JPH06107016A - Driving force distribution controller for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To control a variable torque clutch precisely and to provide a low production cost driving force distribution controller for a four-wheel drive vehicle. CONSTITUTION:Rotation of an electric motor (m) controlled by a controller is transmitted to a push rod 19 via a transmission gear and a converting means as a linear motion, which serves as pushing pressure operating a variable torque clutch in a driving force distribution controller, in which an elastic body such as torsion bar 17 and the like are provided between the transmission gear and the converting means while the first and the second rotational amount detectors 12a, 12b, which are connected to the controller, are provided in the transmission gear and the converting means individually.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressing force generation mechanism of a driving force distribution control device for distributing driving force to front wheels and rear wheels in a four-wheel drive vehicle.

[0002]

2. Description of the Related Art As a conventional drive force distribution control device for a four-wheel drive vehicle, for example, one disclosed in Japanese Patent Laid-Open No. 61-157437 is known. This device directly transmits the driving force from the transmission to either the front wheels or the rear wheels,
The driving force is distributed and transmitted to the other front wheel or rear wheel via the variable torque clutch. The variable torque clutch performs the operation of changing the driving force distribution to the front wheels and the rear wheels by continuously controlling the strength of the connection in the so-called half-clutch state. The strength is controlled by the push rod of the pressing force generating mechanism that operates with hydraulic pressure. That is, the pushing force on the variable torque clutch is adjusted by the push rod, the strength of the connection of the variable torque clutch in the half-clutch state is determined according to the pushing force, and the driving force is distributed to the front wheels and the rear wheels. .

The pressing force generating mechanism is controlled by a controller. This controller inputs information from the rotational force sensors provided on the drive shafts of the front and rear wheels,
The difference between the rotational speeds of the front wheels and the rear wheels is compared and calculated. Then, a signal is sent to the electromagnetic proportional solenoid to correct this difference in the number of revolutions. The electromagnetic proportional solenoid activates the pressure control valve in response to a control signal from the controller to determine the pressure applied to the push rod of the pressing force generating mechanism. This pressure exerts a pressing force on the push rod to control the strength of the connection of the variable torque clutch in the half-clutch state, so that an appropriate driving force is distributed to the front wheels and the rear wheels.

[0004]

The conventional driving force distribution control device as described above does not include means for detecting the pressing force of the push rod of the driving force distribution control device. For this reason, since the output state of the actual pressing force of the push rod cannot be fed back, there is a problem that the variable torque clutch cannot be controlled accurately. Also, since the pressing force generating mechanism that operates the variable torque clutch was operated by hydraulic pressure, piping that constitutes the hydraulic circuit, a pressure control valve for controlling the operation of the push rod, etc. are required, and the number of parts is large. Was becoming. Therefore, there is also a problem that the production cost becomes high. Furthermore, due to the large number of parts, there is a problem in that when this device is incorporated into a vehicle body, there is no choice but to place restrictions on the arrangement, which reduces the degree of freedom in arrangement. An object of the present invention is to provide a driving force distribution control device for a four-wheel drive vehicle that controls a variable torque clutch with high accuracy, has a low production cost, and has a high degree of freedom of incorporation into a vehicle body.

[0005]

In order to solve the above-mentioned problems, according to the present invention, it is possible to change the distribution of the driving force to the front wheels and the rear wheels in the middle of the power transmission system to the front wheels and the rear wheels. A torque clutch is provided, and a pressing force generation mechanism having a push rod and a controller for controlling the operation of the push rod are provided, and the pressing force generation control operation for changing the driving force distribution of the variable torque clutch is controlled by the controller. In a drive force distribution control device for a four-wheel drive vehicle operated by a push rod of a mechanism, an electric motor whose output is controlled by a controller by the pressing force generation mechanism, a transmission gear provided on the output side of the electric motor, and Conversion means for converting the rotation of the transmission gear into linear movement of the push rod; an elastic body such as a torsion bar that links the transmission gear and the conversion means; The first rotation amount detecting device for detecting the rotation amount of the yarn and the second rotation amount detecting device for detecting the rotation amount of the converting means are provided, and these two rotation amount detecting devices are connected to the controller. .

[0006]

When the electric motor whose output is controlled by the controller is rotated, the rotation is converted into a linear motion of the push rod by the transmission gear, the conversion means, and the elastic body such as a torsion bar which links them. In this rotation transmission process, since the transmission gear and the converting means are linked through the elastic body such as the torsion bar, the elastic body is twisted, and the amount of rotation between the transmission gear and the converting means is equal to the twist amount. Difference occurs. The rotation amount of the transmission gear and the rotation amount of the converting means at this time are respectively detected by the first and second rotation amount detection devices and sent to the controller. The controller calculates the actual pressing force of the push rod from the difference in the amount of rotation, and controls the rotation of the electric motor so as to obtain the required pressing force.

[0007]

1 to 4 show an embodiment of the present invention. Here, in the casing 2 of the pressing force generation mechanism 1,
Electric motor m controlled by a controller (not shown)
Is attached, and the hypoid pinion 4 is attached to the output shaft 3. The hypoid pinion 4 is rotatably supported on the casing 2 by bearings 5 and 6. A hypoid gear wheel 7 is provided in the casing 2, and a hypoid gear 7a formed therein,
The hypoid pinion 4 meshes with the hypoid pinion 4 and the hypoid gear wheel 7 to form a transmission gear.

The hypoid gear wheel 7 has a bearing 8
Is rotatably supported by the casing 2, and a support shaft 9 is fitted in the center of the upper portion in the figure.
The support shaft 9 is rotatably supported by a cover 11 by a bearing 10. The cover 11 has a first
Rotary potentiometer 12a as a rotation amount detector
Is attached. The detection shaft 13 of the potentiometer 12a is attached to the upper part of the support shaft 9 and can detect the rotation amount of the hypoid gear wheel 7 connected to the support shaft 9. A recess 14 is formed at the center of the lower part of the hypoid gear wheel 7 in the figure, and one end of a pinion shaft 15 is rotatably supported in the recess 14 by a bearing. The one end of the pinion shaft 15 and the recess 14 of the hypoid gear wheel 7 are linked by a torsion bar 17 as an elastic body.

A pinion 18 is formed on the pinion shaft 15 and engages with a rack 20 formed on a push rod 19 as shown in FIG. Therefore, when the hypoid gear wheel 7 rotates, the pinion shaft 15 rotates via the torsion bar 17. Then, the push rod 1 in which the rack 20 that meshes with the pinion 18 formed in the pinion shaft 15 is formed
9 moves in the axial direction according to the rotation direction of the pinion shaft 15. In this way, the pinion shaft 15 and the push rod 19 constitute a conversion means, and the rotation of the transmission gear is converted into the linear motion of the push rod 19.

Further, a rotary potentiometer 12b as a second rotation amount detecting device is attached to the casing 2 on the other end side of the pinion shaft 15, and its detection shaft 21 is provided at the other end of the pinion shaft 15. It is installed in the center. The potentiometer 12b detects the amount of rotation of the pinion shaft 15. Then, these two potentiometers 12a and 12b are connected to a controller (not shown), and the respective rotation amounts are sent to the controller as signals.

In the pressing force generating mechanism 1 configured as described above, when the electric motor m controlled by the controller rotates, the hypoid pinion 4 provided on the output shaft 3 of the electric motor m rotates and the hypoid gear wheel 7 meshes with the hypoid gear wheel 7. Also rotates. When the hypoid gear wheel 7 rotates, the pinion shaft 15 is passed through the torsion bar 17.
However, the push rod 19 meshing with the pinion shaft 15 does not rotate immediately due to the load of the variable torque clutch (not shown). At this time, the torsion bar 17 is twisted according to the load on the push rod 19 side and the rotation amount of the electric motor m, and then the pinion shaft 15 is rotated. In this way, when the pinion shaft 15 rotates, the push rod 19 moves in the axial direction according to the amount of rotation of the pinion shaft 15 to generate a pressing force on the variable torque clutch.

At this time, the potentiometer 12a attached to the support shaft 9 of the hypoid gear wheel 7 detects the amount of rotation of the hypoid gear wheel 7 and the potentiometer 12b attached to the pinion shaft 15.
Detects the amount of rotation of the pinion shaft 15 and sends each information to the controller. As described above, between the hypoid gear wheel 7 and the pinion shaft 15,
The torsion bar 17 is twisted according to the load of the variable torque clutch and the rotation amount of the electric motor m, and a difference in rotation amount is generated.

This difference in the amount of rotation is arithmetically processed by the controller, and the result is judged as the actual pressing force of the push rod 19. That is, the twist amount of the torsion bar 17 is calculated from the difference between the rotation amounts of the potentiometers 12 a and 12 b, and this twist amount corresponds to the loss of the pressing force of the push rod 19. In other words, the rotation amount of the electric motor m is lost by the amount of the twist and the push rod 19
The pressing force is. Therefore, the pressing force that is lost by the amount of twist is the actual pressing force of the push rod 19, and if the rotation of the electric motor m is controlled so that this pressing force is the required pressing force, the accuracy is always maintained. A high pressing force can be generated on the push rod 19, and accordingly, the operation of the variable torque clutch can be performed accurately.

FIG. 3 is a block diagram showing the above operation, and FIG. 4 is a flow chart showing the operation of the controller. First, the controller receives a command from a switch or the like and rotates the electric motor m by an amount corresponding to the value of the command. Then, as the electric motor m rotates, the hypoid pinion 4 and the hypoid gear wheel 7 rotate. The rotation amount of the hypoid gear wheel 7 is detected by the potentiometer 12a, and the rotation amount of the pinion shaft 15 is detected by the potentiometer 12b.
Detected by.

The two potentiometers 12a, 1
The controller connected to 2b is the rotation amount detected by the potentiometer 12a and the potentiometer 12b.
The actual pressing force of the push rod 15 is calculated from the difference from the rotation amount detected by. This calculated push rod 1
The controller controls the rotation of the electric motor m so that the actual pressing force of 5 becomes the required pressing force. In this way, the actual pressing force of the push rod 15 is fed back to the controller, so that the variable torque clutch can be controlled accurately. Also, unlike conventional hydraulic circuits, many parts are not required, so production cost can be reduced and the number of parts is reduced. The degree of freedom has increased.

[0016]

The first and second rotation amount detecting devices detect the rotation amount on the electric motor side and the rotation amount on the push rod side, and the controller detects the actual pressing force of the push rod from the difference between the rotation amounts. To calculate. Since the electric motor is controlled so that the required pressing force can be obtained, the pressing force can be controlled more accurately than in the conventional example in which there is no means for detecting the pressing force. Further, compared with the conventional hydraulic circuit type, since many parts are not required, it is possible to reduce the production cost, and it is possible to downsize due to the small number of parts, which limits the arrangement of parts on the vehicle body. The degree of freedom in assembling into the car body has increased.

[Brief description of drawings]

FIG. 1 is a sectional view of a pressing force generating mechanism according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a block diagram showing an operation of the driving force distribution controller shown in the embodiment.

FIG. 4 is a flowchart showing the operation of the controller in the embodiment.

[Explanation of symbols]

 1 Pressing force generating mechanism 17 Torsion bar 19 Push rod m Electric motor

Claims (1)

[Claims] 1. A variable torque clutch capable of changing the distribution of driving force to the front wheels and the rear wheels is provided in the middle of a power transmission system for the front wheels and the rear wheels, and a pressing force generating mechanism having a push rod is provided. And a controller for controlling the operation of the push rod, wherein the changing operation of the driving force distribution of the variable torque clutch is operated by the push rod of the pressing force generation mechanism controlled by the controller. In the device, an electric motor whose output is controlled by a controller by the pressing force generating mechanism, a transmission gear provided on the output side of the electric motor, and a conversion means for converting the rotation of the transmission gear into a linear motion of a push rod. An elastic body such as a torsion bar that links the transmission gear with the conversion means; a first rotation amount detection device that detects the rotation amount of the transmission gear; A driving force distribution control device for a four-wheel drive vehicle, comprising: a second rotation amount detection device that detects a rotation amount; and a configuration in which these two rotation amount detection devices are connected to a controller.