Driving force distribution control apparatus

Patent metadata

Field	Value
Publication number	US-9561720-B2
Application number	US-201514637705-A
Country	US
Kind code	B2
Filing date	Mar 4, 2015
Priority date	Mar 12, 2014
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A driving force distribution control apparatus includes: a driving force transmission device including a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and a controller which controls an engagement force of the clutch in accordance with a traveling state. The controller includes a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time. The different-diameter tire detector performs detection of the attachment of the different-diameter tire when it is determined that the wheels are unlikely to slip based on an outside condition.

First claim

The invention claimed is:

1. A driving force distribution control apparatus comprising:
a driving force transmission device comprising a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and
a controller which controls an engagement force of the clutch in accordance with a traveling state,
wherein the controller comprises a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time, and
wherein the different-diameter tire detector determines whether the wheels are likely to slip based on an outside condition, and performs detection of the attachment of the different-diameter tire based on a driving force threshold determined by the determination of whether the wheels are unlikely to slip.

2. The driving force distribution control apparatus according to claim 1 ,
wherein the different-diameter tire detector determines that the wheels are unlikely to slip when the driving force is lower than a threshold which is set based on the outside condition.

3. The driving force distribution control apparatus according to claim 2 ,
wherein the threshold is set based on a friction coefficient of a road surface as the outside condition.

4. A driving force distribution control apparatus comprising:
a driving force transmission device comprising a clutch which can change distribution of a driving force to front wheels and rear wheels of a four-wheel drive vehicle; and
a controller which controls an engagement force of the clutch in accordance with a traveling state,
wherein the controller comprises a different-diameter tire detector which detects an attachment of a different-diameter tire to one of the front wheels and the rear wheels when a rotation speed ratio between the front wheels and the rear wheels continues to be equal to or larger than a reference rotation speed ratio for a predetermined time,
wherein the different-diameter tire detector determines whether the wheels are likely to slip based on a friction coefficient of a road surface, and performs detection of the attachment of the different-diameter tire based on the determination of whether the wheels are unlikely to slip and the driving force,
wherein the different-diameter tire detector determines that the wheels are unlikely to slip when the driving force is less than a first threshold at a time when it is determined that the friction coefficient of the road surface is equal to or greater than a predetermined value, and
wherein the different-diameter tire detector determines that the wheels are unlikely to slip when the driving force is less than a second threshold at a time when it is determined that the friction coefficient of the road surface is less than a predetermined value, wherein the second threshold value is lower than the first threshold value.

Assignees

• Jtekt Corp
• Mazda Motor

Inventors

• Sarai Kotaro
• Kato Tomoaki
• Kawano Hiroto
• Kofu Daisuke
• Yagi Yasushi

Classifications

• B60K23/0808 Primary

  for varying torque distribution between driven axles, e.g. by transfer clutch · CPC title

• B60K17/35

  including arrangements for suppressing or influencing the power transfer, e.g. viscous clutches · CPC title

• B60K2023/0833

  for adding torque to the rear wheels · CPC title

• B60K2023/0858

  with electric means, e.g. electro-hydraulic means · CPC title