JPH052543B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] The present invention relates to a wheel anti-lock device, and more specifically, a device that eliminates a sudden drop in wheel speed, that is, wheel lock, which may occur when braking a vehicle, by reducing brake fluid pressure. It is related to.

[Background of the invention]

Recently, various types of wheel antilock technologies have been proposed to improve safety during vehicle braking. A normally open shut-off valve is placed in the brake fluid pressure transmission path (hereinafter referred to as the main path) that connects the brake equipment, and is normally open and closed when it is necessary to lower the brake fluid pressure. For this purpose, a bypass-connected path (hereinafter referred to as a bypass path) is provided, and this bypass path and the brake equipment side output system of the main path are separated by a pressure reducing valve that is normally closed, and the brake fluid pressure is The brake pressure fluid that flows into the bypass passage through the normally closed pressure reducing valve, which opens when required to lower the brake pressure, is stored in a reservoir mechanism that reduces the fluid pressure by increasing the chamber volume in response to pressure, for example. Furthermore, the pressure liquid stored in the reservoir mechanism is pumped up to the main path by a pressure liquid pumping mechanism including a pump, and the shut-off valve (normally open type) and the pressure reducing valve (normally closed type) are switched on and off. A system has been proposed in which the operation is performed by an electronic control circuit that detects wheel lock during vehicle braking.

If you think about how wheel brake fluid pressure is controlled by a wheel anti-lock device like this, the first step is to close the shut-off valve initially to prevent the brake force from becoming excessively high, and then prevent the brake fluid pressure from increasing any further. If this does not resolve the drop in wheel speed, the brake force is reduced by opening the pressure reducing valve and releasing the brake fluid pressure to the reservoir mechanism. When the brake fluid pressure is restored, the brake fluid pressure is pumped up from the reservoir mechanism to restore the brake fluid pressure.

By the way, in an anti-lock system as typified by the above-mentioned example, the main path for transmitting brake fluid pressure is divided into an input system path and an output system path by a normally open shut-off valve. Since the pressure fluid in the brake device (i.e., the pressure fluid in the output path) is pumped up to the master cylinder side (i.e., the input path side), fluid pressure fluctuations in the master cylinder become large. There is a problem in that the brake pedal that is linked to the master cylinder is given a so-called jerking motion. This jerk is actually perceived by the driver as a fairly large pedal movement,
Moreover, firstly, it occurs in a vibrational manner within an extremely short period of time, and secondly, antilock control is generally rarely performed, so inexperienced drivers may experience a panic attack. This is a serious problem as it may lead to a condition.

Therefore, efforts have been made to avoid this kind of backlash phenomenon.
As shown in Japanese Patent No. 19700, it has been proposed that a check valve that allows pressure fluid to flow only in the downstream direction is disposed further upstream of an input path for pumping up brake fluid pressure.

However, in such a system, it goes without saying that the brake device (hereinafter referred to as W/C in some cases)
A separate path is required to return the hydraulic pressure from the side to the master cylinder (hereinafter referred to as M/C in some cases) when the brake is released, and this hydraulic pressure return path is carried out in the opposite direction (M/C→W/C). It is essential to reliably prevent the flow of pressure fluid and to prevent residual pressure from remaining in the brake device W/C in order to prevent dragging when the brake is released. The difficulty will be great.

Furthermore, in the configuration shown in JP-A No. 55-19700, when the brake fluid pressure is re-pressurized after dropping, the hydraulic pressure of the pumped-up pressure fluid from the bypass passage and the pressure fluid from the master cylinder is increased. Depending on the size, pressure fluid on the high pressure side is gradually applied to the brake device, so in order to avoid changes in brake pedal stroke, the pressure fluid pumped up from the bypass road side must always be at a higher pressure than the master cylinder side. This is necessary. Therefore, when a pressure accumulator is installed on the bypass side to store the pumped-up pressure liquid, the capacity (capacity) of this pressure accumulator and the pump pump must exceed the maximum hydraulic pressure value that may be transmitted from the master cylinder side. That is what is needed. However, such a structure is generally undesirable because it significantly affects the size of the pressure accumulator and the like.

[Purpose of the invention]

The present invention has been developed in view of these points, and one of its purposes is to maintain the main path for transmitting brake fluid pressure open at all times, and to prevent the above-mentioned brake pedal jerk back during anti-lock control. In order to prevent fluctuations, it is an object of the present invention to provide an anti-lock device in which the master cylinder M/C side is pressure-wise separated from the downstream side where brake fluid pressure decreases and increases.

Another object of the present invention is to separate this pressure interlocking relationship between two
This is done mechanically and simply by utilizing the hydraulic pressure difference that occurs between the two parts.

Another object of the present invention is to realize control of lowering and repressurization of brake fluid pressure on the downstream side that is pressure-wise separated from the upstream side, and to temporarily release pressure fluid from within the brake device. The goal is to reduce the capacity of the pressure accumulator that stores pressure, and furthermore, to reduce the capacity of the pump.The aim is to downsize the entire device.

Still another object of the present invention is to completely prevent fluid pressure fluctuations on the upstream side of the main path during antilock control, thereby realizing antilock control that does not give the driver any strange sensations such as jerking. There it is.

[Summary of the invention]

The gist of the present invention for achieving the above object is to provide a normally open gate valve and a normally open first valve in the main path for transmitting brake fluid pressure from the master cylinder to the brake device. is installed to divide the main path into an input system liquid chamber, an intermediate liquid chamber, and an output system liquid chamber, and a normally closed bypass path connected between the output system liquid chamber and the intermediate liquid chamber is provided. Type 2
A valve, a pump mechanism, and a pressure accumulator are provided, and the gate valve closes the gate valve when the liquid pressure in the intermediate liquid chamber becomes higher than the liquid pressure in the output system, and connects the liquid chamber to the input system liquid chamber. An anti-lock device for a vehicle is characterized in that it is configured to cut off communication between an intermediate liquid chamber.

The main path in the present invention is divided by a gate valve into an upstream side where fluid pressure fluctuations do not occur during anti-lock control and a downstream side where fluid pressure fluctuations occur. It is now divided into a room and an output system.

The gate valve in the present invention is configured to control the liquid pressure in the intermediate liquid chamber.
A valve body is formed on the balance piston that moves due to the generation of a pressure difference between Pm and the hydraulic pressure Po in the output system, and it works in cooperation with this valve body to form a communication path (gate) between the input system and intermediate hydraulic pressure. It is a hydraulic response type consisting of a combination of a seat surface that opens and closes, and is usually
The gate is always open due to the relationship Pm=Po (=Pi),
When Po < Pm during anti-lock control, the balance piston moves to close the gate and pressure-block the hydraulic pressure Pi in the input system from the downstream intermediate liquid chamber and the output system's respective liquid chambers Pm and Po. It's becoming like that.

In the present invention, the pressure accumulator interposed in the bypass path functions with the intermediate liquid chamber pressure-blocked from the input system as described above, so its pressure accumulation capacity is the same as that of the master cylinder side. It can be set without being directly related to the generated fluid pressure value (generally less than 100Kg/ ^cm2 , but panic pressure can be as high as 150Kg/ ^cm2 ), and is particularly useful for pedal stroke during anti-lock control. In order to prevent fluctuations (increases), the maximum hydraulic pressure generated on the master cylinder side must be used as a reference, compared to the
A pressure accumulator of 100 kg/cm ² or less is sufficient, and the degree to which it contributes to reducing its capacity and downsizing is extremely large.

[Embodiments of the invention]

The present invention will be described below based on embodiments shown in the drawings.

In the figure, 1 is a brake pedal, 2 is a master cylinder that generates hydraulic pressure according to the pedal force, and 3 is a brake pedal.
6 is a hydraulic pressure transmission pipe that connects the master cylinder 2 to the input port 4 of the normally open gate valve (hereinafter simply referred to as gate valve) 8, and 6 is the hydraulic pressure transmission pipe that connects the output port 5 of the gate valve 8 to the brake device 7. and
Flow path 8 in the gate valve connecting input and output ports 4 and 5
These hydraulic pressure transmission pipes 3 and 6, including pipe a, form a main path. In the following explanation, this will be referred to as main path 3,
6, 8a.

Reference numeral 9 denotes a normally open first valve disposed in the main path 8a, and is composed of a valve seat 10, a valve body 11a formed on a part of a movable iron core 11, a hold spring 12, and a solenoid 13. Normally, the spring force of the hold spring 12 keeps the flow path 8a in a normally open communication state, and the excitation of the solenoid 13 changes the flow path 8a to a closed state. Note that the timing of excitation of the solenoid 13 will be described later.

The first valve 9 divides the main path 8a into an intermediate fluid chamber r _n on the master cylinder side and an output system fluid chamber r _p on the brake device side.

Note that the upstream side of the gate valve 8 (the portion communicating with the port 4) is assumed to be an input system liquid chamber r _i .

The input system liquid chamber r _i is always in communication with the main path 3 and the master cylinder 2, and the output system liquid chamber r _p is always in communication with the main paths 8a, 6 and the brake device 7.

A bypass passage 14 is connected to the main passage 8a in the gate valve, and is connected to the output system liquid chamber r _p by a normally closed second valve 16, and is also connected to the pressure accumulator described later. It is connected to the intermediate liquid chamber r _n via a check valve 15 . Here the second
The valve 16 has an open valve seat 1 on the main path 8a (liquid chamber r _p ) side.
7, the valve body 18a is the hold spring 19
When the movable iron core 18 integrated with the valve body 18a is electromagnetically attracted by the excitation of the solenoid 20, the valve body 18a is separated from the valve seat 17.

In the bypass passage 14, a small-capacity reservoir mechanism 21 is provided next to the second valve 16, and then a pressurized liquid pumping mechanism 22 is provided. The reservoir mechanism 21
This is to facilitate the flow of the pressurized liquid within the main path output system when the second valve is opened, and to cause the hydraulic pressure within the output system to drop suddenly. The pumping pump mechanism 22 is composed of a pair of check valves 23, 23, a reciprocating plunger 24, and an eccentric cam 25 that is assembled to a motor or the like and rotates when necessary to cause the plunger 24 to reciprocate. be.

Reference numeral 26 denotes a pressure accumulator attached to the discharge side of the pump mechanism 21, which holds the pressure liquid pumped up from the pump mechanism 22 inside, and is connected to the intermediate liquid chamber described above.
It functions to feed this pressurized liquid to the intermediate liquid chamber r _n via the check valve 15 facing r _n .

Next, to explain the gate valve 8, the gate valve 8 of this example has a balance piston 29 that is fluid-tightly fitted to a cylinder 27 of a valve body (not shown) and a cup seal 28, and one end of this balance piston 29 is connected to a cylinder 27 of a valve body (not shown). It is provided so that it faces the intermediate liquid chamber r _n through the input system liquid chamber r _i , and the other end faces the output system liquid chamber r _p , and the valve body portion 29a formed on the one end side In cooperation with the seat surface 30, a gate is formed to open and close a communication path between the input system liquid chamber r _i and the intermediate liquid chamber r _n . Reference numeral 31 denotes a lightly loaded hold spring for pushing the balance piston 29 toward the one end to open the gate. Note that the seal cross-sectional area of the seat surface 30 and the seal cross-sectional area of the cup seal 28 are the same.

The above is an outline of the configuration of the wheel lock prevention mechanism for realizing the present invention. In this example, a relief valve 32 is provided for liquid return from the main path output system liquid chamber r _p to the input system liquid chamber r _i . This ensures liquid recirculation even if the pedal pressure is released during anti-lock control.

Next, the operation of the apparatus having the above configuration will be explained.

(Normal example) As is clear from the above, the brake fluid pressure generated in the master cylinder when the vehicle is controlled is transmitted from the input port 4 to the normally open gate valve 8 and first valve 9. →It is transmitted to the brake device via the output port 5, and the required braking force is generated. At this time, the second valve 16 is normally closed.

(During wheel lock prevention control) If this stage is divided into two stages: closing of the first valve 9 and opening of the second valve 16, first, the closing of the first valve 9 is performed by excitation of the solenoid 13. As a result, the communication between the intermediate fluid chamber r _n and the output system fluid chamber r _p is cut off, so that the brake fluid pressure in the brake device 7 remains constant regardless of whether the brake pedal 1 is depressed. It will no longer rise. This operation can be electromagnetically performed extremely quickly as the valve body 11a of the first valve is brought into contact with and seated on the valve seat 10 by the excitation of the solenoid 13.

The electromagnetic closing of the first valve described above may be performed by detecting, by means of an electrical control circuit, that the wheel speed has begun to rapidly decrease as the vehicle is braked. This will be explained later. Furthermore, it is generally desirable for practical purposes that the pump mechanism in the bypass passage be rotated from this point on.

Next, when the solenoid 20 of the second valve 16 is energized, the movable iron core 18 moves downward in the figure against the hold spring 19, and the second valve opens. Therefore, the pressure fluid in the output system (liquid chamber r _p , main path 6, and brake device 7) flows into the reservoir mechanism 21, and the fluid pressure in the brake device 7 drops rapidly. This reduces the excessive braking force that causes the wheels to lock.

Simultaneously with the above operation, the pressurized liquid is pumped up to the pressure accumulator 26 via the pumping pump mechanism 26.

Alternatively, the gate of the gate valve 8 is also closed simultaneously with the above operation. That is, since the first valve 9 is closed and the second valve 16 is opened, the hydraulic pressures in the liquid chambers r _p and r _n become Pr _p < Pr _n , so the hydraulic pressure acting on the balance piston 29 of the gate valve 8 is becomes larger toward the other end, which causes the balance piston to move and the valve body 29a to come into contact with the seat surface 30, closing the gate, and the intermediate liquid chamber r _n and input system liquid chamber r _i It is blocked. This blockage is henceforth Pr _p =
Continue until Pr _n .

The pressure fluid pumped up into the pressure accumulator 26 is checked by the check valve 1.
5 to the intermediate liquid chamber r _n , but this intermediate liquid chamber r _n is connected to the first valve 9 and the gate valve 8.
The pressure fluid is retained in the pressure accumulator 26 because it is sealed off from others by the pressure accumulator 26 .

(When repressurizing the brake fluid pressure in wheel lock prevention control) When the wheel lock is released due to a drop in brake fluid pressure, the excitation of the solenoid 20 is stopped and the second valve 16 returns to the normally closed state.

When it is necessary to re-increase the brake fluid pressure, by returning the first valve 9 to the open state, the pressurized fluid can be returned to the output system fluid chamber _rp . The degree of rework can be done rapidly or slowly by appropriately controlling the opening time or number of times the first valve 9 is opened, and when it is necessary to reduce the pressure again, the second valve 16 can be opened again. Bye.

(Return to normal state) The fluid pressure inside the brake device is sufficiently pressurized, and Pr _n
=Pr _p , the gate valve 8 returns to the open state, and the main path returns to the normal state in which the master cylinder communicates with the brake device.

Next, to briefly explain the operation control of the first valve 9 and the second valve 16 in the wheel lock prevention device configured as described above, as already stated, the operation of the first valve 9 during pressure reduction is different from that during vehicle braking. It is preferable to prevent the hydraulic pressure in the brake system from increasing any further due to the occurrence in the initial stage when the wheel speed drops beyond the appropriate level, so for example, if the detected wheel speed signal V _W , constant set deceleration gradient
At the time point t _p when the deceleration was higher than V _T1 , the first valve 9
On the other hand, the operation of the second valve 16 is controlled by the electromagnetic operation of the first valve 9 described above.
This is often caused when _it is insufficient to stop _the increase in brake fluid pressure due to the operation _of It is preferable to set a pseudo speed V _T2 regulated below a value, compare this V _T2 and V _W , and cause the second valve 16 to be electromagnetically operated at a time point t ₁ when V _T2 >V _W.

In this way, the brake fluid pressure can be maintained and further lowered selectively depending on the degree of decrease in the wheel speed _VW , and desirable wheel brake force control can be achieved.

Note that the circuit configuration for controlling the operation of the first valve and the second valve as described above can be formed using known electrical technology. However, the operation control of the device of the present invention is not limited to the above.

According to the anti-lock device as described above, when the gate valve 8 is in the closed state, the first valve 9 and the second valve 16 are closed.
By appropriately opening and closing the brake fluid pressure, appropriate pressure reduction and repressurization control is performed, and fluid pressure fluctuations within the brake device do not affect the input system at all, so they do not give the driver a sense of discomfort. Therefore, stable braking control is achieved without any problems.

Furthermore, since the pressure accumulator 26 can be designed to be independent of the hydraulic pressure of the input system, it can be sufficiently configured to have a pressure of about 100 kg/cm ² , and the overall size of the device can be significantly reduced.

〔Effect of the invention〕

As described above, the wheel antilock device according to the present invention has a relatively simple structure and can achieve the following various excellent effects.

Brake fluid pressure can be reduced and re-pressurized stably and quickly by operating a solenoid valve.

There is no effect on the brake pedal.

The miniaturization of pressure accumulators, pumps, etc. will be realized.

Since both the gate valve and the first valve, which are interposed in the main path from the master cylinder to the brake device, are of a normally open type, no residual pressure is generated in the brake device when the brake is released. Therefore,
In conventional examples in which a check valve is provided in this path, brake dragging occurs due to residual pressure equivalent to the opening pressure of the check valve, but with the device of the present invention, such problems due to dragging phenomenon do not occur. .

[Brief explanation of the drawing]

The drawing shows the basic structure of an anti-lock device which is an embodiment of the present invention. 1... Brake pedal, 2... Master cylinder, 3, 6... Hydraulic pressure transmission pipe (main path), 4... Input port, 5... Output port, 7... Brake device, 8... Gate valve, 8a... Main path, 9... First valve, 10... Valve seat, 11... Movable iron core, 12...
...Hold spring, 11a... Valve body, 13...
... Solenoid, 14 ... Bypass path, 15 ... Check valve, 16 ... Second valve, 17 ... Valve seat, 18
...Movable iron core, 18a... Valve body, 19... Hold spring, 20... Solenoid, 21... Reservoir mechanism, 22... Pump mechanism, 23... Check valve, 24... Plunger, 25... Offset Core cam, 26... Pressure accumulator, 27... Cylinder, 28...
...Cup seal, 29...Balance piston, 2
9a... Valve body portion, 30... Seat surface, 31... Hold spring, 32... Relief valve.

Claims (1)

[Claims] 1. A normally open gate valve and a normally open first valve are interposed in the main path for transmitting brake fluid pressure from the master cylinder to the brake device, and the main path is connected to the input system fluid chamber and the intermediate fluid chamber. , a normally closed second valve, a pump mechanism,
A pressure accumulator is provided, and the gate valve closes the gate valve when the liquid pressure in the intermediate liquid chamber becomes higher than the liquid pressure in the output system liquid chamber, and the input system liquid chamber and the intermediate liquid chamber are closed. An anti-lock device for a vehicle, characterized in that it is configured to cut off communication.