Braking Device for Vehicle

• US 20070247001A1
• Filed: 11/29/2004
• Published: 10/25/2007
• Est. Priority Date: 12/01/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nakano, Masaki
• Granted Patent: US 8,042,883 B2
• Time in Patent Office: Days
• US Class Current: 303/157
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 7/0007 the motor being electric
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2220/44 Wheel Hub motors, i.e. integrated in the wheel hub
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/461 Speed
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 3/0076 relating to braking
• CPC Class Codes: B60L 3/108 whilst braking, i.e. ABS
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 13/586 the retarders being of the electric type
• CPC Class Codes: B60T 2270/604 Merging friction therewith; Adjusting their repartition
• CPC Class Codes: B60T 8/52 Torque sensing, i.e. wherein the braking action is controlled by forces producing or tending to produce a twisting or rotating motion on a braked rotating member
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 : including control of braking systems
• CPC Class Codes: B60W 10/184 : with wheel brakes
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/15 : Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: F16D 2121/02 : Fluid pressure
• CPC Class Codes: F16D 2127/085 : having additional fluid pressure elements
• CPC Class Codes: F16D 55/00 : Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes similar clutches F16D13/38
• CPC Class Codes: F16D 65/186 : with full-face force-applying member, e.g. annular
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

[Problems] To provide a brake device for a motor vehicle that can suppress variation in braking force applied to a wheel regardless of variation in friction coefficient between a rotator and a braking means in a fluid pressure brake.

[Means for Solving Problems] A brake device for a motor vehicle is provided with a fluid pressure brake 2 (braking means) that applies brake force according to brake fluid pressure to a brake disk (rotator) 20 fixed to a driving wheel (wheel) 3, and has a first feedback mechanism (pressure-reducing means) 15-1 that applies reaction force inputted from the brake disk 20 to the fluid pressure brake 2 in brake operation in a reducing direction of the brake fluid pressure.

Claims

1. A brake device which is adapted for a motor vehicle and has a braking means that applies brake force according to brake fluid pressure to a rotator fixed to a wheel, the brake device is wherein

the brake device has a pressure-reducing means for applying reaction force inputted from the rotator to the braking means in a brake operation in a reducing direction of the brake fluid pressure.

2. The brake device according to claim 1, wherein

the pressure-reducing means is provided with a valve means capable of shifting maintenance and reduction of the brake fluid pressure, and applies the reaction force inputted to the braking means in the reducing direction of the brake fluid pressure in the valve means.

3. The brake device according to claim 1, wherein a brake reaction force detecting mechanism is provided for detecting the reaction force inputted to the braking means, so that the detected reaction force is applied to the valve means in the reducing direction of the brake fluid pressure.

4. The brake device according to claim 1, wherein the brake reaction force detecting means is provided swingably relative to a vehicle body side, and integrated with the braking means so that the reaction force inputted to the braking means can be transformed into a swing movement.

5. The brake device according to claim 4, wherein a drive device is provided to apply driving force to the wheel, and the brake reaction force detecting means includes a machine-side cylindrical case containing the drive device.

6. The brake device according to claim 4, wherein a rotating electric motor is provided for applying regenerative brake force to the wheel, and the brake reaction force detecting means includes a machine-side cylindrical case containing the rotating electric motor.

7. The brake device according to claim 4, wherein the machine-side of the rotating electric machine is rotatably supported by a vehicle body side member, the vehicle body side member is formed with an on-demand brake fluid pressure chamber, a wheel-cylinder fluid pressure chamber and a return fluid pressure chamber, an orifice is provided in a communicating fluid pressure passage between the on-demand brake fluid pressure chamber and the wheel-cylinder fluid pressure chamber, a wheel-cylinder fluid pressure modulator valve is provided in a communicating fluid pressure passage between the wheel-cylinder fluid pressure chamber and the return fluid pressure chamber, and

the pressure-reducing means is a mechanical feedback mechanism for modulating the wheel cylinder fluid pressure so that the sum torque of the regenerative brake torque that is applied through a working arm provided on the machine-side cylindrical case in the opening direction and fluid pressure brake torque due to the wheel cylinder fluid pressure in the opening direction can be balanced with the on-demand brake torque due to the on-demand brake fluid pressure.

8. The brake device according to claim 7, wherein the rotating electric machine is an in-wheel electric motor with reduction gears, in which the electric motor and the reduction gears are arranged in the machine-side cylindrical case fixed to an integral brake caliper in a driving wheel,

the wheel-cylinder fluid pressure modulator valve has a piston and a valve member connected with the piston, where one end portion of the piston is in the on-demand brake fluid pressure chamber to receive torque in a closing direction of the wheel-cylinder fluid pressure modulator valve when the on-demand brake fluid pressure is generated and the valve member opens and closes a valve hole formed in a partition wall between the wheel-cylinder fluid pressure chamber and the return fluid pressure chamber, and

the mechanical feedback mechanism is a first feedback mechanism modulating the wheel cylinder fluid pressure so that torque applied to the piston through the working arm provided on the machine-side cylindrical case in the opening direction can be balanced with the on-demand brake torque acting in the closing direction and determined by the product of the on-demand fluid pressure and an effective pressure receiving area of the piston.

9. The brake device according to claim 7, wherein the rotating electric machine is an on-vehicle electric motor with reduction gears, in which the electric motor and the reduction gears are arranged in the machine-side cylindrical case which is separated from a brake caliper in a driving wheel,

the wheel-cylinder fluid pressure modulator valve has a first piston and a valve member connected with the first piston, where one end portion of the piston is in the on-demand brake fluid pressure chamber to receive torque in a closing direction of the wheel-cylinder fluid pressure modulator valve when the on-demand brake fluid pressure is generated and the valve member opens and closes a valve hole formed in a partition wall between the wheel-cylinder fluid pressure chamber and the return fluid pressure chamber,

the vehicle body side member is formed with a second wheel-cylinder fluid pressure chamber provided with a second piston at a position distanced from the wheel-cylinder fluid pressure modulator valve,

the machine-side cylindrical case is provided with a second working arm receiving torque from a piston rod of the second piston in the opening direction when the wheel cylinder fluid pressure is generated, and

the mechanical feedback mechanism is a second feedback mechanism modulating the wheel cylinder fluid pressure so that torque applied to the first piston through the first working arm provided on the machine-side cylindrical case in the opening direction can be balanced with the on-demand brake torque acting in the closing direction and determined by the product of the on-demand brake fluid pressure and an effective pressure receiving area of the first piston.

10. The brake device according to claim 9, wherein the rotating electric machine is an on-vehicle electric motor with reduction gears, in which the electric motor and the reduction gears are arranged in the machine-side cylindrical case which is separated from a brake caliper in a driving wheel,

the wheel-cylinder fluid pressure modulator valve has a first piston, a second piston and a valve member connected with the first piston and the second piston, where one end portion of the first piston is in the on-demand brake fluid pressure chamber to receive torque in the closing direction when the on-demand brake fluid pressure is generated, one end portion of the second piston is in the wheel-cylinder fluid pressure chamber to receive torque in the opening direction when the wheel cylinder fluid pressure is generated, and the valve member opens and closes a valve hole formed in a partition wall between the wheel-cylinder fluid pressure chamber and the return fluid pressure chamber, and

the mechanical feedback mechanism is a third feedback mechanism modulating the wheel cylinder fluid pressure so that the sum torque of torque applied to the first piston through the first working arm provided on the machine-side cylindrical case in the opening direction and fluid pressure brake torque acting in the opening direction and determined by the product of the wheel cylinder pressure and an effective pressure receiving area of the second piston can be balanced with the on-demand brake torque acting in the closing direction and determined by the product of the on-demand brake fluid pressure and an effective pressure receiving area of the first piston.

11. The brake device according to claim 7, wherein the on-demand brake fluid pressure chamber is a master-cylinder fluid pressure chamber conducting master cylinder fluid pressure generated by a master cylinder according to a brake operation of a brake operating means.

12. The brake device according to claim 7, wherein the on-demand brake fluid pressure chamber is an ABS brake fluid pressure chamber conducting ABS brake fluid pressure from an Antilock Brake System provided at a downstream side of a master cylinder.

13. The brake device according to claim 12, wherein a brake control means is provided for stopping regenerative brake by the rotating electric machine in an Antilock Braking system operation.

14. The brake device according to claim 1, wherein the brake reaction force detecting means is a torque sensor that electrically detects reaction force of the fluid reaction force inputted to a brake caliper, and

the pressure reducing means is an electric feedback circuit that controls the pressure-reducing solenoid valve for decreasing the brake fluid pressure according to a torque value detected by the torque sensor.

15. The brake device according to claim 14, wherein the rotating electric machine is an in-wheel electric motor with reduction gears, in which the electric motor and the reduction gears are arranged in the machine-side cylindrical case fixed to an integral brake caliper in a driving wheel, and

the electric feedback circuit includes a pressure-reducing solenoid valve arranged between a wheel-cylinder fluid pressure passage conducting ABS brake fluid pressure from an Antilock Brake System provided at a downstream side of a master cylinder to a wheel cylinder and a return fluid pressure passage fluidically connected with a fluid pump inlet port side of the Antilock Brake System to control the pressure-reducing solenoid valve according to torque value detected by the torque sensor.

16. The brake device according to claim 14, wherein the rotating electric machine is an on-vehicle electric motor with reduction gears, in which the electric motor and the reduction gears are arranged in the machine-side cylindrical case which is separated from a brake caliper in a driving wheel, and

the electric feedback circuit includes a pressure-reducing solenoid valve arranged between a wheel-cylinder fluid pressure passage conducting ABS brake fluid pressure from an Antilock Brake System provided at a downstream side of a master cylinder to a wheel cylinder and a return fluid pressure passage fluidically connected with a fluid pump inlet port side of the Antilock Brake System to control the pressure-reducing solenoid valve according to torque value detected by the torque sensor.

17. The brake device according to claim 4, wherein

only the braking means is provided for applying fluid pressure brake force to the wheel, and the brake reaction force detecting means is a caliper member integrally formed with a brake caliper of the braking means.