KR102264096B1 - Brake by wire system for preventing sound noise of a solenoid valve - Google Patents

Abstract

The present invention relates to a brake-by-wire system for preventing sound noise of a solenoid valve, a motor that generates braking hydraulic pressure when a driver steps on a brake pedal, and a motor that brakes the braking hydraulic pressure generated in the motor under the control of an electronic control unit A hydraulic brake-by-wire (BBW) system including a hydraulic control unit provided to a caliper, comprising: a pair of solenoid valves controlled by the electronic control unit to transmit or block the brake hydraulic pressure generated by the motor to a flow path; Including, wherein the pair of solenoid valves are each formed of a solenoid valve for low pressure and a solenoid valve for high pressure, and the pair of solenoid valves are configured to be connected in a parallel structure.

Description

BRAKE BY WIRE SYSTEM FOR PREVENTING SOUND NOISE OF A SOLENOID VALVE

The present invention relates to a brake-by-wire system for preventing sound noise of a solenoid valve, and more particularly, a pair of solenoid valves operated under low and high pressure conditions instead of a method of controlling one solenoid valve in a PWM method. It relates to a break-by-wire system for preventing sound noise of a solenoid valve that can be configured in a break-by-wire system to control the solenoid valve under the corresponding conditions, thereby preventing the generation of sound noise from the solenoid valve .

Recently, the required function of the brake system for a vehicle is to enable active control regardless of the driver's pedal force and to implement a vacuum-free braking system through the deletion of a vacuum booster. Solutions for this include EMB (Electro mechanical Brake) and EWB (Electro Wedge Brake) systems, which are electric caliper systems, and EHB (Electro Hydraulic Brake) and AHB (Active Hydraulic Booster), which are hydraulic brake by wire systems (BBW), and electric booster system, etc.

Recently, among the concepts of the above braking system, development and mass production of an electric booster system that has a significant level of braking performance and can secure cost competitiveness in consideration of cost competitiveness, control precision, and braking performance are being actively conducted.

1 is an exemplary view showing a schematic configuration of a conventional hydraulic brake-by-wire system.

As shown in FIG. 1, the conventional hydraulic brake-by-wire (BBW) system requires a solenoid valve that requires constant operation or performs PWM (Pulse Width Modulation) control due to concerns about the operation durability even if it is not the operation. There are solenoid valves (eg SV1, SV2, SV3, SV4) that must be done.

The reason for performing the PWM control as described above is that heat or other durability problems occur when continuously operating under the condition of 100% applied current. Therefore, it is because the durability problem can be solved by applying a current with a low duty when braking with or not braking with a weak braking force, and applying a 100% duty only when a high braking force is required, such as during sudden braking.

However, when PWM control is performed as described above, there is a problem in that a 'beep' sound noise is generated from the solenoid valve. The sound noise is generated by vibration or resonance according to the PWM control cycle. Due to such sound noise, there is a problem in that consumer complaints occur or the product quality is deteriorated.

The background technology of the present invention is disclosed in Korean Patent Application Laid-Open No. 10-2009-0090452 (published on August 26, 2009, an electronically controlled brake system with a simulation function).

The present invention was created to solve the above problems, and instead of a method of controlling one solenoid valve in a PWM method, a pair of solenoid valves operated under low and high pressure conditions are configured in a brake-by-wire system to correspond It is an object of the present invention to provide a brake-by-wire system for preventing sound noise of a solenoid valve, which can control the solenoid valve under each condition, thereby preventing the sound noise from being generated in the solenoid valve.

A brake-by-wire system for preventing sound noise of a solenoid valve according to an aspect of the present invention includes a motor that generates braking hydraulic pressure when a driver steps on a brake pedal, and the braking hydraulic pressure generated by the motor under the control of an electronic control unit. In the hydraulic brake-by-wire (BBW) system including a hydraulic control unit for providing a brake caliper, a pair of solenoids that are controlled by the electronic control unit to transmit or block the braking hydraulic pressure generated by the motor on a flow path valve; including, wherein the pair of solenoid valves are respectively formed of a solenoid valve for low pressure and a solenoid valve for high pressure, and the pair of solenoid valves are configured to be connected in a parallel structure.

In the present invention, the pair of solenoid valves are all normally closed solenoid valves.

In the present invention, the low pressure solenoid valve operates at a pressure smaller than a preset pressure and operates by applying a current smaller than the preset current at 100% duty, and the high pressure solenoid valve is at a pressure greater than the preset pressure. It is characterized in that it is designed to operate by applying a current greater than the preset current at 100% duty.

In the present invention, a pair of solenoid valves connecting the hydraulic control unit, the reservoir, and the flow paths of the master cylinder, and controlled by the electronic control unit to draw or block oil on the flow path; The pair of solenoid valves are each formed of a solenoid valve for low pressure and a solenoid valve for high pressure, and the pair of solenoid valves are configured to be connected in series.

In the present invention, the pair of solenoid valves are all normally open solenoid valves.

In the present invention, the low pressure solenoid valve operates at a pressure smaller than a preset pressure and operates by applying a current smaller than the preset current at 100% duty, and the high pressure solenoid valve is at a pressure greater than the preset pressure. It is characterized in that it is designed to operate by applying a current greater than the preset current at 100% duty.

The present invention configures a pair of solenoid valves that are each operated under low and high pressure conditions in a break-by-wire system instead of a method of controlling one solenoid valve in the PWM method so that the solenoid valve can be controlled separately under the corresponding conditions. , to prevent the generation of sound noise from the solenoid valve.

1 is an exemplary view showing a schematic configuration of a conventional hydraulic brake-by-wire system.
2 is a diagram showing a pair of high-pressure and low-pressure solenoid valves formed in a parallel structure instead of a single solenoid valve controlled by a conventional PWM method in a hydraulic brake-by-wire (BBW) system according to an embodiment of the present invention. An example showing the configuration.
3 is a view showing a pair of high-pressure and low-pressure solenoid valves formed in a series structure instead of one solenoid valve controlled by the conventional PWM method in a hydraulic brake-by-wire (BBW) system according to an embodiment of the present invention. An example showing the configuration.

Hereinafter, an embodiment of a brake-by-wire system for preventing sound noise of a solenoid valve according to the present invention will be described with reference to the accompanying drawings.

In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of the user or operator. Therefore, definitions of these terms should be made based on the content throughout this specification.

For convenience, the configuration of a conventional conventional hydraulic brake-by-wire (BBW) system shown in FIG. 1 will be schematically described. However, it should be noted that the following description is a schematic description for helping the overall understanding of the hydraulic brake-by-wire (BBW) system 100 .

The hydraulic brake-by-wire (BBW) system 100 is a master cylinder, a motor that generates actual hydraulic pressure when the driver steps on the brake pedal, and transmits the braking hydraulic pressure generated by the motor to the brake caliper or an electronic control unit. A hydraulic brake-by-wire (BBW) system 100 according to this embodiment having a hydraulic control unit 130 that is controlled by (not shown) to provide braking hydraulic pressure to the brake caliper, and a pedal simulator. It includes an electronic control unit (not shown) for overall control.

At this time, the inside of the hydraulic control unit 130 is formed in a symmetrical structure that transmits the braking hydraulic pressure corresponding to the front/rear wheels.

Here, the pedal simulator is a mechanical device for giving the driver a feeling of stepping on the pedal only when the driver steps on the brake pedal, and does not generate actual braking force.

In addition, the brake caliper is a hydraulic device that holds the brake by attaching the brake pad of the vehicle to the disc.

Meanwhile, a pedal displacement sensor for detecting the displacement of the brake pedal is installed on one side of the brake pedal, and the pedal displacement sensor detects the displacement of the brake pedal and provides it to the electronic control unit (not shown).

In addition, a reservoir (a kind of brake oil tank) is installed on the other side of the master cylinder.

The outlet side of the reservoir is connected to the master cylinder to supply insufficient oil to the master cylinder so that the master cylinder is always filled with oil. Normal open solenoid valves SV1 and SV2 are respectively connected to the reservoir and the master cylinder, and when the driver steps on the brake pedal, the electronic control unit (not shown) controls the normally open solenoid valves SV1 and SV2. Close (Close).

The hydraulic control unit 130 includes pressurization valves SV6 and SV9 which are normally open solenoid valves provided on the upstream side of the brake caliper, and a normal close provided on the downstream side of the brake caliper. Includes solenoid valves for pressure reducing valves (SV7, SV10).

And it includes an accumulator (ACC) for making the braking hydraulic pressure generated by the hydraulic pump 110 uniform, and a hydraulic pump motor 120 for rotating the hydraulic pump 110 . In addition, as a normally open solenoid valve, when Electronic Stability Control (ESC) (not shown) operates even if the driver does not step on the brake pedal, the valve SV8 that blocks the reservoir and the path (oil path or flow path), and a normal As a close solenoid valve, it includes a valve (SV5) that is opened when the ESC (not shown) operates to draw oil from the reservoir.

The detection information of the pedal displacement sensor is provided to the input side of the electronic control unit (not shown), and the opening degree of the solenoid valves SV1 to SV10 according to the displacement of the brake pedal detected by the pedal displacement sensor during brake-by-wire control to adjust the brake hydraulic pressure applied to the brake caliper.

At this time, in the conventional hydraulic brake-by-wire (BBW) system, there is a solenoid valve (eg, SV1, SV2, SV3, SV4) that needs to perform PWM (Pulse Width Modulation) control due to concerns about operational durability. , As described in the background art, when PWM control is performed, the solenoid valve (eg, SV1, SV2, SV3, SV4) generates a 'beep' sound noise due to repeated solenoid switching at high speed. There is this.

Therefore, in the embodiment according to the present invention, instead of one solenoid valve (eg, SV1, SV2, SV3, SV4) requiring PWM control, a low pressure solenoid valve operated under a low pressure condition and a high pressure solenoid valve operated under a high pressure condition is configured to form a hydraulic path as a pair (eg, a pair configured in a series or parallel structure) (see FIGS. 2 and 3 ).

And by allowing each of the solenoid valves (eg, low pressure solenoid valve, high pressure solenoid valve) to be controlled at 100% duty under the corresponding condition (ie, low pressure or high pressure condition), the solenoid valve (especially the high pressure solenoid valve) to prevent sound noise from occurring. That is, when the duty is not 100%, a “beep” sound noise is generated by performing high-speed switching according to the duty ratio. However, since high-speed switching is not required at 100% duty, sound noise does not occur due to high-speed switching. does not

2 is a diagram showing a pair of high-pressure and low-pressure solenoid valves formed in a parallel structure instead of a single solenoid valve that was previously controlled by PWM in a hydraulic brake-by-wire (BBW) system according to an embodiment of the present invention. It is an example diagram showing the configuration.

In FIG. 1, the normally closed solenoid valves SV3 and SV4 respectively connected to the reservoir and the master cylinder are shown in FIG. 2 instead of the normally closed solenoid valves SV3 and SV4 in this embodiment. As shown, the high-pressure and low-pressure solenoid valves (HSV, LSV) are formed as a pair and connected in a parallel structure.

In this case, the positions of the pair of solenoid valves (eg, high-pressure solenoid valves and low-pressure solenoid valves) connected in the parallel structure may be changed.

For example, if it is assumed that the left solenoid valve connected in the parallel structure is a high pressure solenoid valve (HSV), the right solenoid valve becomes a low pressure solenoid valve (LSV). Conversely, if it is assumed that the left solenoid valve is a low pressure solenoid valve (LSV), the right solenoid valve becomes a high pressure solenoid valve (HSV).

As described above, by connecting a pair of solenoid valves (eg, high-pressure and low-pressure solenoid valves) in a parallel structure, even if any one solenoid valve is closed, the path connected to the motor generating the hydraulic pressure can be opened. there will be

For example, assuming that the left valve of the solenoid valves according to this embodiment is a valve for 70 bar or less (ie, a solenoid valve for low pressure), and assuming that the right valve is a valve for 70 bar or more (ie, a solenoid valve for high pressure), a typical braking force is 70 bar Since it is done below, the right valve (ie, the solenoid valve for high pressure) is not operated, and only the left valve (ie, the solenoid valve for low pressure) is mainly operated.

At this time, the left valve (ie, solenoid valve for low pressure) cannot withstand a large pressure, but is designed to pass only a low current of less than 1A even if 100% duty is applied, and the right valve (ie, solenoid valve for high pressure) can withstand high pressure Even if a high current is applied at 100% duty, the vehicle usually stops within a few seconds and the braking force is completed within a few seconds under conditions that require high voltage (eg, sudden braking), so there is no problem with durability.

3 is a view showing a pair of high-pressure and low-pressure solenoid valves formed in a series structure instead of one solenoid valve controlled by the conventional PWM method in a hydraulic brake-by-wire (BBW) system according to an embodiment of the present invention. It is an example diagram showing the configuration.

In FIG. 1, the normally open solenoid valves SV1 and SV2 respectively connected to the reservoir and the master cylinder are shown in FIG. 3 instead of the normally open solenoid valves SV1 and SV2 in this embodiment. As shown, high-pressure and low-pressure solenoid valves (HSV, LSV) are formed as a pair and connected in a series structure.

In this case, the positions of the pair of solenoid valves (eg, high-pressure solenoid valves and low-pressure solenoid valves) connected in the series structure may be changed.

For example, if it is assumed that the upper solenoid valve connected in the series structure (ie, the upper solenoid valve connected closer to the reservoir or the master cylinder on the path) is the high pressure solenoid valve (HSV), the lower (ie, the reservoir on the path) The solenoid valve of the burr or the lower connected further to the master cylinder becomes the low pressure solenoid valve (LSV). Conversely, if it is assumed that the upper solenoid valve is a low pressure solenoid valve (LSV), the lower solenoid valve becomes a high pressure solenoid valve (HSV).

As described above, by connecting a pair of normally open solenoid valves (eg, high-pressure and low-pressure solenoid valves) in a series structure, even if any one solenoid valve is closed, the path connected to the reservoir or the master cylinder is can be blocked.

For example, among the solenoid valves according to this embodiment, the upper valve is called a valve for 70 bar or less (that is, a solenoid valve for low pressure), and the lower valve is a valve for more than 70 bar (ie, a solenoid valve for high pressure), the normal braking force is made at 70 bar or less Therefore, the lower valve (ie, the solenoid valve for high pressure) is not operated and only the upper valve (ie, the solenoid valve for low pressure) is used.

However, as already described above, the upper valve (that is, the solenoid valve for low pressure) cannot withstand a large pressure, but is designed to pass only a low current of less than 1A even if 100% duty is applied, and the lower valve (that is, the solenoid valve for high pressure) can withstand high voltage with 100% duty, and although high current is applied, the operation is usually completed within a few seconds under conditions requiring high voltage, so there is no problem with durability.

As described above, the hydraulic brake-by-wire (BBW) system to which the solenoid valve structure according to the present embodiment is applied does not have any effect on the operation and it is not necessary to perform duty control of the solenoid valve in the PWM method, that is, like general switching. By performing ON/OFF at 100% duty, that is, it is not necessary to perform high-speed switching according to PWM duty control, it is possible to prevent the generation of sound noise when controlling the solenoid valve.

As described above, the present invention has been described with reference to the embodiment shown in the drawings, but this is merely exemplary, and various modifications and equivalent other embodiments are possible therefrom by those of ordinary skill in the art. will understand the point. Therefore, the technical protection scope of the present invention should be defined by the following claims.

S1 ~ S10 : Solenoid valve
110: hydraulic pump
120: hydraulic pump motor
130: hydraulic control unit

Claims (6)

A hydraulic brake-by-wire (BBW) system comprising a motor that generates braking hydraulic pressure when the driver steps on the brake pedal, and a hydraulic pressure control unit that provides braking hydraulic pressure generated from the motor to the brake caliper under the control of an electronic control unit. in,
A pair of solenoid valves controlled by the electronic control unit to transmit or block the braking hydraulic pressure generated by the motor on the flow path;
The pair of solenoid valves are respectively formed of a solenoid valve for low pressure and a solenoid valve for high pressure, and
The pair of solenoid valves are configured to be connected in a parallel structure,
The low-pressure solenoid valve is operated at a pressure smaller than a preset pressure, and a current smaller than the preset current is applied at 100% duty to operate,
The high-pressure solenoid valve is operated at a pressure greater than the preset pressure, and a current greater than the preset current is applied at 100% duty to operate. A break-by-wire system for preventing sound noise of a solenoid valve.
According to claim 1, The pair of solenoid valves,
Brake-by-wire system for sound noise prevention of solenoid valves, characterized in that all are normally closed solenoid valves.
delete The method of claim 1,
A pair of solenoid valves connecting the hydraulic control unit, the reservoir, and the flow paths of the master cylinder, and controlled by the electronic control unit to draw or block oil on the flow path;
A pair of solenoid valves further comprising the above are respectively formed of a solenoid valve for low pressure and a solenoid valve for high pressure, and
A brake-by-wire system for preventing sound noise of a solenoid valve, characterized in that the pair of solenoid valves further comprising the above are configured to be connected in a series structure.
According to claim 4, The pair of solenoid valves further comprising,
Brake-by-wire system for sound noise prevention of solenoid valves, characterized in that all are normally open solenoid valves.
5. The method of claim 4,
The low-pressure solenoid valve is operated at a pressure smaller than a preset pressure, and a current smaller than the preset current is applied at 100% duty to operate,
The high-pressure solenoid valve is operated at a pressure greater than the preset pressure, and a current greater than the preset current is applied at 100% duty to operate. A break-by-wire system for preventing sound noise of a solenoid valve.

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