JP2670340B2 - Skid prevention device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a skid prevention device for a vehicle brake,
In particular, it relates to an improvement of a reservoir that stores the brake fluid discharged when the wheels are locked.

"Conventional technology" A skid prevention device is provided in the middle of a path for transmitting the pressure of brake fluid in a master cylinder operated by a brake pedal to a wheel cylinder of each wheel.
When the wheels are locked during sudden braking, the brake fluid is repeatedly depressurized and re-pressurized to prevent the wheels from skidding, ensuring directional stability and shortening the braking distance.

Conventionally, as such a skid prevention device, for example,
There is one disclosed in JP-A-63-287650 or JP-B-61-33788. The former is a skid prevention device with a mechanical structure that detects the locked state by utilizing the inertia of the flywheel rotated by the axle and reduces the brake fluid, and the latter is detected by a sensor that constantly detects the rotation of the wheels. An electronic skid prevention device that calculates a wheel speed, a slip ratio, a deceleration, and the like based on a result and controls the brake fluid pressure based on the calculation result.

[Problems to be Solved by the Invention] By the way, such a skid prevention device is provided with a discharge passage for releasing the brake fluid when the wheels are locked and a reservoir for storing the escaped brake fluid. Since it is used only when locked and is not used at all during normal operation, even if a liquid leak should occur, it is difficult to find it.For this reason, like the reservoir provided in the master cylinder, A remaining amount detection mechanism or the like is required, and the failure detection mechanism for brake fluid tends to be complicated.

The present invention has been proposed in view of the above circumstances, and provides a skid prevention device capable of reliably detecting the occurrence of a liquid leak or the like and simplifying a brake fluid failure detection mechanism. To aim.

"Means for Solving the Problem" In the skid prevention device of the present invention, the reservoir has a variable-capacity storage chamber for storing the brake fluid introduced from the discharge passage, and the storage chamber connected to the master cylinder. Communication passage,
A check valve for closing the communication passage by the pressure from the master cylinder, and a forced opening mechanism for opening the check valve in the initial state where the brake fluid in the liquid storage chamber is reduced are provided. To do.

[Operation] In the skid prevention device of the present invention, when the brake is not applied such as during parking or normal traveling, 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 with each other. Becomes Therefore, when a liquid leak or the like occurs, the remaining amount of the reservoir in the master cylinder appears to decrease, and can be determined by the remaining amount detecting mechanism provided in the reservoir. on the other hand,
When the brake is applied, the check valve closes the communication passage by the pressure of the brake fluid, effectively guiding the brake fluid to the wheel cylinder, and when the wheel is locked, the brake fluid discharged from the discharge passage is accumulated. It is stored in the liquid chamber and is sent out again from the reservoir when repressurized.

[Embodiment] An embodiment of the skid prevention device of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of a mechanical structure, in which reference numeral 1 denotes an apparatus main body, reference numeral 2 denotes a reservoir, and lock detection for detecting a locked state of wheels in the apparatus main body 1. A section 3, a hydraulic pressure modulating section 4 for reducing the pressure of the brake fluid to the wheel cylinder, and a pump section 5 for repressurizing the reduced pressure of the brake fluid are provided.

In the lock detection unit 3, a flywheel 8 is attached to a shaft 6 that is rotated in conjunction with an axle via a ball / ramp mechanism 7, and a lever 9 is provided in the vicinity of the flywheel 8 so that the flywheel 8 is By moving along the shaft 6, the lever 9 is pressed to operate the pressure release valve 10 of the hydraulic pressure modulator 4.

The hydraulic pressure modulator 4 has an input flow path 15 leading to the master cylinder.
And a cutoff valve 17 and a cylinder chamber 18 are provided in series between the output passage 16 communicating with the wheel cylinder and the cylinder chamber 18 is connected to the discharge passage 19 via the pressure release valve 10. When the pressure release valve 10 is opened by the operation of the flywheel 8, the pressure in the output passage 16 causes the pressure reducing piston 20 in the cylinder chamber 18 to operate, and the brake fluid in the cylinder chamber 18 is discharged. Road
The output flow path 16, that is, the brake fluid in the wheel cylinder is depressurized while being discharged to 19, and the cutoff valve 17 cuts off the input flow path 15 and the output flow path 16 by the movement of the piston 20.

The pump section 5 has a pump chamber 25 formed between the input flow path 15 and the discharge path 19, and a pump piston 26 therein is provided to face a cam 27 integral with the shaft 6. The discharge passage 19 and the cylinder chamber 18 of the hydraulic pressure modulation section 4 are connected to the chamber 25 via ball valves 28 and 29, respectively. Then, the pump piston 26 is reciprocated by being pressed against the cam 27 by the pressure difference between the input flow path 15 and the cylinder chamber 18, and the brake chamber 18 of the hydraulic pressure modulation unit 4 is sucked in the brake fluid from the discharge path 19. The pressure reducing piston 20 is moved to pressurize the brake fluid in the wheel cylinder.

The reservoir 2 has a stepped sleeve member 31 housed therein, and a reservoir chamber 32 for accumulating brake fluid therein.
And the atmosphere chamber 33 that is open to the atmosphere, the return spring
It is partitioned in a liquid-tight manner by a reservoir piston 35 urged by 34, and in the liquid storage chamber 32, a transportation path 36 leading to the discharge path 19 of the apparatus main body 1 and a communication path 37 leading to the middle of the input flow path 15.
And are connected.

In this case, the reservoir piston 35 is housed in the large-diameter portion of the sleeve member 31, and the rod 38 integral with the reservoir piston 35 is inserted in the small-diameter portion, and the storage is made by the gap between the rod 38 and the sleeve member 31. Passage leading to liquid chamber 32
39 are formed. Then, in the middle of the sleeve member 31, a hole 40 communicating with the passage 39 therein is opened.
The transportation path 36 is connected to 40. In addition, 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 communicated with a communication passage 37 in front of the sleeve member 31. A valve chamber 42, a ball valve 43 for closing the passage 39 by being pressed against the tip of the sleeve member 31 in the valve chamber 42, and a spring 44 for urging the ball valve 43 in the closing direction. It is composed of a retainer 45 for supporting the spring 44 at the front position of the sleeve member 31. Then, when the reservoir piston 35 pushes back the brake fluid in the liquid storage chamber 32 to be in the initial state, the tip of the rod 38 projects from the sleeve member 31, and as shown in FIG. It is designed to be separated from the tip of the sleeve member 31, and these reservoir piston 35 and rod 3
8, and check valve 41 by return spring 34
The forcible opening mechanism 46 for opening the above is configured. Reference numeral 47 denotes a plug for closing the large diameter portion of the sleeve member 31 and surrounding the atmosphere chamber 33, reference numeral 48 denotes a hole for opening the atmosphere chamber 33 to the atmosphere, and reference numerals 49, 50, and 51 denote seal members.

In the skid prevention device constructed as described above, the reservoir 2 has the rod 38 of the reservoir piston 35 pushed by the return spring 34 and the ball valve of the check valve 41 when the brake is not applied, as shown in FIG. Since the body 43 is separated from the distal end of the sleeve member 31, the master cylinder, the liquid storage chamber 32, and the discharge path 36 of the apparatus main body 1 are in a state of mutual communication.

At the time of normal braking, the brake fluid from the master cylinder is discharged from the device body 1 as shown by the arrow (a) in FIG.
When the pressure flows into the input flow path 15, the pressure acts on the valve chamber 42 of the check valve 41 through the communication passage 37, and pushes the ball valve body 43 to retreat the reservoir piston 35, thereby causing the sleeve member 31 to retract.
The passage 39 inside is closed. Therefore, the brake fluid is
It is effectively guided to the apparatus main body 1 without flowing into the reservoir 2 and acts on the wheel cylinder as shown by the arrow (b).

On the other hand, when the wheels are locked at the time of sudden braking, the brake fluid discharged from the discharge passage 19 flows from the hole 40 through the transport passage 36 to the passage 39 in the sleeve member 31 as shown by an arrow in FIG.
To the liquid storage chamber 32 while moving the reservoir piston 35.
Accumulated inside.

At the time of re-pressurization, the brake fluid in the liquid storage chamber 32 is sucked into the pump chamber 25 through the transport path 36 by the action of the pump piston 26 of the apparatus main body 1, and the hydraulic pressure modulation unit 4 It is pushed out into the cylinder chamber 18.

That is, this skid preventive device sets the reservoir 2 and the master cylinder in a communicating state in the initial state where the brake is not applied, and in the event that a liquid leak occurs in the discharge passage 19, the reservoir 2, etc. It is possible to make a distinction by a remaining amount detection mechanism provided in the reservoir by causing the remaining amount to decrease.
In this embodiment, an air chamber 33 is formed in the reservoir 2 of the skid prevention device so that a change in the capacity of the liquid storage chamber 32 is absorbed by the air chamber 33. It is possible to suppress the pressure change and prevent damage to the seal member.

On the other hand, FIG. 3 shows another embodiment in which the present invention is applied to an electronic skid prevention device. Its reservoir 2
Since it has the same configuration as that of one embodiment, a schematic configuration of the apparatus main body 61 will be described. Between the input flow passage 63 from the master cylinder 62 and the output flow passage 65 to the wheel cylinder 64, solenoids 66 and 67 are provided. Driven cut-off valve 68
And a pressure release valve 69 are provided in series. Then, the reservoir 2 is connected to the discharge passage 70 from the pressure release valve 69 via the transport passage 71, and the suction passage 72 is connected in the middle of the discharge passage 70 to communicate with the accumulator 74 via the pump 73. The accumulator 74 is connected to the input channel 63 by the return channel 75. On the other hand, between the output flow path 65 and the input flow path 63, a relief flow path 76 bypassing the cutoff valve 68 and the like is connected, and is opened and closed by a check valve 77. . A check valve 78 is also provided in the input passage 63.

Then, the solenoids 66 and 67 of the cutoff 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 wheels 79, During braking, the brake fluid is guided from the input passage 63 to the wheel cylinder 64 via the output passage 65, and when the wheels 79 are locked, the cutoff valve 68 shuts off the passage and the pressure release valve.
69 switches the flow passages so that the output flow passage 65 and the discharge passage 70 are in communication with each other, and the brake fluid in the wheel cylinder 64 is stored in the reservoir 2
Lead to. At this time, the pump 73 also operates to send the brake fluid to the accumulator 74. Then, when the wheel 79 recovers to the predetermined deceleration, the pressure release valve 69 is switched to close the output flow path 65, whereby the pressure in the wheel cylinder 64 is maintained, and then the locked state is released. Then, the cutoff valve 68 also opens the flow path,
Accumulator 74 brake fluid to wheel cylinder 64
It is sent to.

Also in this electronic skid prevention device, the reservoir 2 is connected to the input passage 63 from the master cylinder 62 and the communication passage 82.
When the brake is not applied, such as during parking, the master cylinder 62 is in communication.

[Effects of the Invention] As apparent from the above description, according to the skid prevention device of the present invention, the check valve of the reservoir is opened by the forced opening mechanism in the initial state where the brake is not applied, and the reservoir chamber and the master chamber are opened. Since the cylinder and the cylinder are in communication with each other, in the unlikely event of a liquid leak, 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 leak detection means in the skid prevention device. Therefore, the brake fluid failure detection mechanism can be simplified, the cost can be saved accordingly, and the management becomes easy. In addition, the check valve provided in the communication passage of the reservoir closes the communication passage when the brake is operated, so that the brake fluid can be effectively guided to the wheel cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are longitudinal sectional views showing an embodiment in which the skid prevention device of the present invention is applied to a mechanically configured one. FIG. The figure shows the operation. FIG. 3 is a piping system diagram applied to an electronic system. 1 ... Device main body, 2 ... Reservoir, 3 ... Lock detector, 4 ... Hydraulic pressure modulator, 5 ... Pump, 10 ... Pressure release valve, 15 ... Input flow path, 16 ... Output Flow path, 17 ... Cut-off valve, 19 ... Discharge path, 20 ... Decompression piston, 31 ...
… Sleeve member, 32 …… Storing chamber, 33 …… Atmosphere chamber, 34 ……
Return spring, 35 …… Reservoir piston, 36 ……
Transport route, 37 Communication passage, 38 Rod, 41 Check valve, 46 Forced release mechanism, 62 Master cylinder, 63
… Input channel, 64… wheel cylinder, 65… output channel, 68… cut-off valve, 69… pressure release valve, 70…
… Discharge path, 71 …… Transport path, 73 …… Pump, 74 …… Accumulator, 80 …… Sensor, 82 …… Communication path.

Claims (1)

(57) [Claims] 1. When a wheel is locked, it is interposed between a master cylinder and a wheel cylinder to discharge brake fluid to a reservoir through a discharge path to reduce the pressure in the wheel cylinder and lock the wheel cylinder. In the skid prevention device for returning the brake fluid from the reservoir to re-pressurize the inside of the wheel cylinder when is released, the reservoir has a variable-capacity storage chamber for storing the brake fluid introduced from the discharge passage, A communication path connecting the 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 is opened when the brake fluid in the storage chamber is in an initial state of reduced quantity. A skid prevention device comprising a forced opening mechanism.