KR100506011B1 - Electronic control brake system for automobile - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled brake system for a vehicle, and its object is to raise the hydraulic pressure in the hydraulic brake in a faster time to ensure the stability of the vehicle.

According to the electronic brake system for a vehicle according to the present invention for this purpose; Switch valves 91 and 92 for opening and closing the connecting flow path 80 when a stronger braking pressure is required for either the hydraulic circuit of the primary hydraulic circuit 60 or the secondary hydraulic circuit 70 in the TCS mode. By operating the, the hydraulic pressure discharged from the first pump 64 and the second pump 74 can be delivered to any one hydraulic circuit. As a result, the braking pressure of the wheel brakes 51 and 52 rises quickly, thereby reducing the driving time of the pumps 64 and 74, thereby ensuring the vehicle stability more quickly.

Description

Electronic control brake system for automobiles

The present invention relates to an electronically controlled brake system for a vehicle, and more particularly to an electronically controlled brake system capable of implementing an ABS mode and a TCS mode.

In general, a vehicle is provided with a booster, a master cylinder, and the like, which generate a braking pressure by operating a brake pedal and transmit the brake pressure to the wheel brake side, thereby reducing the speed or maintaining a stationary state. However, such a general vehicle may have a slip phenomenon due to a braking pressure or a road surface during a braking action.

In order to solve this problem, in recent years, the anti-lock brake system (ABS) to prevent slipping by electronically controlling the braking pressure of the wheel brake during braking, and in combination with the anti-lock brake system Electronically controlled brake systems have been developed, such as a Traction Control System (TCS), which prevents excessive slippage of the drive wheels during rapid start or acceleration of a vehicle. 1 is a hydraulic system showing a brake traction control system of the conventional electronically controlled brake system.

Referring to FIG. 1, a conventional brake traction control system is associated with a primary hydraulic circuit 10 associated with a primary port 2a of a master cylinder 1, and a secondary port 2b of a master cylinder 1. The secondary hydraulic circuit 20 is provided, and the primary hydraulic circuit 10 and the secondary hydraulic circuit 20 are connected to the two wheel brakes 3a and 3b, respectively, and are symmetric with each other. Here, reference numeral 1a is a conventional oil tank which is employed in a general brake system having a pair of hydraulic circuits and is connected to supply oil to the master cylinder 1 provided in tandem, and such an oil tank 1a is An inner lower space is partitioned into one space associated with the primary port 2a and the primary hydraulic circuit 10 through the partition wall and the other space associated with the secondary port 2b and the secondary hydraulic circuit 20, respectively. The upper space of the partition wall is provided so that both sides communicate with each other, and the oil to be filled in the oil tank 1a is usually provided so that the minimum level is higher than the partition wall.

Each of the hydraulic circuits 10 and 20 has a plurality of solenoid valves 11a, 11b, 21a and 21b for controlling the braking hydraulic pressure delivered to the wheel brakes 3a and 3b and in the ABS decompression mode. Low-pressure accumulators 12 and 22 for temporarily storing oil discharged from the wheel brakes 3a and 3b, and pumps 13 and 23 for sucking and discharging oil stored in the low-pressure accumulators 12 and 22. And oil suction passages 14 and 24 connecting the respective ports 2a and 2b side of the master cylinder 1 to the inlet side of each pump 13 and 23, and this oil suction passage 14 Normally closed electric shuttle valves (15, 25) installed in the middle of (24) to open and close them, each port (2a) (2b) and the pump (13) (23) of the master cylinder (1) Traction control solenoid valves 17 and 27 installed in the middle of the main flow paths 16 and 26 connecting the outlet side of the outlet and electronic control units (ECU, not shown) for controlling electrical components. ) The.

The plurality of solenoid valves are divided into NO type solenoid valves 11a and 21a disposed upstream of each wheel brake 3a and 3b and NC type solenoid valves 11b and 21b disposed downstream. Controlled by an electronic control unit. That is, after detecting the vehicle speed, the electronic control unit controls the opening / closing operation of each solenoid valve 11a, 21a, 11b, 21b.

In addition, the low pressure accumulators 12 and 22 are independently provided in connection with the downstream side of the NC type solenoid valves 11b and 21b to temporarily store the oil escaping from the wheel brakes 3a and 3b in the ABS decompression mode. do.

Such a plurality of solenoid valves 11a, 11b, 21a, 21b, each pump 13, 23, a normal closed electric shuttle valve 15, 25, a low pressure accumulator 12, 22, etc. It is compactly installed in a hydraulic block (not shown) on a rectangular parallelepiped made of aluminum.

The operation of the vehicle equipped with the brake traction control system configured as described above will be described as an example.

If the road starts to slip on the accelerator pedal (not shown) in a slippery road condition, slipping occurs and this is detected by the electronic control unit through the wheel sensor. In this case, the shuttle valves 15 and 25 of the oil suction passages 14 and 24 are opened, and the normally open solenoid valve 17 of the main passage 16 is closed and the pumps 13 and 23 are operated. Is driven to perform the TCS mode.

That is, the master cylinder 1 side oil is sucked into the inlets of the pumps 13 and 23 through the oil suction passage 14, and the oil discharged to the outlets of the pumps 13 and 23 is the main passage 16. It is transmitted to the wheel brakes 3a and 3b through the 26 and the open NO solenoid valves 11a and 21a to act as a braking pressure.

Accordingly, even if the driver steps on the accelerator pedal and the vehicle does not step on the brake pedal 5 at the time of starting the vehicle, a predetermined lock is applied to the wheel, and thus the vehicle starts slowly and stably even under a slip condition because the road surface is not good.

However, in the conventional brake traction control system, since the primary hydraulic circuit 10 and the secondary hydraulic circuit 20 are respectively connected to the two wheel brakes 3a and 3b, for example, the primary hydraulic circuit ( When the braking pressure is to be transmitted to the wheel brake 3a associated with 10), the hydraulic circuit used to actually increase the braking pressure is one primary hydraulic circuit 10. In this case, the oil supplied from the pump 23 of the secondary hydraulic circuit 20 is returned to the master cylinder 1 without being used as a braking pressure.

Accordingly, even if only one of the primary hydraulic circuit 10 or the secondary hydraulic circuit 20 is used, it is not a problem when the braking pressure rise of the wheel brakes 3a and 3b is sufficient, but the wheel brakes 3a and 3b are used. Problems arise when the rate of increase of the braking pressure is lower than the required level. That is, in order to increase the braking pressure of the wheel brakes 3a and 3b, the driving time of the pumps 13 and 23 becomes long, and the starting stability of the vehicle is secured later.

The present invention is to solve this problem; SUMMARY OF THE INVENTION An object of the present invention is to provide an electronically controlled brake system capable of increasing vehicle brake hydraulic pressure in a short time to ensure vehicle stability more quickly.

The present invention for achieving this object is;

Primary hydraulic circuit for controlling the hydraulic pressure generated at the primary port of the master cylinder and the hydraulic pressure discharged from the first pump to the wheel brake on one side, and the braking pressure and the second brake pressure generated at the secondary port of the master cylinder In an electronically controlled brake system for a vehicle having a second hydraulic circuit for controlling the hydraulic pressure discharged from the pump to be transmitted to the other wheel brake,

One end is connected to the first pump outlet side flow path of the primary hydraulic circuit and the other end is connected to the second pump outlet side flow path of the hydraulic circuit;

It is further provided with a switching valve which keeps the connection flow path normally closed and opens when strong braking pressure is required for either the hydraulic circuit of the primary hydraulic circuit or the secondary hydraulic circuit in the TCS mode.

The hydraulic pressure discharged from the first pump and the second pump can be delivered to any one hydraulic circuit.

In addition, the switching valve is characterized in that consisting of the NC-type solenoid valve which is opened in the set TCS mode conditions.

In addition, the NC type solenoid valve is characterized in that the two are arranged in series.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings. (The electronically controlled brake system for a vehicle according to the present invention takes a brake traction control system as an example.)

Referring to FIG. 2, the electronically controlled brake system for a vehicle according to the present invention connects a primary port 31 of the master cylinder 30 and two wheel brakes 51 to control the hydraulic pressure transmission 60. ), The secondary hydraulic circuit 70 for controlling hydraulic pressure transmission by connecting the second port 32 of the master cylinder 30 and the other two wheel brakes 52, and the primary hydraulic circuit 60 A connection flow path 80 connecting the outlet flow path of the first pump 64 to the outlet flow path of the second pump 74 of the secondary hydraulic circuit 70, and a switching valve 91 for selectively opening and closing the connection flow path 80. 92, and an electronic control unit (ECU, not shown) for controlling the electric drive elements, which are compactly installed in the hydraulic block (not shown). Here, reference numeral 100 denotes a conventional oil tank which is employed in a general brake system having a pair of hydraulic circuits and is connected to supply oil to the master cylinder 30 provided in tandem. An inner lower space is partitioned into one space associated with the primary port 31 and the primary hydraulic circuit 60 through the partition wall and the other space associated with the secondary port 32 and the secondary hydraulic circuit 70, respectively. The upper space of the partition wall is provided so that both sides communicate with each other, and the oil to be filled in the oil tank 100 is usually provided so that the minimum level is higher than the partition wall.

The primary hydraulic circuit 60 includes a plurality of solenoid valves 61 and 62 for controlling braking hydraulic pressure transmitted to two wheel brakes 51 and oil or master cylinders exiting from the wheel brakes 51. The first pump 64 for sucking and pumping oil from the oil 30, the low pressure accumulator 63 for temporarily storing the oil exiting the wheel brake 51, and the oil of the master cylinder 30 in the TCS mode An oil suction passage (65) for guiding suction to the inlet of the first pump (64) is included.

The plurality of solenoid valves 61 and 62 are associated with the upstream and downstream sides of the wheel brakes 51, which are normally open solenoids disposed upstream of each wheel brake 51 and are normally kept open. Valve 61 (hereinafter referred to as NO solenoid valve), and a normally closed solenoid valve (62, hereinafter referred to as NC solenoid valve) disposed downstream thereof and kept normally closed. The opening / closing operation of the solenoid valves 61 and 62 is controlled by an electronic control unit that detects the vehicle speed through wheel sensors (not shown) disposed on each wheel side, and NC-type solenoid valves according to decompression braking ( The oil 62 is opened and the oil discharged from the wheel brake 51 side is temporarily stored in the low pressure accumulator 63.

The first pump 64 is driven by the motor 33 to suck and discharge the oil stored in the low pressure accumulator 63 (in the ABS boosting or holding mode), so that the hydraulic pressure is supplied to the wheel brake 51 side or the master cylinder 30. Will be delivered to the side.

In addition, the main flow path 67 connecting the primary port 31 of the master cylinder 30 and the outlet of the first pump 64 has an NO solenoid valve 68 for traction control control (hereinafter referred to as TC solenoid valve). Is installed). The TC solenoid valve 68 is normally kept open so that the braking hydraulic pressure generated in the master cylinder 31 during normal braking through the brake pedal 40 is transmitted to the wheel brake 51 side through the main flow passage 67. In the brake traction control mode described later, the closing operation is performed by the electronic control unit.

In addition, the main flow path 67 is connected with a relief flow path 69 connecting the outlet port of the first pump 64 and the primary port 31 of the master cylinder 30 while rotating the TC solenoid valve 68. The relief valve 69a is provided here. The relief flow passage 69 and the relief valve 69a are for refluxing the braking hydraulic pressure discharged from the first pump 64 when the traction control is higher than necessary to return them to the master cylinder 30 side.

In addition, the oil suction passage 65 is branched from the main passage 67 to guide the oil of the master cylinder 30 to be sucked to the inlet side of the first pump 64, where the oil is the first pump 30 Normally closed electric shuttle valves 66 (hereinafter referred to as shuttle valves) are provided to flow only to the inlets. That is, the electrically operated shuttle valve 66 is installed in the middle of the oil suction flow path 65 to operate normally and open in the TCS mode.

The second hydraulic circuit 70 also has a plurality of solenoid valves 71 and 72 for controlling the braking hydraulic pressure transmitted to the remaining two wheel brakes 52, and oil or master that has escaped from the wheel brakes 52. A second pump 74 for sucking and pumping oil from the cylinder 30, a low pressure accumulator 73 for temporarily storing oil exiting the wheel brake 52, and oil of the master cylinder 30 in the TCS mode. It guides to be sucked into the inlet of the second pump (74) and includes an oil suction passage (75) in which a shuttle valve (76) is disposed halfway. Since the configuration of the secondary hydraulic circuit 70 is substantially the same as the configuration of the primary hydraulic circuit 60, repeated description of the same components is omitted. In addition, the first pump 64 and the second pump 74 are driven with a phase difference of 180 degrees by one motor 33.

On the other hand, one end of the connection flow path 80 is connected to the main flow path 67 between the outlet side of the first pump 64 and the TC solenoid valve 68 of the primary hydraulic circuit 60, and the other end thereof has a second hydraulic circuit ( 70 is connected to the main flow path 77 between the outlet side of the second pump 74 and the TC solenoid valve 78. Accordingly, the outlet side of the first pump 64 and the second pump 74 communicate with each other through the connection flow path 80.

In addition, the switching valves 91 and 92 are intended to selectively open the connection flow path 80 in the TCS mode while keeping the connection flow path 80 normally closed.

That is, the switching valves 91 and 92 are operated when the braking pressure is required for one of the hydraulic circuits of the primary hydraulic circuit 60 and the secondary hydraulic circuit 70 in the TCS mode, and thus the primary hydraulic pressure is applied. An embodiment of the present invention allows the hydraulic pressure discharged from the first pump 64 of the circuit 60 and the second pump 74 of the secondary hydraulic circuit 70 to be transferred to any one hydraulic circuit. In the switching valve is composed of two normal open type, NC type solenoid valves (91, 92).

These NC type solenoid valves 91 and 92 are arranged in series in the middle of the connecting flow path 80. This means that the overall brake is prevented even if one of the two NC type solenoid valves 91 and 92 fails. This is to fail safe for the system to work reliably.

Next, the operation and effects thereof of the electronically controlled brake system according to the present invention configured as described above will be described with reference to FIGS. 3 to 6.

First, if a slip phenomenon occurs during braking in a vehicle equipped with an electronically controlled brake system, ABS operation is performed by mixing into three modes such as decompression, boosting, and maintenance based on signals input from each wheel sensor. Each of the control modes are not controlled in the same state on all four wheels. The control mode is controlled by mixing three modes separately according to the road condition and the ABS control state. ) Step by step are as follows.

That is, when the brake pedal 40 is braked by the hydraulic pressure generated by the master cylinder 30 by stepping on the brake pedal 40 and the brake pressure on the wheel brake 51 side associated with the primary hydraulic circuit 60 is greater than the road surface condition, By lowering to an appropriate pressure, the electronic control unit performs the ABS pressure reduction mode by opening the NC-type solenoid valve 62.

Accordingly, as in the direction of the arrow in FIG. 3, a part of the hydraulic pressure is released from the wheel brake 51, which is temporarily stored in the low pressure accumulator 63. Through this process, the braking pressure of the wheel brakes 51 mounted on each wheel is lowered, thereby preventing the sliding phenomenon on the road surface.

On the other hand, if the ABS decompression mode lasts for a long time, the vehicle braking efficiency is lowered. In this case, the electronic control unit drives the motor 33 to increase the hydraulic pressure of the wheel brake 51, whereby the primary hydraulic circuit 60 The ABS boosting mode is performed through the hydraulic pressure discharged from the first pump 64. That is, as indicated by the arrow in FIG. 4, the oil stored in the low pressure accumulator 63 is pressurized through the first pump 64, and toward the wheel brake 51 through the open-type NO solenoid valve 61. By transmission, the braking pressure is increased.

At this time, the hydraulic pressure discharged from the second pump 74 of the secondary hydraulic circuit 70 is returned to the master cylinder 30 according to the braking pressure condition or the wheel brake 52 associated with the secondary hydraulic circuit 70. Delivered to the side.

In addition, in order to reach a state in which the braking pressure generates the optimum braking force or to prevent resonance of the vehicle, an ABS pressure holding mode for maintaining the braking pressure in a constant state is required. That is, the ABS pressure holding mode prevents the pressure change in the wheel brake 51 and closes the NO type solenoid valve 61 of the primary hydraulic circuit 60 to block the hydraulic pressure from being transmitted. Accordingly, the hydraulic pressure discharged from the first pump 64 is transmitted to the master cylinder 30 via the open TC solenoid valve 68, whereby the ABS pressure maintaining mode is stably performed.

Next, the operation of the TCS mode of the electronically controlled brake system according to the present invention will be described in the case of a rapid start of the vehicle.

If the road starts to slip on the accelerator pedal (not shown) in a slippery road condition, slipping occurs and this is detected by the electronic control unit through the wheel sensor. In this case, the shuttle valve 66 of the oil suction passage 65 is opened, the TC solenoid valve 68 of the main passage 67 is closed, and the first pump 64 is driven by driving the motor 33. And the second pump 74 pumps oil to perform the TCS mode.

That is, as indicated by the arrow in FIG. 5, the master cylinder 30 side oil is sucked into the inlet of the first pump 64 through the oil suction flow path 65, and then the outlet of the first pump 64 is continued. The oil discharged to the vehicle is transferred to the wheel brake 51 through the main flow path 67 and the open NO solenoid valve 61 to act as a braking pressure. At this time, the oil discharged from the second pump 74 of the secondary hydraulic circuit 70 is delivered to the wheel brake 52 or the master cylinder 30 side in accordance with the TCS mode conditions.

As a result, a predetermined lock is applied to the wheel even when the driver steps on the accelerator pedal and does not step on the brake pedal 40 when the vehicle starts immediately. Thus, the vehicle starts slowly and stably even under a slip condition because the road surface is not good.

On the other hand, when a strong braking pressure is required for the wheel brake 51 associated with the primary hydraulic circuit 60 in the TCS mode, two NC-type solenoid valves 91 and 92 provided in the connection passage 80 are provided. Is opened and the NO brake solenoid valve 71 upstream of the wheel brake 52 of the secondary hydraulic circuit 70 is closed.

Accordingly, as shown by arrows in FIG. 6, the hydraulic pressure discharged from the second pump 74 of the secondary hydraulic circuit 70 as well as the hydraulic pressure discharged from the first pump 64 may be the primary hydraulic circuit 60. By passing to the wheel brake 51 side associated with), the braking pressure rise of the wheel brake 51 is made faster. In this way, the hydraulic pressure concentrated toward the primary hydraulic circuit 60 is then returned to the oil tank 100 via the master cylinder 30, and then through the partition upper space of the oil tank 100 inside the oil tank 100. Maintaining equilibrium at each of the hydraulic circuits (60, 70) side is distributed to the normal driving state when the primary hydraulic circuit (60) side as well as the wheel brake 52 associated with the secondary hydraulic circuit (70) normally braking You can do it.

On the contrary, when a strong braking pressure is required for the wheel brake 52 associated with the secondary hydraulic circuit 70, the NO type solenoid valve 61 upstream of the wheel brake 51 of the primary hydraulic circuit 60 is closed. As a result, the braking pressure of the wheel brake 52 on the side of the secondary hydraulic circuit 70 rises more quickly.

As described in detail above, according to the electronically controlled brake system for a vehicle according to the present invention, when a stronger braking pressure is required for the hydraulic circuit of either the primary hydraulic circuit or the secondary hydraulic circuit in the TCS mode, By operating the switching valve to open and close, all of the hydraulic pressure discharged from the first pump and the second pump can be transmitted to any one hydraulic circuit. As a result, the braking pressure of the wheel brake increases quickly, thereby reducing the driving time of the pump and ensuring the vehicle stability more quickly.

1 is a hydraulic system showing a conventional electronically controlled brake system for a vehicle.

2 is a hydraulic system showing an electronic brake system for a vehicle according to the present invention.

Figure 3 shows the ABS decompression mode of the brake system according to the present invention.

Figure 4 shows the ABS boost mode of the brake system according to the present invention.

5 and 6 show the TCS mode of the brake system according to the invention.

* Description of the symbols for the main parts of the drawings *

30. Master cylinder 60, 70. Hydraulic circuit

61,71..NO solenoid valve 62,72.NC solenoid valve

64,74 pump 65,75 oil suction flow path

66,76..Shuttle valve 67,77..main euro

80. Connecting flow path 91, 92. Switching valve

Claims (3)

Primary hydraulic circuit for controlling the hydraulic pressure generated at the primary port of the master cylinder and the hydraulic pressure discharged from the first pump to the wheel brake on one side, and the braking pressure and the brake generated at the secondary port of the master cylinder In an electronically controlled brake system for a vehicle having a second hydraulic circuit for controlling the hydraulic pressure discharged from two pumps to be transmitted to the wheel brakes on the other side, One end is connected to the outlet side flow path 67 of the first pump 64 of the primary hydraulic circuit 60 and the other end is connected to the outlet side flow path 77 of the second pump 74 of the secondary hydraulic circuit 70. A connection passage 80 to be connected, The connection flow path 80 is normally kept closed and opened when a strong braking pressure is required for any one of the primary hydraulic circuit 60 or the secondary hydraulic circuit 70 in the TCS mode. Further provided with actuating switching valves (91) (92), An electronically controlled brake system for a vehicle, characterized in that both of the hydraulic pressure discharged from the first pump (64) and the second pump (74) can be transferred to any one hydraulic circuit. The method of claim 1, The switching valve is an electronically controlled brake system for a vehicle, characterized in that consisting of the NC-type solenoid valve (91) (92) which is opened in the set TCS mode conditions. The method of claim 2, The NC type solenoid valve (91) (92) is an electronically controlled brake system for a vehicle, characterized in that two are arranged in series.