JP2010089626A - Drag preventing method in brake device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably prevent dragging of a hydraulic disc brake device with a simple structure.
A brake fluid pressure generated by a master cylinder 11 in response to a braking operation in which a driver steps on a brake pedal 12 is transmitted to wheel cylinders 16, 17; 20, 21 via a VSA device 24 to brake the wheels. To do. Since the VSA device 24 includes in-valves 56 and 58, out-valves 60 and 61, and a pump 64, the in-valves 56 and 58 are closed and the out-valves 60 and 61 are opened after the driver's braking operation is completed. By driving the pump 64 in this state, the pump 64 was driven when the brake fluid supplied to the wheel cylinder was returned from the second fluid passage 53 to the master cylinder 11 via the pump 64 and the first fluid passage 52. Excess brake fluid can be returned to the master cylinder 11 by that amount, whereby the piston of the wheel cylinder can be retracted excessively to prevent dragging.
[Selection] Figure 2

Description

  The present invention relates to a vehicle brake device including a brake fluid pressure control unit disposed between a brake fluid pressure generating unit that generates a brake fluid pressure in response to a driver's braking operation and a disc brake device that brakes a wheel. The present invention relates to a drag prevention method.

In a disc brake device that can also be used as a parking brake, the brake pad that faces the brake disc is configured to be able to advance and retract with an electric motor and a ball screw mechanism, and the brake pad is pressed against the brake disc to perform braking. Patent Document 1 below discloses that the disc brake device is prevented from being dragged by returning to a position where a predetermined pad clearance is formed.
JP 2006-240584 A

  By the way, the above conventional one has a special structure in which the brake pad is driven forward and backward by an electric motor and a ball screw mechanism, and the brake pad is driven by driving the piston of the disc brake device with the brake hydraulic pressure generated by the master cylinder or the like. There is a problem that it cannot be applied to a general disc brake device that presses against a brake disc.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably prevent dragging of a hydraulic disc brake device with a simple structure.

  In order to achieve the above object, according to the invention described in claim 1, between the brake fluid pressure generating means for generating the brake fluid pressure according to the braking operation of the driver and the disc brake device for braking the wheel. The brake fluid pressure control means is arranged in the first fluid path connected to the brake fluid pressure generating means, the second fluid path connected to the disc brake device, An in-valve disposed between the first fluid passage and the disc brake device, an out valve disposed between the disc brake device and the second fluid passage, and the first fluid from the second fluid passage. In a vehicular brake device including a pump for supplying brake fluid to a fluid passage, the pump is driven with the in-valve closed and the out-valve opened after the driver's braking operation is completed. It is, and returning a part of the brake fluid supplied to the disc brake device in the brake fluid pressure generating means via the pump, preventing method drag in the vehicle brake system is proposed.

  Note that the VSA device 24 of the embodiment corresponds to the brake fluid pressure control means of the present invention, and the fluid path 52 and the fluid path 53 of the embodiment respectively correspond to the first fluid path and the second fluid path of the present invention. .

  According to the first aspect of the present invention, the brake fluid pressure generated by the brake fluid pressure generating means in response to the driver's braking operation is transmitted to the disc brake device via the brake fluid pressure control means to brake the wheel. Since the brake fluid pressure control means includes the first fluid passage, the second fluid passage, the in-valve, the out-valve and the pump, the pump is closed with the in-valve closed and the out-valve opened after the driver's braking operation is completed. When the brake fluid supplied to the disc brake device is returned from the second fluid passage to the brake fluid pressure generating means via the pump and the first fluid passage, the excess brake is driven by the amount of driving the pump. The fluid can be returned to the brake fluid pressure generating means, whereby the piston of the disc brake device can be retracted excessively to prevent dragging.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 and FIG. 2 show an embodiment of the present invention. FIG. 1 is a hydraulic circuit diagram of a vehicle brake device, and FIG. 2 is a diagram showing an operation when a brake pedal is returned.

  As shown in FIG. 1, the tandem master cylinder 11 includes two hydraulic chambers 13A and 13B that output brake hydraulic pressure in accordance with the pedaling force of the driver stepping on the brake pedal 12, and one hydraulic pressure is provided. The chamber 13A is connected to, for example, the wheel cylinders 16 and 17 of the disc brake devices 14 and 15 of the left front wheel and the right rear wheel via the fluid paths Pa, Pb and Pc (first system), and the other hydraulic chamber 13B. Is connected to the wheel cylinders 20 and 21 of the disc brake devices 18 and 19 of the right front wheel and the left rear wheel, for example, via liquid passages Qa, Qb and Qc (second system).

  A VSA (vehicle stability assist) device 24 is disposed between the liquid paths Pa and Qa and the liquid paths Pb and Pc; Qb and Qc.

  The structure of the VSA device 24 is well known. The first brake actuator 51A for controlling the first system of the disc brake devices 14 and 15 for the left front wheel and the right rear wheel, the disc brake device 18 for the right front wheel and the left rear wheel, A second brake actuator 51B that controls the 19 second system is provided with the same structure.

  Hereinafter, as a representative example, the first brake actuator 51A of the first system of the disc brake devices 14 and 15 for the left front wheel and the right rear wheel will be described.

  The first brake actuator 51A includes a fluid passage Pa that communicates with one hydraulic chamber 13A of the master cylinder 11, and fluid passages Pb and Pc that communicate with the left front wheel and right rear wheel wheel cylinders 16 and 17, respectively. It is arranged between.

  The first brake actuator 51A has a common liquid path 52 and a liquid path 53 for the left front wheel and right rear wheel wheel cylinders 16 and 17, and a variable opening degree disposed between the liquid path Pa and the liquid path 52. A regulator valve 54 composed of a normally open solenoid valve, a check valve 55 arranged in parallel to the regulator valve 54 and allowing the brake fluid to flow from the liquid passage Pa side to the liquid passage 52 side, and a liquid passage An in-valve 56 made up of a normally-open electromagnetic valve disposed between the fluid path Pc and the fluid path Pc, and disposed in parallel to the in-valve 56, allows the brake fluid to flow from the fluid path Pc side to the fluid path 52 side. A check valve 57, an in-valve 58 composed of a normally-open electromagnetic valve disposed between the liquid passage 52 and the liquid passage Pb, and the liquid passage Pb side arranged in parallel to the in-valve 58. A check valve 59 that allows the brake fluid to flow to the liquid path 52 side, an out valve 60 that is a normally closed electromagnetic valve disposed between the liquid path Pc and the liquid path 53, and the liquid path Pb and the liquid path 53. An out valve 61 composed of a normally closed electromagnetic valve disposed between, a low pressure accumulator 62 connected to the liquid path 53, and disposed between the liquid path 53 and the liquid path 52, from the liquid path 53 side to the liquid path 52 side. A check valve 63 that allows the brake fluid to flow to the pump, a pump 64 that is disposed between the check valve 63 and the fluid path 52 and supplies the brake fluid from the fluid path 53 side to the fluid path 52 side, and the pump 64 An electric motor 65 to be driven, and a suction valve 66 made up of a normally closed electromagnetic valve disposed between the check valve 63 and the intermediate position of the pump 64 and the liquid passage Pa are provided.

  The electric motor 65 is shared with the pumps 64 and 64 of the first and second brake actuators 51A and 51B. However, dedicated electric motors 65 and 65 are provided for the pumps 64 and 64, respectively. It is also possible to provide it.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When the driver steps on the brake pedal 12 to perform braking and the master cylinder 11 generates brake fluid pressure, the electric motor 65 of the VSA device 24 stops operating and the regulator valves 54 and 54 are demagnetized and opened. The suction valves 66, 66 are demagnetized and closed, the in valves 56, 56; 58, 58 are demagnetized and opened, and the out valves 60, 60; 61, 61 are demagnetized and closed. Therefore, the brake hydraulic pressure output from the pair of hydraulic chambers 13A and 13B of the master cylinder 11 passes through the in-valves 56 and 56; 58 and 58 that are opened from the regulator valves 54 and 54, and the wheel cylinders 16 and 17; 20 and 21 can brake the four wheels.

  When the driver is not stepping on the brake pedal 12, the pumps 64, 64 are driven by the electric motor 65 with the suction valves 66, 66 excited and opened, and the suction valves 66, 66 are passed from the master cylinder 11 side. The brake fluid sucked and pressurized by the pumps 64 and 64 is supplied to the regulator valves 54 and 54 and the in valves 56 and 56; 58 and 58. Accordingly, the regulator valves 54, 54 are excited to adjust the opening, thereby adjusting the brake fluid pressure in the fluid passages 52, 52, and the brake valve pressure is opened to a predetermined opening by excitation. By selectively supplying the wheel cylinders 16, 17; 20, 21 via 56; 58, 58, the braking force of the four wheels can be individually controlled even when the driver does not step on the brake pedal 12. Can do.

  Therefore, the braking force of the four wheels is individually controlled by the first and second brake actuators 51A and 51B, and the braking force of the inner turning wheel is increased to improve the turning performance, or the braking force of the outer turning wheel is increased to stabilize straight running. Performance can be improved.

  When the driver steps on the brake pedal 12 suddenly in order to avoid a collision, the brake fluid pressure generated by the master cylinder 11 is further increased by the pumps 64 and 64, and the wheel is driven by the increased brake fluid pressure. Maximum braking force is generated in the cylinders 16, 17; That is, when the pumps 64 and 64 are driven by the electric motor 65 with the regulator valves 54 and 54 excited and closed, and the suction valves 66 and 66 excited and opened, the brake fluid generated by the master cylinder 11 is generated. The pressure is sucked into the pumps 64 and 64 through the suction valves 66 and 66, and further supplied to the wheel cylinders 16, 17; 20 and 21 through the in-valves 56, 56; Assisting the driver's braking operation can generate a large braking force for avoiding a collision.

  When the driver depresses the brake pedal 12 and detects, for example, that the left front wheel is in a locking tendency by stepping on the low friction coefficient road, based on the output of the wheel speed sensor Sa ... One brake valve 51A of the brake actuator 51A is energized and closed, and one of the out valves 61 is excited and opened to release the brake fluid pressure of the left front wheel wheel cylinder 16 to the low pressure accumulator 62. After the pressure is reduced to a predetermined pressure, the out valve 61 is demagnetized and closed, thereby maintaining the brake fluid pressure of the wheel cylinder 16 of the left front wheel. As a result, when the locking tendency of the wheel cylinder 16 of the left front wheel is resolved, the brake fluid pressure from the one hydraulic chamber 13A of the master cylinder 11 is opened by demagnetizing the in-valve 58, and the wheel of the left front wheel The braking force is increased by supplying the cylinder 16 and increasing the pressure to a predetermined pressure.

  When the left front wheel becomes locked again due to this pressure increase, by repeating the pressure reduction → holding → pressure increase, the ABS (anti-lock brake) that minimizes the braking distance while suppressing the lock on the left front wheel is repeated.・ System) Control can be performed.

  The ABS control when the left front wheel wheel cylinder 16 tends to lock has been described above. However, the right rear wheel wheel cylinder 17, the right front wheel wheel cylinder 20, and the left rear wheel wheel cylinder 21 tend to lock. The ABS control can be performed in the same manner.

  By the way, if the pad clearance is not secured between the brake pads of the disc brake devices 14, 15; 18, 19 and the brake disc, the brake pads are braked even when the disc brake devices 14, 15; Dragged by the disc causes problems such as acceleration of brake pad wear and deterioration of fuel consumption.

  Therefore, in the present embodiment, as shown in FIG. 2, when braking is finished and the driver returns the brake pedal 12, the in-valves 56, 56; 58, 58 that are normally open are closed, Normally, with the closed out valves 60, 60; 61, 61 closed, the pumps 64, 64 are driven to suck the brake fluid from the fluid path 53 into the fluid path 52.

  When braking is finished and the brake pedal 12 is returned, the volume of the pair of hydraulic chambers 13A, 13B of the master cylinder 11 increases, so that the wheel cylinders 16, 17; 20, 21 of the disc brake devices 14, 15; The brake fluids of the following are the fluid paths Pb, Pc; Qb, Qc → opened out valves 60, 60; 61, 61 → fluid path 53 → pumps 64, 64 → fluid path 52 → opened regulator valve 54 → fluid path Pa, Qa → Returned to the hydraulic chambers 13A, 13B of the master cylinder 11. At this time, the brake fluid corresponding to the volume expansion of the hydraulic chambers 13A and 13B of the master cylinder 11 is discharged from the disc brake devices 14, 15; 18, 19 and further brake fluid is generated by the operation of the pumps 64 and 64. Is discharged to the master cylinder 11. As a result, the pistons of the disc brake devices 14, 15; 18, 19 are pulled back excessively, and a pad clearance between the brake pad and the brake disc is ensured to prevent the occurrence of dragging.

  The brake fluid exceeding the volume expansion is returned to the hydraulic pressure chambers 13A and 13B of the master cylinder 11, but the brake fluid is supplied to the reservoir of the master cylinder 11, so that there is no problem.

  As described above, according to the present embodiment, the in-valves 56, 56; 58, 58 and the out-valves 60, 60; 61, 61 of the VSA device 24 are not added to the existing brake device. By merely controlling the opening and closing and driving the pumps 64 and 64, the disc brake devices 14, 15; 18, 19 can be reliably prevented from being dragged.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the brake fluid pressure control means of the present invention is not limited to the VSA device 24 according to the embodiment, and may have any configuration corresponding to the in valves 56 and 58, the out valves 60 and 61, and the pump 64.

  Further, in the embodiment, braking is performed with the brake fluid pressure generated by the master cylinder 11, but the brake fluid generated by an electric braking force generating means such as a slave cylinder that is operated by an electric signal based on the driver's braking operation. The brake may be performed by pressure.

Hydraulic circuit diagram of vehicle brake system Diagram showing the action when the brake pedal is returned

Explanation of symbols

11 Master cylinder 14 Disc brake device 15 Disc brake device 18 Disc brake device 19 Disc brake device 24 VSA device (brake hydraulic pressure control means)
52 Liquid path (first liquid path)
53 Liquid path (second liquid path)
56 In valve 58 In valve 60 Out valve 61 Out valve 64 Pump

Claims (1)

Brake fluid pressure control disposed between the brake fluid pressure generating means (11) for generating the brake fluid pressure according to the driver's braking operation and the disc brake device (14, 15; 18, 19) for braking the wheel. Means (24),
The brake fluid pressure control means (24) is connected to the first fluid path (52) connected to the brake fluid pressure generating means (11) and the disc brake device (14, 15; 18, 19). A second fluid passage (53); an in-valve (56, 58) disposed between the first fluid passage (52) and the disc brake device (14, 15; 18, 19); and the disc brake device. (14, 15; 18, 19) and an out valve (60, 61) disposed between the second liquid path (53) and the second liquid path (53) to the first liquid path (52). A brake device for a vehicle comprising a pump (64) for supplying brake fluid to
After the driver's braking operation is completed, the disc brake device (64, 58) is closed and the pump (64) is driven with the out valve (60, 61) opened. 14, 15; 18, 19) A part of the brake fluid supplied to the brake fluid pressure generating means (11) is returned to the brake fluid pressure generating means (11) via the pump (64). Method.

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