JP2003291676A - Drive device for front and rear wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device for a front and rear wheel drive vehicle capable of exhibiting an excellent mounting property to the vehicle and capable of reducing exclusive design for the front and rear wheel drive vehicle when constituting the front and rear wheel drive vehicle. <P>SOLUTION: In this drive device for the front and rear wheel drive vehicle, one of front and rear wheels is driven by an engine 11 and the other of the front and rear wheels is driven by an electric motor 14. This drive device is provided with the electric motor 14, and a high voltage battery 17 for supplying electric power to the electric motor 14 in order to drive the electric motor 14. The electric motor 14 is driven by the electric power supplied from the high voltage battery 17. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for front and rear wheel drive vehicles.

[0002]

2. Description of the Related Art As one type of drive device for an automobile, there is a drive device for a front and rear wheel drive vehicle in which one of the front and rear wheels is driven by a main drive means and the other of the front and rear wheels is driven by an auxiliary drive means. . The drive device of this type drives the auxiliary drive device together with the main drive device at the time of starting the vehicle or traveling at a low speed to drive the front wheels and the rear wheels of the vehicle together to form four-wheel drive traveling, One example is JP-A-2001-253.
In Japanese Patent Laid-Open No. 256-256, it is proposed under the name of "vehicle drive device".

The vehicle drive system drives the front wheels by an engine, which is an internal combustion engine, and drives the rear wheels by an electric motor, and is a first generator and a first generator driven by the engine. A low-voltage battery that stores the electric power generated by the engine, a second generator driven by the engine, and is configured to supply the electric power generated by the second generator to the electric motor to drive the rear wheel side. There is.

According to the vehicle drive device, a long drive transmission mechanism such as a long drive shaft for transmitting the driving force of the engine to the rear wheels, which is indispensable in a normal four-wheel drive vehicle, is provided. It becomes unnecessary, and the weight of the vehicle can be reduced and the energy can be largely saved.

[0005]

By the way, the vehicle drive device is intended to have good mountability so that it can be easily mounted in a narrow space of a vehicle. However, in the vehicle drive device, a dedicated generator (second generator) for driving the rear wheel side is indispensable, and the second generator directly drives the rear wheel side. Therefore, it is necessary to adopt a large one for generating a large amount of electric power, and the second generator is driven by an engine that drives the front wheels, and the installation position is specified. There are still problems in improving mountability.

Further, when a four-wheel drive vehicle is constructed by adopting the vehicle drive device, the vehicle drive device requires a dedicated generator (second generator) for driving the rear wheel side. Therefore, it is necessary to newly design a four-wheel drive vehicle different from a two-wheel drive vehicle. Therefore, the cost is significantly increased as compared with the case where the four-wheel drive vehicle is configured based on the two-wheel drive vehicle.

Therefore, a main object of the present invention is to provide a drive device for a front-rear wheel drive vehicle, which can be easily mounted on the vehicle and can omit the exclusive design of the four-wheel drive vehicle.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a drive system for a front and rear wheel drive vehicle. The drive device according to the present invention is a drive device for a front-rear wheel drive vehicle of a type in which one of the front and rear wheels is driven by the main drive means and the other of the front and rear wheels is driven by the auxiliary drive means. And an exclusive high-voltage battery for supplying electric power to the electric motor to drive the electric motor.

In the drive device according to the present invention, the generator driven by the main drive means, the low voltage battery for storing the electric power generated by the generator, and the electric power of the low voltage battery are converted into the high voltage. In addition, a DC-DC converter that stores electricity in the high-voltage battery can be provided.

Further, in the drive device according to the present invention,
As the electric motor, an electric motor capable of selectively converting and outputting electric energy and mechanical energy can be adopted, and the high-voltage battery can be configured to receive supply of regenerative electric power generated by the electric motor. .

Further, in the drive device according to the present invention,
A generator driven by the main drive means, a low-voltage battery that stores the power generated by the generator, and a DC-DC that converts the power of the low-voltage battery into a high voltage and stores the high-voltage battery. With a configuration that includes a converter,
Further, as the electric motor, an electric motor capable of selectively converting and outputting electric energy and mechanical energy is adopted, and the high-voltage battery uses the stored power from the low-voltage battery and the regenerative power generated by the electric motor. Can be configured to be supplied with both electric power.

In each of these driving devices according to the present invention, a separately excited electric motor can be adopted as the electric motor. In addition, in each of these drive devices according to the present invention, a clutch is provided to connect and disconnect the transmission of the driving force of the electric motor to the wheel side, and the high voltage battery supplies electric power to the electric motor during acceleration or low vehicle speed of the vehicle. It is possible to adopt a configuration including a control means for instructing to supply.
In this case, the control means may be configured to determine when the vehicle is accelerating or when the vehicle speed is low, based on one or both of the wheel speed signal and the accelerator opening signal.

The control means is instructed to cut off the transmission of the driving force to the wheel side of the electric motor at times other than when the vehicle is accelerating or when the vehicle speed is low, corresponding to each component equipped in each drive device. Equipped with a control function, it has a control function to instruct the high-voltage battery to store the regenerative power generated by the electric motor that is the auxiliary drive when the vehicle decelerates or runs steadily. A configuration having a control function for instructing to store the regenerative power generated by the electric motor in the high-voltage battery when the amount is less than the predetermined amount can be adopted.

[0014]

In the drive device for the front and rear wheel drive vehicle according to the present invention, the stored power of the high voltage battery is adopted as the drive source for driving the electric motor which is the auxiliary drive means for driving the other of the front and rear wheels. The use of a dedicated generator, which is the drive source of the electric motor, has been abolished. The battery can be mounted anywhere in a narrow space of the vehicle, and therefore the mountability of the drive device on the vehicle is extremely good.

Further, as the drive source of the electric motor, the stored electric power of the high-voltage battery is adopted instead of the electric power generated by the dedicated generator for driving the electric motor. A high-voltage battery can be placed in an appropriate part of the vehicle structure, and it is not necessary to drastically change the design of the two-wheel drive vehicle, and the dedicated design of the four-wheel drive vehicle when configuring the four-wheel drive vehicle is unnecessary. Becomes For this reason,
An increase in cost for constructing a four-wheel drive vehicle can be significantly reduced.

In the drive device according to the present invention, a low-voltage battery that stores the electric power generated by the generator driven by the main drive means is selected as the power source for storing the high-voltage battery, and the low-voltage battery It may be configured to include a DC-DC converter that converts electric power into a high voltage and stores the electric power in the high voltage battery. D with such a configuration
Like the high-voltage battery, the C-DC converter can be mounted anywhere in a narrow space of the vehicle, and therefore, good mountability of the drive device in the vehicle can be sufficiently ensured.

Further, in the drive device according to the present invention,
An electric motor that can selectively output electric energy and mechanical energy for output is adopted as an electric motor, and the electric motor is selected as a power source for storage of a high-voltage battery, and regenerative power generated by the electric motor is selected. Can be configured to store a high voltage battery. With this configuration, it is possible to effectively use the regenerative electric power generated by the electric motor to improve the energy use efficiency and to omit the use of the DC-DC converter.

Further, in the drive device according to the present invention,
Both the electric motor and the low-voltage battery are selected as power sources for storing the high-voltage battery, and both the stored power from the low-voltage battery and the regenerative power generated by the electric motor are supplied. can do. With such a configuration, it is possible to achieve both effects of each of the above-described drive devices, and it is possible to configure the most excellent drive device.

In each of these drive devices, a clutch for intermittently transmitting the driving force of the electric motor to the wheel side, and
The drive device can be configured to include a control unit that controls each component of the drive device in accordance with the state of the vehicle. As a result, the drive device is driven to accurately form the intended vehicle state, Therefore, the energy utilization efficiency can be further improved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a drive device for a front and rear wheel drive vehicle. FIG. 1 shows a first embodiment according to the present invention.
4 schematically shows a four-wheel drive vehicle equipped with the above drive device. The drive device includes a first drive mechanism 10a that drives the front wheels and a second drive mechanism 10b that drives the rear wheels.
And a control device 10c that comprehensively controls both drive mechanisms 10a and 10b.

The first drive mechanism 10a includes an engine 11 which is an internal combustion engine and an alternator 12 which is a generator. In the first drive mechanism 10a, the driving force of the engine 11 is the transmission 13a and the reduction gear train 13
b, transmitted to each drive shaft 13d via the front differential 13c,
The front wheels 13e are driven by d. During this time, the engine 11 drives the alternator 12 to generate electric power. The generated electric power is stored in the low voltage battery 15. The low-voltage battery 15 is a battery for driving an auxiliary device, and is, for example, a 12V battery.

The second drive mechanism 10b includes a separately excited electric motor 14, a DC-DC converter 16, a high voltage battery 17, and a clutch 18. The high-voltage battery 17 is a dedicated battery for driving the electric motor 14, and is, for example, a 36V battery.

The electric motor 14 is a separately excited electric motor 14 which can selectively convert electric energy and mechanical energy and output the electric energy. In the second drive mechanism 10b, the electric motor 14 is driven by being supplied with electric power, and the driving force of the electric motor 14 is transmitted to each drive shaft 19c via the reduction gear train 19a, the electromagnetic clutch 18, and the rear differential 19b. The rear wheels 19d are driven by the drive shafts 19c. In addition, the electric motor 14 functions as a generator to generate regenerative electric power when receiving the driving force from the rear wheel 19d side. The generated regenerative power is stored in the high voltage battery 17 via the control device 10c.

As shown in FIG. 2, the control device 10c outputs a sensor signal from a sensor signal output unit 10c1 having an accelerator opening sensor, a wheel speed sensor, a brake sensor, a high voltage battery voltage sensor, a 4WD switch sensor and the like. It is composed of an input unit 10c2, a CPU 10c3, and a control unit 10c4 based on a command signal, and has a control function of controlling the success or failure of the four-wheel drive state, and a control function of controlling driving and switching of the electric motor 14. The control device 10c has four
When the WD switch is ON, control for selecting the operating state of the electric motor 14 is performed. The control for selecting the operating state of the electric motor 14 determines the state in which the electric motor 14 should operate based on signals from the accelerator opening sensor, the wheel speed sensor, the brake sensor, and the voltage sensor of the high-voltage battery 17. And the electric motor 1 as determined
4 controls the operation.

The control device 10c controls the electric motor 14 to generate electric power when the battery voltage of the high voltage battery 17 is below a predetermined value, the vehicle speed is below a predetermined value, and the brake is in operation. FIG. 3 is a flowchart showing an example of operation control of the electric motor 14 by the control device 10c. The control device 10c executes a program for controlling the electric motor 14 based on the flowchart shown in FIG. 3 with the 4WD switch turned on.

When it is determined in step 21 that the 4WD switch is ON, the microcomputer constituting the control device 10c determines in step 22 that the operating state of the electric motor 14 should be selected. . Also,
When it is determined in step 21 that the 4WD switch is in the OFF state, the microcomputer turns off the clutch 18 in step 23 and ends the execution of the control program.

In step 22, the microcomputer determines whether or not the electric motor 14 should select the power generation operation for power generation control. The determination of the power generation control is made based on the voltage of the high-voltage battery, the wheel speed, and the operating state of the brake. When the voltage of the high-voltage battery is a predetermined value or less, the wheel speed is less than the predetermined value, and the brake is operating. Is determined to be power generation control, the program proceeds to step 24a,
The clutch 18 is turned on in step 24a, and step 2
At 4b, the electric motor 14 is controlled to be in a power generation operable state.
As a result, the electric motor 14 is driven by the driving force from the rear wheel 19d side to generate regenerative electric power. The generated regenerative power is supplied to the high voltage battery 1 via the control device 10c.
7 is stored, and the voltage of the high-voltage battery 17 is raised above a predetermined value.

When the microcomputer determines in step 22 that the power generation control is not to be performed, the microcomputer advances the program to step 25, and in step 25, the electric motor 1
4 determines drive control whether drive operation should be selected. The drive control is determined based on signals from an accelerator opening sensor, a wheel speed sensor, etc., and when the vehicle is in a low speed state and the accelerator opening is above a certain level, it is determined to be drive control.
The program proceeds to step 26a, the clutch 18 is turned on in step 26a, the electric motor 14 is controlled to be drivable in step 26b, and the electric motor 14 is controlled from the high voltage battery 17 via the control device 10c.
Supply power to. As a result, the rear wheels 19d are driven by the drive of the electric motor 14 to bring the vehicle into the four-wheel drive state.

If it is determined in step 25 that the drive control is not being executed, the microcomputer advances the program to step 27 to turn off the clutch 18, and in step 28 the high voltage battery 17 is set.
The electric motor 14 is maintained in a non-driving state without supplying electric power from the electric motor 14 to the electric motor 14.

As described above, in the drive system, the vehicle can be smoothly changed to the four-wheel drive state when necessary by the operation of the control device 10c, and the rear wheels 19d.
The electric power that is the drive source of the high voltage battery 17 can be stored according to the consumption without any trouble, but the electric power stored in the high voltage battery 17 is used as the drive source that drives the electric motor 14 that is the drive means of the rear wheels 19d. The use of a dedicated generator for driving the electric motor 14 has been eliminated. The high-voltage battery 17 can be mounted anywhere in a narrow space of the vehicle, and therefore the mountability of the drive device on the vehicle is extremely good.

Further, as a drive source of the electric motor 14, a stored electric power of the high voltage battery 17 is adopted instead of a dedicated generator for driving the electric motor 14, so that a four-wheel drive vehicle has a two-wheel drive structure. The design of the vehicle does not need to be changed significantly, and the dedicated design of the four-wheel drive vehicle is unnecessary for the configuration of the four-wheel drive vehicle. Therefore, an increase in cost for constructing a four-wheel drive vehicle can be significantly reduced.

Further, in the drive device, the low voltage battery 15 for storing the electric power generated by the alternator 12 driven by the engine 11 which is the main drive means is selected as the power source for storing the high voltage battery 17. It is configured to include a DC-DC converter 16 that converts the stored power of the low-voltage battery 15 into a high voltage and stores it in the high-voltage battery 17. The DC-DC converter 16 is
Like the high-voltage battery 17, it can be mounted anywhere in a narrow space of the vehicle, and therefore, good mountability of the drive device in the vehicle can be sufficiently ensured.

In the drive system, the rear wheels 19
As the driving means of d, the separately excited electric motor 14 capable of selectively converting and outputting electric energy and mechanical energy is adopted, and the electric motor 14 is selected as a power source for storing the high voltage battery 17. The high voltage battery 17 is also charged with the regenerative electric power generated by the electric motor 14. According to such a configuration, the regenerated electric power of the electric motor 14 can be effectively used, and the energy use efficiency can be improved.

Further, in the drive system, the clutch 18 for intermittently transmitting the drive force of the electric motor 14 to the rear wheel 19d side, and the control system for controlling each component of the drive system according to the state of the vehicle. 10c is provided. As a result, the drive device can be operated so as to accurately form the intended vehicle state, and the utilization efficiency of energy can be further enhanced overall.

FIG. 4 schematically shows a four-wheel drive vehicle formed by mounting a second drive device according to the present invention. The drive device includes a first drive mechanism 30 that drives the front wheels 33a.
a, a second drive mechanism 30b that drives the rear wheel 39c, and a control mechanism 30c that controls the second drive mechanism 30b.

In the drive device, the second drive mechanism 3
0b is slightly different from the first drive mechanism 30b,
Other configurations are substantially the same. Therefore,
In the drive device, the same components and parts as those of the first drive device are denoted by reference numerals in the thirties, which are similar to the reference numerals, and detailed description thereof will be omitted.

Second drive mechanism 3 which constitutes the second drive device
0b includes a separately excited electric motor 34, a high-voltage battery 37, and a clutch 38.
Does not have a converter. In the second drive mechanism 30b, the high-voltage battery 37 is separated from the low-voltage battery 35, and the low-voltage battery 35 is a battery dedicated to driving auxiliary equipment.
Has not become a power source. The electric motor 34 is a separately excited electric motor capable of selectively converting electric energy and mechanical energy and outputting the electric energy and mechanical energy.

In the second drive mechanism 30b, the electric motor 34 is driven by being supplied with electric power from the high voltage battery 37 via the control device 30c, and the driving force of the electric motor 34 is reduced by the reduction gear train 39a and the electromagnetic force. It is transmitted to each drive shaft 39c via the clutch 38 and the rear differential 39b, and each drive shaft 39c drives the rear wheel 39d. Further, the electric motor 34 is
When receiving the driving force from the rear wheel 39d side, it functions as a generator to generate regenerative electric power. The generated regenerative power is stored in the high voltage battery 37 via the control device 30c.

Controller 30c constituting the second drive device
Controls the second drive mechanism 30b. This allows the second
In the drive device of No. 1, when necessary, the vehicle can be smoothly changed to the four-wheel drive state, and the electric power that is the drive source of the rear wheels 39d is stored in the high-voltage battery 37 according to the consumption without any trouble. Is something that can be done.

Thus, in the second drive device,
The electric power stored in the high-voltage battery 37 is used as a drive source for driving the electric motor 34, which is the drive means for the rear wheels 39d, and the use of a dedicated generator for driving the electric motor 34 is eliminated. The high-voltage battery 37 can be mounted anywhere in a narrow space of the vehicle, and therefore the mountability of the drive device on the vehicle is extremely good.

The second drive device is different from the first drive device in that the power of the low voltage battery 35 is not used as the power source of the high voltage battery 37, but is substantially the same as the first drive device. It has the effect of.
However, in comparison with the first drive device, the second drive device does not include a DC-DC converter, and thus has better vehicle mountability and can reduce cost. It is possible.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a four-wheel drive vehicle configured by mounting a first drive device according to the present invention.

FIG. 2 is a schematic configuration diagram of a control device that constitutes the drive device.

FIG. 3 is a flowchart of a control program executed by the control device.

FIG. 4 is a schematic configuration diagram of a four-wheel drive vehicle configured by mounting a second drive device according to the present invention.

[Explanation of symbols]

10a, 30a ... 1st drive mechanism, 10b, 30b ... 2nd
Drive mechanism, 10c, 30c ... Control device, 11, 31 ... Engine, 12, 32 ... Alternator, 13a, 33a ...
Transmission, 13b, 33b ... Reduction gear train, 1
3c, 33c ... front differential, 13e,
33e ... front wheels, 14, 34 ... electric motors, 15, 35 ...
Low voltage battery, 16 ... DC-DC converter, 1
7, 37 ... High-voltage battery, 18, 38 ... Electromagnetic clutch, 19a, 39a ... Reduction gear train, 19b, 39b ... Rear differential, 19c, 39c ... Drive shaft, 19d, 39d ... Rear wheel.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60K 6/04 710 B60K 6/04 710 17/04 ZHV 17/04 ZHVG B60L 11/14 B60L 11/14 ( 72) Inventor Naoyuki Sakai 1-1, Asahi-machi, Kariya city, Aichi Toyota Koki Co., Ltd. (72) Inventor Akihiro Ohno 1-1, Asahi-cho, Kariya city, Aichi Toyota koki Co., Ltd. (72) Inventor Hiroshi Takuno 1-1, Asahi-cho, Kariya-shi, Aichi Toyota Koki Co., Ltd. (72) Inventor Fukami Imai 1-1, Asahi-cho, Kariya-shi, Aichi Toyota Koki Co., Ltd. (72) Inventor Yoshiyuki Shibata Aichi 1-chome, Asahi-cho, Kariya-shi, Toyoda Machinery Co., Ltd. (72) Inventor Akira Kodama 1-1-chome, Asahi-machi, Kariya city, Aichi Toyota Koki Co., Ltd. (Reference) 3D039 AA02 AA03 AB02 AB27 AC03 3D043 AA05 AB01 AB17 EA01 EA05 EA18 EA42 EB03 EB07 EB12 EE02 EE07 EF09 EF12 EF19 5H115 PG04 PI16 PI22 PI24 PO02 PO02 PO15 PO02 PO02 PO15 PO02 POE POQ

Claims (11)

[Claims] 1. A drive device for a front and rear wheel drive vehicle in which one of the front and rear wheels is driven by a main drive means and the other of the front and rear wheels is driven by a sub drive means, wherein the drive device is the sub drive means. And a high-voltage battery that supplies electric power to the electric motor to drive the electric motor. 2. The drive device according to claim 1, wherein the drive device includes a generator driven by the main drive means, a low-voltage battery for storing electric power generated by the generator, and a low-voltage battery. A drive device for a front-rear wheel drive vehicle, comprising a DC-DC converter for converting electric power of a voltage battery into a high voltage and storing the electric power in the high voltage battery. 3. The drive device according to claim 1, wherein the electric motor constituting the drive device is an electric motor capable of selectively converting electric energy and mechanical energy and outputting the electric energy and the mechanical energy. A driving device for a front-rear wheel drive vehicle, wherein the voltage battery receives supply of regenerative electric power generated by the electric motor. 4. The drive device according to claim 1, wherein the drive device includes a generator driven by the main drive means, a low-voltage battery storing electric power generated by the generator, and a low-voltage battery. A DC-DC converter for converting the electric power of the voltage battery into a high voltage and storing it in the high voltage battery;
The electric motor is an electric motor capable of selectively converting electric energy and mechanical energy and outputting the electric energy, and the high-voltage battery includes stored power of the low-voltage battery and regenerative power generated by the electric motor. A drive device for front and rear wheel drive vehicles, which is supplied with both electric power. 5. The front-rear wheel drive vehicle according to any one of claims 1 to 4, wherein the electric motor constituting the drive device is a separately excited electric motor. Drive. 6. The drive device according to claim 1, wherein the drive device includes a clutch that intermittently transmits the driving force of the electric motor to the wheel side. Drive device for front and rear wheel drive vehicles. 7. The drive device according to claim 1, wherein the drive device instructs to supply electric power from the high voltage battery to the electric motor when the vehicle is accelerated or at a low vehicle speed. A drive device for a front-rear wheel drive vehicle, comprising: 8. The drive device according to claim 7, wherein the control means determines whether the vehicle is accelerating or low based on one or both of a wheel speed signal and an accelerator opening signal. Drive device for front and rear wheel drive vehicles. 9. The drive device according to claim 7 or 8, wherein the control means included in the drive device cuts off the transmission of the drive force to the wheel side of the electric motor except when the vehicle is accelerating or at a low vehicle speed. A drive device for a front-rear wheel drive vehicle, which is provided with a control function for instructing to do so. 10. The drive device according to claim 7, wherein the control means included in the drive device is regenerative power generated by an electric motor that is an auxiliary drive means during deceleration of the vehicle or during steady running of the vehicle. A drive device for a front and rear wheel drive vehicle having a control function for instructing to store electric power in a high voltage battery. 11. The drive device according to claim 10, wherein the control means included in the drive device supplies regenerative electric power generated by the electric motor to the high-voltage battery when the remaining amount of stored electricity in the high-voltage battery is less than a predetermined amount. A drive device for a front-rear wheel drive vehicle having a control function for instructing to store electricity in a vehicle.