EP-4227200-B1 - VEHICLE BRAKE FLUID PRESSURE CONTROL DEVICE

Inventors

• TSUDA FUMIYA

Dates

Publication Date

20260506

Application Date

20210916

Claims (7)

1. A vehicle brake fluid pressure control device comprising: a wheel speed detection device (32) configured to detect wheel speed of a wheel; a braking force control device (50) configured to execute an anti-lock brake control for adjusting a braking force acting on a wheel brake by compressing, decompressing, or maintaining a brake fluid pressure acting on the wheel brake; and an electronic control device (200), wherein the electronic control device includes: a change amount calculation unit (220) that calculates a change in wheel speed over time; a change amount determination unit (230) that determines whether the sign of the change in wheel speed is positive or negative; and a brake control unit (260) that controls the braking force control device; and the device is characterised in that : during execution of a first decompression control, in which a braking force acting on the wheel brake is further reduced by a decompression amount larger than a decompression amount of the brake fluid pressure in the anti-lock brake control in a state where the braking force acting on the wheel brake is reduced in the anti-lock brake control, when the change in wheel speed is determined to be a positive value by the change amount determination unit, the brake control unit stops the first decompression control.
2. The vehicle brake fluid pressure control device according to claim 1, wherein the change amount calculation unit (220) calculates the change in wheel speed by subtracting a wheel speed calculated for an (n-1)th time from a wheel speed detected for an nth time, and the change amount determination unit (230) determines that the change in wheel speed is a positive value when the wheel speed detected for the nth time is larger than the wheel speed calculated for the (n-1)th time.
3. The vehicle brake fluid pressure control device according to claim 1, wherein the change amount determination unit (230) determines that the change in wheel speed is a positive value when the change in wheel speed is equal to or greater than a threshold value.
4. The vehicle brake fluid pressure control device according to any one of claims 1 to 3, wherein the brake control unit (260) stops the first decompression control when the change amount determination unit determines that the change in wheel speed is a positive value and the wheel speed is equal to or greater than a predetermined value.
5. The vehicle brake fluid pressure control device according to any one of claims 1 to 4, wherein the electronic control device (200) includes a friction calculation unit that determines a coefficient of friction between the wheel and a road surface, and the brake control unit (260) stops the first decompression control when the change amount determination unit determines that the change in wheel speed is a positive value and the coefficient of friction is equal to or greater than a threshold value of the coefficient of friction.
6. The vehicle brake fluid pressure control device according to any one of claims 1 to 5, wherein the vehicle brake fluid pressure control device is mounted on a bar handle vehicle, the wheel speed detection device detects wheel speeds of wheels on a front side and a rear side, and the brake control unit starts to adjust a braking force acting on the wheel brake on a rear side after starting adjusting a braking force acting on the wheel brake on a front side.
7. The vehicle brake fluid pressure control device according to any one of claims 1 to 5, wherein the vehicle brake fluid pressure control device is mounted on a bar handle vehicle, the wheel speed detection device detects a wheel speed of the wheel on a front side, and the brake control unit adjusts a braking force acting on the wheel brake on a front side.

Description

Technical Field The present invention relates to a vehicle brake fluid pressure control device. Background Art As a brake fluid pressure control device mainly used in a bar handle type vehicle such as a motorcycle, a motor tricycle, and an all-terrain vehicle (ATV), there is a brake fluid pressure control device capable of executing an anti-lock brake control for stopping wheel locking by compressing, decompressing, or maintaining a brake fluid pressure acting on wheel brakes. As the above-described brake fluid pressure control device, there is a brake fluid pressure control device that, during execution of a control for decompressing the brake fluid pressure, stops decompression of the brake fluid pressure when grip of a wheel starts to recover and acceleration of the wheel increases (for example, see PTL 1). In addition, as the above-described brake fluid pressure control device, there is a brake fluid pressure control device that, during execution of a control for decompressing the brake fluid pressure, stops decompression of the brake fluid pressure when grip of a wheel starts to recover and deceleration of the wheel decreases (for example, see PTL 2). EP 1294599 B1, over which the independent claim is characterised, discloses a method for controlling an antilock braking system (ABS) in the event that a roadway defect (e.g. pothole) is encountered. US 6,601,927 B2 discloses a method for detecting lifting of the rear wheel of a two-wheeled vehicle, and controlling braking. Citation list Patent Literature PTL 1: Japanese Patent No. 3629896PTL 2: JPH05-39020A Summary of Invention Technical Problem When the decompression of the brake fluid pressure is stopped based on the acceleration or deceleration of the wheel, as in the above-described vehicle brake fluid pressure control device in the related art, since an amount of change of the acceleration or deceleration is large, it is difficult to adjust a timing of stopping the decompression of the brake fluid pressure. Furthermore, in these vehicle brake fluid pressure control devices, when a wheel slip amount is large, the brake fluid pressure may be further decompressed by increasing a decompression amount as compared to that in normal decompression of the brake fluid pressure. In this case, in the above-described vehicle brake fluid pressure control device in the related art, even though the normal decompression of the brake fluid pressure is stopped, the increased decompression amount continues to act on the wheel brakes, and therefore, there is a problem that a braking force continues to decrease due to the increased decompression amount even though a wheel speed has started recovering. An object of the invention is to solve the above-described problem and provide a vehicle brake fluid pressure control device capable of precisely adjusting a timing of stopping the increase in the decompression amount and improving feeling of braking when the brake fluid pressure is further decompressed by increasing a decompression amount as compared to that in the normal decompression of the brake fluid pressure. Solution to Problem In order to solve the above problem, according to the present invention there is provided a vehicle brake fluid pressure control device according to claim 1. The amount of change in wheel speed clearly shows a timing at which the wheel speed starts recovering. Accordingly, in the vehicle brake fluid pressure control device according to the invention, it is possible to precisely adjust a timing of stopping a control for reducing the braking force by stopping a control for reducing the braking force further than a normal braking force based on the amount of change in wheel speed. Therefore, feeling of braking can be improved. In the above-described vehicle brake fluid pressure control device, for example, the change amount calculation unit calculates the amount of change by subtracting a wheel speed calculated for an (n-1)th time from a wheel speed detected for an nth time. In this case, it is preferable that the change amount determination unit easily determine a positive value or a negative value of the amount of change by determining that the amount of change is a positive value when the wheel speed detected for the nth time is larger than the wheel speed calculated for the (n-1)th time. In the above-described vehicle brake fluid pressure control device, for example, the change amount determination unit determines that the amount of change is a positive value when the amount of change is equal to or greater than a threshold value of the amount of change. In this case, the wheel speed can be reliably increased by changing the threshold value of the amount of change according to the wheel speed. In the above-described vehicle brake fluid pressure control device, for example, the brake control unit stops the first decompression control when the change amount determination unit determines that the amount of change is a positive value and the whee