JPH0979202A - Reservoir accumulated liquid level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the position of a piston in an indirectly uncontacted manner by estimating a reservoir accumulated liquid level on the basis of an electric signal out of a pressure sensor of an air chamber. SOLUTION: Pressure in an air chamber 80 is detected by a pressure sensor 90 as reference air pressure, opening a pressure reducing valve 42, and air is supplied by an air supply unit 94, while pressure in the air chamber 80 is detected by the pressure sensor 90 as judging air pressure, from which the reference air pressure is subtracted, thereby operating an air pressure variation. If this air pressure variation is more than the setting value, the reservoir volume is proper, but if it is less than that, it is so judged as to be insufficient. Next, a hydraulic fluid is supplied by a hydraulic fluid supply unit 96, and pressure in the air chamber 80 is detected by the pressure sensor 90 as the judging air pressure, from which the reference air pressure is subtracted, operating an air pressure variation. In this case, if this variation is less than the setting value, there is no liquid leakage in a brake unit, but if it is more than the setting value, it is so judged as to be leaked. Therefore, in order to detect the reservoir liquid level, a piston position is detectable by means of noncontact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a technique for detecting the amount of hydraulic fluid accumulated in a reservoir in which a piston is fitted in a housing.

[0002]

2. Description of the Related Art A reservoir exists as a device for accumulating hydraulic fluid, and as one type of the reservoir, a reservoir chamber for accumulating hydraulic fluid in front of the piston by fitting a piston in a housing, Air chambers are formed on the rear side, respectively, and there is already a reservoir for accumulating the hydraulic fluid in the reservoir chamber by retracting the piston. Reservoirs of this kind are used, for example, at least together with control valves to form hydraulic actuators, such hydraulic actuators being used, for example, in antilock brake systems for vehicles, traction brake systems, etc.
It constitutes the whole or a part of a hydraulic circuit for electromagnetically controlling the hydraulic pressure of the controlled object.

For example, in an antilock brake system, a pressure source and a brake cylinder (an example of a controlled object) are connected to each other via a control valve, and the brake cylinder is connected to a reservoir via the control valve. Here, the control valve includes at least a pressure increasing state in which the brake cylinder is substantially shut off from the reservoir to communicate with the pressure source, and the brake cylinder is boosted by the pressure source, and a pressure is substantially shut off from the pressure source to the reservoir. The communication is switched to a depressurized state in which the hydraulic fluid in the brake cylinder is allowed to be discharged to the reservoir and the brake cylinder is depressurized. In this brake system, generally, at least the control valve and the reservoir constitute a brake unit, and the control valve and the reservoir are mounted on the vehicle as the brake unit, thereby constituting the brake system in the vehicle. In this brake system, it can be considered that only the brake unit constitutes the hydraulic actuator, or that the entire brake system constitutes the hydraulic actuator.

When using a reservoir of the above type,
It may be necessary to detect the reservoir volume that it stores hydraulic fluid. Hereinafter, this case will be described by taking as an example the case where the reservoir is used in an antilock brake system.

For example, while the vehicle is traveling and during the antilock control, the hydraulic fluid accumulated in the reservoir is pumped up by the pump, but in order to prevent the pump from being wastefully operated and to reduce the operating noise, the reservoir storage is reduced. It may be necessary to detect whether or not the liquid volume is substantially zero.

During normal braking, the working fluid is originally prevented from being discharged from the brake cylinder to the reservoir chamber by the control valve or the like. However, if the control valve or the like is defective, the working fluid is scheduled to flow from the brake cylinder to the reservoir chamber. It will be discharged outside. Therefore, at the time of normal braking, the reservoir liquid amount that should have been essentially 0 is not 0 for some reason, that is, the hydraulic fluid in the brake cylinder leaks to the reservoir via the control valve unexpectedly. In some cases, it may be necessary to detect the leaked liquid at an early stage, and in this case, it is necessary to detect whether or not the reservoir liquid storage amount is substantially zero. In addition, if liquid leakage occurs,
During normal braking, so-called brake release occurs, in which the brake operation amount exceeds the planned amount. Also, during antilock control, hydraulic fluid has already accumulated in the reservoir before the first depressurization, and sufficient brake cylinders are available during the first depressurization. There are problems such as not being able to obtain the amount of pressure reduction and not being able to obtain a sufficient amount of pressure increase for the brake cylinder when increasing the pressure. Therefore, it is necessary to detect the liquid leak at an early stage and warn the driver.

The detection of the reservoir liquid storage amount is not necessary only after the reservoir is mounted on the vehicle, but is also necessary before the mounting of the reservoir on the vehicle, that is, for example, the inspection performed before shipping. There are cases.

For example, in the antilock brake system, when the operating state of the reservoir is not proper and the maximum reservoir volume which is the volume of hydraulic fluid that can actually accumulate in the reservoir is insufficient with respect to the design value, The amount of hydraulic fluid that can actually be discharged from the brake cylinder to the reservoir during depressurization in antilock control is less than the design value, and a normal amount of depressurization cannot be obtained. Therefore, the maximum value of the reservoir liquid storage amount is detected by artificially operating a brake unit including at least a reservoir and a control valve (for example, by opening the control valve to supply fluid to the passage in the brake unit), If the value is smaller than the design value, it is necessary to stop the shipment of the brake unit as a defective product.

Further, as described above, if the brake unit leaks liquid, there is a problem that the brake is released during normal braking, and there is a problem that the desired effect cannot be obtained during antilock control. Therefore, the brake unit is artificially operated (for example,
The amount of reservoir liquid is detected by closing the control valve and supplying hydraulic fluid to the passage in the brake unit, and if the value is not substantially 0, the brake unit stops shipment as a defective product. It is necessary.

Against the background of the circumstances explained above,
Japanese Patent Laid-Open No. 60764 discloses the following as a technique for detecting a reservoir liquid storage amount that is implemented after mounting on a vehicle. It is a technique for detecting the reservoir liquid amount during use of a brake system, and a switch that mechanically opens and closes by a relative displacement between the housing and a piston to which the housing is fitted is provided between the housing and the piston. The switch shall output a different signal when the reservoir volume is maximized and the piston is bottoming into the housing, and when it is not, and the signal from that switch is taken in only during normal braking. Is a technique for determining whether or not the reservoir liquid storage amount has become maximum.

Further, the following is already known as a technique for detecting a reservoir liquid storage amount which is carried out before mounting on a vehicle. It is a detector for detecting the position of the piston in the reservoir (for example, a dial gauge, provided with a communication hole in the housing of the reservoir for always communicating the air chamber with the atmosphere).
Insert the linear gauge detector) from the outside of the housing into the air chamber through its communication hole and make contact with the rear surface of the piston.In this state, the hydraulic actuator is artificially operated under predetermined conditions. The suitability of the operating state of the hydraulic actuating device is determined based on the change in the piston position that is detected.

[0012]

However, in the technique for detecting the amount of reservoir liquid stored in a vehicle, which is described in the above publication, the position of the piston is directly positioned on the piston to detect the amount of reservoir liquid stored. Since it is a contact type in which contact is detected, there is a problem that the contact of the switch is easily worn.

Further, the above-mentioned technique for detecting the reservoir liquid storage amount, which is carried out before mounting on a vehicle, has the following problems. That is, the communication hole formed in the reservoir always communicates with the atmosphere, and since the communication hole is large enough to allow the detector to pass therethrough, foreign matter such as water or mud enters the air chamber through the communication hole. , It may cause the failure of the reservoir.
Therefore, an extra cap for closing the communication hole is required, and there are problems that the number of parts increases, the device cost increases, and the device assembly becomes complicated.

Under these circumstances, the present invention solves these problems by detecting the pressure of the air chamber in the reservoir and indirectly detecting the position of the piston in a contactless manner in order to detect the reservoir liquid storage amount. The problem was to solve it.

[0015]

[Solution Means, Actions and Effects of the First Invention]
To solve the problem, a device for detecting the amount of accumulated liquid in a reservoir provided with the housing, piston, reservoir chamber and air chamber described above is (a) a pressure sensor for detecting the pressure of the air chamber, and (b) a pressure sensor It is possible to solve the problem by including a reservoir liquid storage amount estimating means for estimating the reservoir liquid storage amount based on the electric signal.

When the hydraulic fluid flows into the reservoir chamber, the position of the piston changes, and the volume of the air chamber formed behind it changes according to the position of the piston. On the other hand, the volume of the air chamber can be detected as the pressure of the air chamber. Therefore, the position of the piston can be indirectly detected as the pressure of the air chamber. Therefore, based on such knowledge, in the reservoir liquid storage amount detecting device according to the first aspect of the invention, the pressure sensor detects the pressure of the air chamber in the reservoir, and the reservoir liquid storage amount estimating means detects the pressure from the pressure sensor. The reservoir liquid storage amount is estimated based on the electric signal.

Therefore, according to the first aspect of the invention, since the position of the piston is detected in a non-contact manner for detecting the reservoir liquid storage amount, the problem of contact wear does not occur and the reliability of the reservoir liquid storage amount detection is improved. The effect of improvement is obtained.

Further, according to the first aspect of the present invention, the size of the communication hole for communicating the air chamber with the atmosphere is sufficient to enable pressure transmission from the air chamber to the pressure sensor, and in the case of adopting the prior art. Thus, there is no need to make it large enough to allow passage of the detector. That is, it is possible to reduce the size of the communication hole that always communicates with the atmosphere to the extent that water, mud, etc. can be prevented from entering without the attachment of a cap.

Therefore, according to the first aspect of the present invention, it is not necessary to attach a cap to prevent water, mud, etc. from entering the reservoir through the communication hole, so that the number of parts of the reservoir can be reduced. It is also possible to obtain an effect that the device cost can be reduced and the device can be easily assembled.

[0020]

[Solution Means, Actions and Effects of the Second Invention]
It is an object of the present invention to provide a method for inspecting a hydraulic pressure device, to which the technical idea of the first invention is applied.
At least a control valve and a reservoir chamber that accumulates hydraulic fluid in front of the piston when the piston is fitted in the housing and an air chamber in the rear are formed, and the hydraulic fluid is stored in the reservoir chamber when the piston retracts. The method of inspecting a hydraulic actuator having a reservoir for accumulating the liquid is operated in a pseudo manner under a predetermined condition and the pressure change in the air chamber at that time is detected. The suitability of the operating state of the hydraulic actuator is determined based on the above.

Therefore, according to the second aspect of the invention, since the position of the piston is detected in a non-contact manner for detecting the reservoir liquid storage amount, the problem of contact wear does not occur, and further, the communication hole that always communicates with the atmosphere. Since it is possible to reduce the size, it is possible to provide a method for inspecting a hydraulic pressure device that does not require a cap to be attached to the reservoir in order to prevent water, mud, etc. from entering the reservoir through the communication hole. Is obtained.

The second invention will be supplementarily described below. (1) The "hydraulic actuating device" itself constitutes, for example, the entire hydraulic circuit that electromagnetically controls the hydraulic pressure of the controlled object, such as an anti-lock brake system, a traction brake system, or In some cases, only part of the hydraulic circuit may be configured.

(2) In the case of carrying out the second invention, as a medium to be supplied to the hydraulic actuator in order to artificially operate the hydraulic actuator, the hydraulic fluid originally used in the hydraulic actuator is used. Of course, the same can be used, but instead of the hydraulic fluid, another medium, for example,
Other liquids and gases such as air can also be used.

(3) When the second invention is applied to a brake unit as a hydraulic actuator, the brake unit is inspected before it is mounted on a vehicle and the brake unit has not yet constituted the brake system. Alternatively, the inspection may be performed after the vehicle is mounted and the brake system is configured.

(4) The second invention can also be implemented in the following modes. A control valve in the hydraulic pressure actuating device is brought into a state in which hydraulic fluid is allowed to flow into the reservoir via the control valve, and an electric signal is taken in from the pressure sensor to detect a reference air pressure of the air chamber, After that, gas (air or the like) or liquid (working liquid or the like) is supplied to the passage in which the hydraulic fluid should originally flow in the hydraulic pressure device, and after the elapse of the set time, an electric signal is again taken in from the pressure sensor to make the air chamber A method for inspecting a hydraulic pressure device, which detects a judgment air pressure, and judges that the reservoir maximum volume, which is a volume capable of accumulating hydraulic fluid in a reservoir, is insufficient when the judgment air pressure is not higher than a reference value by a set value or more.

The control valve in the hydraulic pressure operating device is set to a state in which the hydraulic fluid is allowed to flow into the reservoir via the control valve, and an electric signal is taken in from the pressure sensor to change the reference air pressure of the air chamber. After that, the gas (air, etc.) or liquid (working liquid, etc.) is supplied to the passage through which the working liquid originally should flow in the hydraulic actuator.
After the set time has elapsed, an electric signal is again taken in from the pressure sensor to detect the judgment air pressure of the air chamber, and when the judgment air pressure is within the reference air pressure range in which the width is not 0, the volume in which the reservoir can accumulate the working fluid. A method for inspecting a hydraulic pressure device, which determines that the maximum volume of the reservoir is normal and determines that it is abnormal if the maximum volume of the reservoir is not within the reference air pressure range.

The control valve in the fluid pressure operating device is set to a state in which the working fluid is prevented from flowing into the reservoir via the control valve, and an electric signal is taken in from the pressure sensor to set the reference air pressure of the air chamber. After that, the gas (air, etc.) or liquid (working liquid, etc.) is supplied to the passage through which the working liquid originally should flow in the hydraulic actuator.
After the elapse of the set time, the electric signal is again taken in from the pressure sensor to detect the judgment air pressure in the air chamber, and when the judgment air pressure is higher than the reference air pressure by the set value or more, the liquid pressure leak has occurred in the hydraulic actuator. Method for inspecting hydraulic actuator.

(5) "Control valve" includes a control valve for hydraulic pressure control and a control valve for direction switching, and also includes an electromagnetic type and a pilot type.

[0029]

[Solution Means, Actions and Effects of the Third Invention]
An object of the present invention is to provide an apparatus suitable for carrying out the method for inspecting a hydraulic pressure device according to the second aspect of the present invention, wherein at least a control valve and a housing are fitted with a piston so as to be axially displaceable. A hydraulic actuator having a reservoir chamber for accumulating hydraulic fluid in the front of the piston and an air chamber in the rear of the piston, and a reservoir for accumulating the hydraulic fluid in the reservoir chamber when the piston retracts is inspected. The device is (a) a pressure sensor that detects the pressure in the air chamber, and (b) a hydraulic actuator that is operated in a simulated manner under predetermined conditions, and at that time the electrical signal output from the pressure sensor It is characterized by including a determining means for determining whether or not the operating state of the hydraulic operating device is appropriate based on the change.

In the hydraulic pressure device inspection apparatus according to the third aspect of the invention, a pressure sensor for detecting the pressure of the air chamber in the reservoir is provided based on the same knowledge as the basis of the first aspect of the invention, and the determination means is used. , The hydraulic actuator is operated in a pseudo manner under a predetermined condition, at which time the pressure of the air chamber is detected by the pressure sensor, and the determination means further determines the change in the electrical signal from the pressure sensor. The suitability of the operating state of the hydraulic actuator is determined.

Therefore, according to the third aspect of the invention, it is possible to obtain the effect of providing the hydraulic pressure device inspection apparatus suitable for carrying out the hydraulic pressure device inspection method according to the second aspect.

The third invention will be supplementarily described below. (1) The “hydraulic actuating device” is the same as in the second invention.
For example, it may form the entire hydraulic circuit by itself, or may form only part thereof.

(2) Even in the case of carrying out the third invention, even if the same medium as the original working fluid is used as the medium to be supplied to the hydraulic pressure actuator in order to artificially operate the hydraulic actuator. Other media may be used.

(3) In the same manner as in the second aspect of the invention, when the third aspect of the invention is applied to a brake unit as a hydraulic pressure actuating device, the brake unit still constitutes a brake system before being mounted on a vehicle. The brake unit may be inspected in a state where the brake system is not installed, or the state in which the brake system is configured after the vehicle is mounted may be inspected.

(4) The third invention can also be implemented in the following modes. Further, in the hydraulic pressure operation device, an air supply device for supplying air to a passage through which the hydraulic fluid should normally flow is included, and the determination means is configured to perform the hydraulic pressure operation prior to the operation of the air supply device. The control valve in the device is set to a state in which the air is allowed to flow into the reservoir through the control valve, the electric signal is taken in from the pressure sensor to detect the reference air pressure, and then the air supply device is operated. Air is supplied to the hydraulic pressure device, and after the set time elapses, the electric signal is again fetched from the pressure sensor to detect the judgment air pressure.If the judgment air pressure is not higher than the reference air pressure by the set value or more, the reservoir stores the working fluid. A hydraulic actuator inspection device that determines that the reservoir maximum volume, which is the volume that can be accumulated, is insufficient.

Further, the hydraulic operating device includes an air supply device that supplies air to a passage through which the hydraulic fluid should normally flow, and the determination means includes the air supply device prior to the operation of the air supply device. The control valve in the fluid pressure actuating device is brought into a state in which air is allowed to flow into the reservoir via the control valve, and an electric signal is taken in from the pressure sensor to detect the reference air pressure, and then the air supply device is turned on. Actuate to supply air to the hydraulic actuator,
After the set time has elapsed, the electric signal is again taken in from the pressure sensor to detect the judgment air pressure, and if the judgment air pressure is within the reference air pressure range where the width is not 0, the reservoir maximum that is the volume that can accumulate the working fluid A hydraulic actuating device inspection device that determines that the volume is appropriate and determines that it is abnormal when it is not within the reference air pressure range.

In these embodiments, air is used as a medium to be supplied to the hydraulic actuator in order to artificially operate the hydraulic actuator, but other gas or liquid is used. It is also possible. Air was used because it is easier to handle than when using liquids.

Further, the hydraulic pressure operation device includes a hydraulic fluid supply device for supplying hydraulic fluid to a passage through which the hydraulic fluid should flow, and the determination means is configured to operate the hydraulic fluid supply device prior to the operation of the hydraulic fluid supply device. The control valve in the pressure actuating device is set to a state in which the working fluid is prevented from flowing into the reservoir via the control valve, and an electric signal is taken in from the pressure sensor to detect the reference air pressure, and then the hydraulic fluid supply device. To supply hydraulic fluid to the hydraulic actuator,
After the set time has elapsed, the electric signal is again taken in from the pressure sensor to detect the judgment air pressure, and if the judgment air pressure is higher than the reference air pressure by the set value or more, it is judged that there is a liquid leak in the hydraulic actuator. Pressure actuator inspection device.

(5) The "control valve" includes a control valve for hydraulic pressure control and a control valve for direction switching, as in the second invention, and also includes an electromagnetic type and a pilot type.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. The present embodiment is a brake unit inspection method and a brake unit inspection device that inspect a brake unit in an antilock brake system. That is, in the present embodiment, the brake unit is an example of the “hydraulic pressure actuating device” in the present invention.

FIG. 1 shows the brake unit inspection device and an anti-lock type brake system (hereinafter, simply referred to as "brake system") including a brake unit to be inspected by the brake unit inspection device.

The braking system has a master cylinder 10 as a pressure source. The master cylinder 10 is a tandem type in which two independent pressure chambers are arranged in series, and mechanically applies hydraulic pressure to each of the pressure chambers in accordance with the operation force of a brake pedal 12 as a brake operation member. generate. Master cylinder 10 and brake pedal 12
Are linked to each other via the booster 14. The booster 14 boosts the operating force of the brake pedal 12 and transmits it to the master cylinder 10.

Two independent brake systems are connected to each pressurizing chamber of the master cylinder 10. Since these brake systems have the same configuration,
Only one brake system will be illustrated and described by text, and the other brake systems will not be illustrated.

Two brake cylinders 22 are connected to the pressurizing chamber by a brake passage 20. The brake passage 20 branches in a bifurcated manner, and is composed of one main trunk passage 24 and two branch passages 26, and each of the brake cylinders 22 is connected to the tip of each of the branch passages 26. Each brake cylinder 22 suppresses the rotation of the wheel by pressing the friction pad 27 against the disk rotor 28 that rotates with the wheel by the hydraulic pressure acting on the brake cylinder 22.

A holding solenoid valve (an example of a control valve) 30 is provided in the middle of each branch passage 26. Each holding solenoid valve 30 is a normally-open solenoid on-off valve. Each holding solenoid valve 3
0 is in the open state during normal braking, and permits the flow of hydraulic fluid between the master cylinder 10 and each brake cylinder 22. At the time of antilock control, when it is necessary to maintain the hydraulic pressure of each brake cylinder 22 or to reduce the hydraulic pressure, the brake cylinder 22 is closed and the master cylinder 10 and each brake cylinder 22 are cut off from each other. When it is necessary to increase the pressure of each brake cylinder 22, the brake cylinder 22 is opened and the master cylinder 10 and each brake cylinder 22 are communicated with each other.

In the middle of each branch passage 26, one end of each reservoir passage 32 is further connected between the connection position of each holding solenoid valve 30 and each brake cylinder 22. Each reservoir passage 32 is connected to the reservoir 40 at the other end, and is connected to each brake cylinder 22 and the reservoir 4.
0 is connected. However, each pressure reducing electromagnetic valve (an example of a control valve) 42 is provided in the middle of each reservoir passage 32. Each pressure reducing solenoid valve 42 is a normally closed solenoid opening / closing valve, is in a closed state during normal braking, shuts off the brake cylinder 22 and the reservoir 40 from each other, and depressurizes each brake cylinder 22 during antilock control. When necessary, it is opened to allow hydraulic fluid in each brake cylinder 22 to drain to the reservoir 40, while each brake cylinder 22 needs to be boosted or held in pressure. If there is, it is closed.

The holding solenoid valve 30 and the pressure-reducing solenoid valve 42 described above are the solenoids of the controller 4
4 is connected. The controller 44 monitors the wheel speed, which is the peripheral speed of each wheel, and the vehicle speed, which is the traveling speed of the vehicle, by a wheel speed sensor 46 provided for each wheel,
When the slip ratio of each wheel becomes excessive, the anti-lock control is started, and the brake pressure of each wheel is controlled via the holding solenoid valve 30 and the pressure reducing solenoid valve 42, whereby the wheels are locked when the vehicle is braked. Prevent that.

One end of a recirculation passage 50 is also connected to the reservoir 40. The other end of the return passage 50 is connected to the main passage 24, and a pump 52 is provided on the way. The pump 52 is driven by a motor (not shown), and pumps up the hydraulic fluid accumulated in the reservoir 40 and returns it to the master cylinder 10. In the middle of the return passage 50, a discharge valve 54, which is a check valve on the discharge side of the pump 52, and a suction valve 5, which is a check valve on the suction side, are further provided.
6 are provided respectively, and further, in the portion between the pump 52 and the connection point of the main passage 24, the pump 52
A damper 58 is provided for reducing pulsation due to, and a check valve for preventing backflow of the hydraulic fluid from the master cylinder 10 to the pump 52 is provided at a portion between the damper 58 and a connection point of the main passage 24. A valve 60 is provided.

In the brake system configured as described above, the portion surrounded by the broken line in the drawing constitutes the brake unit. That is, in the present embodiment, the brake unit 62 includes the holding solenoid valve 30, the pressure reducing solenoid valve 42, the reservoir 40, the pump 52, a motor (not shown), the damper 58, the discharge valve 54, the suction valve 56, and the check valve 60. It is configured to include. However,
Brake units to be used respectively in the two brake systems connected to the master cylinder 10 are integrated into a brake unit 62. Although the brake unit 62 is provided with a plurality of ports for connecting to the master cylinder 10 and the brake cylinder 22 respectively (shown by white circles in the figure),
Before mounting on the vehicle, all of these ports are closed by plugs.

Here, the structure of the reservoir 40 will be described in detail. A bottomed cylinder bore 72 is formed in the housing 70 of the brake unit 62, and a piston 74 is slidably fitted in the cylinder bore 72. An O-ring 76 as a sealing member is arranged between the cylinder bore 72 and the piston 74, and the cylinder bore 72 of the piston 74 is fitted in a substantially airtight manner. By fitting the piston 74 into the cylinder bore 72,
The space in the cylinder bore 72 is divided into two. It is partitioned into a reservoir chamber 78 on the bottom side and an air chamber 80 on the opening side. In the reservoir chamber 78 of the reservoir 40, the reservoir passage 32 and the return passage 5 are provided.
0 and 0 respectively. The air chamber 80 is closed by a plate 82 as a closing member, and the plate 8
By disposing the spring 84 as an elastic member between the piston 2 and the piston 74, the piston 74 is oriented in a direction in which the volume of the air chamber 80 is constantly expanded, that is, the reservoir chamber 7
The volume of 8 is urged in the direction of decreasing. Plate 8
2 is a communication hole 86 for communicating the air chamber 80 with the atmosphere.
Is penetrated.

Therefore, the hydraulic fluid does not substantially exist in the reservoir chamber 78 at the time of normal braking, but at the time of pressure reduction in the antilock control, the hydraulic fluid in the brake cylinder 22 withdraws the piston 74 against the elastic force of the spring 84. Then, the volume of the reservoir chamber 78 is increased to flow into the reservoir chamber 78. Further, the piston 74 reduces the volume of the air chamber 80 as the piston 74 retracts.

The brake unit inspection device is of a type in which the brake unit 62 is inspected before being mounted on a vehicle, and the actual value of the reservoir volume (maximum volume), which is the volume of hydraulic fluid that can be accumulated in the reservoir 40, is equal to the design value. 1 and the brake unit 62, as shown by the chain double-dashed line in FIG. 1, with the check valve 60 and the pressure reducing solenoid valve 42 as the boundary, the primary hydraulic circuit on the master cylinder side and the secondary hydraulic circuit on the reservoir side. When it is partitioned into the hydraulic circuit on the side, the hydraulic fluid leaks from the hydraulic circuit on the primary side to the hydraulic circuit on the secondary side, which is the reservoir 4
And whether or not they are accumulated in 0 are respectively checked. If the actual value of the reservoir volume is insufficient, there will be a problem of insufficient pressure reduction in antilock control, and if there is liquid leakage, so-called brake omission will occur during normal braking, and pressure reduction will occur during antilock control. There is a problem of insufficient amount and insufficient amount of increased pressure. Therefore, in order to prevent such an improper brake unit 62 from being mounted on the vehicle, it is inspected and excluded before shipment.

Therefore, the brake unit inspection device is
Pressure sensor 90 and determination device (an example of determination means) 92
And an air supply device 94 for supplying air to the brake unit 62 to be inspected, and a hydraulic fluid supply device 96 for supplying hydraulic fluid.

The pressure sensor 90 includes a sensor body 100 for converting pressure into an electric signal and a sensor housing 10 for bringing the sensor body 100 into close contact with the plate 82.
2 is provided. An air passage 104 that communicates with the atmosphere and also communicates with the sensor body 100 is formed in the sensor housing 102, and an O-ring 106 as a seal member is fixedly held at an opening of the air passage 104. The pressure sensor 90 is brought into close contact with the plate 82 via the O-ring 106 when the operator inspects the brake unit 62.

On the other hand, the determination device 92 includes CPU 110, R
Computer 11 including OM 112 and RAM 114
It is mainly composed of 6. The pressure sensor 90 is connected to the input side of the determination device 92. On the other hand, an air supply device 94 and a hydraulic fluid supply device 96 are respectively connected to the output side thereof, and when the brake unit 62 is inspected, the pressure reducing solenoid valve 42 of the brake unit 62 to be inspected is also connected. The determination device 92 is a ROM
The brake unit 62 is inspected by the CPU 110 executing the reservoir volume suitability determination program and the liquid leakage presence / absence determination program stored in 112 in advance while using the RAM 114.

The operator attaches the pressure sensor 90 to the reservoir 40.
The determination device 92 is operated in a state where the determination device 92 is brought into close contact with. Accordingly, the determination device 92 first executes the reservoir volume suitability determination program.

The reservoir volume suitability determination program is shown in the flow chart of FIG. In this program, first, in step S1 (hereinafter simply referred to as “S1”; the same applies to other steps), the pressure sensor 90 causes the pressure of the air chamber 80 to be the reference air pressure P _0.
Is detected as Next, in S2, the pressure reducing solenoid valve 4
A signal that excites it and opens it is output to 2. Then, in S3, by the air supply device 94,
Air is supplied from any port of the brake unit 62. Then, in S4, the set time T ₁
Is waited for and the pressure sensor 90 detects the pressure of the air chamber 80 as the determination air pressure P in S5. Further, in S6, the air pressure change amount ΔP is calculated by subtracting the reference air pressure P _O from the determination air pressure P.

Thereafter, in S7, the air pressure change amount ΔP
Is determined to be less than the set value ΔP _D1 . Here, the "set value ΔP _D1 " indicates that the reservoir 40 is appropriate and S3
The air pressure change amount ΔP that is generated in the air chamber 80 when the piston 74 is displaced from the non-acting position to the regular maximum stroke position by the supply of the air is set in advance. If it is assumed that the air pressure change amount ΔP is equal to or larger than the set value ΔP _D1 this time, the determination is NO, and in S8,
It is determined that the reservoir volume is appropriate. After that, S9
At, a signal for demagnetizing and closing the pressure reducing solenoid valve 42 is output. This completes one execution of the program.

On the other hand, if it is assumed that the air pressure change amount ΔP is smaller than the set value ΔP _D1 this time, the determination in S7 is YE.
S becomes, and it is determined in S10 that the reservoir volume is insufficient. Then, it transfers to S9.

Subsequently, the determination device 92 executes the liquid leakage presence / absence determination program. Figure 3 shows the program for determining liquid leakage
It is shown in the flow chart. In this program, first, in S11, the pressure of the air chamber 80 is detected as the reference air pressure P ₀ by the pressure sensor 90. Next, in S12, the hydraulic fluid supply device 96 supplies hydraulic fluid from the port of the brake unit 62 that belongs to the primary hydraulic circuit.

Subsequently, in S13, it is waited for the set time T ₂ to elapse, and if so, the pressure sensor 90 detects the pressure of the air chamber 80 as the judgment air pressure P in S14. Further, in S15, the air pressure change amount ΔP is calculated by subtracting the reference air pressure P _O from the determination air pressure P.

Thereafter, in S16, the air pressure change amount Δ
It is determined whether P is larger than the set value ΔP _D2 . Here, the “set value ΔP _D2 ” is preset as the amount of pressure change that occurs in the air chamber 80 when the leakage of the hydraulic fluid from the primary hydraulic circuit to the secondary hydraulic circuit is the maximum allowable value. ing. If it is assumed that the air pressure change amount ΔP is less than or equal to the set value ΔP _D2 this time, the determination is NO, and it is determined in S17 that there is no liquid leakage of the brake unit 62. This completes one execution of the program.

On the other hand, if it is assumed that the air pressure change amount ΔP is larger than the set value ΔP _D2 this time, the determination in S16 is YE.
In S18, it is determined that the brake unit 62 has a liquid leak in S18. This completes one execution of the program.

By the way, the present embodiment relates to a brake unit inspection technique to which the reservoir liquid storage amount detection technique of indirectly detecting the reservoir liquid storage amount as the pressure value of the air chamber 80 is applied. The quantity detection technique can be implemented even while the vehicle is traveling. However,
In this case, the air chamber 80 is always a closed space and acts as an air spring, and the force for urging the piston 74 to the reservoir chamber 78 is easily affected by external factors such as temperature. In view of this, in the present embodiment, the technique for detecting the amount of reservoir liquid storage is performed only when the brake unit is inspected before the vehicle is mounted, and is not performed when the vehicle is traveling, which is an inconvenience when the air chamber 80 acts as an air spring. Is avoiding.

However, an air chamber opening / closing mechanism for opening / closing the air chamber 80 is provided so that the air chamber opening / closing mechanism closes the air chamber 80 only when the reservoir liquid storage amount detecting technique is implemented, and in other cases. If the air chamber opening / closing mechanism is made to open the air chamber 80, it is possible to implement the above-mentioned reservoir liquid storage amount detection technique while the vehicle is running, while avoiding the inconvenience when the air chamber 80 acts as an air spring as much as possible. Is possible.

As is apparent from the above description, according to the present embodiment, the position of the piston 74 can be detected as the pressure of the air chamber 80, so that the communication hole 86 can be brought into contact with the position of the piston 74. It is not necessary to make the detector large enough to pass through. The communication hole 86 allows the air to flow between the air chamber 80 and the outside air, and
It suffices to have a size that prevents 0 from acting as an air spring, and the diameter can be reduced to, for example, about 1 mm. Therefore, according to the present embodiment, it is not necessary to attach a cap to the communication hole 86 in order to prevent the entry of water or the like into the air chamber 80, so the number of parts of the brake unit 62 is reduced, and by extension, the device is reduced. The effect that the cost is reduced and the device is easily assembled can be obtained.

In addition, in addition, in the present embodiment,
The brake unit inspection device is of a type that includes both the air supply device 94 and the hydraulic fluid supply device 96 at the same time, but it is not essential to implement the present invention, for example, the hydraulic fluid supply device. It is possible to implement the present invention in a form in which only 96 is provided and is used for both the reservoir volume suitability determination and the liquid leakage determination.

In addition, in the present embodiment, whether or not the reservoir volume is appropriate is determined to be insufficient when the air pressure change amount ΔP is smaller than the set value ΔP _D1 . As shown in FIG. 4, in S27, it is determined whether or not the air pressure change amount ΔP is within a setting range in which the width is not 0. If it is within the setting range, it is determined in S28 that the reservoir volume is normal, and the setting is performed. If it is not within the range, the present invention can be implemented in a mode in which it is determined in S30 that the reservoir volume is abnormal. The contents of the other steps of the reservoir volume suitability determination program shown in the figure are the same as the corresponding steps of the program shown in FIG.

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 diagram illustrating a brake unit inspection device that is an embodiment of the present invention, a brake unit that is an inspection target, and an antilock brake system that includes the brake unit.

FIG. 2 is a flowchart showing a reservoir volume suitability determination program executed by a computer in the determination device in FIG.

FIG. 3 is a flowchart showing a liquid leakage presence / absence determination program executed by a computer in the determination apparatus in FIG.

FIG. 4 is a flow chart showing a reservoir volume suitability determination program used in a brake unit inspection method and a brake unit inspection device according to another embodiment of the present invention.

[Explanation of symbols]

 30 Holding Solenoid Valve 40 Reservoir 42 Pressure Reduction Solenoid Valve 78 Reservoir Chamber 80 Air Chamber 62 Brake Unit 90 Pressure Sensor 92 Judgment Device

Claims (3)

[Claims] 1. When a piston is fitted in a housing, a reservoir chamber for accumulating hydraulic fluid is formed in the front of the piston and an air chamber is formed in the rear of the piston, and the hydraulic fluid is stored in the reservoir chamber by retracting the piston. Is a device for detecting the amount of stored liquid in a reservoir that stores the pressure, and a reservoir liquid amount for estimating the amount of stored liquid based on an electric signal from the pressure sensor that detects the pressure in the air chamber. A reservoir liquid storage amount detection device comprising: an estimation unit. 2. A control valve and a reservoir chamber for accumulating hydraulic fluid at the front of the piston when the piston is fitted in the housing and an air chamber at the rear of the piston, respectively. A method for inspecting a hydraulic pressure actuator provided with a reservoir for accumulating hydraulic fluid in a reservoir chamber, wherein the hydraulic actuator is operated in a pseudo manner under predetermined conditions, and the air chamber A method for inspecting a hydraulic pressure device, comprising detecting a change in pressure and determining whether or not the operating state of the hydraulic pressure device is appropriate based on the detection result. 3. A control chamber, a reservoir chamber for accumulating hydraulic fluid at the front of the piston when the piston is fitted in the housing, and an air chamber at the rear of the piston, respectively. A device for inspecting a hydraulic pressure operating device including a reservoir for accumulating hydraulic fluid in a reservoir chamber, the pressure sensor detecting the pressure of the air chamber, and the hydraulic pressure operating device simulated under predetermined conditions. Hydraulically operated device inspection, wherein the hydraulically operated device includes a determination unit that determines whether or not the operating state of the hydraulically operated device is appropriate based on a change in an electric signal output from the pressure sensor at that time. apparatus.