JPH09263231A - Brake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to find the abnormal condition of a hydraulic pressure control device for anti-lock control, in a brake system furnishing the residual amount alarming device of a reservior, as well as using a reservior for master cylinder, commonly in the normal braking condition and in the anti-lock control condition. SOLUTION: In order to find the abnormal condition of a hydraulic pressure control device for anti-lock control, a float 40 and a level switch 46, of a reservoir liquid amount detecting device 30, are utilized, in a reservoir for master cylinder, a housing 36 to house the float 40 allowable to displace up and down is provided, the upper part space of the float 40 is blocked by a different float 50 and a stopper 54, and by feeding the brake liquid exhausted from the hydraulic pressure control device to the upper part space so as to depress the float 40, it is decided that this brake system is abnormal, when the brake liquid amount exhausted from a brake cylinder through the hydraulic pressure control device in a normal braking condition, at the amount more than the scheduled amount, is more than a set amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brake system capable of automatically controlling a brake fluid pressure of a wheel, and in particular, a brake of a type in which a master cylinder reservoir is commonly used during normal braking and hydraulic pressure control. It concerns the improvement of the system.

[0002]

2. Description of the Related Art Brake systems capable of automatically controlling wheel brake fluid pressure for vehicle control such as anti-lock control and traction control are conventionally (a) a hydraulic pressure source including at least a master cylinder, and (b) A hydraulic pressure that is installed separately from the master cylinder reservoir that is installed in the master cylinder and that supplies the accumulated brake fluid to the master cylinder, (c) the brake cylinder that activates the wheel brakes, and (d) the master cylinder reservoir. A control reservoir,
(e) The hydraulic pressure source, the hydraulic pressure control reservoir, and the hydraulic pressure control device provided between the brake cylinders are included.

Here, the "hydraulic pressure control device" realizes an increased pressure state in which the brake cylinder is disconnected from the hydraulic pressure control reservoir and connected to the master cylinder during normal braking, and the hydraulic pressure is applied to the brake cylinder during hydraulic pressure control. A plurality of hydraulic pressure control states including a pressure increase state in which the brake cylinder is disconnected from the control reservoir and connected to the hydraulic pressure source and a pressure reduction state in which the brake cylinder is disconnected from the master cylinder and connected to the hydraulic pressure control reservoir are selectively selected. The configuration is realized.

The master cylinder always functions as a hydraulic pressure source for the brake cylinder during normal braking, but during hydraulic pressure control, the master cylinder functions as a hydraulic pressure source for the brake cylinder, as in normal braking. There is a type of brake system in which an electrically controlled hydraulic pressure source (for example, a pump) different from the master cylinder functions as a hydraulic pressure source for the brake cylinder. Therefore,
The "hydraulic pressure source" is configured to include at least the master cylinder.

In this conventional braking system,
As described above, if the main fluid passage connecting the master cylinder and the brake cylinder to each other is damaged and the brake fluid leaks to the outside, the remaining amount of the brake fluid in the master cylinder reservoir decreases. Such anomalies are usually detected automatically by a warning device and the driver can quickly notice anomalies in the braking system.

Further, in this conventional brake system, the reservoirs are provided for the master cylinder and the hydraulic pressure control, respectively. On the other hand, in a vehicle brake system, a master cylinder reservoir is provided regardless of whether or not a hydraulic control device is installed. Therefore, in order to reduce the number of reservoirs used in the entire brake system, the master cylinder reservoir is commonly used during normal braking and hydraulic pressure control as described in JP-A-5-501689. A brake system with a shared reservoir has already been proposed.

[0007]

However, in the conventional brake system for shared use of the reservoir, when the main fluid passage is damaged and the brake fluid leaks to the outside, the remaining amount of the brake fluid in the master cylinder reservoir remains. Since it becomes less than the set value, it is possible to automatically detect such an abnormality by the warning device, but the hydraulic pressure control device fails even if the hydraulic pressure control device has failed and normal braking is being performed. , If a situation occurs where the brake fluid in the brake cylinder unexpectedly allowed to flow to the master cylinder reservoir, if it was a reservoir-independent brake system, it would accumulate in the hydraulic pressure control reservoir. The brake fluid to be applied is stored in the master cylinder reservoir, and the brake fluid remains in the master cylinder reservoir. There does not decrease. Therefore, in the conventional brake system for shared use of the reservoir, there is a problem that the failure of the hydraulic pressure control device cannot be automatically detected by the warning device.

Therefore, in the first to fourth inventions according to claims 1 to 4, in the brake system of the type in which the master cylinder reservoir is commonly used during normal braking and during hydraulic pressure control, the first warning device causes the liquid to flow. The problem was to make it possible to detect an abnormality in the pressure control device.

In particular, the second aspect of the present invention is the first aspect of the present invention, in which a second warning device is provided for detecting that the remaining amount of the brake fluid in the reservoir is below a preset level and warning the driver of the fact. The purpose of the present invention is to make it possible to detect abnormalities in the components of the brake system other than the hydraulic pressure control device.

According to a third aspect of the present invention, in the second aspect of the present invention, the first warning device is constructed by diverting some components of the second warning device to detect an abnormality in the hydraulic control device. Therefore, it is an object to suppress the number of additional parts and the cost increase.

The fourth invention is made to provide a desirable embodiment of the third invention.

[0012]

[Means for Solving the Problem, Operation and Effect of the First Invention] In order to solve the problem, the first invention provides a brake system including a master cylinder, a reservoir (for master cylinder), a brake cylinder and a hydraulic control device. ,
Detects that the amount of brake fluid discharged from the brake cylinder to the reservoir through the hydraulic pressure control device is equal to or greater than a set value even during the normal braking, and warns the driver of that. A warning device is provided.

The "hydraulic pressure control device" is, for example,
In the same vehicle, each brake cylinder independently or commonly to two brake cylinders is provided with one electromagnetic switching valve capable of switching to a plurality of hydraulic pressure control states including a pressure increase state and a pressure reduction state. And a pressure increasing valve which is one electromagnetic on-off valve capable of switching between a pressure increasing state and a holding state and a pressure reducing valve which is one electromagnetic on-off valve capable of switching between a pressure reducing state and a holding state. It can be a format.

Therefore, according to the first aspect of the present invention, there is provided the warning device for detecting the abnormally large amount of the brake fluid discharged from the brake cylinder to the master cylinder reservoir through the fluid pressure control device during the normal braking. Therefore, although the master cylinder reservoir is used for both normal braking and hydraulic pressure control, it is possible to detect an abnormality in the hydraulic pressure control device and improve vehicle safety. .

[0015]

[Means for Solving the Problem, Action and Effect of the Second Invention] A second invention is a brake system according to the first invention for solving the problem, in addition to the first warning device as the warning device. , (A) a float that is displaced according to the height of the level of the brake fluid stored in the reservoir, and (b) a signal that indicates when the height of the float is below a set height. And a second warning device having (c) a warning device that is activated when the sensor outputs the signal and that warns a driver of an abnormality of the brake system. .

The "sensor" may include, for example, a permanent magnet that is displaced along with the float, and a level switch whose contact portion opens and closes according to the magnetic force of the permanent magnet.

Further, the "warning device" may be a device that warns the driver by sound, light, vibration, or the like.

Therefore, according to the second aspect of the invention, it is possible to detect an abnormality in the components of the brake system other than the hydraulic pressure control device.

[0019]

A third aspect of the present invention is a brake system according to a second aspect of the present invention, wherein the first warning device is (d) the brake. A float depressing mechanism that depresses the float in the second warning device by the brake fluid discharged from the cylinder to the reservoir via the fluid pressure control device; and (e) the sensor in the second warning device outputs the signal. And a warning device actuating means for actuating the warning device in the second warning device when the above is performed.

Therefore, according to the third aspect of the present invention, the float, the sensor and the warning device of the second warning device can be used to detect an abnormality in the hydraulic pressure control device. It is also possible to obtain the effect that it is possible to suppress the number of additional parts and cost increase for detecting the abnormality.

[0021]

[Means for Solving the Problem, Operation and Effect of the Fourth Invention] In order to solve the problems, a fourth invention is a brake system according to the third invention, wherein the float depressing mechanism is (f).
A housing for accommodating the float so as to be vertically displaceable,
(g) A closing member that closes an upper space that is a portion above the float in the space inside the housing, and that displacement in a direction in which the volume of the upper space increases is restricted, ) A return fluid passage that connects the upper space to the brake cylinder via the hydraulic pressure control device and guides the brake fluid discharged from the brake cylinder via the hydraulic pressure control device to the upper space. .

The "closing member" may be, for example, a fixed member that does not displace with respect to the housing. Further, a displacement member that displaces with respect to the housing may be used, but in this case, it is necessary that the float pressing mechanism further has a stopper that defines an upper end position of the displacement member. Is.

Therefore, according to the fourth invention, the third
The effect that one desirable embodiment of an invention is provided is obtained.

[0024]

Supplementary Explanation of the Invention Hereinafter, the present invention will be supplementarily described by listing other embodiments in the same expression form as the claims. (1) The brake system according to claim 3 or 4, wherein the first warning device further includes (a) a determination unit that determines whether or not hydraulic pressure control is being performed, and (b) a determination unit. When it is determined that the hydraulic pressure control is being performed, the braking system includes a prohibiting unit that prohibits the abnormality determination based on the signal from the sensor. That is, during hydraulic pressure control, the hydraulic pressure control device may operate normally and enter a depressurized state. In this case, even if the hydraulic pressure control device is normal, the brake fluid is supplied to the reservoir and the sensor operates. There is a possibility of outputting the signal. Therefore, if the abnormality determination is performed based on the signal from the sensor regardless of during the normal braking or the hydraulic pressure control, an erroneous abnormality determination may be performed during the hydraulic pressure control. . Therefore, in the present embodiment, based on such knowledge, the abnormality determination based on the signal from the sensor is prohibited during the hydraulic pressure control, thereby improving the reliability of the abnormality determination. (2) The brake system according to claim 1 or 2, wherein the first warning device is a float in the second warning device, in addition to the first sensor that diverts the sensor in the second warning device. Includes a second sensor that outputs a signal indicating that when is above the set height, and
Further, (a) a return fluid passage for guiding the brake fluid discharged from the brake cylinder through the fluid pressure control device to a reservoir chamber in the reservoir, and (b) the signal is output from the second sensor. And a second warning device that sometimes warns the driver that the hydraulic control device is abnormal. (3) Any one of claims 1 to 4, the embodiment (1) or
In the brake system of (2), two brake systems that extend independently from each other of the two pressurizing chambers of the master cylinder that are independent of each other are diagonally configured, and (a) the master system for each brake system. From the middle of the front wheel brake passage that connects each pressurizing chamber of the cylinder to the front wheel brake cylinder, the rear wheel brake passage branches to the rear wheel brake cylinder. (B) A normally open solenoid valve is provided in the rear wheel brake passage. An intermediate valve is provided as a component of the fluid pressure control device, and (c) is normally closed in a reservoir passage extending from a portion of the rear wheel brake passage between the intermediate valve and the rear wheel brake cylinder to the reservoir. A pressure reducing valve, which is an electromagnetic valve, is provided as a component of the fluid pressure control device, and (d) extends from the reservoir and includes the intermediate portion of the front wheel brake passage and the rear wheel brake passage. A pump passage leading to either the more the front wheel brake passage-side portion, a pump for pumping the brake fluid from the reservoir is provided, (e)
The controller executes anti-lock control for preventing the left and right front wheels and the left and right rear wheels from locking by controlling the intermediate valve and the pressure reducing valve when the vehicle is braked. When it is determined that the brake system (particularly the pressure reducing valve) is abnormal during normal braking by the warning device of
A brake system that closes the intermediate valve, disconnects the rear wheel brake cylinder and the pressure reducing valve from the master cylinder, the pump, and the front wheel brake cylinder, and enables the master cylinder or the pump to increase the pressure of the front wheel brake cylinder. According to the present embodiment, even if the pressure reducing valve fails and the rear wheel brake cylinder becomes inoperable,
The operation of the front wheel brake cylinders is secured, and the effect that all brake cylinders become inoperable can be avoided. (4) In the brake system according to the embodiment (3), further, in the portion between the master cylinder and the branch point to the rear wheel brake passage in the front wheel brake passage, at least the master cylinder in the normal braking state. Flow control device that allows the flow of the brake fluid from the master cylinder to the both brake cylinders and blocks the flow of the brake fluid from the master cylinder to the both brake cylinders at least in the antilock control state (an example of which will be described later). The brake system in which the master cylinder cut valve according to the embodiment of the invention is provided.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, more specific embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a brake system mounted on a four-wheel vehicle and capable of antilock control. In the figure, reference numeral 10 is a brake pedal as a brake operating member. The brake pedal 10 is linked to a master cylinder 14 via a booster 12. The master cylinder 14 is a tandem type in which two independent pressurizing chambers are arranged in series with each other, and a hydraulic pressure having a height corresponding to the brake operating force is mechanically generated in each of the pressurizing chambers. The master cylinder 14 has a reservoir 16 for supplying the accumulated brake fluid to the master cylinder 14.
Is attached.

As shown in FIG. 2, the reservoir 16 is provided with a bottomed cylindrical housing 20 fixed to the housing 18 of the master cylinder 14. A reservoir chamber 22 for accumulating the brake fluid is formed in the housing 20. The reservoir chamber 22 communicates with each pressurizing chamber of the master cylinder 14 through each of the communication passages 24 and 26. The opening of the housing 20 can be closed by a removable cap 28. In the cap 28,
An air hole 30 that constantly communicates with the atmosphere and a filter 32 that prevents foreign matter such as dust from entering the reservoir chamber 22 through the air hole 30 are provided.

In the reservoir chamber 22, the reservoir chamber 2
A reservoir fluid amount detection device 30 for detecting the height of the liquid level of the brake fluid accumulated in No. 2 is provided. Hereinafter, this device will be described in detail with reference to FIG. In addition,
In the figure, (a) shows a state in which the amount of brake fluid in the reservoir 26 is normal and no brake fluid is supplied from a brake cylinder described later, and (b) shows the reservoir 26.
Shows an abnormally small amount of brake fluid and no brake fluid is being supplied from the brake cylinder.
Indicates that the amount of brake fluid in the reservoir 26 is normal, and
The state where the brake fluid is being supplied from the brake cylinder is shown.

The reservoir liquid amount detecting device 30 is provided with an outer housing 32 having a bottomed cylindrical shape. Inside the outer housing 32, a cylindrical inner housing 36 extending substantially parallel to the inner housing 36 is provided. The inner housing 36 is formed so as to be inscribed in the outer housing 32. The height of the inner housing 36 is substantially equal to that of the outer housing 32.

A hollow shaft portion 38 extending substantially directly above the bottom portion of the outer housing 32 is located substantially in the center of the inner housing 36. On the outer peripheral portion of the shaft portion 38, an annular first float 40 and a fixed base 42 are provided.
And are arranged side by side. The inner peripheral surface of the first float 40 and the outer peripheral surface of the shaft portion 38 are fitted so as to be displaceable in the axial direction thereof, that is, in the vertical direction. A permanent magnet 44 is substantially concentrically fixed to the inner peripheral portion of the first float 40, while a level switch 46 that operates according to the magnetic force of the permanent magnet 44 is provided in the hollow portion of the shaft portion 38. It is provided. The level switch 46 is, for example, a reed switch, and when the permanent magnet 44 is close to the contact portion of the level switch 46, the contact portion becomes conductive and outputs an ON signal. It is designed to output the OFF signal when in the state. That is, the level switch 46 and the permanent magnet 4
The sensor is constituted by 4 and.

Therefore, when the remaining amount of the brake fluid in the reservoir chamber 22 is normal, the first float 40 is pushed up against the gravity due to the buoyancy, as shown in FIG. The OFF signal is output from the level switch 46 away from the contact portion of the level switch 46. On the other hand, when the remaining amount of the brake fluid in the reservoir chamber 22 is insufficient, the first float 40 descends due to gravity and the permanent magnets 4 as shown in (b) of FIG.
4 is brought close to the contact portion of the level switch 46, and the ON signal is output from the level switch 46. Based on the principle as described above, it becomes possible to detect an abnormality that the remaining amount of the brake fluid in the reservoir 16 is insufficient.

A second float 50 is fitted on the shaft portion 38 above the first float 40 so as to be displaceable. Of the upper and lower surfaces of the second float 50, the first float 4
The lower surface facing 0 is locally projected, and the projection 52 secures a liquid chamber 53 (upper space) between the first float 40 and the second float 50. A stopper 54 is provided at the upper end of the shaft portion 38, and the stopper 54 defines the upper end position of the second float 50.

A gap is secured between the outer peripheral surface of each of the first float 40 and the second float 50 and the inner peripheral surface of the inner housing 36. Further, the inner housing 36 is formed with a communication hole 58 for always communicating the liquid chamber 56 formed between the first float 40 and the base 42 with the reservoir chamber 22. Also, the inner housing 3
In 6 is formed a communication hole 62 that is in constant communication with the liquid chamber 53 between the second float 50 and the first float 40. Further, a communication hole 64 that is always in communication with the master cylinder 14 is formed near the bottom of the outer housing 32.

The master cylinder 14 to which the reservoir 16 having the above-described structure is mounted is connected to the brake cylinders 72 of the respective wheels via the brake unit 70 represented by the frame of two-dot chain line in FIG. There is. The present brake system is composed of two brake systems independent of each other, and one brake system is composed of portions corresponding to the two brake cylinders 72 of the left and right front wheels, and the other brake system. The system is composed of portions corresponding to the two brake cylinders 72 for the left and right rear wheels. In other words, this brake system is a front and rear two-system type. However, in the figure, 1
For each brake system, only a portion corresponding to one brake cylinder 72 is representatively shown (however, one pump is provided for each brake system and two pumps belong to one brake system). It is designed to be shared between the brake cylinders). The configuration of the brake system will be briefly described below with reference to this drawing.

The master cylinder 14 is connected to the master cylinder side port 76 of the brake unit 70 by the main fluid passage 74, while the brake cylinder 72 is connected to the main fluid passage 78.
Is connected to the brake cylinder side port 80 of the brake unit 70.

In the brake unit 70, the ports 76 and 80 are connected by a main liquid passage 82, and a pressure increasing valve 84, which is a normally open electromagnetic on-off valve, is provided in the middle of the main liquid passage 82. . A return passage 86 with a check valve that bypasses the pressure increasing valve 84 is further connected to the main liquid passage 82. A portion of the main liquid passage 82 that connects the pressure increasing valve 84 and the brake cylinder side port 80 is connected to the reservoir side port 88 by a return liquid passage 89. A decompression valve 90, which is a normally closed electromagnetic on-off valve, is provided in the return liquid passage 89. That is, the pressure increasing valve 84 and the pressure reducing valve 90 cooperate with each other to form a hydraulic pressure control device. Return liquid passage 89
A portion of the main fluid passage 82 that connects the pressure reducing valve 90 and the reservoir side port 88 is connected to a portion of the main fluid passage 82 that connects the master cylinder side port 80 and the pressure increasing valve 84. A pump 96 driven by a motor 94 is provided in the pump liquid passage 92. A discharge valve 98 is provided on the discharge side of the pump 96, and a suction valve 100 is provided on the suction side. In addition,
The pump 96 is merely for recirculation, and the master cylinder 14 functions as the hydraulic pressure source of the brake cylinder 72 during the antilock control as in the normal braking.

The pressure increasing valve 84, the pressure reducing valve 90, and the motor 94 are connected to the controller 110, respectively. The controller 110, as shown in FIG.
The main component is a computer 118 including 112, ROM 114 and RAM 116. On the input side of the controller 110, four wheel speed sensors 120 that detect the wheel speed that is the peripheral speed of each wheel, a brake switch 122 that detects the operation of the brake pedal 10 by the driver, and the level switch 46 are provided. And are connected respectively. On the other hand, the pressure increasing valve 84, the pressure reducing valve 90, the motor 94, and the warning device 124 are connected to the output side. Various control programs are stored in advance in the ROM 114, including an antilock control routine for controlling the brake fluid pressure of each wheel via the pressure increasing valve 84 and the pressure reducing valve 90 so that each wheel is not locked during vehicle braking. The anti-lock control is executed by the CPU 112 executing the control program while using the RAM 116.

By the way, the brake unit 70 is
As shown in FIG. 1, it is connected to the reservoir 16 at its reservoir side port 88. Reservoir side port 8
8 is connected to the communication hole 62 of the reservoir 16 by the reservoir fluid passage 130, whereby the brake fluid discharged from the brake cylinder 72 via the pressure reducing valve 90 is
As shown in FIG. 3A, the liquid flows into the liquid chamber 53 between the first float 40 and the second float 50. That is, when the brake fluid discharged from the brake cylinder 72 via the pressure reducing valve 90 is discharged to the reservoir 16, the brake fluid first flows into the fluid chamber 53 that is substantially independent of the original reservoir chamber 22. .

When the brake fluid flows into the liquid chamber 53, the volume of the liquid chamber 53 increases, and the second float 50 has a force for pushing it up, and the first float 40 has a force for pushing it down. To work. However, since the upper limit of movement of the second float 50 is defined by the stopper 54, as a result, the first float 40 is pushed down as shown in (c) of the figure, and the amount of brake fluid discharged. Is greater than or equal to the set value, the permanent magnet 44 of the first float 40
Is detected by the level switch 46, and an ON signal is output.

After that, when the brake fluid stops flowing into the fluid chamber 53, the brake fluid in the fluid chamber 53 communicates with the gap between the outer peripheral surface of the first float 40 and the inner peripheral surface of the inner housing 36. It flows into the reservoir chamber 22 through the hole 58 in order,
Both the first float 40 and the second float 50,
As shown in (a) of the figure, the original position determined by the height of the brake fluid level is restored.

During normal braking, if the pressure reducing valve 90 is normal, the brake fluid is not discharged from the brake cylinder 72 via the pressure reducing valve 90. However, for example, the pressure reducing valve 90 does not return to the closed state, In an abnormal state in which the brake fluid is maintained in the open state or in a abnormal state in which the closed state is restored but the sealing performance is deteriorated due to foreign matter being caught, the brake fluid is discharged unscheduledly. Therefore, if the signal from the level switch 46 is monitored, it is possible to detect an abnormality in the brake system that the normal braking force is reduced due to a failure of the pressure reducing valve 90. However, when the brake cylinder 72 is depressurized by the pressure reducing valve 90 during the antilock control, the brake cylinder 7 that has passed through the pressure reducing valve 90.
The brake fluid from 2 will be discharged as scheduled. Therefore, if the signal of the level switch 46 is monitored regardless of the time, there is a possibility that the anti-lock control makes an erroneous determination that the pressure reducing valve 90 is abnormal although it is normal. Therefore, in order to improve the reliability of the abnormality determination, it is desirable to prohibit the signal monitoring of the level switch 46 during the antilock control.

Based on the above knowledge, in the present embodiment, the abnormality determination of the braking system is performed. To perform this abnormality determination, the abnormality warning routine shown in the flowchart of FIG. ing.

This routine is executed at regular intervals. At the time of each execution, first, step S1 (hereinafter, simply "S
1 ". The same for the other steps)
The signal is taken in from the level switch 46 and it turns on
It is determined whether or not it is a signal. That is, it is determined whether or not the first float 40 is detected by the level switch 46. Assuming that the signal of the level switch 46 is not the ON signal this time, the determination is NO, and one execution of this routine ends.

On the other hand, assuming that the signal of the level switch 46 is the ON signal this time, the determination in S1 is YE.
In S2, it is determined in S2 whether or not the antilock control is being executed. Assuming that the anti-lock control is not being performed this time, the determination becomes NO, and in S3, the warning device 124 is operated to notify the driver that there is an abnormality in the brake system. In this case,
After that, the execution of this routine is stopped until the key switch of the vehicle is operated from OFF to ON again, and the warning device 1
24 continues to operate. On the other hand, if it is assumed that the antilock control is currently being performed, the determination in S2 is YES.
Then, S3 is skipped, and one execution of this routine ends. Therefore, even if the signal of the level switch 46 is the ON signal this time, no abnormality warning is issued and an erroneous abnormality determination is avoided. In this case, this routine is then executed again.

As is clear from the above description, in this embodiment, the inner housing 36 (housing), the second float 50 (closing member), the stopper 54, and the communication hole 6 are provided.
2. The reservoir liquid passage 130 and the return liquid passage 89 cooperate with each other to form a float pressing mechanism, and the portion of the computer 118 that executes the abnormality warning routine of FIG. Of.

Next, another embodiment will be specifically described with reference to the drawings. The present embodiment is different from the above-described embodiment only in the configuration of the reservoir liquid amount detection device, and is common to the other portions, and therefore only the different configuration will be specifically described. Further, the reservoir liquid amount detection device also has a part in common with that described above, and the detailed description thereof will be omitted by using the same reference numeral for that part.

The details of the reservoir liquid amount detecting device 200 in this embodiment are shown in FIG. The reservoir liquid amount detection device 200 also includes an outer housing 32 and an inner housing 36, both of which have a cylindrical shape. However, in this reservoir liquid amount detection device 200, the second float 50 and the stopper 54 in the previous embodiment are used.
Instead, a partition plate 202 whose position is fixed is provided.
The partition plate 202 closes the upper end of the inner housing 36, and defines an increase limit of the volume of the liquid chamber 53 that is the upper space of the first float 40.

Therefore, in the present embodiment, if the brake fluid is discharged from the brake cylinder 72 to the reservoir 16 via the pressure reducing valve 90, the brake fluid will flow to the fluid chamber 53 that is substantially independent of the original reservoir chamber 22. It flows in and the volume of the liquid chamber 53 is increased. However, its volume 53
Is controlled by the partition plate 202,
The first float 40 is pushed down, and when the amount of brake fluid discharged from the brake cylinder 72 via the pressure reducing valve 90 is large, the first float 40 is pushed down to the position of the level switch 46 as shown in FIG. First float 4
0 will be detected by the level switch 46.

Another embodiment will be specifically described with reference to the drawings.

Both of the two embodiments described above are antilock type brake systems having a pressure increasing valve and a pressure reducing valve, but this embodiment has an antilock / locking system having a master cylinder cut valve, a pressure increasing valve and a pressure reducing valve. It is a traction type braking system.

Master cylinder 14 and brake cylinder 7
In the brake unit 210 provided between the master cylinder cut valve 212 and the main fluid passage 82, the master cylinder cut valve 212 is provided at a portion connecting the master cylinder side port 76 and the pressure increasing valve 84, as shown in FIG. ing. The master cylinder cut valve 212 is a normally open electromagnetic opening / closing valve, which is open during both normal braking and antilock control, and is closed during traction control to allow the pump 96 to function as a hydraulic pressure source. Therefore, at the time of traction control, the pump 96 is operated with the master cylinder cut valve 212 closed, and the brake fluid in the reservoir 16 is pumped up, so that the brake cylinder 7 of the drive wheel is driven.
2 is supplied to the drive wheel 2, so that idling of the drive wheels is suppressed.

The master cylinder cut valve 212 is provided with a passage 216 that bypasses it.
A check valve 218 is provided in the middle of the passage 216. The check valve 218 allows the flow of brake fluid from the master cylinder 14 side to the brake cylinder 72 side,
The flow in the opposite direction is blocked.

That is, in the present embodiment, the master cylinder 14 functions as a hydraulic pressure source for the brake cylinder 72 both during normal braking and during antilock control, but during traction control, the pump 96 causes the brake cylinder 72 to operate. It functions as a hydraulic pressure source.

Another embodiment will be specifically described with reference to the drawings. It should be noted that the same reference numerals are used for the elements that are common to the previous embodiment, and detailed description thereof is omitted.

Although all of the three embodiments described above are two-system front and rear brake systems, this embodiment is a diagonal two-system antilock brake system.

That is, as shown in FIG. 8, two brake systems extending independently from each pressurizing chamber of the master cylinder 14 are diagonally constructed.
In the figure, only the brake system to which the brake cylinder 72 for the right front wheel FR and the brake cylinder 72 for the left rear wheel RL belong is representatively shown.

One pressurizing chamber of the master cylinder 10 is connected to the front wheel brake cylinder 72 by a front wheel brake passage 222. The rear wheel brake passage 224 is branched from the middle of the front wheel brake passage 222, and the rear wheel brake cylinder 72 is connected to the tip thereof.

A master cylinder cut valve 226, which is an electromagnetic valve as a flow control device, is provided in a portion of the front wheel brake passage 222 on the master cylinder 14 side from the connection position with the rear wheel brake passage 224. The master cylinder cut valve 226 is open in the normal braking state, and allows the front wheel brake cylinder 72 and the rear wheel brake cylinder 72 to communicate with the master cylinder 14 to allow the master cylinder 14 to increase the pressure of the brake cylinders 72, 72. On the other hand, in the anti-lock control state, the brake cylinders 72, 72 are closed and the brake cylinders 72, 72 are shut off from the master cylinder 14 to allow the pump 96 to increase the pressure of the brake cylinders 72, 72. The master cylinder cut valve 226 is provided with a return passage 232 with a check valve that bypasses it. This is for promptly returning the brake fluid from the brake cylinders 72, 72 to the master cylinder 14.

An intermediate valve 240, which is a normally open electromagnetic valve, is provided in the rear wheel brake passage 224. Further, in the portion of the rear wheel brake passage 224 between the intermediate valve 240 and the rear wheel brake cylinder 72, the reservoir fluid passage 2 is provided.
42 is connected. The reservoir liquid passage 242 extends from the communication hole 62 of the reservoir 16, and a pressure reducing valve 246, which is a normally closed electromagnetic valve, is provided in the middle thereof.

The pump liquid passage 2 is provided in the reservoir liquid passage 242.
48 are connected. A pump 96 is provided in the middle of the pump liquid passage 248. The brake fluid discharge port of the pump fluid passage 248 is connected to a portion of the rear wheel brake passage 224 closer to the master cylinder 14 than the intermediate valve 240.

The intermediate valve 24 in the rear wheel brake passage 224
The portion connecting 0 and the rear wheel brake cylinder 72 is connected to the portion connecting the master cylinder 14 and the master cylinder cut valve 226 in the front wheel brake passage 222 by the return passage 254. In this return passage 254,
A check valve 256 is provided which blocks the flow of the brake fluid in the direction from the master cylinder 14 to the rear wheel brake cylinder 72 but allows the flow in the opposite direction. This is to prevent the residual pressure from being generated in the rear wheel brake cylinder 72 due to the valve opening pressure of the first check valve 262 described later.

A proportioning valve (hereinafter simply referred to as "P valve") 258 is provided in a portion of the rear wheel brake passage 224 between a connection position with the reservoir fluid passage 242 and the rear wheel brake cylinder 72. ing. P
As is well known, the valve 258 transmits the input pressure as it is to the rear wheel brake cylinder 72 as the output pressure before the input pressure (master cylinder pressure or pump discharge pressure) reaches the break point pressure. After the input pressure reaches the break point pressure, in order to avoid the rear wheel preceding lock caused by the load movement to the front of the vehicle, the rear wheel brake cylinder 72 uses the hydraulic pressure obtained by reducing the input pressure at a constant ratio as the output pressure. introduce.

A pressure reducing device 260 is provided in the rear wheel brake passage 224 on the master cylinder 14 side from the connection position with the pump fluid passage 248.

The reason why the decompression device 260 is provided is as follows. That is, in the conventional braking device, even when a load-sensing P-valve is used, especially in a light braking area when the vehicle is loaded and the front wheel braking force and the rear wheel braking force are close to 0 (for example, at the beginning of braking operation). , When braking on a road surface having a low friction coefficient, such as the area before the break point of the load-sensing P valve, the actual distribution line of the braking force is the rear wheel with respect to the ideal distribution line. The braking force deviates slightly to the side where it decreases, and it becomes impossible to sufficiently increase the rear wheel braking force in the region where the rear wheel is not locked. Such a situation is constant at least in the light braking area regardless of whether the actual distribution line is empty or loaded, and the gradient of the actual distribution line in the light braking area is equal to that when the vehicle is empty. It is caused by the fact that the wheel leading lock is set so as not to occur. Therefore, in order to solve such a situation, it is necessary to prepare a plurality of braking force distributions having different characteristics at least in the light braking region and selectively realize them. Therefore, the applicant of the present invention, in the antilock control state, the pump 9
The discharge pressure of No. 6 is reduced and transmitted to the front wheel brake cylinder 72, the hydraulic pressure of the rear wheel brake cylinder 72 is relatively increased compared to that in the normal braking state, and the rear wheel braking force is rapidly increased sufficiently in the light braking region. Therefore, the pressure reducing device 260 is provided in order to shorten the braking distance.

The depressurizing device 260 is constructed such that the first check valve 262 whose valve opening pressure is not substantially 0 and the second check valve 264 whose valve opening pressure is substantially 0 are opposite to each other and arranged in parallel. It is connected. In the present embodiment, since the pump 96 serves as a pressure source in the antilock control state, the first check valve 262 moves from the pump 96 to the front wheel brake cylinder 72.
It functions as a non-return valve that allows the flow of brake fluid in the direction of to the direction above the set valve opening pressure.

In this embodiment, the controller 11
0 performs the antilock control and the abnormality warning as in the previous embodiment, and further, by executing the abnormality warning routine, the brake system (particularly, the pressure reducing valve 24
If it is determined that 6) is abnormal, the fail-safe routine represented by the flowchart in FIG. 9 is executed.

First, in S11, it is determined whether or not it is determined that the brake system has an abnormality by executing the abnormality warning routine. If it is not determined that there is an abnormality, the determination becomes NO, and one execution of this routine ends. On the other hand, if it is determined that there is an abnormality, the determination becomes YES, and in S12, the intermediate valve 240 expected to be normal is closed. As a result, the rear wheel brake cylinder 72 and the pressure reducing valve 246 are connected to the front wheel brake cylinder 72 and the pump 96.
Is shut off from the master cylinder 14 during normal braking.
Thus, during antilock control, the pump 96 can increase the pressure of the front wheel brake cylinder 72.

Therefore, according to this embodiment, even if the pressure reducing valve 246 fails and the rear wheel brake cylinder 72 becomes inoperable, the operation of the front wheel brake cylinder 72 is ensured and all the brake cylinders 72 are operated. It is possible to obtain the effect of avoiding the occurrence of the inoperable situation.

Another embodiment will be specifically described with reference to the drawings. Note that this embodiment differs from all the above-described embodiments only in the structure of the reservoir and is common to the other parts, and therefore only the structure of the different reservoir will be described in detail with reference to the drawings.

As shown in FIG. 10, the reservoir 270 is
It has a housing 274 forming a reservoir chamber 272. A shaft portion 276 extends from the bottom of the housing 274 almost directly above the housing portion 274.
The individual floats 278 are fitted so as to be vertically displaceable. A permanent magnet 279 is attached to the float 278. The shaft portion 276 is provided with a first level switch 284 and a second level switch 286 at a lower position and an upper position thereof, respectively. Further, in the housing 274, a partition plate 288 that extends substantially vertically is provided near the float 278. This partition plate 288
Is for suppressing the liquid surface of the brake fluid in the reservoir chamber 272 from inclining due to the inclination of the reservoir 270 accompanying the inclination of the vehicle body.

The first level switch 284 performs the same function as a conventional level switch. That is, it fulfills the function of detecting that the remaining amount of the brake fluid in the reservoir chamber 272 is below the set value. In contrast,
The second level switch 286 has a function of detecting an abnormality in the hydraulic control device. A brake cylinder 72 is connected to the reservoir chamber 272 in a communication hole 290 via a hydraulic pressure control device (not shown) so that the brake fluid leaked from the hydraulic pressure control device unexpectedly. If the amount of leaked brake fluid increases, the remaining amount of brake fluid in the reservoir chamber 272 increases, and the float 278 is detected by the second level switch 286.
This makes it possible to detect an abnormality in the hydraulic control device.

Although some embodiments of the present invention have been described above, other than these, various modifications and improvements are made based on the knowledge of those skilled in the art without departing from the scope of the claims. The present invention can be implemented in

[Brief description of drawings]

FIG. 1 is a system diagram showing an entire two-system front-and-rear type anti-lock brake system that is an embodiment of the present invention.

FIG. 2 is an enlarged front sectional view showing a master cylinder 14 and a reservoir 16 in FIG.

3 is an enlarged front sectional view of a reservoir liquid amount detection device 30 in FIG.

FIG. 4 is a block diagram showing an electrical configuration of the brake system.

5 is a flowchart showing an abnormality warning routine stored in a ROM of the computer shown in FIG.

FIG. 6 is a front cross-sectional view showing a reservoir fluid amount detection device in a brake system, which is another embodiment of the present invention, taken out.

FIG. 7 is a system diagram showing an entire front / rear two-system antilock / traction type brake system which is still another embodiment of the present invention.

FIG. 8 is a system diagram showing an entire diagonal two-system type anti-lock type brake system which is another embodiment of the present invention.

FIG. 9: ROM of the computer of the braking system
4 is a flowchart showing a fail-safe routine stored in FIG.

FIG. 10 is a front cross-sectional view showing a reservoir in a brake system according to still another embodiment of the present invention.

[Explanation of symbols]

 14 Master Cylinder 16 Reservoir 30 Reservoir Liquid Amount Detector 36 Inner Housing 40 First Float 44 Permanent Magnet 46 Level Switch 53 Liquid Chamber 62 Communication Passage Hole 72 Brake Cylinder 84 Pressure Boosting Valve 89 Return Fluid Passage 90 Pressure Reduction Valve 110 Controller 130 Reservoir Fluid Passage

Claims (4)

[Claims] 1. A hydraulic pressure source including at least a master cylinder, a reservoir attached to the master cylinder for supplying accumulated brake fluid to the master cylinder, a brake cylinder for operating a brake of a wheel, and those hydraulic pressure sources. It is provided between the reservoir and the brake cylinder. During normal braking, the brake cylinder is shut off from the reservoir to connect to the master cylinder to achieve the increased pressure state. At the time of hydraulic control, the brake cylinder is shut off from the reservoir. System including a hydraulic pressure control device that selectively realizes a plurality of types of hydraulic pressure control states including a pressure increase state in which a hydraulic pressure source is connected and a pressure reduction state in which a brake cylinder is disconnected from a hydraulic pressure source and connected to a reservoir. In the above, in the normal braking, the fluid pressure control device is operated from the brake cylinder. The brake system is provided with a warning device that detects that the amount of the brake fluid discharged to the reservoir through the above is greater than or equal to a set value and warns the driver of this. 2. The brake system according to claim 1, wherein, in addition to the first warning device as the warning device, (a) depending on the height of the liquid level of the brake fluid accumulated in the reservoir. A displacing float, (b) a sensor that outputs a signal indicating that when the height of the float becomes less than or equal to a set height, and (c) the sensor acts when the sensor outputs the signal, A brake system comprising: a second warning device having a warning device for warning a driver of an abnormality of the brake system. 3. The brake system according to claim 2, wherein the first warning device includes: (d) the second warning device generated by the brake fluid discharged from the brake cylinder to the reservoir via the hydraulic pressure control device. A float depressing mechanism for depressing the float of the warning device; and (e) the second warning device when the sensor of the second warning device outputs the signal.
And a warning device actuating means for actuating a warning device in the warning device of 1. 4. The brake system according to claim 3, wherein the float push-down mechanism includes (f) a housing for accommodating the float so as to be vertically displaceable, and (g) a space in the housing from the float. A closing member that closes the upper space that is the upper part, in which displacement in a direction in which the volume of the upper space increases is regulated, and (h) the upper space is passed through the hydraulic pressure control device and A brake system comprising: a return fluid passage connected to the brake cylinder and for guiding the brake fluid discharged from the brake cylinder through the fluid pressure control device to the upper space thereof.