JPH02246857A - anti-skid device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a skid prevention device for a vehicle brake, and particularly to an improvement in a reservoir for storing brake fluid discharged when a wheel is locked.

``Prior art'' A skid prevention device is installed in the middle of a path that transmits the pressure of brake fluid in a master cylinder operated by a brake pedal to the wheel cylinder of each wheel, and when sudden braking occurs, the wheels become locked. When this happens, the brake fluid is repeatedly depressurized and repressurized to prevent wheels from skidding, ensure directional stability, and shorten braking distance.

Conventionally, as such a skid prevention device, for example, Japanese Patent Application Laid-Open No. 83-287650 or Japanese Patent Publication No. 81-3
There is one shown in Publication No. 3788. The former is a mechanical skid prevention device that uses the inertia of the flywheel rotated by the axle to detect a locked state and depressurize the brake fluid, while the latter uses a sensor that constantly detects wheel rotation. This is an electronic skid prevention device that calculates wheel speed, slip rate, deceleration, etc. based on the results, and controls brake fluid pressure based on the calculated results.

``Problems to be Solved by the Invention'' By the way, such skid prevention devices are provided with a discharge path for releasing brake fluid when the wheels are locked, and a reservoir for storing the released brake fluid. Since it is used only when locked and not used at all during normal operation, even if a fluid leak were to occur, it would be difficult to detect.For this reason, like the reservoir installed in the master cylinder, A remaining amount detection mechanism, etc. is required, and the brake fluid failure detection mechanism tends to become complicated.

The present invention has been proposed in view of the above circumstances, and aims to provide a skid prevention device that can reliably detect the occurrence of fluid leakage, etc., and can simplify the brake fluid failure detection mechanism. The skid prevention device of the present invention has a reservoir with a variable capacity liquid storage chamber for storing brake fluid introduced from the discharge path, and a master cylinder that connects the liquid storage chamber with the liquid storage chamber. A communication passage tangential to the master cylinder, a check valve that closes the communication passage by pressure from the master cylinder, and a forced opening mechanism that opens the check valve when the brake fluid in the fluid storage chamber is in an initial state reduced. It is characterized by being

"Operation" In the skid prevention device of the present invention, when the brake is not applied, such as when parking or driving normally, the check valve of the reservoir is opened by the forced opening mechanism, and the master cylinder and the liquid storage chamber are in communication state. becomes. Therefore, when liquid leakage or the like occurs, it appears as a decrease in the remaining amount of the reservoir in the master cylinder, and can be determined by the remaining amount detection mechanism provided in the reservoir. On the other hand, when the brakes are applied, the check valve closes the communication passage due to the pressure of the brake fluid, effectively guiding the brake fluid to the wheel cylinder, and when the wheels are locked, the brake fluid is discharged from the discharge passage. is stored in the liquid storage chamber, and is pumped out from the reservoir again when pressurized again.

"Example" Hereinafter, an example of the skid prevention device of the present invention will be described based on the drawings.

FIG. 1 and FIG. 2 show an embodiment with a mechanical configuration, where the symbol if indicates the main body of the device, the symbol 2 indicates the reservoir,
Inside the device body l, there are provided a lock detection section 3 that detects the locked state of the wheels, a fluid pressure modulation section 4 that reduces the pressure of brake fluid to the wheel cylinder, and a pump section 5 that repressurizes the reduced pressure of the brake fluid. .

In the lock detection unit 3, a flywheel 8 is attached to a shaft 6 which is rotated in conjunction with the axle via a ball ramp mechanism 7, and a lever 9 is provided near the flywheel 8 so that the flywheel 8 can be rotated. By moving along the shaft 6, the lever 9 is pressed, and the pressure release valve 10 of the hydraulic pressure modulating section 4 is operated.

The hydraulic pressure modulator 4 has an input flow path 15 leading to the master cylinder.
A cut-off valve 17 and a cylinder chamber 18 are provided in series between the pressure release valve 10 and the output flow path 16 communicating with the wheel cylinder.
When the pressure release valve 10 is opened by operating the flywheel 8, the pressure in the output flow path 16 operates the pressure reducing piston 20 in the cylinder chamber 18. , cylinder chamber 18
While discharging the brake fluid in the output passage 16 to the discharge passage 19.
In other words, while reducing the pressure of the brake fluid in the wheel cylinder, the movement of the piston 20 causes the cut-off valve 1 to open.
7 blocks the input flow path 15 and the output flow path 16.

The pump section 5 has a pump chamber 25 formed between the input channel 15 and the discharge channel 19, and a pump piston 2 therein.
6 is provided to face a cam 27 integral with the shaft 6, and the discharge passage 19 and the cylinder chamber 18 of the hydraulic pressure modulating section 4 are tangential to the pump chamber 25 via ball valves 28 and 29, respectively. It is said that the structure is as follows. Then, the pump piston 26 is pressed against the cam 27 due to the pressure difference between the input flow path 15 and the cylinder chamber 18, causing it to reciprocate and suck the brake fluid from the discharge path 19, while the hydraulic pressure modulating section 4
The pressure reducing piston 20 is moved to pressurize the brake fluid in the wheel cylinder.

The reservoir 2 has a liquid storage chamber 3 in which brake fluid is stored in a stepped sleeve member 31 housed therein.
2 and an atmospheric chamber 33 open to the atmosphere are liquid-tightly partitioned by a reservoir piston 35 biased by a return spring 34, and the liquid storage chamber 32 is connected to a transport passageway 19 of the apparatus main body 1. The passage 36 and a communication passage 37 communicating halfway through the input flow passage 15 are tangential to each other.

In this case, the reservoir piston 35 is housed in the large diameter part of the sleeve member 31, and a rod 38 that is integrated with the reservoir piston 35 is inserted into the small diameter part, and the gap between the rod 38 and the sleeve member 31 allows storage. Liquid chamber 32
A passage 39 is formed which leads to. In the middle of the sleeve member 31, a hole 4 communicating with the passage 39 inside the sleeve member 31 is provided.
0 is opened, and the transport path 36 is tangent to the chain hole 40. Further, the communication passage 37 is communicated with a passage 39 in the sleeve member 31 via a check valve 41 provided at the tip of the sleeve member 31, and the check valve 41 is located in front of the sleeve member 31. A valve chamber 42 that communicates with the communication passage 37, a ball valve body 43 that closes the passage 39 by being pressed against the tip of the sleeve member 31 within the valve chamber 42, and a ball valve body 43 that is biased in the closing direction. The retainer 45 is configured to support the spring 44 at a position in front of the sleeve member 31. Then, when the reservoir piston 35 pushes back the brake fluid in the liquid storage chamber 32 and returns to the initial state, the tip of the rod 38 protrudes from the sleeve member 31 and pushes the ball valve body 43 as shown in FIG. The reservoir piston 35, rod 38, and return spring 3 are spaced apart from the tip of the sleeve member 31.
4 constitutes a forced opening mechanism 46 that opens the check valve 41. In addition, the reference numeral 47 is a plug that closes the large diameter part of the sleeve member 31 and surrounds the atmospheric chamber 33, and the reference numeral 48 is a hole that opens the atmospheric chamber 33 to the atmosphere.
9, 50, and 51 indicate seal members.

In the skid prevention device configured in this way, the reservoir 2 is connected to the ball valve of the check valve 41 when the rod 38 of the reservoir piston 35, which is pushed by the return spring 34, is pushed by the return spring 34, as shown in FIG. 1, when the brake is not applied. By separating the body 43 from the tip of the sleeve member 31, the master cylinder and the liquid storage chamber 32 are separated from each other.
and the discharge passage 36 of the apparatus main body 1 are in communication with each other.

During normal braking, when brake fluid from the master cylinder flows into the input flow path 15 of the device body 1 as shown by the arrow (A) in FIG. It acts on the valve chamber 42 of the valve 41, pushes the ball valve body 43, moves the reservoir piston 35 backward, and closes the passage 39 in the sleeve member 31. Therefore, the brake fluid is effectively guided into the device main body 1 without flowing into the reservoir 2, and is made to act on the wheel cylinder as shown by the arrow (b).

On the other hand, when the wheels are locked during sudden braking, the brake fluid discharged from the discharge passage 19 is guided from the hole 40 to the passage 39 in the sleeve member 31 via the transport passage 36, as shown by the arrow in FIG. , is accumulated in the liquid storage chamber 32 while moving the reservoir piston 35.

At the time of repressurization, the brake fluid in the liquid storage chamber 32 is sucked into the pump chamber 25 via the transport path 36 by the action of the pump piston 26 of the device main body l, and the brake fluid is transferred to the hydraulic pressure modulating section 4 via the pump chamber 25. It is pushed out into the cylinder chamber 18.

That is, this skid prevention device establishes communication between the reservoir 2 and the master cylinder in the initial state where the brake is not applied, and in the event that fluid leaks from the discharge path 19, the reservoir 2, etc., the reservoir in the master cylinder is connected. This can be caused as a decrease in the remaining amount of the reservoir, and can be determined by a remaining amount detection mechanism provided in the reservoir.

Friend, in this embodiment, an atmospheric chamber 33 is formed in the reservoir 2 of the skid prevention device so that changes in the volume of the liquid storage chamber 32 are absorbed by the atmospheric chamber 33, and changes in brake fluid due to temperature changes, etc. It is possible to suppress pressure changes and prevent damage to the sealing member.

On the other hand, FIG. 3 shows another embodiment in which the present invention is applied to an electronic type skid prevention device. The reservoir 2 has the same configuration as that of the first embodiment, so to explain the general configuration of the device body 61, a solenoid 66 is connected between the input flow path 63 from the master cylinder 62 and the output flow path 65 to the wheel cylinder 64. - A cut-off valve 68 and a pressure release valve 69 driven by 67 are provided in series. The reservoir 2 is tangentially connected to the discharge path 70 from the pressure release valve 69 via a transport path 71, and a suction path 72 is tangentially connected in the middle of the discharge path 70, which communicates with the accumulator 74 via a pump 73. The accumulator 74 is connected to the input flow path 63 by a return flow path 75.
is tangent to.

On the other hand, a relief flow path 76 is connected between the output flow path 65 and the input flow path 63, bypassing the cut-off valve 68, etc., and is opened and closed by a check valve 77. . Further, a check valve 78 is also interposed in the input flow path 63.

Then, the solenoids 66 and 67 of the cut-off valve 68 and the pressure release valve 69 are controlled based on the control signal output from the control unit 81 by the sensor 80 that detects the locked state of the wheel 79.
During normal braking, brake fluid is guided from the manual flow path 63 to the wheel cylinder 64 via the output flow path 65, and
When the brake fluid in the wheel cylinder 64 is locked, the cut-off valve 69 shuts off the flow path, and the pressure release valve 69 switches the flow path to communicate the output flow path 65 and the discharge path 70. Lead to reservoir 2. At this time, the pump 73 also operates to feed brake fluid to the accumulator 74. When the wheel 79 recovers to a predetermined deceleration, the pressure release valve 69 is switched to close the output flow path 65, thereby maintaining the pressure in the wheel cylinder 64, and then releasing the locked state. Then,
The cut-off valve 68 also opens the flow path to send the brake fluid from the accumulator 74 to the wheel cylinder 64.

In this electronic skid prevention device as well, the reservoir 2 is connected tangentially to the input flow path 63 from the master cylinder 62 via the communication path 82, and is in communication with the master cylinder 62 when the special parking brake is not applied. It is something.

"Effects of the Invention" As is clear from the above explanation, according to the skid prevention device of the present invention, in the initial state when the brake is not applied, the check valve of the reservoir is opened by the forced opening mechanism, and the fluid storage chamber and master Because it communicates with the cylinder,
In the unlikely event that liquid leakage occurs, it can be detected as a decrease in the remaining amount of the reservoir in the master cylinder, and there is no need to provide a separate liquid leakage detection means in the skid prevention device. Therefore, it is possible to simplify the brake fluid failure detection mechanism, thereby saving costs and making management easier.

Further, since the communication passage is closed by the check valve provided in the communication passage of the reservoir when the brake is activated, it is possible to effectively guide the brake fluid to the wheel cylinder.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional views showing an embodiment of the skid prevention device of the present invention applied to a mechanical structure, with FIG. 1 showing the skid prevention device when it is not in operation, and FIG. 2 when it is in operation. FIG. 3 is a piping system diagram applied to an electronic configuration. 1...Device body, 2...Reservoir 3
...Lock detection section, 4...Liquid pressure modulation section, 5...Pump section, lO...Pressure release valve, 15... Input flow path, 16...Output flow path, 17...Cut-off valve, 19...
...Discharge passage, 20...Reducing piston, 31...
... Sleeve member, 32 ... Liquid storage chamber, 33
...Atmospheric chamber, 34...Return spring, 35...Reservoir piston, 36...
...Transport route, 37...Connection path, 38...
...Rod, 41...Check valve, 46...
... Forced opening mechanism, 62 ... Master cylinder, 63 ... Input flow path, 64 ... Wheel cylinder, 65 ... Output flow path, 68・・・・・・
...Cut-off valve, 69...Pressure release valve,
70...Discharge route, 71...Transportation route, 7
3...Pump, 74...Accumulator, 80...Sensor, 82...Communication path.

Claims (1)

[Claims] The brake fluid is interposed between the master cylinder and the wheel cylinder, and when the wheel is in a locked state, discharges brake fluid to a reservoir through a discharge path to reduce the pressure inside the wheel cylinder, and also prevents the wheel from being locked. In the skid prevention device that returns brake fluid from the reservoir to repressurize the inside of the wheel cylinder when the condition is released, the reservoir includes a liquid storage chamber with a variable capacity that stores brake fluid introduced from the discharge path; A communication path that connects the liquid storage chamber to the master cylinder, a check valve that closes the communication path by pressure from the master cylinder, and a check valve that opens the check valve when the brake fluid in the liquid storage chamber is in an initial state reduced. A skid prevention device characterized by being provided with a forced opening mechanism.