is fixed to the upper surface of the upper plate portion 27u of the rear cross member 27. Even if a rearward stress acts on the seat post 23, the seat post 23 is supported by the upper frame 4 fixed to the rear cross member 27.

[0027] As shown in Figure 2, the upper frame 4 is provided with a base portion 41. The base portion 41 is positioned on top of the upper frame 4. The base portion 41 is a gate-shaped member having a left wall portion 411, a right wall portion 412, and an upper wall portion 413. The upper frame 4 is sandwiched between the left wall portion 411 and the right wall portion 412. The left wall portion 411 is fixed to the left side of the upper frame 4. The right wall portion 412 is fixed to the right side of the upper frame 4.

[0028] A shock absorber mounting bracket 42 is fixed to the base portion 41. Hereinafter, the "shock absorber mounting bracket" will be referred to as the "SA bracket". The SA bracket 42 has a mounting portion 42f to which the shock absorber 55 shown in Figures 3 and 4 is attached. The SA bracket 42 is made of plate material. The mounting portion 42f is provided so as to protrude from both the left and right sides of the base portion 41 in the left-right direction and rearward. The mounting portion 42f is inclined diagonally upward as it moves away from the base portion 41. The upper end 55u of the shock absorber 55 is fixed to the mounting portion 42f.

[0029] ≪Cover≫ Cover 3 includes a front cover 31, a floor cover 32, and a rear cover 33, as shown in Figure 1. The front cover 31 covers the steering column 21 and the front end 22a of the main frame 22, as shown in Figure 2. In this embodiment, a battery 7 is mounted behind the front cover 31. The floor cover 32 is positioned on the front 22f of the main frame 22, as shown in Figure 2, and covers the front 22f excluding the front end 22a. The feet of an occupant seated in the seat 16 rest on the floor cover 32. The rear cover 33 covers the area around the seat post 23 and the rear 22r of the main frame 22, as shown in Figure 2. The suspension device 5 and motor 6, as shown in Figures 3 and 4, are located inside the rear cover 33. Other components, such as a control unit for controlling the motor 6, are also located inside the rear cover 33. Unlike this embodiment, the battery 7 that supplies power to the motor 6 may be located inside the rear cover 33.

[0030] ≪Suspension≫ Vehicle 1 of the embodiment is equipped with a suspension system 5, as shown in Figures 3 and 4. The suspension system 5 supports the rear wheels 12 shown in Figure 1. The rear wheels 12 are located at the rear 22r of the main frame 22, as shown in Figure 2. As shown in Figure 4, one suspension system 5 is provided on each of the left and right sides of the rear 22r of the main frame 22. The left and right suspension systems 5 are independent of each other. The left and right suspension systems 5 support the left and right rear wheels 12, respectively. Each suspension system 5 comprises an arm 50, a coil spring 53, and a shock absorber 55. In Figures 3 and 4, the coil spring 53 is shown in a simplified manner.

[0031] The arm 50 is a member that supports the rear wheel 12 so that it can swing up and down. The arm 50 extends in the left-right direction. The arm 50 in this embodiment is a box-shaped body having a front part 50f, a rear part 50b, an upper part 50u, and a side part 50s, with an open lower part. When viewed from the rear of the vehicle 1, the shape of the arm 50 is an inverted trapezoid shape. The inner end of the arm 50 is supported by the rear cross member 27 by a pivot shaft 51. The inner end is the end closest to the rear part 22r. The pivot shaft 51 extends in the front-rear direction. The pivot shaft 51 is inserted so as to pass through the front part 50f and the rear part 50b. Both ends of the pivot shaft 51 are fixed to the front plate part 27f and the rear plate part 27r of the rear cross member 27, respectively. The outer end of the arm 50 can swing up and down around the pivot shaft 51. The outer end is the end furthest from the rear 22r, in other words, the end closest to the rear wheel 12. The upper part 50u connects the upper ends of the front part 50f and the rear part 50b. The side part 50s connects the outer ends of the front part 50f and the rear part 50b. A through hole 50h is formed in the side part 50s.

[0032] The coil spring 53 is a component that absorbs vibrations and shocks from the road surface. Known configurations can be used for the coil spring 53. In this embodiment, the coil spring 53 is attached to the outer circumference of the shock absorber 55. That is, the shock absorber 55 is positioned inside the coil spring 53. Unlike this embodiment, the coil spring 53 may be positioned away from the shock absorber 55.

[0033] The shock absorber 55 is a component that dampens the expansion and contraction of the coil spring 53. Known configurations can be used for the shock absorber 55. The lower end 55d of the shock absorber 55 is fixed to the upper part 50u of the arm 50. The upper end 55u of the shock absorber 55 is fixed to the mounting portion 42f of the SA bracket 42.

[0034] The SA bracket 42, to which the upper end 55u of the shock absorber 55 is fixed, is located above the upper frame 4. Therefore, in the vehicle 1 of this embodiment, a shock absorber 55 with a long stroke length can be used. A shock absorber 55 with a long stroke length can quickly dampen the expansion and contraction of the coil spring 53.

[0035] Motor Vehicle 1 of the embodiment is equipped with a motor 6, as shown in Figures 3 and 4. The motor 6 drives the rear wheels 12 shown in Figure 1. In the embodiment, one motor 6 is provided for each of the left and right rear wheels 12, and the left and right rear wheels 12 are driven independently. In the embodiment, the motor 6 is located inside the arm 50 and fixed to the arm 50. The motor 6 has a rotating shaft 60 to which the rear wheels 12 are attached. The rotating shaft 60 passes through a through hole 50h. Unlike the embodiment, the motor 6 may be an in-wheel motor located inside the rear wheel 12.

[0036] The present invention is not limited to these examples and is intended to include all modifications within the meaning and scope of the claims, as shown by the claims. For example, the bend 22c may bend outward from the vehicle 1 to widen the gap between the main frames 22 from front to rear. Also, although the bend 22c in the embodiment is bent in two directions, the bend 22c may be bent in only one direction. The bend 22c may be bent in only one direction, either inward or outward from the vehicle 1, or in only one direction, either upward or downward. [Explanation of Symbols]

[0037] 1. Small electric vehicle (vehicle) 11 Front wheels, 12 Rear wheels 15-inch handlebars, 16-inch seats 2. Vehicle frame 21 Steering column 22 Mainframes 22a front end, 22f front, 22r rear 22c Bending section, 22d Second bending section 23 Seatpost 25 Cross members 25f front piece, 25u side piece, 25r rear piece 26 Front cross member 27 Rear cross member 27f Front panel, 27r Rear panel, 27u Top panel 3 Cover 31 Front cover 32 Floor Covers 33 Rear cover 4. Upper frame 41 Base 411 Left wall section, 412 Right wall section, 413 Upper wall section 42 Shock absorber mounting bracket (SA bracket) 42f Mounting section 5. Suspension System 50 Arm 50f front, 50b rear, 50u top, 50s side 50h through hole 51 Pivot axis 53 Coil Springs 55 Shock absorbers 55d bottom edge, 55u top edge 6 motors 60 Rotation axis 7 Batteries

Claims

[Claim 1] A pair of main frames are arranged side by side from front to rear of the vehicle, It comprises a cross member connecting the pair of main frames, Each of the pair of main frames has a bent portion formed between its front and rear sections. The cross member is arranged to straddle the front and rear of the bent portion. Small electric vehicle.

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