JPH01311945A - Anti-skid device - Google Patents

Abstract

PURPOSE:To give an exact braking feeling during running on snow road by providing a by-path portion for releasing interruption when the decelerating speed is less than a designated value in an ABS control valve adapted to interrupt between a master cylinder and a wheel cylinder on detecting a slip of a wheel and conduct designated hydraulic pressure control. CONSTITUTION:Hydraulic pressure generated by a master cylinder 7 is supplied to a wheel cylinder 8 through a hydraulic pressure adjusting mechanism 4, and when a slip is detected by a wheel speed sensor 2, the master cylinder 7 and the wheel cylinder 8 are interrupted by operation of a passage switching means 12 by a control device 3 to conduct designated ABS control. At that time, when the vehicle decelerating speed detected by a decelerating speed sensor 48 is less than a designated value, an electromagnetic switch valve 50 is opened to communicate a by-pass passage, so that a change of hydraulic pressure of the wheel cylinder 8 is transmitted to the master cylinder 7 side. During running on snow road, an exact braking feeling can be given to a driver.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an anti-skid device for a vehicle, and more specifically, the present invention relates to an anti-skid device for a vehicle. This invention relates to an anti-skid device that prevents transmission.

"Prior Art" Conventionally, an anti-skid device includes a wheel speed sensor that detects the speed of a wheel, a control device that inputs a detection signal from the wheel speed sensor to detect the slip state of the wheel, and a master cylinder and a wheel. The control device is installed in a passage communicating with the cylinder, and is activated when the control device detects a wheel slip state to cut off communication between the master cylinder and the wheel cylinder and reduce the brake fluid pressure on the wheel cylinder side. There are known devices equipped with a hydraulic pressure adjustment mechanism.

In such an anti-skid device, communication between the master cylinder and the wheel cylinder can be cut off by the fluid pressure adjustment mechanism, so even if the brake fluid pressure decreases due to the operation of the anti-skid device, it is not transmitted to the brake pedal. This has the advantage of not causing discomfort to the driver.

``Problem to be solved by the invention'' However, on the other hand, especially on roads with a low coefficient of friction such as snowy roads, the driver has to sense whether the anti-skid device is operating or not, that is, whether the wheels are slipping. I sometimes feel anxious because I can't do anything. In addition, the anti-skid device may operate with a much smaller braking force than the driver expects, and in such cases the anti-skid device may give the feeling that the brakes are not working, resulting in a loss of brake feel. was.

"Means for Solving the Problem" In view of such circumstances, the present invention provides the above-mentioned anti-skid device with a deceleration detection means for detecting the deceleration of the vehicle, and also bypasses the above-mentioned hydraulic pressure adjustment mechanism. A communication passage is provided to communicate the master cylinder and the wheel cylinder, and an on-off valve and an orifice are provided in the communication passage to open and close the communication passage. The above-mentioned on-off valve is opened at that time.

Effect J According to the above configuration, the deceleration of the vehicle when the anti-skid device is activated can be detected by the deceleration detection means. When the anti-skid device is activated, the on-off valve can be opened to transmit changes in brake fluid pressure on the wheel cylinder side to the master cylinder, thereby confirming that the anti-skid device is activated. It can be communicated to the driver.

On the other hand, when the anti-skid device is activated when the vehicle decelerates significantly, the on-off valve can be closed to prevent fluctuations in brake fluid pressure on the wheel cylinder side from being transmitted to the master cylinder side. Therefore, it is possible to prevent the driver from feeling uncomfortable under such circumstances.

``Embodiment'' The present invention will be described below with reference to the illustrated embodiment. In the figure, the anti-skid device is equipped with a plurality of wheel speed sensors 2 provided for each wheel 1 of a vehicle, and the detection from each wheel speed sensor 2 is A signal is input to the control device 3. This control device 3 detects whether or not each wheel 1 is in a slip state from the detection signal of each wheel speed sensor 2, and when it is determined that it is in a slip state, the hydraulic pressure adjustment mechanism 4 for the wheel 1 is It is now possible to control brake fluid pressure by controlling each of these.

Each of the hydraulic pressure adjustment mechanisms 4 is provided in the middle of a passage 9, IO, which communicates a master cylinder 7 that is interlocked with a brake pedal 6 and a wheel cylinder 8 of each wheel 1 via a brake booster 5, and controls the When the device 3 detects the slip state of the wheel 1, it is activated to cut off the communication between the master cylinder 7 and the wheel cylinder 8, and reduce the brake fluid pressure on the wheel cylinder 8 side, thereby preventing the slip state of the wheel 1. It is now possible to eliminate.

The hydraulic pressure adjustment mechanism 4 includes a pressure control means 11 and a flow path switching means 12, and the inside of the cylindrical housing 13 of the pressure control means 11 is divided into upper and lower chambers by a partition wall 14 provided at a central position. In addition, the inner diameter of the upper chamber is set larger than the inner diameter of the lower chamber.

A piston 16 is slidably fitted in a chamber above the partition wall 14 in a fluid-tight manner.
This lever divides the chamber into an upper pressure chamber A and a lower pressure chamber B. Then, the lower pressure chamber B is connected to the passage 1
0 to the wheel cylinder 8 of the wheel 1, and the upper pressure chamber A communicates to the passage switching means 12 via a passage 18.

On the other hand, a first cut-off valve 21 made of a stepped cylindrical member is slidably fitted in the chamber below the partition wall 14 in a liquid-tight manner. It is divided into an upper pressure chamber C and a lower pressure chamber C. The upper pressure chamber C divided by the first cut-off valve 21 is communicated with the master cylinder 7 via the passage 9, and the lower pressure chamber C is communicated with the passage switching means 12 via the passage 23. It communicates.

Further, a through hole 24 is formed in the center of the partition wall 14 of the housing I3, and the pressure chamber B,
Therefore, the master cylinder 7 and the wheel cylinder 8 are communicated with each other. Then, the upper small diameter portion of the first cut-off valve 21 is loosely fitted into the through hole 24 and protrudes upward, and a valve portion is formed on the lower surface of the partition wall 14 at the end surface of the stepped portion that is continuous with the small diameter portion. By seating the valve seat on the valve seat, communication between the pressure chambers B and C can be cut off.

Further, the shaft portion of the first cut-off valve 21 is formed with a bottomed stepped hole 25 that opens on the upper surface of the small diameter portion, and the lower large diameter portion side of the stepped hole 25 is formed in the shaft portion of the first cut-off valve 21. It is opened on the circumferential surface of the cut-off valve 21. Therefore, the pressure chamber B communicating with the wheel cylinder 8 and the pressure chamber C communicating with the master cylinder 7 also communicate through the stepped hole 25.

A second cut-off valve 27 is provided in the stepped hole 25, which is normally biased upwardly by a spring 26 to close the stepped hole 25. This second cut-off valve 2
A part of 7 loosely fits through the stepped hole 25 and protrudes into the pressure chamber B, and when it comes into contact with the piston 16, it is pushed downward and can open the stepped hole 25. ing.

Note that slits are formed on the upper surface of the piston 16, on the upper surface of the partition wall 14, and on the upper and lower sides of the first cut-off valve 21, respectively, to ensure that the liquid can flow through these slits.

Next, in the housing 31 of the flow path switching means 12, passages 32 and 33 are formed continuously in the vertical direction, and
A passage 34 is formed in the lateral direction from the center of both roads 32 and 33. and the lateral passage 34 is the passage 18 mentioned above.
The lower passage 33 is connected to the pressure chamber A of the pressure control means 11 through the passage 23, and the upper passage 32 is connected to the reservoir tank 37 through the passage 36. They are connected to each other.

The reservoir tank 37 is connected to the pump 3 via a passage 38.
The discharge side of this pump 39 is connected to a passage 23 communicating with the pressure chamber via a passage 35, and an accumulator 40 is provided in the middle of this passage 35.

Inside the housing 31 of the flow path switching means 12, a discharge side solenoid valve 41 opens and closes the passage 32 communicating with the reservoir tank 37, and a supply side solenoid valve 42 opens and closes the passage 33 communicating with the pump 39 and the accumulator 40. Each electromagnetic valve 41 , 42 has a valve body 43 , a spring 44 that biases the valve body 44 to close each passage 32 , 33 in the free state, and a solenoid 46 whose energization is controlled by the control device 3 . It is equipped with

When the solenoid 46 is energized, the discharge side solenoid valve 41 is configured to displace the valve body 43 in a direction that moves it away from the valve seat against the spring 44.
2, when the solenoid 46 is energized, the valve body 43 is further displaced together with the spring 44 in the direction of seating on the valve seat.

In the above configuration, under normal conditions, the discharge side solenoid valve 4
The solenoids 46 of the solenoid valve 1 and the supply side solenoid valve 42 are not energized, and the hydraulic pressure accumulated in the accumulator 40 is constantly introduced into the pressure chamber of the pressure control means 11 via the passage 35.23. . The hydraulic pressure introduced into the pressure chamber then causes the first cut-off valve 21 to rise.

Further, since the pressure accumulated in the accumulator 40 is sufficiently high, this oil pressure is applied to the valve body 4 of the supply side solenoid valve 42.
3 and causes it to open against the spring 44. Therefore, the oil pressure in the accumulator 40 is
is also introduced into the pressure chamber A of the pressure control means 11 via the
Push down the piston 16. Note that the supply side solenoid valve 4
The hydraulic pressure that pushes open the second valve body 43 also acts on the valve body 43 of the discharge side solenoid valve 41, but the pressure receiving area for this valve body 43 should be set small, or the elastic force of the spring 44 should be set large. This prevents the valve body of the discharge side solenoid valve 41 from being opened.

In this way, under normal conditions, the hydraulic pressure of the accumulator 40 is simultaneously introduced into the pressure chambers A and D of the pressure control means 11 to push down the piston 16 and at the same time raise the first cut-off valve 21. Since the area is set larger than the pressure receiving area of the first cut-off valve 21, the piston 16 is lowered to a position where it comes into contact with the upper surface of the partition wall 14, and the first cut-off valve 21 is moved by the piston 16. It will be pushed down.

As a result, the pressure chambers B and C communicate with each other via the through hole 24 and the stepped hole 25 in the first cut-off valve 21, so that the master cylinder 7 and the wheel cylinder 8 communicate with each other through the passage 9. , 1O.

Therefore, if the brake pedal 6 is depressed in this state, the brake fluid pressure generated in the master cylinder 7 is introduced into the wheel cylinder 8, and normal brake operation is performed.

Next, when the wheels 1 slip as a result of the brake operation, the control device 3 detects this based on the detection signal from the wheel speed sensor 2. Then,
The control device 3 excites the solenoid 46 of the supply side solenoid valve 42 to press the valve body 43 of the supply side solenoid valve 42 against the valve seat 45 to close the passage 33, and also closes the passage 33.
Since the solenoid 46 of No. 1 is energized and its valve body 43 is removed from the valve seat, the introduction of hydraulic pressure from the accumulator 40 to the pressure chamber A is cut off, and at the same time, the pressure chamber A is communicated with the reservoir tank 37. Become so.

As a result, when the pressure in the pressure chamber A decreases, the piston 16 is raised by the brake fluid pressure in the pressure chamber B. Then, since the hydraulic pressure in the accumulator 40 is always introduced into the pressure chamber, the first cut-off valve 21 is pushed upward by the hydraulic pressure and closes the through hole 24, and the second cut-off valve 27 is also closed. It is raised by the spring 26 to close the stepped hole 25. However, as a result, communication between pressure chambers B and C is cut off, and therefore communication between master cylinder 7 and wheel cylinder 8 is cut off.

Furthermore, when the piston 16 rises, the volume of the pressure chamber B is expanded, so the oil pressure in the wheel cylinder 8 is reduced by the increased volume, thereby reducing the braking force on the wheel 1. When the oil pressure in the wheel cylinder 8 is reduced to an optimal state in this way, the control device 3
deenergizes the discharge side solenoid valve 41 to close it and maintain the oil pressure in the wheel cylinder 8 at its optimum pressure.

When it becomes necessary to increase the oil pressure in the wheel cylinder 8 from this state, the control device 3 deenergizes the supply side solenoid valve 41 to open it. Then pressure chamber A
Since the hydraulic pressure inside the accumulator 40 is introduced into the
The piston 16 can be pushed down again to increase the oil pressure in the wheel cylinder 8. Further, by deenergizing the solenoid 46 of each electromagnetic valve 41, 42, the normal state can be restored.

However, when the anti-skid device described above is in operation, communication between the master cylinder 7 and the wheel cylinder 8 is cut off, and pressure fluctuations on the wheel cylinder 8 side are not transmitted to the master cylinder 7 side. Therefore, as mentioned above, especially on road surfaces with a low coefficient of friction such as snowy roads, the driver cannot sense whether the anti-skid device is operating or not, so the driver may feel uneasy or feel that the brakes are not working. Sometimes I got a feeling.

Therefore, in the final embodiment, a deceleration sensor 48 is provided to detect the deceleration of the vehicle and input the detection signal to the control device 3, and the pressure control means 11 of the hydraulic pressure adjustment mechanism 4 is bypassed. A communication passage 49 is provided to communicate the master cylinder 7 and the wheel cylinder 8, and an electromagnetic on-off valve 50 and an orifice 51 for opening and closing the communication passage 49 are provided in series. The electromagnetic on-off valve 50 normally closes the communication passage 49, and therefore, it is clear that in that state, the same effect as described above can be obtained.

On the other hand, the control device 3 detects the deceleration of the vehicle from the deceleration sensor 48 when operating the anti-skid device. If the deceleration of the vehicle is less than a predetermined value even though the vehicle is in a slip state, the electromagnetic on-off valve 50 is opened.

In this state, the master cylinder 7 and the wheel cylinder 8 communicate with each other via the communication passage 49 and the orifice 51 provided therein, so that fluctuations in brake fluid pressure on the wheel cylinder 8 side are transmitted to the master cylinder 7. The driver can therefore sense that the anti-skid device has been activated.

At this time, by appropriately setting the passage area of the orifice 51, it is possible to limit the brake fluid pressure flowing from the master cylinder 7 to the wheel cylinder 8 via the communication passage 49, so that the anti-skid device This can prevent adverse effects on the operation of the

Further, in the above embodiment, the deceleration sensor 48 is provided to detect deceleration, but instead of this, the deceleration is calculated based on the wheel speed input from the wheel speed sensor 2 to the control device 3, and each The deceleration may be detected by comparing the deceleration of the wheels.

"Effects of the Invention" As described above, according to the present invention, it is possible to prevent the driver from feeling uncomfortable by preventing the driver from sensing that the anti-skid device has been activated under normal conditions, and Under conditions where the frictional force of the road surface is low, such as on roads, the driver can sense that the anti-skid device is operating, so under such conditions the brake system provides a sense of security to the driver. The effect of imparting a feeling can be obtained.

[Brief explanation of the drawing]

The figure is a circuit diagram showing one embodiment of the present invention. 1 - Wheels 2 - Wheel speed sensor 3 - Control device 4... Fluid pressure adjustment mechanism 6... Brake pedal 7... Master cylinder 8... Wheel cylinder 9, lO - Passage 11 -... Pressure control means
12--Flow path switching means 48--Deceleration sensor (deceleration detection means) 49-Series passage 50--Solenoid on-off valve 51--Orifice patent applicant Jidosha Kiki Co., Ltd.

Claims (1)

[Scope of Claims] A wheel speed sensor that detects the speed of the wheel, a control device that inputs a detection signal from the wheel speed sensor to detect the slip state of the wheel, and a passage that communicates the master cylinder and the wheel cylinder. a hydraulic pressure adjustment mechanism, which is installed in the wheel cylinder and is activated when the control device detects a wheel slip state to cut off communication between the master cylinder and the wheel cylinder and reduce brake hydraulic pressure on the wheel cylinder side. In the anti-skid device equipped with the above-mentioned anti-skid device, a deceleration detection means for detecting the deceleration of the vehicle is provided, and a communication passage is provided to bypass the hydraulic pressure adjustment mechanism and communicate the master cylinder and the wheel cylinder, and this communication passage is provided with a deceleration detection means for detecting the deceleration of the vehicle. An anti-skid device comprising an on-off valve and an orifice for opening and closing the anti-skid device, wherein the control device opens the on-off valve when deceleration at the time of detecting the slip condition is equal to or less than a predetermined value.