VEHICLE BRAKING FORCE CONTROL DEVICE

• US 20150008726A1
• Filed: 03/05/2013
• Published: 01/08/2015
• Est. Priority Date: 03/05/2012
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Minami, Tatsuya
• Granted Patent: US 9,988,029 B2
• Time in Patent Office: Days
• US Class Current: 303/14
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60T 11/103 in combination with other control devices conjoint control of brake system and at least another sub-unit B60W10/188
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 2270/414 Power supply failure
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/885 using electrical circuitry

Abstract

A vehicle braking force control device includes a braking force control unit. The braking force control unit is configured to shift to a drive state so as to use an auxiliary power source when a main power source fails, and to limit current outputted to an electric actuator of a braking device for producing braking hydraulic pressure when a transition is made to the drive state using the auxiliary power source. The braking force control unit has two current limit values used during actuation of the electric actuator by the auxiliary power source, the current limit values being a first current limit value for ensuring increased-braking-hydraulic-pressure characteristics, and a second current limit value for ensuring a necessary minimum braking hydraulic pressure, the second current limit value being less than the first current limit value.

Claims

1. A vehicle braking force control device comprising:

a braking force control unit configured to shift to a drive state so as to use an auxiliary power source when a main power source fails, and to limit current outputted to an electric actuator of a braking device for producing braking hydraulic pressure when a transition is made to the drive state using the auxiliary power source,

the braking force control unit having two current limit values used during actuation of the electric actuator by the auxiliary power source, the current limit values being a first current limit value for ensuring increased-braking-hydraulic-pressure characteristics, and a second current limit value for ensuring a necessary minimum braking hydraulic pressure, the second current limit value being less than the first current limit value, and the braking force control unit being configured to impose the first current limit value immediately after the transition to the drive state using the auxiliary power source until the braking hydraulic pressure reaches the necessary minimum braking hydraulic pressure, and to shift the limiting from the first current limit value to the second current limit value after the braking hydraulic pressure has reached the necessary minimum braking hydraulic pressure.

3. The vehicle braking force control device according to claim 1, wherein

the braking force control unit is configured to return to the first current limit value when a driver operation equivalent value falls below a reset threshold representing the release of the brake pedal and when the electric actuator is being actuated by the auxiliary power source and a shift has been made to the second current limit value.

4. The vehicle braking force control device according to claim 1, wherein

the braking force control unit is configured to use the output current consumption time as a condition of shifting between the first current limit value and the second current limit value to set the first current limit value immediately after a shift to a drive state using the auxiliary power source, and to shift to the second current limit value when the time during which the output current exceeds the second current limit value in the drive state using the auxiliary power source is greater than the time during which the necessary minimum braking hydraulic pressure can be outputted with the output response characteristics of the first current limit value.

5. The vehicle braking force control device according to claim 1, wherein

the braking force control unit is configured to use the braking hydraulic pressure as a condition of shifting between the first current limit value and the second current limit value to set the first current limit value immediately after a shift to a drive state using the auxiliary power source, and to shift to the second current limit value when the braking hydraulic pressure exceeds the necessary minimum braking hydraulic pressure during the drive state using the auxiliary power source.

6. The vehicle braking force control device according to claim 3, wherein

the braking force control unit is configured to use the output current consumption time as a condition of shifting between the first current limit value and the second current limit value to set the first current limit value immediately after a shift to a drive state using the auxiliary power source, and to shift to the second current limit value when the time during which the output current exceeds the second current limit value in the drive state using the auxiliary power source is greater than the time during which the necessary minimum braking hydraulic pressure can be outputted with the output response characteristics of the first current limit value.

7. The vehicle braking force control device according to claim 3, wherein

the braking force control unit is configured to use the braking hydraulic pressure as a condition of shifting between the first current limit value and the second current limit value to set the first current limit value immediately after a shift to a drive state using the auxiliary power source, and to shift to the second current limit value when the braking hydraulic pressure exceeds the necessary minimum braking hydraulic pressure during the drive state using the auxiliary power source.

2. (canceled)