JP2003326995A - Drive for front and rear wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a tooth beat sound from being generated due to backlash in a driving force transmission mechanism connected to an electric motor, 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 a pre-torque imparting means for imparting very small pre-torque to the electric motor, and the backlash between gears in the driving force transmission mechanism is put close to prevent the tooth beat sound from being generated due to the backlash, by imparting the very small pre-torque all the time to the electric motor. <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 automobile are driven together to form a front and rear two-wheel drive traveling state. It is proposed in Japanese Patent No. 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 this type of drive unit, an electric motor is generally adopted as the sub-driving means, as seen in the above-mentioned vehicle drive unit, but the electric motor is sub-driven. Since the driving force transmission mechanism connected to the wheels has many gear trains, the driving force transmission mechanism has a lot of play. These backlashes cause a rattling noise. In particular, these rattles and rattling noises caused by the rattling are amplified and increased by the speed reducer when a means for connecting the electric motor to the driving force transmission shaft or the like via the speed reducer is adopted.

Therefore, in the drive device of this type, it is preferable to prevent the rattling noise caused by the rattling that may occur in the driving force transmission mechanism, and the object of the present invention is to prevent the rattling noise. This is to prevent or suppress the occurrence of rattling noise.

[0007]

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 electric motor, which is a sub-driving means for driving the sub-driving wheel side, is provided, the main driving means drives the main driving wheel side to form an independent driving traveling state of the main driving wheel, and the main driving means 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 driving the main drive wheel side and driving the auxiliary drive wheel side by the electric motor is applied. . Therefore, the drive device for a front-rear wheel drive vehicle according to the present invention is characterized by including a pre-torque applying means for applying a minute torque to the electric motor.

A drive device for a front-rear wheel drive vehicle according to the present invention includes a clutch for connecting and disconnecting the drive force transmittable connection between the electric motor and the auxiliary drive wheel side, and when driving the auxiliary drive wheel side. In addition, it is possible to configure a drive device in which the electric motor and the auxiliary drive wheel side are connected by the clutch so that the driving force can be transmitted, and the electric motor drives the auxiliary drive wheel side. Further, in the drive device, the electric motor and the driving force transmission path on the side of the auxiliary drive wheel may be always connected.

In these driving devices, the pre-torque applying means may apply a pre-torque to the electric motor by applying a current of a predetermined value from the power supply to the electric motor.

In addition, in these drive devices according to the present invention, an electric power generated by the generator is constituted by an engine which is the main drive means and a generator which is driven by the engine to generate electric power. And a high voltage current is applied to the electric motor when the electric motor is driven, and a low voltage current is applied to the electric motor when the pre-torque of the electric motor is applied. it can.

[0011]

In the drive device for the front and rear wheel drive vehicle according to the present invention, there is provided the pre-torque applying means for applying a minute torque to the electric motor, and the electric motor is always operated when the drive device is operated. Pre-torque is applied. The pre-torque applied to the electric motor is
It functions as backlash reduction to one side between the tooth portions of the gear train and the like that form the driving force transmission mechanism. For this reason, it is possible to prevent or significantly suppress the occurrence of rattling noise due to backlash in the drive device.

The pre-torque applying means in the drive device according to the present invention can be specifically configured to apply a predetermined value of current from the power supply to the electric motor to apply the pre-torque to 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, which is the other of the front and rear wheels. An electric motor, which is a sub-driving unit for driving the wheel side, is provided, the main driving unit drives the main driving wheel side to form an independent driving traveling state of the main driving wheel, and the main driving unit drives the main driving unit. 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 driving the drive wheels and driving the auxiliary drive wheels by the electric motor. There are many types of drive devices for front and rear wheel drive vehicles of this type, and in this embodiment, two types of drive devices shown in FIGS. 1 and 4 are exemplified.

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 a first drive mechanism 10a that drives the front wheel side that is the main drive wheel, a second drive mechanism 10b that drives the rear wheel side that is the auxiliary drive wheel, and a second drive mechanism 10b. The controller 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, and is stored in the low-voltage battery 14 via the DC-DC converter 16. The electric motor 15 is an electric motor 15 capable of selectively switching between electric energy and mechanical energy for output.
Therefore, as the electric motor 15, a separately excited motor,
A DC motor, a brushless motor or the like can be adopted as appropriate.

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 a traveling direction sensor S7 (shift position sensor, rear lamp lighting detection sensor, etc.) that detects the backward movement of the vehicle. The MPU (microprocessor) 10c1 and drive The circuit 10c2 is provided.

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 S7 via an interface. Take in the electric motor 15 and the electromagnetic clutch 18
It determines the operating state of the electric motor 15, the electromagnetic clutch 18, etc. as a command signal and outputs it to the drive circuit 10c2 via the interface. 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
ON-OFF control of the electromagnetic clutch 18 is performed. MPU1
The control program included in 0c1 holds a control program that applies a minute torque to the electric motor 15.

That is, the control device 10c controls the success or failure of the four-wheel drive state, drives the electric motor 15,
It has a control function of controlling switching and a control function of applying a minute torque to the electric motor 15.

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
A switch sensor S5 for detecting the state of the WD switch, a motor sensor S6 for detecting the rotation state of the electric motor 15,
Based on the signal from the traveling direction sensor S7 that detects the reverse movement of the vehicle, the state in which the electric motor 15 should operate and the state in which the electromagnetic clutch 18 should operate are determined. The determination result is output to the drive circuit 10c2 as a command signal, and the drive circuit 10c2
c2 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 be in a power generation operable state. As a result, the electric motor 15 is operated by the rear wheel 1
It is driven by the driving force from the 9d side to generate regenerative electric power. The generated regenerative power is used by the drive circuit 1 of the control device 10c.
It is stored in the high-voltage battery 17 via 0c2 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. The motor drive torque T which is a command torque based on the method described later.
Is calculated, and the electromagnetic clutch 18 is turned on in step 108.
Then, in step 109, the electric current applied to the electric motor 15 is controlled to a value according to the command torque T, and electric power is supplied from the high voltage battery 17 to the electric motor 15 via the drive circuit 10c2 of the control device 10c. As a result, the rear wheels 19d are driven by the drive of 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 microcomputer advances the program to step 110 to turn off the electromagnetic clutch 18, and in step 111, the high voltage battery 17 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 operates the electric motor 15
To the electric motor 15, the drive torque T, which is the command torque, is calculated, and the traveling direction of the vehicle is detected. The current value corresponding to is controlled. A detailed description of this point will be given later.

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, a stored electric power of the high-voltage battery 17 is adopted instead of a dedicated generator for driving the electric motor 15, 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 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 a 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. According to such a configuration, the regenerated electric power of the electric motor 15 can 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 can be operated so as to accurately form the intended vehicle state, and the efficiency of energy utilization can be further enhanced overall.

Although the drive unit is an extremely effective drive unit for constructing the four-wheel drive vehicle of the type as described above, the control unit 10c constituting the drive unit operates the electric motor 15 during this period. On the other hand, a pre-torque (a small torque) is applied to reduce play in the driving force transmission mechanism, and a rattling noise caused by the play is prevented. In addition,
This point will be described 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 when the electromagnetic clutch 25 is turned on and engaged, the driving force of the electric motor 24 is reduced by the reduction gear train 2.
6a, the electromagnetic clutch 25, and the rear differential 26b, and is transmitted to each drive shaft 26c,
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 switching 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 controls the throttle opening sensor S1, the wheel speed sensor S2, the brake sensor S3, the low voltage battery voltage sensor S4, the switch sensor S5 for detecting the state of the WD switch, and the electric motor. The MPU, which is connected to the motor sensor S6 for detecting the rotation state of the motor 24 and the vehicle traveling direction sensor S7,
(Microprocessor) 20c1 and drive circuit 20c2
Is equipped with.

The MPU 20c1 has a CPU and a memory that holds 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 S7. 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 a control program for applying a minute torque to the electric motor 15, 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 changeover switch 27. It has a control function for controlling and a control function for applying a minute torque to the electric motor 24.

The microcomputer constituting the control device 20c determines whether the four-wheel drive state should be selected when the 4WD switch is ON, and when the four-wheel drive state is 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. Brake sensor S3, low-voltage battery voltage sensor S4, switch sensor S5 that detects the state of the 4WD switch, motor sensor S6, vehicle direction sensor S7. The four-wheel drive state is formed when a sufficient amount of electricity is stored in the low-voltage battery 28, such as when the vehicle runs at low speed or at low speed.

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. Step 1
In 25, a motor drive torque T that is a command torque is calculated based on a method described later, and in step 126, the electromagnetic clutch 25 is turned on, the changeover switch 27 is switched to the electric motor 24 side, and the generator 22 is set to high. Switch to the voltage generation side.

In step 126, the motor drive torque T, which is a command torque, is calculated based on the method described below, and the electric current applied to the electric motor 24 is controlled to a value according to the command torque T so that the electric motor 24 is controlled. Generator 2
High-voltage power is supplied from 2 to form the vehicle in a four-wheel drive state.

The microcomputer circulates and executes the above control program based on the flowchart. During this period, the microcomputer operates the electric motor 24.
A small torque is always applied to the drive torque T, the drive torque T that is the command torque is calculated, and the traveling direction of the vehicle is detected to detect the forward and reverse directions of the current applied to the electric motor 24 and the command torque. The current value corresponding to is controlled. A detailed description of this point will be given later.

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 drive torque T that is the command torque based on the flowchart shown in FIG. 7 and determines the traveling direction of the vehicle when the four-wheel drive state is formed. Then, the forward and reverse directions of the applied current to the electric motor and the applied current are controlled to a current value corresponding to the driving torque T.

If the microcomputer constituting the control device determines that the four-wheel drive state is to be formed,
The program for calculating the driving torque T is executed, and in step 131, the detection signal from the wheel speed sensor is read and the rotation speed difference ΔN between the front and rear wheels is calculated based on the detection signal.

The microcomputer then reads in step 132 the detection signals from the throttle sensor and the other sensors and is preset.
(A) Throttle opening and throttle sensitive torque T
The driving torque T (T1 + T2) to be commanded is calculated from 1 (including the pre-torque PT0) and the relationship between the front and rear wheel rotational speed difference ΔN and the ΔN sensitive torque T2 shown in FIG.

In step 133, the microcomputer determines the traveling direction of the vehicle, and in step 134
At, the forward / reverse of the applied current to the electric motor with respect to the traveling direction of the vehicle and the applied current are controlled to a current value according to the drive torque T. The pre-torque PT0 is always applied to the electric motor, and the forward and reverse directions are selected according to the traveling direction of the vehicle.

As described above, in each drive device, a small torque (pre-torque PT0) is applied to the electric motors 15 and 24.
A pre-torque applying means for applying the pre-torque PT0 is constantly applied to the electric motors 15 and 24 when the drive device is operating. Electric motor 1
The pre-torque applied to the gears 5, 24 is applied in a direction corresponding to the traveling direction of the vehicle, and is used as backlash to one side between the tooth portions of the gear trains 19a, 36a and the like that configure the driving force transmission mechanism. Function. Therefore, it is possible to prevent or significantly suppress the occurrence of rattling noise due to backlash in each drive device.

[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 flow chart for executing a program for calculating a drive torque included in the control device.

FIG. 8 is a graph (a) showing a relationship between a throttle opening and a throttle sensitive torque T1 which is a basis for calculating the driving torque, and a graph showing a relationship between front and rear wheel rotational speed differences ΔN and ΔN sensitive torque ( b).

[Explanation of symbols]

10, 20 ... Four-wheel drive vehicle, 10a, 20a ... 1st drive mechanism, 10b, 20b ... 2nd 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

Claims (5)

[Claims] 1. A main drive means for driving a main drive wheel side which is one of the front and rear wheels, and an electric motor which is an auxiliary drive means for driving a sub drive wheel side which is the other of the front and rear wheels. The main drive wheels are driven by the main drive wheels to form an independent drive traveling state, and the main drive means drives the main drive wheels and the electric motor drives the sub drive wheels. 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, wherein the drive device includes pre-torque applying means for applying a minute torque to the electric motor. Drive device for front and rear wheel drive vehicles. 2. The drive device for a front-rear wheel drive vehicle according to claim 1, further comprising a clutch for connecting and disconnecting the electric motor and the auxiliary drive wheel side, the clutch capable of transmitting and receiving a driving force, the auxiliary drive wheel side. For driving a front-rear wheel drive vehicle of a type in which the electric motor and the auxiliary drive wheel side are connected by the clutch so that the driving force can be transmitted, and the electric motor drives the auxiliary drive wheel side. The drive device for a front-rear wheel drive vehicle, comprising: a pre-torque applying means for applying a minute torque to the electric motor. 3. A drive device for a front-rear wheel drive vehicle according to claim 1, wherein the electric motor and a drive force transmission path on the side of the auxiliary drive wheel are always connected to each other. A drive device for a front-rear wheel drive vehicle, wherein the drive device includes pre-torque applying means for applying a minute torque to the electric motor. 4. The drive device for a front-rear wheel drive vehicle according to claim 1, wherein the pre-torque applying means applies a current of a predetermined value from a power source to the electric motor. A drive device for a front-rear wheel drive vehicle, characterized in that a minute torque is applied to a motor. 5. A drive device for a front and 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 generator for generating electric power is provided, the electric power generated by the generator is controlled, a high voltage current is applied to the electric motor when the electric motor is driven, and a low voltage is applied when a pre-torque is applied to the electric motor. Is applied to the electric motor, the drive device for a front-rear wheel drive vehicle.