JP2003326991A - Drive for front and rear wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent mutual interference between a brake and an electric motor generated when the brake is actuated in front and rear wheel drive travel or the like, in a drive for driving a rear wheel side by the electric motor independent of an engine that is a driving means for a front wheel side. <P>SOLUTION: This drive is provided with an output control means for controlling an output from the motor to the rear wheel side in response to a brake actuation condition or a brake actuation operation, and the mutual interference between the brake and the electric motor is prevented by regulating, to a prescribed value or less, the output from the motor to the rear wheel side in the brake actuation condition or the brake actuation operation. <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, one of the front and rear wheels, the main drive wheel side, is driven by the main drive means, and the other of the front and rear wheels, the sub drive wheel side, is the auxiliary drive means. There are drive devices for front and rear wheel drive vehicles of the driven type. The drive device of this type drives the main drive wheels by the main drive means during normal traveling to form an independent drive traveling state of the main drive wheels, and when the vehicle is starting or traveling at low speed, By driving the auxiliary drive means, both the front and rear wheels (main drive wheel and auxiliary drive wheel) of the vehicle are driven together to form a front and rear two-wheel drive traveling state.
It is proposed in Japanese Patent Laid-Open No. 001-253256 under the name of "vehicle drive device".

Specifically, the vehicle drive system is a system in which the front wheel side is driven by an engine which is a main drive means, and the rear wheel side is driven by an electric motor which is an auxiliary drive means, and is driven by the engine. A first generator, a low-voltage battery that stores the electric power generated by the first generator, and a second generator that is driven by the engine are provided, and the electric power generated by the second generator is supplied to the electric motor. It is configured to drive the rear wheel side.

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 greatly saved.

[0005]

By the way, in the drive device of this type, as seen in the above-mentioned vehicle drive device, the auxiliary drive means is provided even when the brake is actuated during the front and rear two-wheel drive traveling. The drive state on the side of the auxiliary drive wheel due to is continued. When such a state occurs in a front-rear wheel drive vehicle, the brake and the sub drive means interfere with each other to impair the durability of the drive device, damage the sub drive means, and consume unnecessary energy. Become. Therefore, it is an object of the present invention to address these issues.

[0006]

The present invention relates to a drive device for a front and rear wheel drive vehicle, which is a main drive means for driving the main drive wheel side, which is one of the front and rear wheels, and the other of the front and rear wheels. An auxiliary drive unit for driving the auxiliary drive wheel side is provided, and the main drive wheel is driven by the main drive unit to form an independent drive traveling state of the main drive wheel, and the main drive wheel is provided by the main drive unit. The present invention is applied to a drive device for a front-rear wheel drive vehicle of a type in which a two-wheel drive traveling state of both drive wheels is formed by the drive on the side and the drive on the side of the auxiliary drive wheels by the auxiliary drive means.

Therefore, the drive device for the front-rear wheel drive vehicle according to the present invention controls the output from the auxiliary drive means to the auxiliary drive wheel side in accordance with the operation state of the brake or the operation operation of the brake. It is characterized by having means.

In the drive device for a front-rear wheel drive vehicle according to the present invention, the output control means controls the output of the auxiliary drive means to a predetermined value or less in accordance with the operating state of the brake or the operating operation of the brake. And a control function of stopping the supply of the drive source to the sub-driving unit when the main driving unit is driven when the brake is actuated.

In the drive device according to the present invention, the main drive means for driving the main drive wheel side which is one of the front and rear wheels, and the electric motor which is the sub drive means for driving the auxiliary drive wheel side which is the other of the front and rear wheels. And an electromagnetic clutch for connecting and disconnecting the power transmission between the electric motor and the sub-driving means, the main driving means driving the main driving wheel side with the electromagnetic clutch disconnected. Both of these drives are formed by driving the main drive wheel side by the main drive means and by driving the auxiliary drive wheel side by the auxiliary drive means in a state where the drive wheels are driven independently and the electromagnetic clutch is engaged. A drive device for a front-rear wheel drive vehicle of a type that forms a two-wheel drive traveling state of wheels can be applied.

In this case, the output control means may have a control function of restricting the output torque of the electric motor to a predetermined value or less in accordance with the operating state of the brake or the operating operation of the brake. The electric motor may be configured to have a control function of stopping the supply of electric power to the electric motor when the main drive means is driven when the brake is operated, and the electric motor is operated when the brake is operated while the vehicle is traveling. Can be configured to have a control function of stopping the supply of electric power to the electromagnetic clutch and disconnecting the coupling of the electromagnetic clutch.

In these drive devices according to the present invention, an engine that is the main drive means and a generator that drives the engine to generate electric power are provided, and the electric power generated by the generator is controlled, The electric motor may be supplied with electric power to drive the electric motor.

[0012]

In the drive device for the front and rear wheel drive vehicle according to the present invention, the output control for controlling the output from the auxiliary drive means to the auxiliary drive wheel side in accordance with the operation state of the brake or the operation operation of the brake. Since the means is provided, the following operational effects are exhibited. That is, it is possible to prevent the brake from interfering with the sub-driving means such as the electric motor and improve the durability of the driving device. In addition, it is possible to prevent the drive device from being damaged when the main drive means such as the engine is continuously driven unnecessarily such as by emptying the vehicle, or when the parking brake is operated during traveling such as a harsh test. Further, when the front and rear wheels are not required to be driven, it is possible to prevent the wasteful consumption of energy by restricting the drive of the auxiliary drive means such as the electric motor.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a drive device for a front and rear wheel drive vehicle, which comprises a main drive means for driving the main drive wheel side, which is one of the front and rear wheels, and a sub drive, the other of the front and rear wheels. An auxiliary drive means for driving the wheel side is formed, the main drive wheel drives the main drive wheel side to form an independent drive traveling state of the main drive wheel, and the main drive means drives the main drive wheel side. The present invention is applied to a drive device for a front-rear wheel drive vehicle of a type that forms a two-wheel drive traveling state of both drive wheels by drive and drive of the auxiliary drive wheels by the auxiliary drive means. The drive system for front and rear wheel drive vehicles of this type includes:
There are many types of drive devices, and this embodiment exemplifies two types of drive devices developed by the present inventors and shown in FIGS. 1 and 4.

FIG. 1 schematically shows a first four-wheel drive vehicle 10 which is constructed by mounting a first drive device according to the present invention. The first drive device controls the first drive mechanism 10a that drives the front wheel side that is the main drive wheel, the second drive mechanism 10b that drives the rear wheel side that is the auxiliary drive wheel, and the control that controls the second drive mechanism 10b. The device 10c is provided.

The first drive mechanism 10a includes an engine 11 which is an internal combustion engine and a generator 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 generator 12 to generate electric power. The generated electric power is stored in the low voltage battery 14. The low-voltage battery 14 is a battery for driving auxiliary equipment, and is, for example, a 12V battery.

The second drive mechanism 10b includes an electric motor 15,
A DC-DC converter 16, a high voltage battery 17, and an electromagnetic clutch 18 are provided. The high-voltage battery 17 is a dedicated battery for driving the electric motor 15, and is, for example, a 36V battery. Electric motor 1
Reference numeral 5 denotes an electric motor 15 capable of selectively switching between electric energy and mechanical energy and outputting the electric energy. As the electric motor 15, a separately excited motor, a DC motor, a brushless motor or the like can be appropriately adopted. .

In the second drive mechanism 10b, the electric motor 15 is driven by the supply of electric power, and the driving force of the electric motor 15 passes through the reduction gear train 19a, the electromagnetic clutch 18, and the rear differential 19b, and each drive shaft 19c. The rear wheels 19d are driven by the drive shafts 19c. In addition, the electric motor 15 is
When receiving a driving force from the rear wheel 19d side, it functions as a generator to generate regenerative electric power. The generated regenerative electric power is stored in the high voltage battery 17 via the drive circuit 10c2 which constitutes the control device 10c.

As shown in FIG. 2, the control device 10c includes a throttle opening sensor S1, a wheel speed sensor S2, a brake sensor S3, a high voltage battery voltage sensor S4, a switch sensor S5 for detecting the state of a WD switch, and an electric motor. It is connected to a motor sensor S6 that detects the rotation state of the motor 15, and is an MPU (microprocessor) 10c.
1 and a drive circuit 10c2.

The MPU 10c1 has a CPU and a memory for holding a control program and data for controlling the electric motor 15 and the electromagnetic clutch 18, and outputs detection signals output from the respective sensors S1 to S6 via an interface. Take in the electric motor 15 and the electromagnetic clutch 18
And the like, and outputs a command torque for the electric motor 15 and a condition for operating the electric motor 15, the electromagnetic clutch 18, etc. to the drive circuit 10c2 as an instruction signal.

The drive circuit 10c2 controls the drive and power generation of the electric motor 15 based on the command signal from the MPU 10c1 and also controls the ON / OFF (coupling / disconnection) of the electromagnetic clutch 18. The control program included in the MPU 10c1 holds an output control program for controlling the output from the electric motor to the rear wheel 19d side in accordance with the operating state of the brake or the operating operation of the brake.

The control device 10c has the 4WD switch turned on.
The electric motor 15 and the electromagnetic clutch 1
Control for selecting the operating state of No. 8 is performed. Control device 10c
Is a throttle opening sensor S1, a wheel speed sensor S2, a brake sensor S3, a high voltage battery voltage sensor S4, 4
Based on signals from the switch sensor S5 that detects the state of the WD switch and the motor sensor S6 that detects the rotational state of the electric motor 15, the state in which the electric motor 15 should operate and the state in which the electromagnetic clutch 18 should operate should be determined. At the same time, the command torque for the electric motor 15 is calculated.
The determination result and the command torque are output to the drive circuit 10c2 as a command signal, and the drive circuit 10c2 controls the operation of the electric motor 15 and the electromagnetic clutch 18 based on the command signal.

FIG. 3 is a flow chart for executing a control program for controlling the operation of the electric motor 15 and the electromagnetic clutch 18 by the control device 10c. Control device 10
The microcomputer composing c is step 101.
When it is determined that the 4WD switch is in the ON state, in step 102, it is determined that the operating state of the electric motor 15 should be selected. Further, when the microcomputer determines in step 101 that the 4WD switch is in the OFF state, it also turns off the electromagnetic clutch 18 in step 103 and ends the execution of the control program.

The microcomputer executes step 102.
At, the power generation control is determined whether or not the electric motor 15 should select the power generation operation. The determination of the power generation control is performed based on the voltage of the high voltage battery 17, the wheel speed, and the operating state of the brake, and the voltage of the high voltage battery 17 is equal to or less than a predetermined value.
When the wheel speed is equal to or lower than a predetermined value and the brake is in the operating state, it is determined to be power generation control, and the program is executed in step 104.
And the electromagnetic clutch 18 is turned on in step 104.
Then, in step 105, the electric motor 15 is controlled to a power generation operable state. As a result, the electric motor 15 is driven by the driving force from the rear wheel 19d side to generate regenerative electric power. The generated regenerative power is stored in the high voltage battery 17 via the drive circuit 10c2 of the control device 10c, and raises the voltage of the high voltage battery 17 to a predetermined value or more.

The microcomputer executes step 102.
When it is determined that the power generation control is not performed, the program proceeds to step 106, and in step 106, the drive control is determined whether or not the electric motor 15 should select the drive operation. The drive control is determined based on signals from a throttle opening sensor, a wheel speed sensor, etc. When the vehicle is in a low speed state and the throttle opening is equal to or more than a certain value, drive control is determined, and the program proceeds to step 107. Proceed.

The microcomputer executes step 107.
Then, the motor output torque T is calculated on the basis of the method described later and used as the command torque, the electromagnetic clutch 18 is turned on in step 108, and the electric motor 15 is controlled to be in a drivable state in step 109, and the high voltage battery is 17 to the electric motor 1 via the drive circuit 10c2 of the control device 10c.
Supply power to 5. As a result, the electric motor 15 is driven, and the rear wheels 19d are driven by the output from the electric motor 15 to bring the vehicle into the four-wheel drive traveling state.

When the microcomputer determines in step 106 that the drive control is not performed, the program proceeds to step 110 to turn off the electromagnetic clutch 18, and in step 111, the high voltage battery 17 is set. The electric motor 15 is maintained in a non-driving state without supplying electric power to the electric motor 15.

The microcomputer circulates and executes the above control program based on the flowchart. During this period, the microcomputer reads the detection signal of the brake sensor S3, and the electric motor 15 to be described later.
Output control for limiting the output torque from the rear wheel to the rear wheel 19d side is performed.

As described above, in the front and rear wheel drive vehicle 10 equipped with the drive device, the control device 10c can be used to smoothly change the vehicle to the four-wheel drive state when necessary and the rear wheels 19d. The power that is the driving source of
Although the electricity can be stored according to the consumption without any problem, the electricity stored in the high-voltage battery 17 is used as a drive source for driving the electric motor 15 that is the drive means for the rear wheels 19d, and the electric motor 15 is used. The use of a dedicated generator to drive is abolished. 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 15, by replacing the dedicated generator for driving the electric motor 15 with the electric power stored in the high-voltage battery 17, the four-wheel drive vehicle has a two-wheel drive vehicle. There is no need to significantly change the design of (4), and the exclusive design of the four-wheel drive vehicle when configuring the four-wheel drive vehicle becomes unnecessary. 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 14 for storing the electric power generated by the generator 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 14 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.

Further, in the drive system, the rear wheels 19
An electric motor 15 capable of selectively converting and outputting electric energy and mechanical energy is adopted as the driving means of d, and the electric motor 15 is selected as a power source for storing the high voltage battery 17, and the electric motor 15 The high-voltage battery 17 is also charged with the regenerative electric power generated in Step 1. With such a configuration, the regenerated electric power of the electric motor 15 can also be effectively used, and the energy utilization efficiency can be improved.

Further, in the drive system, the electromagnetic clutch 18 for intermittently transmitting the drive force of the electric motor 15 to the rear wheel 19d side, and the control for controlling each component of the drive system according to the state of the vehicle. The device 10c is provided. As a result, the drive device operates so as to accurately form the intended drive state of the vehicle, and overall, the energy utilization efficiency is further enhanced.

As described above, the drive device is an extremely effective drive device for constructing a four-wheel drive vehicle of this type. However, the control device 10c constituting the drive device is a four-wheel drive vehicle. When, for example, output control for restricting the output from the electric motor 15 to the rear wheel 19d side is performed according to the brake operating state or the brake operation operation, and the vehicle falls into the brake operating state during four-wheel drive traveling, etc. To solve various problems. A detailed description of this point will be given later.

FIG. 4 schematically shows a second four-wheel drive vehicle 20 formed by mounting the second drive device according to the present invention. The drive device includes a first drive mechanism 2 that drives the front wheels.
0a, the second drive mechanism 20b for driving the rear wheel side, and the second
A control device 20c for controlling the drive mechanism 20b is provided.

The first drive mechanism 20a includes an engine 21 which is an internal combustion engine and a generator 22 which is a generator. In the first drive mechanism 20a, the driving force of the engine 21 is the transmission 23a and the reduction gear train 23.
b, transmitted to each drive shaft 23d via the front differential 23c,
The front wheels 23e are driven by d. During this time, the engine 21 drives the generator 22 to generate electric power.

The second drive mechanism 20b includes an electric motor 24 and an electromagnetic clutch 25. Electric motor 24
Drive by being supplied with high voltage power. When the electric motor 24 is driven while the electromagnetic clutch 25 is ON, the driving force of the electric motor 24 is reduced by the reduction gear train 26a, the electromagnetic clutch 25, and the rear differential 26b.
Is transmitted to each drive shaft 26c, and the rear wheel 26d is driven by each drive shaft 26c.

The generator 22 constituting the first drive mechanism 20a is a generator having a variable generated voltage, and the low voltage battery 28 and the electric motor 24 are connected via the changeover switch 27.
It is configured to be selectively connected to and. The low-voltage battery 28 is used for various accessory parts 2 mounted on the vehicle.
9 to drive 9. The changeover operation of the changeover switch 27 is performed via the drive circuit 20c2 of the control device 20c.

As shown in FIG. 5, the controller 20c includes a throttle opening sensor S1, a wheel speed sensor S2, a brake sensor S3, a low voltage battery voltage sensor S4, a switch sensor S5 for detecting the state of a WD switch, and an electric motor. It is connected to a motor sensor S6 that detects the rotation state of the motor 24, and is an MPU (microprocessor) 20c.
1 and a drive circuit 20c2.

The MPU 20c1 has a CPU and a memory for holding a control program and data for controlling the generator 22, the electromagnetic clutch 25 and the changeover switch 27, and interfaces the detection signals output from the respective sensors S1 to S6. The generator 22, the electric motor 24, the electromagnetic clutch 25, and the changeover switch 27 to be operated, and the generator 2
2. The state in which the electric motor 24, the electromagnetic clutch 25, and the changeover switch 27 should be operated is output as a command signal to the drive circuit 20c2 via the interface. The drive circuit 20c2, based on the command signal from the MPU 20c1,
The switching operation of the changeover switch 27 is controlled, and the generator 2
2 controls the generated power, controls the drive of the electric motor 24, and controls the ON / OFF of the electromagnetic clutch 25. The control program included in the MPU 20c1 holds an output control program for controlling the output of the electric motor according to the operation state of the brake or the operation operation of the brake, as in the first drive device.

That is, the control device 20c controls the success or failure of the four-wheel drive state, the control function of controlling the electric power generated by the generator 22, the control function of controlling the drive of the electric motor 24, and the output of the electric motor 24. It has a control function to regulate.

When the 4WD switch is ON, the microcomputer constituting the control device 20c determines whether or not the four-wheel drive state should be selected, and when the four-wheel drive state is determined to be selected. Determines whether or not the switching state of the changeover switch 27 can be selected, and when it determines that the changeover switch 27 is in the state where the changeover state can be selected, the changeover switch 27 is switched and The electromagnetic clutch 25 is turned on to perform the coupling operation, and the power generation state of the generator 22 is switched from the low voltage side to the high voltage side to connect the generator 22 to the electric motor 24.

As a result, the generator 22 supplies high-voltage electric power to the electric motor 24 to drive the electric motor 24 to form the vehicle in the four-wheel drive state. The microcomputer determines whether or not the four-wheel drive state should be selected by determining the throttle opening sensor S1 and the wheel speed sensor S1.
2, the brake sensor S3, the low-voltage battery voltage sensor S4, 4WD based on the detection signal from the switch sensor S5 that detects the state of the switch, low-voltage battery when starting, accelerating, running at low speed, etc. When a sufficient amount of electricity remains in 28, the four-wheel drive state is established.

The microcomputer constituting the control device 20c executes the above control program based on the flowchart shown in FIG. The microcomputer monitors the remaining amount of the stored power of the low-voltage battery 28 in step 121, advances the program to step 122 when it determines that the remaining amount of the stored power is less than the predetermined value A, and stores the stored power. If it is determined that the remaining amount of electric power is equal to or greater than the predetermined value A, the program proceeds to step 123.

The microcomputer executes the step 122.
At, the current consumption of the electric power on the low voltage side is monitored, and if the consumption is less than the predetermined value B, the program proceeds to step 123, and if the consumption is the predetermined value B or more, The program proceeds to step 124. As a result, the connection relationship between the generator 22, the low-voltage battery 28, and the accessory component 29 is maintained, and the generator 22 continues to supply the low-voltage power to the low-voltage battery 28 and the accessory component 29.

The microcomputer executes the step 123.
Then, it is determined whether or not the vehicle should be driven by four wheels. If it is determined that the vehicle is not driven by four wheels, the program proceeds to step 124. As a result, the generator 22, the low-voltage battery 28, and the auxiliary component 2
9, the generator 22 continues to supply low-voltage power to the low-voltage battery 28 and the auxiliary component 29.

The microcomputer executes the step 123.
If it is determined that the vehicle is in the state of four-wheel drive, the program proceeds to step 125. In step 125, the microcomputer calculates the motor output torque T based on the method described later to calculate the command torque, turns on the electromagnetic clutch 25 in step 126, switches the changeover switch 27 to the electric motor 24 side, At the same time, the generator 22 is switched to the high voltage power generation side. As a result, the electric motor 24 is driven by being supplied with high-voltage electric power from the generator 22 to form the vehicle in the four-wheel drive state.

The microcomputer circulates and executes the above control program based on the flowchart. During this period, the microcomputer reads the output signal of the brake sensor S3, and the electric motor 24, which will be described later, is read.
Output control is performed to regulate the output torque of the.

As described above, in the drive device, the vehicle can be smoothly formed into the four-wheel drive state when necessary by the operation of the control device 20c. However, in the drive device, the engine that is the main drive means is used. As a generator that is driven by 21 to generate electric power, a generator 22 having a variable generated voltage is adopted instead of the conventional generator.
Is configured to be selectively connectable to the low-voltage battery 28 and the auxiliary component 29, which are the conventional low-voltage system accessories, and the high-voltage electric motor 24. Thereby, in the drive device, the generator 22 can drive the electric motor 24 to drive the rear wheel 26d side, and the electric power of the generator 22 can form the vehicle in the four-wheel drive state.

Further, in the drive device, as the generator that is driven by the engine 21 that is the main drive means to generate electric power, the generator 22 having a variable generated voltage is adopted instead of the conventional generator. Since the generator 22 is used as the drive source of the electric motor 24, a dedicated generator for driving the electric motor 24 and other drive means dedicated to the electric motor are unnecessary. Therefore, the mountability of the drive device in the vehicle is extremely good.

Further, since the drive unit is constituted by adopting the generator 22 of which the generated voltage is variable as the generator which is driven by the engine 21 as the main drive means to generate electric power, the drive unit is concerned. When a four-wheel drive vehicle is configured by adopting the above, it is not necessary to drastically change the configuration of the two-wheel drive vehicle, and the dedicated design of the four-wheel drive vehicle when configuring the four-wheel drive vehicle can be omitted.

Therefore, the increase in cost for constructing a four-wheel drive vehicle can be greatly reduced. Further, since the drive device itself does not require addition of a new expensive component, the cost increase for constructing the four-wheel drive vehicle can be further greatly reduced.

When the vehicle is required to be in the four-wheel drive state in the drive system, for example, electric power is supplied from the generator 22 to the electric motor 24 for a short time such as when the vehicle starts or runs at low speed. Therefore, the electric power to the auxiliary component 29 side of the low voltage system is the same as that of the conventional low voltage battery 27.
In this case, the required power to the low-voltage auxiliary component 29 side may be temporarily insufficient.

In this drive device, assuming this case, if the required power to the side of the auxiliary component 29 of the low voltage system is temporarily insufficient, the electric motor 24 of the high voltage system of the generator 22 is supplied. The control device 20c having a control function of canceling the connection is adopted. As a result, the formation of the four-wheel drive state of the vehicle can be temporarily interrupted, and the shortage of required power to the low voltage system auxiliary device side can be compensated.

Thus, the four-wheel drive vehicles 10 and 2 described above are used.
In each of the drive devices configuring 0, the control device calculates the command torque based on the method shown in the flowchart of FIG. 7 when the four-wheel drive state is formed. When it is determined that the four-wheel drive state is formed, the microcomputer constituting the control device executes the program for calculating the designated torque, reads the detection signal from the wheel speed sensor in step 131, and At 132, the rotational speed difference ΔN between the front and rear wheels is calculated based on the detection signal.

Next, in step 133, the microcomputer reads the detection signals from the throttle sensor and other sensors, calculates the output torque T in step 134, and outputs this as the command torque to the drive circuit of the control device. Then, in step 135, the current applied to the electric motor is controlled according to the command torque.

In the calculation of the output torque, the throttle sensitive torque T1 to be applied to the electric motor and the preset same are set from the preset relationship diagram of the throttle opening and the throttle sensitive torque shown in FIG. 8A. From the relationship diagram between the rotational speed difference ΔN of the front and rear wheels shown in FIG.
Calculate the ΔN sensitive torque T2 applied to the electric motor,
Sum of throttle sensitive torque T1 and ΔN sensitive torque T2 (T
1 + T2) is the command torque T.

The control devices constituting the respective drive devices execute the above control programs, predict the occurrence or occurrence of the brake operating state while the vehicle is traveling by four-wheel drive, and respond to them. An output control program that regulates the output (output torque) from the electric motor to the rear wheels is executed. 9 to 12 show flowcharts for executing the output control programs of the four types, respectively.

The flowchart shown in FIG. 9 shows the torque output from the electric motor to the rear wheels when a parking brake or a brake (collectively referred to as a brake) is activated while the vehicle is running on four wheels. The output control program is regulated to a predetermined value.

The microcomputer executes step 201.
When the brake operating state is determined and it is determined that the brake is in the non-operating state, execution of the program is terminated, and when it is determined that the brake is operating,
In step 202, the magnitude of the torque value T of the command torque and the set specified torque value T0 is determined.

The microcomputer executes step 202.
When it is determined that the torque value T of the command torque is less than the specified torque value T0, the execution of the program is terminated, and when it is determined that the torque value T of the command torque is equal to or greater than the specified torque value T0. At step 203, the current applied to the electric motor is controlled so that the output torque from the electric motor to the rear wheel side becomes equal to or less than the specified torque value T0.
Terminates program execution.

As a result, the interference between the electric motor and the brake can be prevented, and the durability of the drive device can be improved. The microcomputer circulates and executes the control program based on the flowchart.

The flowchart shown in FIG. 10 executes an output control program for maintaining the electric motor in a non-driving state by stopping the supply of electric power to the electric motor when the engine is run dry during braking. Is.

The microcomputer executes step 210.
When the brake operating state is determined and it is determined that the brake is not operating, the program proceeds to step 211 to continue the normal drive control of the electric motor to determine whether the brake is operating. If there is a certain determination, it is determined in step 212 whether or not the throttle opening is within the set maximum allowable value C that forms the four-wheel drive state.

The microcomputer executes step 212.
If it is determined that the throttle opening is within the set maximum allowable value C for forming the four-wheel drive state, the program continues the normal drive control of the electric motor in step 211 to open the throttle. When it is determined that the degree is equal to or greater than the set maximum allowable value C that forms the four-wheel drive state,
The program proceeds to step 213, and in step 213, it is determined whether or not this state has passed the set fixed time.

The microcomputer executes the step 213.
When it is determined that the throttle opening is equal to or larger than the set maximum allowable value C for forming the four-wheel drive state for a certain period of time, in step 214, the engine is deflated. Then, the supply of electric power to the electric motor is stopped, the electric motor is maintained in the non-driving state, and the execution of the program ends.

As a result, the control device stops the supply of the electric power which is continuously supplied to the electric motor due to the continuous engine exhaustion, and prevents the electric motor from being damaged due to temperature rise, burning, and the like. be able to.

The flowchart shown in FIG. 11 executes an output control program for stopping the torque output from the electric motor to the rear wheels when the parking brake is applied.

The microcomputer executes step 221.
If it is determined that the parking brake has not been actuated, the execution of the program is terminated. If it is determined that the parking brake has been actuated, the program is executed in step 222.
Proceed to.

The microcomputer executes the step 222.
Then, if it is determined that the vehicle speed is lower than the set specified speed D, the execution of the program is ended, and if it is determined that the vehicle speed is equal to or higher than the set specified speed D, the program proceeds to step 223. In step 223, the coupling of the electromagnetic clutch is cut off (OFF) and the supply of electric power to the electric motor is stopped to stop the electric motor.

As a result, it is possible to protect the drive unit when the parking brake is applied during traveling such as a severe test. The microcomputer circulates and executes the control program based on the flowchart.

The flow chart shown in FIG. 12 executes an output control program for stopping the operation of the second drive mechanism on the rear wheel drive side when the parking brake is applied and four-wheel drive traveling is unnecessary.

The microcomputer executes step 231.
If it is determined that the parking brake has not been actuated, the execution of the program is terminated. If it is determined that the parking brake has been actuated, the program is executed in step 232.
Proceed to.

The microcomputer executes step 232.
When the vehicle speed is determined by, the execution of the program is terminated when it is determined that the vehicle speed is not zero, and when the vehicle speed is determined by zero, the program proceeds to step 233, and the throttle opening degree is determined at step 233. Is determined. When the microcomputer determines in step 233 that the throttle opening is not zero, it ends the execution of the program,
When it is determined that the throttle opening is zero, the program proceeds to step 234, and in step 234, it is determined whether or not the vehicle stop state has passed the set fixed time.

The microcomputer executes the step 234.
When it is determined that the vehicle stop state has not passed the set certain time, the program execution is terminated, and it is determined that the vehicle stop state has not passed the set certain time. Step 235 the program into
Proceed to. In step 235, the microcomputer disconnects (turns off) the electromagnetic clutch and stops the supply of electric power to the electric motor to stop the electric motor.

As a result, the second wheel on the rear wheel drive side when the parking brake is applied and four-wheel drive traveling is unnecessary.
The operation of the drive mechanism can be maintained in a stopped state, wasteful consumption of energy can be prevented, and fuel consumption can be improved. The microcomputer circulates and executes the control program based on the flowchart.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a first 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 for executing a control program included in the control device.

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

FIG. 5 is a schematic configuration diagram of a control device that constitutes the drive device.

FIG. 6 is a flowchart for executing a control program included in the control device.

FIG. 7 is a flowchart showing a method of calculating a command torque performed by the control device of each drive device according to the present invention.

FIG. 8 is a graph (a) showing a relationship between a preset throttle sensitive torque T1 and a throttle opening, which is a basis for calculating a command torque, and a rotation difference ΔN and ΔN sensitive torque between front and rear wheels. It is a graph (b) which shows the relationship of T2.

FIG. 9 is a flowchart for executing an output control program according to an example included in the control device according to the present invention.

FIG. 10 is a flowchart for executing an output control program according to another example included in the control device according to the present invention.

FIG. 11 is a flowchart for executing an output control program according to another example included in the control device according to the present invention.

FIG. 12 is a flowchart for executing an output control program according to another example of the control device of the present invention.

[Description of Reference Signs] 10, 20 ... Four-wheel drive vehicle, 10a, 20a ... First drive mechanism, 10b, 20b ... Second drive mechanism, 10c, 20c ...
Control device 11,21 ... Engine, 12, 22 ... Generator, 13a, 23a ... Transmission, 13
b, 23b ... Reduction gear train, 13c, 23c ... Front differential, 13e, 23e ... Front wheel, 14, 28
… Low voltage battery, 15, 24… Electric motor, 16…
DC-DC converter, 17 ... High-voltage battery, 1
8, 25 ... Electromagnetic clutch, 19a, 26a ... Reduction gear train, 19b, 26b ... Rear differential, 19
c, 26c ... Drive shaft, 19d, 26d ... Rear wheel, 27 ... Changeover switch, 29 ... Auxiliary equipment parts.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoyuki Sakai             1-1 Asahi-cho, Kariya city, Aichi             Machine Co., Ltd. F-term (reference) 3D039 AA03 AB01 AB27                 3D043 AA07 AB01 AB17 EA02 EA05                       EA18 EA42 EE03 EE09 EF09                       EF12 EF14 EF19

Claims (8)

[Claims] 1. A main drive by the main drive means, comprising main drive means for driving the main drive wheel side which is one of the front and rear wheels, and auxiliary drive means for driving the auxiliary drive wheel side which is the other of the front and rear wheels. The main drive wheels are driven independently by the drive on the wheel side, and the main drive means drives the main drive wheels and the sub drive means drives the auxiliary drive wheels to drive both drive wheels. Is a drive device for a front-rear wheel drive vehicle of a type that forms a two-wheel drive traveling state, the drive device from the auxiliary drive means to the auxiliary drive wheel side in accordance with an operation state of a brake or an operation operation of the brake. A drive device for a front-rear wheel drive vehicle, comprising an output control means for controlling output. 2. The drive device for a front-rear wheel drive vehicle according to claim 1, wherein the output control means sets the output of the auxiliary drive means to a predetermined value or less in accordance with a brake operating state or a brake operating operation. A drive device for a front-rear wheel drive vehicle having a control function of regulating. 3. A drive device for a front-rear wheel drive vehicle according to claim 1, wherein said output control means supplies a drive source to said auxiliary drive means when said main drive means is driven when a brake is actuated. A drive device for a front and rear wheel drive vehicle having a control function of stopping the vehicle. 4. A main drive means for driving a main drive wheel side which is one of the front and rear wheels, an electric motor which is a sub drive means for driving the auxiliary drive wheel side which is the other of the front and rear wheels, and the electric motor and An electromagnetic clutch is provided that connects and disconnects power transmission with the sub-driving means, and the main driving means drives the main driving wheels to drive the main driving wheels independently while the electromagnetic clutch is disconnected. And driving the main drive wheel side by the main drive means and the sub drive wheel side by the auxiliary drive means to drive the two wheels in the two-wheel drive state. A drive device for a front-rear wheel drive vehicle of the type to be formed, wherein the drive device controls output from the auxiliary drive means to the auxiliary drive wheel side in accordance with an operation state of a brake or an operation operation of the brake. means Drive for the front and rear wheel drive vehicle, characterized in that it comprises. 5. The drive device for a front-rear wheel drive vehicle according to claim 4, wherein the output control means sets an output torque of the electric motor to a predetermined value or less in accordance with a brake operating state or a brake operating operation. A drive device for a front-rear wheel drive vehicle having a control function of regulating. 6. The drive device for a front-rear wheel drive vehicle according to claim 4, wherein the output control means stops supply of electric power to the electric motor when the main drive means is driven during brake operation. A drive device for a front-rear wheel drive vehicle having a control function. 7. The drive device for a front-rear wheel drive vehicle according to claim 4, wherein the output control means stops the supply of electric power to the electric motor when the brake is operated while the vehicle is traveling. A drive device for a front-rear wheel drive vehicle having a control function of disconnecting an electromagnetic clutch. 8. A drive device for a front-rear wheel drive vehicle according to claim 1, wherein the drive device is driven by the engine which is the main drive means and the engine. A front and rear wheel drive vehicle characterized by comprising a generator for generating electric power, controlling electric power generated by the generator, and supplying electric power to the electric motor to drive the electric motor. Drive.