Electronically controlled hydraulic brake system

Abstract

An electronically controlled hydraulic brake system comprising: a brake operating member; a reservoir containing a brake fluid; a front and a rear wheel cylinder; a front and a rear pressure-increase valve; a front and a rear pressure-decrease valve; a power-operated pressure source; a front and a pressure-decrease passage respectively connecting the front and rear pressure-decrease valves with the reservoir; an operating state detecting device detecting an operating state of the brake operating member, based on which the brake fluid is (i) supplied to the front and rear wheel cylinders from the power-operated pressure source by operation of the front and rear pressure-increase valves, so as to increase pressure in the front and rear wheel cylinders, and (ii) discharged from the front and rear wheel cylinders to the reservoir via the front and rear pressure-decrease passages, by operation of the front and rear pressure-decrease valves so as to decrease the pressure in the front and rear wheel cylinders; and pulse transmission restraining means restraining transmission of a pressure pulse from the brake fluid at a junction between the front and rear pressure-decrease passages to the brake fluid in the rear pressure-decrease passage.

Description

technical field [0001] The present invention relates to a hydraulic braking system for a motor vehicle, and more particularly to an electronically controlled hydraulic braking system in which the hydraulic pressure in the wheel cylinder of the brake for braking the rotation of the wheels of the motor vehicle is controlled by an electronic control unit . Background technique [0002] As disclosed in the specification of JP-A-2002-541010, there is known a type of electronically controlled hydraulic brake system in which the operating state of the brake operating member is detected by an operating state detecting device, and based on the detected operation state to control the pressure in the front wheel cylinder for the front wheels and the pressure in the rear wheel cylinder for the rear wheels. That is, when the pressure in the wheel cylinders is to be increased, the brake fluid is supplied from the power-operated hydraulic pressure source to the front and rear wheel cylind...

AI Technical Summary

Problems solved by technology

When meeting at this junction, a pressure pulse occurs and, due to the lower flow rate in the rear pressure reduction channel than in the front pressure reduction channel, this pressure pulse is transmitted to the rear pressure reduction channel than to the front pressure reduction channel. The pressure reduction channel is more intense, or a pressure pulse occurs in the front pressure reduction channel and is transmitted to the rear pressure reduction channel due to a lower flow rate in the rear pressure reduction channel than in the front pressure reduction channel. The pressure reducing channel is more intense than that transmitted to the front pressure reducing channel, creating a noise that is uncomfortable for the occupants or driver of the vehicle

[0006] Furthermore, there is also the possibility that pressure pulses are transmitted not only to the rear pressure reduction channel, but also to the front pressure reduction channel, but the noise generated in the rear pressure reduction channel is greater than in the front pressure reduction channel The noise produced, or at least the tendency to be more uncomfortable to the passengers or driver in the rear pressure reducing passages than in the front pressure reducing passages

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