JP3840461B2 - 8-wheel drive electric vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an eight-wheel drive electric vehicle in which electric energy stored in a battery is supplied to a rotary electric motor for traveling, and wheels are driven by the rotary electric motor.
[0002]
[Prior art]
Compared to gasoline or diesel vehicles driven by an internal combustion engine that burns fossil fuels, electric vehicles whose wheels are driven by the electrical energy stored in the batteries are free from exhaust problems and are expected to spread from the standpoint of environmental measures. It is rare.
By the way, the weight of the battery, the mounting method, the driving method, and the like are the bottleneck in its spread. Therefore, various battery mounting methods, that is, battery storage methods, driving methods, and the like have been proposed.
[0003]
As a battery storage method, a method of storing in a space such as a hood of a vehicle body, a trunk room, or the like, or a battery storage method called a backbone method as described in JP-A-52-35023 has been proposed. That is, there is also known a backbone system in which a tunnel-shaped storage casing is provided in the front-rear direction of an automobile, and a battery is taken in and out from the front or rear of the storage casing.
Furthermore, Japanese Laid-Open Patent Publication No. 7-47842 proposes a frame-like floor structure in which the floor of the vehicle body is composed of a plurality of hollow frames having a substantially rectangular cross section, and batteries are accommodated in these frames. Has been. Hereinafter, this type of floor structure is referred to as a battery built-in frame (BBF structure) in this specification.
[0004]
On the other hand, as a driving method of an electric vehicle, four types of methods are known as shown in FIG. These methods are easily understood from the drawings and will not be described in detail. However, the method shown in FIG. 5A is called a conventional method, and the conventional internal combustion engine is replaced with a rotary electric motor. The system shown in (b) is a so-called no-transmission system in which the transmission is excluded from the system shown in (a), and the system in (c) is equipped with a rotary electric motor for the number of drive wheels. Defuresu method to remove the braking system type and shown (d), the is-wheel system incorporating a rotary electric motor on the inside of the vehicle wheel not on the vehicle body.
[0005]
A preferred form of the in-wheel system is proposed by Japanese Patent Laid-Open No. 7-81430. In this in-wheel system, a rotary electric motor for driving forms an integral structure with a reduction gear, a bearing brake and the like, and all or a part of this integral structure is housed in a wheel portion of a wheel.
[0006]
[Problems to be solved by the invention]
As described above, by adopting the BBF structure in the electric vehicle, a part of the problem of the battery housing method has been solved. In particular, in the BBF structure, there is an advantage that it is not necessary to provide a new space for battery storage and that the entire vehicle body can be reduced in weight because the battery storage container and the frame structure can be used together. In addition, since a heavy battery is stored under the floor, there is an advantage that the center of gravity of the vehicle body is low, and the stability and riding comfort of the automobile are improved. However, there are also points to be improved. For example, since the BBF requires that most of the floor surface be used in a planar shape, it may cause spatial interference with other components such as a driving device.
[0007]
In addition, by adopting an in-wheel system for the drive unit, there is no need to provide a special space for the drive unit on the vehicle body, resulting in a loss of energy transmission in the entire drive unit from the rotary motor to the tire. There is also an advantage that it disappears. However, the in-wheel method has a drawback that the load holding is deteriorated because of the so-called unsprung weight.
An object of the present invention is to provide an electric vehicle that eliminates the above-described conventional problems or disadvantages. Specifically, the effective use space of the vehicle body is wide, the entire vehicle body can be reduced in weight, and the center of gravity of the vehicle body is provided. The purpose is to provide an electric vehicle that is low in vehicle stability, ride comfort and road holding.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention first applies both the BBF structure and the in-wheel method simultaneously in one vehicle. That is, the BBF structure is adopted to reduce the disadvantages of the in-wheel method, and the adoption of the in-wheel method is intended to reduce the disadvantages of the BBF structure to achieve the above object. By adopting both types in this way, an electric vehicle with a wide effective use space, a light weight of the entire vehicle body, a low center of gravity of the vehicle body, good vehicle stability and ride comfort, and good road holding can be obtained. . In particular, the rotary electric motor is configured to be mounted on eight wheels in order to actively reduce the deterioration of road holding.
As described above, by storing the battery in the frame of the BBF structure, the effective use space is widened, but in the electric vehicle, in addition to the battery and the drive device, a control device that controls the speed and torque of the rotary motor, Car-mounted chargers, air conditioners, etc. are also installed, but all or part of them are preferably housed in the interior space of the floor structure in the same manner as batteries, so that the effective volume inside the vehicle body can be increased. It becomes possible.
[0009]
Also, if the wheel house protrudes greatly into the vehicle body as in a conventional automobile, the effective use space cannot be widened. This problem can be solved by making the wheel diameter smaller than that of the conventional one, for example, by half. When the diameter of the wheel is reduced in this way, the load resistance per wheel decreases and the vibration that the vehicle body receives from the road surface also increases. Therefore, the present invention is configured to suppress the vibration received by the vehicle body from the road surface as much as possible by replacing one wheel of the automobile with two small-diameter wheels arranged at the front and rear.
[0010]
That is, in order to achieve the above object, the invention according to claim 1 is configured such that the electric energy stored in the battery is supplied to the rotary electric motor of the in-wheel drive device, and the wheel is driven by the rotary electric motor. In the electric vehicle according to the present invention, the floor structure of the vehicle is composed of a plurality of axially hollow frames, whereby the rigidity of the floor structure is enhanced, and the battery is The front wheel and the rear wheel are composed of two small-diameter wheels continuously attached in the front-rear direction, and the rotary electric motor is attached to the wheel portion of each of the continuously provided wheels, The rotary electric motor and the floor structure are connected via a suspension device.
[0011]
Embodiment
Embodiments of the present invention will be described below. FIG. 1 is a schematic perspective view of a floor structure and a driving device of a passenger electric vehicle according to a reference example of the present invention having a part of the same structure as that of the embodiment of the present invention . As shown in the figure, the floor structure 1 is configured such that the upper surface is substantially flat from four hollow bodies having a substantially rectangular cross section. That is, it is composed of axially hollow side frames 2 and 2 'located on both sides of the vehicle and similarly axially hollow center frames 3 and 3' located inside thereof. These frames 2, 3,... Are arranged in parallel to each other to have a predetermined width, and after a reinforcing subframe is attached, doors are provided on the side frames 2, 2 ′, and the center frame 3, 3 ′ is attached with a well-known seat, steering wheel, accelerator or brake pedal, cowl, lever for determining the traveling direction, and the like, thereby constituting the basic part of the electric vehicle. However, these are not shown in the figure.
[0012]
As described above, the floor structure 1 is formed to have a predetermined width from the side frames 2 and 2 ′ and the center frames 3 and 3 ′. Etc. are not particularly limited. However, it is desirable to form by, for example, an aluminum extrusion technique. The center frames 3 and 3 ′ and the side frames 2 and 2 ′ formed in this way can be divided into a plurality of parts in the front-rear direction due to the strength enhancement and the size of the stored items. Does not show an example of partitioning. The center frames 3 and 3 are substantially equal to the length obtained by subtracting the front and rear collision buffer portions from the entire length of the automobile, and the height and width are the same as the shape or size of the batteries B, B ′,. In consideration, the height of the batteries B, B,... Is slightly higher and the width is made slightly wider. The side frames 2, 2 'are shorter than the center frames 3, 3' only by the wheel house, and the height is substantially the same as the center frames 3, 3 '.
[0013]
According to the reference example , the floor structure 1 is composed of the center frame 3, 3 ′ having the hollow cross section and the side frames 2, 2 ′. Although the battery can be housed, the reference example shown in FIG. 1 shows an example in which the battery is housed in the center frames 3 and 3 ′ located at the center. In this case, the batteries B, B,... Can be stored from the front or the rear. However, in the reference example shown in FIG. 1, a drive device including a drive motor and a speed reducer for driving the wheels 8, 8 is arranged on the right rear side in FIG. 1. D is put in and out. Further, the side frames 2 and 2 ′ include a control device 4 and 4 ′ for controlling the speed, torque, and the like of a rotary electric motor, which will be described later, a charger 5 for charging the batteries B, B,. Etc. are stored.
[0014]
Since the in-wheel drive devices 7 and 7 'themselves can be applied with a device as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-81430, it will not be described in detail, but in order to reduce the rotational speed of the rotary motor. It is integrally formed from a reduction gear mechanism, a mechanical brake, a bearing for supporting rotation, and the like. And the outer frame which is attached to the inside of the wheels 8 and 8 'of the driving wheel and to which the armature of the rotary electric motor is fixed is attached to the suspension arm. Tires 9 and 9 'are attached to the wheels 8 and 8' to enable traveling. Arms, springs, dampers, and the like that form a suspension are attached to the in-wheel drive devices 7 and 7 ', but are omitted in FIG. The front wheels 10, 10 'are also attached to the center frame 3, 3' via arms, springs, dampers, etc. that form subframes and suspensions, but are omitted in FIG. Specific examples are shown in FIGS.
[0015]
FIG. 2 is a perspective view schematically showing an embodiment of a floor structure of an electric vehicle and a driving apparatus according to the present invention. Since the floor structure 1 has the same BBF structure as that of the reference example shown in FIG. In this embodiment, the wheel diameter is reduced compared to the conventional one to secure a wider effective use space, and the reduction in load resistance per wheel caused by the wheel diameter reduction is placed on two wheels. It is supplemented by replacing. That is, the floor structure 1 is supported by four relatively small-diameter rear wheels 13, 14, 13 ', 14' and four relatively small-diameter front wheels 15, 16, 15 ', 16'. Yes. According to the present embodiment, the in-wheel drive devices 7 and 7 ′ are applied. The in-wheel drive devices 7 and 7 'are attached to all eight front and rear wheels 13 to 16'. However, FIG. 2 shows an example in which the in-wheel drive devices 7 and 7 ′ are attached only to the rear wheels 13 and 13 ′. These wheels 13 to 16 'are similarly attached to the center frame 3, 3' via arms, springs, dampers and the like forming a suspension structure. Specific examples of how to attach them are shown in FIGS. Is shown in
[0016]
FIGS. 3A and 3B show the first embodiment of the suspension device 20, in which FIG. 3A is a plan view and FIG. 3B is a front view thereof. Since the floor structure 1 is the same as the reference example described above , the same reference numerals are attached and the description is not repeated. According to the present embodiment, the floor structure 1 is suspended by the double wishbone type 20, 20 ′. That is, the center frames 1 and 1 ′ are provided with first horizontal subframes 21 and 21 ′, and vertical second subframes 22 and 22 ′. And between the 1st sub-frame 21 and 21 'and the outer frame of a rotary electric motor, the buffer members 23 and 23' which consist of a spring and a damper are provided. Thereby, the rotary electric motor and the floor structure 1 are connected via the suspension device. A lower arm 25, 25 'is provided between the second subframe 22, 22' and the wheels 16, 15, 16, 16 ', and the center frame 1, 1' and the wheels 16, 15, 16, 16 'are provided. Upper arms 26 and 26 'are provided between the upper and lower ends.
[0017]
4A and 4B are diagrams showing another embodiment of the suspension, in which FIG. 4A is a plan view showing a specific example of a suspension in which only a pair of wheels 15 and 16 are taken out, and FIG. 4B is a front view. It is. Since the floor structure 1 is the same as the form shown by FIGS. 1-3, the same referential mark is attached | subjected and duplication description is not carried out. In the present embodiment, the floor structure 1 is supported by two wheels 16 and 15 by a suspension 30 that is a combination of a bogie structure and a double wishbone system 20. That is, the suspension 30 of the present embodiment includes a rigid structural member 31 that joins two wheels 16 and 15, and the structural member 31 with respect to the horizontal axis in FIG. The auxiliary structure member 32 is attached to the auxiliary structure member 32 so as to be freely rotatable, and the double wishbone type 20 is attached to the auxiliary structure member 32. In the present embodiment, the outer frame to which the armature of the rotary electric motor is fixed is attached to the structural member 31 although not shown in the drawing.
[0018]
Next, the operation of the above embodiment will be described. The electric vehicle according to the present embodiment can be driven by the same driving method as that of a normal passenger car. That is, when the lever for determining the traveling direction is tilted to the “forward” display side, for example, and the accelerator pedal is depressed, the electric power stored in the batteries B, B,. Similarly, the speed and torque control devices 4 and 4 'stored in the side frames 2 and 2' are fed to the rotary motors in the in-wheel drive devices 7 and 7 ', and the rotary motors rotate. Begin. This rotational force is transmitted to the wheel rims 8, 8 'and the tires 9, 9' through the reduction gears in the in-wheel drive devices 7, 7 ', and the electric vehicle starts. When the brake pedal is depressed during the stop, first, the control devices 4 and 4 'for speed, torque and the like stored in the side frames 2 and 2' work, and the in-wheel drive devices 7 and 7 ' The rotary electric motor works as a generator to generate electricity with the mechanical force to decelerate the car, and the electric power obtained here passes through the control devices 4 and 4 'and is stored in the center frames 3 and 3 and'. The charged battery is charged. When the vehicle is stopped in an emergency or when the vehicle is stopped from an extremely low speed, an in-wheel drive device or a mechanical brake housed in another wheel is simultaneously operated to obtain a deceleration force.
[0019]
The present invention is not limited to the above embodiment, and can be implemented in various forms. For example, although the number of center frames 3 and 3 ′ is two in the above embodiment, a small battery that is lightened by increasing the number of frames can be applied. The side frames 2 and 2 'contain a control device 4, a 4' charger 5, an in-vehicle cooling / heating device 6 and the like. If all of these devices cannot be stored, some of them are stored. Is done. It is obvious that the suspensions 20 and 30 are not limited to the above-described embodiment, and can be implemented by other suspension systems such as a strut system and a trailing arm system. Furthermore, although the present embodiment relates to a passenger electric vehicle, it is clear that the present invention can be widely applied to trucks, buses, and the like.
【The invention's effect】
As described above, according to the present invention, the floor structure of an automobile is composed of a plurality of frames that are hollow in the axial direction, whereby the rigidity of the floor structure is enhanced, and the battery has the floor structure. Stored in the body, the front wheel and the rear wheel are composed of two small-diameter wheels continuously attached in the front-rear direction, and the rotary electric motor is attached to the wheel portion of each continuously provided wheel, Since the rotary electric motor and the floor structure are connected via a suspension device, the following effects specific to the present invention can be obtained. A wide space in the passenger compartment can be used effectively. And since the battery is accommodated in the hollow body which comprises the floor structure, the position of the gravity center of an electric vehicle is low. In addition , despite the use of an in-wheel drive device, the influence of unsprung weight can be minimized and the ride comfort of the vehicle is improved. In particular, the output of the rotary motor can be distributed to eight wheels, and the weight of the rotary motor per unit can be reduced, so that the load holding of the wheels can be improved. Since the small diameter of the wheels, the reduction of the effective space due to protrude inside the wheel house cabin for the wheel can be suppressed to a minimum, the effect of being able to further expand the available space in the passenger compartment Is obtained. Moreover, since it is possible to suppress significantly the interference between the door and the wheel house is Installing the side of the car, increasing the degree of freedom of a position for attaching the door, the ease of passengers getting on and off is increased as a result, hence the passenger compartment The effect that it becomes possible to use the space of this more effectively can also be expected.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a reference example of the present invention having a part of the same structure as that of an embodiment of the present invention .
FIG. 2 is a perspective view showing an embodiment of an electric vehicle according to the present invention.
FIG. 3 is a diagram showing an embodiment of a suspension device, in which (a) is a plan view and (b) is a front view.
FIG. 4 is a view showing another embodiment of the suspension device, in which (a) is a plan view and (b) is a front view.
FIGS. 5A and 5B are diagrams schematically illustrating a driving method of an electric vehicle, and FIGS. 5A to 5D are plan views illustrating different examples. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Floor structure 2, 2 'Side frame 3, 3' Center frame 4, 4 'Control device 5 Charger 6 Air-conditioning device 7, 7' In-wheel drive device 20, 20 'Suspension 30, 30' Suspension

Claims (1)

In an electric vehicle in which electric energy stored in a battery is supplied to a rotary electric motor of an in-wheel type driving device, and wheels are driven by the rotary electric motor.
The automobile floor structure is composed of a plurality of axially hollow frames, whereby the rigidity of the floor structure is enhanced, and the battery is housed in the floor structure,
The front wheel and the rear wheel are composed of two small-diameter wheels continuously attached in the front-rear direction, and the rotary electric motor is attached to a wheel portion of each of the continuously provided wheels. The floor structure is connected via a suspension device, and is an 8-wheel drive electric vehicle .

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