JPH0789355A - Automobile using structural member as conductor - Google Patents

Abstract

PURPOSE:To lighten weight in an automobile as a whole so as to improve a traveling characteristic of the automobile by making the whole or a part of a structural member of a vehicle body of a conductor and electrically connecting a battery and a motor together so as to use the structural body of the automobile as a conductor at the same time. CONSTITUTION:A structural body 1, which constructs a space frame of an electric automobile and is provided with a feeding function at the same time, is desirably formed of Al alloy extruded material such as 6063, 6061, 6201 and is provided with an inner hollow 2 extending in the longitudinal direction. In a formation of the structural body 1, thickness t0 of a mounting part for installation of a bolt 3 is larger than the thickness t1-t3 of other parts, and a conductor 4 to be connected with a negative pole of a battery 5 is installed in the structural body 1 by means of the bolt 3. The space frame 7 is used as a common member, which connects the negative side of the battery 5 to a motor 6, for the negative pole. In this way, one of two bold conducting wires connecting the battery 5 and the motor 6 together can be omitted, so that lighting in weight can be accomplished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is particularly effective for electric vehicles that are required to be light in weight, and is a vehicle that uses other energy in combination with electricity or a vehicle equipped with an ordinary gasoline engine, diesel engine, or the like. Also applies to

[0002]

2. Description of the Related Art Electric vehicles are evaluated as a transportation means effective for environmental protection because they do not generate exhaust gas.
In an electric vehicle, a chassis is used as one conductor and appropriate wiring is provided as the other conductor, as in a vehicle equipped with a gasoline engine, a diesel engine, or the like. In an electric vehicle, the battery weight is 300-50
Since it is as large as 0 kg and the mileage per charge is limited, the demand for weight reduction of the vehicle body becomes much more severe than that of a vehicle using other energy sources.
As a power source for electric vehicles, various motors such as DC brushless type and induction type are used. Since a very large electric current is instantaneously applied when starting or accelerating an electric vehicle, a motor having a power of about 50 to 100 kW is taken into consideration, for example, for each drive wheel or each drive shaft in consideration of acceleration, climbing, etc. It is required to load one or several pieces separately. On the other hand, it is not preferable to use a large number of batteries arranged in series in terms of safety and balance of each unit cell. Therefore, it is necessary to set the output voltage of the battery as low as about 250 to 50 V as compared with the output of the motor.

[0003]

When considering mounting on an electric vehicle, the current flowing from the battery to the motor is
It becomes a large current of several hundred amperes. When used as a regenerative brake, the motor is used as a generator, and the battery is energized from the motor via the controller. Therefore, the voltage drop in the power supply path becomes a big problem. The voltage drop can be suppressed by using thick conductors. However, a conductor for supplying a large current of about several hundred A is usually 30 to 70 kg, which is very heavy, which causes an increase in the weight of the entire electric vehicle, which requires severe weight reduction. Also, electric cars
The weight of the battery is extremely large as compared with a vehicle equipped with a gasoline engine or a diesel engine, and the weight increase cannot be denied even if the transmission, differential gear, shaft, etc. are omitted. Further, for the spread of electric vehicles, drivability such as how to increase the mileage per charge and to improve the acceleration performance, climbing performance, etc. is an important issue. Battery improvement, body shape design,
The driveability can be improved to some extent by reducing the friction of the power transmission mechanism and adopting tires having good rolling resistance. However, under the present circumstances where the weight reduction of the vehicle body is not achieved, there is a limit to the improvement of drivability.

This problem exists not only in electric vehicles but also in fuel cells, hybrid cells in which a conventional engine is used in combination with a battery, and the like in vehicles using other energy in combination with electricity. Also, in automobiles equipped with gasoline engines, diesel engines, etc., the current supplied tends to increase with the increase in various electrical components, while the use of thin-walled members has increased in order to reduce weight. Therefore, it has the same problem. The present invention is
The present invention has been devised to solve such a problem, and aims to reduce the weight of the entire vehicle and improve the running performance of the vehicle by using the structure of the vehicle as a conductor.

[0005]

In order to achieve the object, the present invention is a structural member of a vehicle body in an automobile equipped with an engine that uses electricity, fossil fuel or synthetic fuel as individual energy, or various energy in combination. Part or all of the above is made a conductor, and the battery and the motor are electrically connected. As the structural member, there are a strength member, a space frame, a honeycomb structure and the like.
As the material of the structural member, there are 6063, 6061, 620.
An Al alloy extruded material such as 1 is used alone or in combination. Further, a composite material in which an insulating material is sandwiched between Al alloy extruded materials, or a composite material in which a strength member and a good conductor are clad or joined to form an integrated structure can be used as the structural member. Also, 6063, 6061, 62
Alternatively, an Al alloy extruded material such as 01 may be used as a structural member, and the structural member may be insulated and separated into a plus side and a minus side with an insulator. These structural members are connected to the battery and / or the controller unit using a stainless steel having a high tightening strength or a clad material of Cu and an Al alloy.

[0006]

In the present invention, the structure of the automobile has a function as a conductor in advance. Since the structure has a larger cross-sectional area than a conductor dedicated to power feeding, it has a small current resistance and enables power feeding without a large voltage drop. In addition, the large-thickness structure has both the function of lowering the electric resistance as the power feeder and the function of increasing the strength as the strength member. The structure is used as at least one of the conductors, and the weight of the automobile is reduced accordingly.
In addition, Al, Al in which an insulator such as synthetic resin is sandwiched between
When using a laminated body of alloy or the like, it is possible to reduce the weight by two conductors. Moreover, since it is thick, the contact resistance when it is fastened to another conductor with a bolt or the like can be sufficiently reduced, and voltage drop and heat generation can be suppressed at the main body and the joint portion. When a particularly strong structure is used for mounting a heavy battery pack, an increase in contact resistance can be avoided even if a load is concentrated on the mounting portion. For example, even when a honeycomb structure is used, a joint having low contact resistance and high mechanical strength can be formed by passing the frame inside or on the side.

The structure having a function as a conductor is used, for example, as a part or the whole of the space frame honeycomb structure in the floor, the lower part, etc. near the power unit.
This structure acts as a positive-side conductor and / or a negative-side conductor or an electric conductor having an intermediate voltage therebetween. When the structure also serves as a conductor, it is possible to reduce the stray current, and the electrolytic corrosion caused by the stray current is suppressed. When configuring a space frame, the shape and material of the joining members,
Even for joining methods such as welding, it is necessary to design the contact resistance in the energized portion to be reduced. As for the structural members, Al such as 6063, 6061, 6201
It is preferable to use an alloy or an improved material thereof, or a material having good conductivity such as EC grade as a cladding or a combination thereof for the conductive portion. In order to increase the tightening strength and reduce the contact resistance at the joint portion to the battery, the control system, etc., stainless steel, Cu, Cu alloy, etc. may be used as a clad or a tie. As the clad material, those manufactured by extrusion, those manufactured by resin material and composite extrusion, and resin sandwiched Al
There are clad materials. By using the clad material, it is possible to further improve the strength and omit the conductor.

[0008]

【Example】

Example 1 An Al alloy 6201 was used in part A of FIG. 1 as a structural material for forming a space frame of an electric vehicle. The shape, wall thickness, etc. were determined so that the lightest weight and maximum strength could be obtained in the proper design of each member by computer simulation. In addition, regarding the thickness distribution, in order to reduce the contact resistance at the time of mounting the terminal, consider welding, tightening with bolts and nuts, polishing the connection part, compound application, etc., and even if the tightening force is increased, material destruction and deformation will not occur. A part was thickened so as to exhibit less strength. An example of thickening is shown in FIG. The structure 1 that also has a power supply function is
The wall thickness t ₀ of the portion having the internal cavity 2 extending in the longitudinal direction and having the bolt 3 attached thereto is larger than the wall thicknesses t _{1 to} t _{3 of the} other portions. Further, the conductor 4 connected to the negative pole of the battery is attached to the structure 1 with the bolt 3. In addition to this, it goes without saying that various thickenings can be adopted.

The structure 1 has a sectional shape corresponding to the vehicle body design. The structure 1 reduces the contact resistance of this portion, suppresses the voltage drop, and improves the efficiency of power supply from the battery or the control unit to the motor. As a result, the electric vehicle can travel a long distance. Further, as shown in FIG. 3, the space frame 7 may be used as a negative pole common member that connects the negative side of the battery 5 to the motor 6. The space frame 7 corresponds to a member provided on both sides or one side of the honeycomb structure, and is formed in a sectional shape having a predetermined sectional area. As a result, one of the two thick conductors connecting the battery 5 and the motor 6 is omitted, and the weight is reduced.

For example, an aluminum space frame in which a current of 200 V is applied to a drive motor of 75 KW in total has a size of 100 mm × 100 mm and has a wall thickness t _0.
It was used as a 7mm, to set the other wall thickness t ₁ ~t ₃ to 3mm. This space frame has a current density of 25 A / cm ^2.
Has a cross-sectional area sufficient to allow a current of 375 A to flow, and when the total length is 4 m, the weight is 16.6 kg / one side. The space frame as a structural member that does not pass an electric current has a size of 100 mm × 100 mm × 3 mm and has a weight of 12.6 kg per 4 m. If a Cu material is used as the other conductor and the current density is 35 A / cm ² ,
The cross-sectional area of the Cu material required to pass a current of 375 A is 10
It will be 71 mm ² . This is a weight of 3 per 4 m in length.
Equivalent to 8.1 kg.

Therefore, the weight of the structure including the power feeding mechanism is calculated as follows when the structure is provided with two left and right members connecting the front and rear of the vehicle. (1) Case in which the negative side of the battery is connected to the motor through the structure 12.6 kg + 16.6 kg + 38.1 kg = 67.3
kg (2) Case in which both positive and negative sides are connected to the motor through the structure 16.6 kg x 2 = 33.2 kg (3) Case in which the battery is connected to the motor by the Cu material for energization 12.6 kg x 2 pcs + 38.1 kg x 2 pcs = 101.4
kg As is apparent from this comparison, the case (1) according to the present invention achieves a weight reduction of 34.1 kg and the case (2) has a lighter weight than the case (3) employing the conventional energization method. A weight reduction of 68.2 kg is achieved.

Example 2: Based on the results of Example 1, the frame and chassis were used as the negative conductor. In this case, as shown in FIG. 4, the negative side of the battery 5 is
The frame 8 and the chassis 9 were connected as conductors to the motor 6. Further, the control unit 10 was incorporated in the middle of the negative side conductive path. On the other hand, the positive side of the battery 5 was connected to the motor 6 via a conductor 11 such as a copper wire or an Al conductor. The motor 6 has a ground 12 with respect to the chassis 9. Case 1 (method of replacing engine with motor) FIG. 5 shows a layout adopting a battery driving method instead of the existing engine driving. In this case, the battery 5 is installed in the space of each part. The battery 5 is connected to the motor 6 via the control unit 10 on the negative side via the frame 8 and the chassis 9 and on the positive side via the conductor 11 such as a copper wire and an Al conductor. The output from the motor 6 is transmitted from the transmission 13 or the torque converter to the drive wheels 15 via the differential gear 14.

Case 2 (system in which a motor is combined with a differential gear) This is a system in which power is distributed from one motor to the left and right drive wheels via the differential gear, and its layout is shown in FIG. In this case, the output shaft of the motor 6 is the reducer 1
It is connected to the differential gear 14 via 6. Case 3 (Each Wheel Drive System) Each drive wheel 15 is provided with a motor 6 as shown in FIG. The output of the motor 6 is passed through the speed reducer 16 to drive wheels 15
Communicate to. In this case, the differential gear 14 can be omitted. Although the two-wheel drive is shown in FIG. 7, it is also possible to use the four-phosphorus drive by a similar method. Case 4 (Direct drive method) This method is also called an in-wheel motor method.
As shown in FIG. 3, the motor 6 is incorporated into the wheel, and the rotor of the motor 6 directly rotates the drive wheel 15.

Example 3: Based on the result of Example 1, as a modification thereof, as shown in FIG. 9, both the plus side and the minus side are shared by the chassis 8 and the frame 9. Positive side chassis 8 and frame 9 and negative side chassis 8
And the intermediate member 1 acting as an insulator between the frame 9 and the frame 9.
7 was placed. For the intermediate member 17, various types can be adopted depending on the materials to be combined. For example, when the plastic intermediate member 17 is used, the plus side and the minus side are insulated. As plastics, PV
Various materials such as C, Bakelite, polyethylene and polypropylene can be used, but glass fiber reinforced epoxy resin is preferably used. The intermediate member 17 may be a metal base such as Al, and plastics for insulating the plus side and the minus side may be combined. For example, as shown in FIG. 10, an insulator 19 such as plastics or neoprene rubber is sandwiched between Al base bodies 18, and both ends 20, 20 are attached to the chassis 8 or the frame 9.
Connect and fix to.

The positive side frame 8 and the negative side frame 8 can be directly connected by an insulator 19 as shown in FIG. In this case, the insulator 19 preferably has a curved shape in order to give some elasticity. When the honeycomb structure is also used as a conductor, the structure shown in FIG.
As shown in FIG. 2, the insulator 1 made of plastics or the like is provided between the honeycomb structure 20 and the frames 21 arranged on both sides of the honeycomb structure 20.
9 is interposed. The frames 21 on both sides are used as positive and negative conductors, respectively. Also,
The core of the honeycomb structure may be an insulator. Such a honeycomb structure 20 is laid on most of the floor surface of the vehicle as shown by hatching in FIG.
Is effectively used for connection between the motor 6 and the motor 6. Further, one Al frame can be provided with the functions of both the positive side conductor and the negative side conductor. In this case, for example, as shown in FIG.
An insulator 24 is sandwiched between the conductor 23 and the 1-made conductor 23. Usually, the inner Al conductor 22 is used on the plus side and the outer Al conductor 23 is used on the minus side. This integrated structure is placed on the center line and effectively exhibits the function of suppressing the front-back twisting phenomenon.

Alternatively, as shown in FIG. 15, it is also possible to form an integral structure in which an inner Al conductor 25 that functions as a minus side or a plus side is further incorporated via an insulator 24. By arranging two of these integrated structures as a set in the center as shown in FIG. 16, the weight and stability of the vehicle body can be reduced. The conductor / combined structure of FIGS.
The battery 5 is selected as appropriate considering the shape of each part of the vehicle body.
And a motor 6 is connected to form a power supply path. Case 1 (system in which engine is replaced with motor) Instead of the existing engine drive, the battery drive system whose layout is shown in FIG. 17 is adopted. Both the positive side terminal and the negative side terminal of the battery 5 are connected to the motor 6 via the frame 8 and the chassis 9, and the control unit 10 is arranged in the middle of this power supply path. The output of the motor 6 is transmitted to the drive wheels 15 via the transmission 13 and the differential gear 14.

Case 2 (system in which a motor and a differential gear are combined) The battery 5 is connected to the motor 6 with the frame 8 and the chassis 9 as conductors. Then, the output of the motor 6 is
As shown in FIG. 18, power is transmitted to the left and right drive wheels 15, 15 via the differential gear 14. Case 3 (Each Wheel Drive System) As shown in FIG. 19, the motor 6 is arranged corresponding to each drive wheel 15, and the differential gear 14 is omitted. The motor 6 is connected to the battery 5 via the frame 8 and the chassis 9 similarly to the cases 1 and 2. The output of the motor 6 is transmitted to the drive wheels 15 via the speed reducer 16. Case 4 (Direct Drive System) As shown in FIG. 20, the motor 6 is incorporated in each drive wheel 15 and the drive wheel 15 is directly rotated by the rotor of the motor 6. Even in this case, for the connection between the battery 5 and the motor 6, the conductive / combined structure having the structure shown in FIGS. 10 to 16 is selected in consideration of the application site.

[0018]

As described above, in the present invention, the vehicle body structural member such as the chassis and the frame also serves as the power feeding path connecting the battery and the motor. Therefore, it is particularly suitable for an electric vehicle in which the demand for weight reduction is severe, and since the cross-sectional area of the power supply path can be increased, energy loss due to a voltage drop is suppressed, and electric energy is efficiently consumed for traveling of the vehicle. Further, even in a conventional vehicle equipped with a gasoline engine, a diesel engine, etc., a power supply path for various electric devices is similarly constructed.

[Brief description of drawings]

[Fig. 1] Schematic side view of an automobile

[Fig. 2] Connection part of frame that also serves as a conductor

[Fig. 3] Power supply path between the battery and the motor formed by the space frame

FIG. 4 is a schematic plan view of an automobile in which a frame and a chassis serve as a negative side power supply path.

FIG. 5: Method in which the engine is replaced by a motor

FIG. 6 Method of combining a motor with a differential gear

[Fig. 7] System in which a motor is associated with each drive wheel

[Figure 8] Direct drive method

FIG. 9 is a schematic plan view of an automobile in which both the positive and negative power feeding paths are shared by the frame and the chassis.

FIG. 10: Al base body separated by an insulator

FIG. 11: Frame connected by an insulator

FIG. 12: Insulated and separated honeycomb structure

FIG. 13 is a plan view showing a portion where a honeycomb structure is laid.

FIG. 14: Composite body having positive side power feeding line and negative side power feeding line

FIG. 15: Complex with three types of feeding lines

FIG. 16 is a plan view showing a place where the composite is incorporated.

FIG. 17: Method in which engine is replaced by motor

FIG. 18: Method of combining a motor with a differential gear

FIG. 19 is a system in which a motor is associated with each drive wheel.

[Figure 20] Direct drive method

[Explanation of symbols]

A: Place where the space frame also serving as a conductor is arranged 1: Structure 2: Internal cavity 3: Bolt 4: Conductor 5: Battery 6: Motor 7: Space frame 8: Frame 9: Chassis 10: Control unit 11: Conductive Body 1
2: ground 13: transmission 14: differential gear 15: drive wheel 16: reduction gear 17: intermediate member that acts as an insulator 18: Al
Base 19: Insulator 20: Honeycomb structure
21: frame 22: inner Al conductor 23: outer Al conductor 24: insulator 25: inner Al conductor

Claims (10)

[Claims] 1. An automobile in which a part or all of a structural member of a vehicle body is a conductor and a battery and a motor are electrically connected. 2. The automobile according to claim 1, wherein the structural member is a strength member, a space frame or a honeycomb structure. 3. The automobile according to claim 1, which is equipped with an engine that uses electricity, fossil fuel, or synthetic fuel as individual energy, or uses various types of energy together. 4. The material of the structural member is 6063, 60
The automobile according to claim 1, wherein an Al alloy extruded material such as 61, 6201 is used. 5. The material of the structural member is 6063, 60.
The automobile according to claim 1, wherein an Al alloy extruded material such as 61, 6201 is used alone. 6. The material of the structural member is 6063, 60
The automobile according to claim 1, wherein an Al alloy extruded material such as 61, 6201 is used in combination. 7. The automobile according to claim 1, wherein a composite material in which an insulating material is sandwiched between extruded Al alloy materials is used as the structural member. 8. The automobile according to claim 1, wherein a composite material in which a strength member and a good electric conductor are clad or joined to form an integral structure is used as the structural member. 9. Al such as 6063, 6061, 6201
The automobile according to claim 1, wherein the alloy extruded material is used as a structural member, and the structural member is insulated and separated into a plus side and a minus side with an insulator. 10. The vehicle according to claim 1, wherein the structural member is connected to the battery and / or the controller unit by using a stainless steel having a high tightening strength or a clad material of Cu and an Al alloy.