Four-wheel drive vehicle and control apparatus for four-wheel drive vehicle

Patent metadata

Field	Value
Publication number	US-10293687-B2
Application number	US-201715725400-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Oct 11, 2016
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A control apparatus for a four-wheel drive vehicle includes a current detector configured to output a detection signal in accordance with the magnitude of an actual control current, a target current value calculator configured to calculate a target current value that is a target value of the control current, and a current controller configured to control a current output circuit to output the control current having the target current value calculated by the target current value calculator based on a result of detection performed by the current detector. When the four-wheel drive vehicle is in a two-wheel drive mode in which first and second friction clutches are released, the current controller performs zero-point adjustment for adjusting a zero point of the control current to be output from the current output circuit.

First claim

What is claimed is:

1. A four-wheel drive vehicle, comprising:
main driving wheels to which a driving force of a drive source is constantly transmitted;
a driving shaft configured to transmit the driving force in a fore-and-aft direction of the vehicle;
auxiliary driving wheels to which the driving force of the drive source is transmitted via the driving shaft;
a first driving force transmission apparatus and a second driving force transmission apparatus arranged such that the driving shaft is interposed between the first driving force transmission apparatus and the second driving force transmission apparatus in a driving force transmission path to the auxiliary driving wheels; and
a control apparatus configured to control the first driving force transmission apparatus and the second driving force transmission apparatus, wherein
the first driving force transmission apparatus includes a dog clutch configured to transmit the driving force through engagement between projections and recesses,
the second driving force transmission apparatus includes:
an outer rotational member and an inner rotational member that are supported so as to be coaxially rotatable relative to each other;
an outer clutch plate configured to rotate together with the outer rotational member;
an inner clutch plate configured to rotate together with the inner rotational member; and
a pressing mechanism configured to press the outer clutch plate and the inner clutch plate in an axial direction by a pressing force in accordance with a control current supplied from the control apparatus,

the control apparatus includes:
a current output circuit configured to output the control current to the pressing mechanism;
a current detector configured to output a detection signal in accordance with a magnitude of the control current that is actually output from the current output circuit;
a target current value calculator configured to calculate a target current value that is a target value of the control current to be supplied to the pressing mechanism; and
a current controller configured to control the current output circuit so that the control current having the current value calculated by the target current value calculator based on a result of detection performed by the current detector is output to the pressing mechanism, and

when the four-wheel drive vehicle is in a two-wheel drive mode in which transmission of the driving force that is performed by both of the first driving force transmission apparatus and the second driving force transmission apparatus is interrupted, the current controller is configured to perform zero-point adjustment for storing information that the detection signal output from the current detector indicates a zero point of the control current to be output from the current output circuit.

2. The four-wheel drive vehicle according to claim 1 , wherein the current controller is configured to perform the zero-point adjustment when a first predetermined time has elapsed since the four wheel drive vehicle is switched to the two-wheel drive mode, and to repeatedly perform, when the two-wheel drive mode continues afterwards, the zero-point adjustment every time a second predetermined time longer than the first predetermined time has elapsed.

3. The four-wheel drive vehicle according to claim 1 , wherein, when a starter switch for starting the drive source is turned ON, the current controller is configured to perform the zero-point adjustment before the control current is output from the current output circuit to the pressing mechanism.

4. The four-wheel drive vehicle according to claim 1 , wherein
the pressing mechanism includes:
a hydraulic pump;
a piston configured to press the outer clutch plate and the inner clutch plate by receiving a hydraulic pressure of hydraulic oil supplied to a cylinder chamber; and
a solenoid valve configured to regulate the pressure of the hydraulic oil to be supplied from the hydraulic pump to the cylinder chamber, and

the control apparatus is configured to output the control current to the solenoid valve.

5. The four-wheel drive vehicle according to claim 1 , wherein
the pressing mechanism includes:
an electric motor;
hydraulic pump to be driven by the electric motor; and
a piston configured to press the outer clutch plate and the inner clutch plate by receiving a hydraulic pressure of hydraulic oil supplied from the hydraulic pump to a cylinder chamber, and

the control apparatus is configured to output the control current to the electric motor.

6. The four-wheel drive vehicle according to claim 1 , wherein
the pressing mechanism includes:
a cam mechanism configured to generate the pressing force through relative rotation between a par of cam members arranged coaxially with the outer rotational member and the inner rotational member; and
an electromagnetic actuator configured to rotate the pair of cam members relative to each other, and

the control apparatus is configured to output the control current to the electromagnetic actuator.

7. A control apparatus to be mounted on a four-wheel drive vehicle including main driving wheels to which a driving force of a drive source is constantly transmitted, a driving shaft configured to transmit the driving force in a fore-and-aft direction of the vehicle, auxiliary driving wheels to which the driving force of the drive source is transmitted via the driving shaft, and a first driving force transmission apparatus and a second driving force transmission apparatus arranged such that the driving shaft is interposed between the first driving force transmission apparatus and the second driving force transmission apparatus in a driving force transmission path to the auxiliary driving wheels, the control apparatus comprising:
a control unit; and
a current output circuit, wherein
the control apparatus is configured to control the first driving force transmission apparatus and the second driving force transmission apparatus,
the first driving force transmission apparatus includes a dog clutch configured to transmit the driving force through engagement between projections and recesses,
the second driving force transmission apparatus includes:
an outer rotational member and an inner rotational member that are arrange so as to be coaxially rotatable relative to each other;
a friction clutch including an outer clutch plate configured to rotate together with the outer rotational member, and an inner clutch plate configured to rotate together with the inner rotational member; and
a pressing mechanism configured to press the outer clutch plate and the inner clutch plate in an axial direction by pressing force in accordance with a control current supplied from the current output circuit,

the control unit includes:
a target current value calculator configured to calculate a target current value that is a target value of the control current to be supplied to the pressing mechanism;
a current detector configured to output a detection signal in accordance with a magnitude of the control current that is actually output from the current output circuit; and
a current controller configured to control the current output circuit so that the control current having the current value calculated by the target current value calculator based on a result of detection performed by the current detector is output to the pressing mechanism, and

when the four-wheel drive vehicle is in a two-wheel drive mode in which transmission of the driving force that is performed by both of the dog clutch and the friction clutch is interrupted, the current controller is configured to perform zero-point adjustment for storing information that the detection signal output from the current detector indicates a zero point of th

Assignees

• Jtekt Corp

Inventors

• Nozu Tomohiro
• Nagayama Go
• Niimi Shotaro
• Kakita Akiyoshi
• Sarai Kotaro

Classifications

• B60K2023/0866

  with hydraulic means only · CPC title

• B60Y2400/421

  Dog type clutches or brakes · CPC title

• F16D2500/1022

  Electromagnet · CPC title

• F16D2500/70406

  Pressure · CPC title

• B60K17/348

  having differential means for driving one set of wheels, e.g. the front, at one speed and the other set, e.g. the rear, at a different speed (B60K17/346 takes precedence) · CPC title