KR100337635B1 - Anti-lock brake system for vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antilock brake system that prevents road slippage of a vehicle wheel, and more particularly, to an antilock brake system for a vehicle having improved configuration of bypass flow paths and check valves of an NC type solenoid valve.

The anti-lock brake system according to the present invention includes a first bypass passage formed between two adjacent NC-type solenoid valves and a second bypass passage connected to an inlet side of the low pressure accumulator at the middle of the first bypass passage. By installing a bidirectional check valve shared by the two NC-type solenoid valves at the branch points of the first bypass passage and the second bypass passage, the internal structure of the modulator block is simplified and the check valve can be easily installed. This is to make the volume smaller.

Description

Antilock Brake System for Vehicles {ANTI-LOCK BRAKE SYSTEM FOR VEHICLE}

The present invention relates to an anti-lock brake system for preventing road slipping of a vehicle wheel, and more particularly, to an anti-lock brake system for a vehicle having improved configuration of a bypass flow path and a check valve of an NC type solenoid valve.

Among the hydraulic brake devices mounted on a vehicle, there is an anti-lock brake system (ANTI-LOCK BRAKE SYSTEM) which periodically prevents the slip of the wheel by intermittently braking hydraulic pressure transmitted to the wheel side.

As shown in FIG. 1, the vehicle anti-lock brake system includes a first and second installed in the middle of a hydraulic line connected from the master cylinder 1 to each wheel side wheel cylinders 2a, 2b, 2c, and 2d of the vehicle. And the first, second, third and fourth NCs installed in the third and fourth normal open solenoid valves 3a, 3b, 3c, and 3d, and return passages through which oil is returned from each wheel side. Normal Close) solenoid valves (4a, 4b, 4c, 4d) are provided.

In addition, the anti-lock brake system is provided with hydraulic pumps 5a and 5b for re-pressurizing the oil returning from the wheel side and generating the braking pressure, and low pressure accumulators 6a and 6b on the upstream and downstream sides of the hydraulic pumps 5a and 5b. ) And high pressure accumulators 7a and 7b. And these devices are all configured in one modulator block (not shown), the operation is controlled by the ECU (ELECTRIC CONTROL UNIT, not shown). That is, the ECU controls the opening and closing of the NO type and NC type solenoid valves to control the braking hydraulic pressure supplied to the wheel side, and simultaneously controls the driving of the hydraulic pumps 5a and 5b to repressurize the fluid returned along the hydraulic line to the wheel side. As a result, intermittent braking is achieved.

Each of the NO solenoid valves 3a, 3b, 3c, and 3d has bypass passages 8a, 8b, 8c, and 8d connecting the inlet and outlet sides of the NO solenoid valves 3a, 3b, 3c, and 3d. Each of the bypass passages 8a, 8b, 8c, and 8d blocks the flow of oil during the braking operation, and the oil of each wheel cylinder 2a, 2b, 2c, and 2d when the braking operation is released. Check valves 9a, 9b, 9c, and 9d are provided to open the flow path so as to quickly return to 1). In addition, the NC solenoid valve 4a can be quickly returned to the surroundings of the NC solenoid valves 4a, 4b, 4c, and 4d so that the residual amount of oil accumulated in the low pressure accumulators 6a and 6b can be quickly recovered. Bypass passages 10a, 10b, 10c, and 10d connecting the inlet and outlet sides of 4b, 4c, and 4d are provided, and check valves 11a, 11b, 11c, and 11d are provided in the bypass passage. In this case, the conventional anti-lock brake system adopts a method of forming a respective bypass flow path in the modulator block and mounting a check valve, or a bypass flow path and a check valve are integrally formed in each NO or NC solenoid valve. It has been done in such a way as possible.

However, the conventional anti-lock brake system having such a configuration has separate bypass flow paths 10a, 10b, 10c, 10d and check valves 11a, 11b, 11c, and 11d for each NC type solenoid valve 4a, 4b, 4c, and 4d. Since the flow path structure inside the modulator block and the configuration of each NC type solenoid valve (when the check valve is integrally formed) have a complicated problem, the complexity of the structure has a problem that the volume of the modulator block is large. .

The present invention is to solve such a problem, an object of the present invention is to improve the bypass flow path and the check valve of the NC type solenoid valve so that two adjacent NC type solenoid valves share one check valve, The present invention provides a vehicle anti-lock brake system that not only simplifies the configuration inside the modulator block and facilitates mounting of the check valve, but also makes it possible to reduce the volume of the modulator block.

1 is a hydraulic circuit diagram of a conventional anti-lock brake system.

2 is a hydraulic circuit diagram of an anti-lock brake system to which a bidirectional check valve according to the present invention is applied.

3 is a cross-sectional view showing the mounting structure of the flow path and the bidirectional check valve in the modulator block of the anti-lock brake system according to the present invention.

Figure 4 is a detailed cross-sectional view showing the configuration of the bidirectional check valve according to the present invention.

Explanation of symbols on the main parts of the drawings

20: master cylinder, 21a, 21b, 21c, 21d: wheel cylinder,

22a, 22b, 22c, 22d: NO type solenoid valve,

23a, 23b, 23c, 23d: NC type solenoid valve,

24a, 24b: hydraulic pump, 25a, 25b: low pressure accumulator,

26a, 26b: high pressure accumulator, 27: first bypass flow path,

28: second bypass flow path, 30: bidirectional check valve,

31: valve housing, 32: through flow path,

33a, 33b: opening and closing ball, 34a, 34b: ball receiving groove,

35, 36: ball support member.

An anti-lock brake system for a vehicle according to the present invention for achieving the above object includes a master cylinder for generating braking pressure, a wheel cylinder provided on each wheel to exert a braking force by brake fluid pressure, and the wheels in the master cylinder. A plurality of NO-type solenoid valves installed in the middle of the flow path where oil is supplied to the cylinder, a plurality of NC-type solenoid valves installed in the middle of the flow path in which oil is returned from the wheel cylinder to the master cylinder, and the NC-type solenoid valve And a hydraulic pump installed in the middle of the return passage connecting the master cylinder to pump oil, and a low pressure accumulator installed in the middle of the flow path connecting the NC solenoid valve and the hydraulic pump to accumulate oil. In the anti-lock brake system, the NC type solenoid valve A first bypass passage connecting two NC-type solenoid valve outlet flow passages, a second bypass passage branched from the middle of the first bypass passage and connected to the low pressure accumulator, and a second bypass passage from the low pressure accumulator And a bidirectional check valve installed at a branch point of the first bypass passage and the second bypass passage such that oil flows only toward the inlets of the two NC type solenoid valves through the first bypass passage.

For this configuration, the NC solenoid valve is fixedly installed in a box-shaped modulator block having a plurality of flow paths formed therein, and a plurality of valve coupling grooves recessed for coupling the NC solenoid valve to one surface of the modulator block. And the first bypass passage penetrates two valve coupling grooves adjacent to each other at the side of the modulator block, and the second bypass passage intersects the first bypass passage between the two valve coupling grooves. And the bidirectional check valve is press-fitted into one of the first bypass passages and fixed to a branch point with the second bypass passages.

The bidirectional check valve may include a valve housing having a through flow passage through which both ends penetrate therein, and two opening and closing balls installed in a ball receiving groove formed at both ends of the valve housing so as to open and close both ends of the through flow passage. The ball support member is fixed to the opening of each ball receiving groove to prevent the ball from opening and closing the ball housing member having a first through-hole for the flow of the fluid, the through the passage and the second bypass flow passage circumference It characterized in that it comprises a second through-hole formed in.

The first bypass passage may have a larger inner diameter at which the bidirectional check valve enters based on the branch point, so that the first bypass passage may be caught at the bifurcation point when the bidirectional check valve is press-fitted.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the vehicle anti-lock brake system according to the present invention is installed in the middle of a hydraulic line connected to the wheel cylinders 21a, 21b, 21c, and 21d on each wheel side of the master cylinder 20, and is provided with a supply flow path. The first, second, third and fourth NO (open) solenoid valves 22a, 22b, 22c, and 22d for opening and closing the valve are provided. And second, third, and fourth NC (Normal Close) solenoid valves 23a, 23b, 23c, and 23d. At this time, when the NO type solenoid valves 22a, 22b, 22c, and 22d are open, the NC type solenoid valves 23a, 23b, 23c, and 23d are closed so that the braking pressure is applied to the wheel side, and the NO type solenoid valve ( When 22a, 22b, 22c, and 22d are closed, the NC type solenoid valves 23a, 23b, 23c, and 23d are opened to release the brake pressure of the wheels.

In addition, the anti-lock brake system includes a hydraulic pump 24a for re-pressurizing oil returned from the wheel cylinders 21a, 21b, 21c, 21d on each wheel side to the upstream side of the NO solenoid valves 22a, 22b, 22c, and 22d. 24b) is provided, and the low pressure accumulators 25a and 25b and the high pressure accumulators 26a and 26b which form a buffer space BUFFER are provided on the upstream and downstream sides of the hydraulic pumps 24a and 24b. At this time, the low pressure accumulators 25a and 25b provided upstream of the hydraulic pumps 24a and 24b function to temporarily accumulate the brake oil returning from the wheel side and to be supplied to the hydraulic pumps 24a and 24b. The high pressure accumulators 26a and 26b installed downstream of the 24a and 24b store the oil pressurized by the hydraulic pumps 24a and 24b so that the pressure pulsation due to the operation of the hydraulic pumps 24a and 24b is attenuated. Function. And these devices are controlled by the ECU (ELECTRIC CONTROL UNIT, not shown). That is, the ECU controls each NO-type and NC-type solenoid valve to open and close the flow path supplied to each wheel side, and also controls the driving of the hydraulic pumps 24a and 24b to control the low pressure accumulators 25a and 25b through the return flow path. The fluid returned to the wheel is re-pressurized to the side of the wheel to perform intermittent braking.

In addition, each NO type solenoid valve 22a, 22b, 22c, 22d is provided with a bypass flow path 40a, 40b, 40c, 40d for the NO type solenoid valve connecting the inlet side and the outlet side of the NO solenoid valve. In this bypass passage, the flow of oil is interrupted during the braking operation, and when the braking operation is released, the flow path is opened so that oil of each wheel cylinder 21a, 21b, 21c, 21d can be quickly returned to the master cylinder 20. Check valves 41a, 41b, 41c, 41d are provided.

And around the NC solenoid valves 23a, 23b, 23c, and 23d so as to allow reverse flow of oil remaining in the low pressure accumulators 25a and 25b when the braking operation is released. A first bypass passage 27 connecting the outlets of 23c and 23d, and a second bypass passage 28 branched from the middle of the first bypass passage 27 and connected to the low pressure accumulators 25a and 25b. The bidirectional check valve 30 is installed at the branch point where the second bypass passage 28 branches. That is, in the present invention, two NC-type solenoid valves adjacent to each other share one check valve instead of two check valves, which are conventionally configured separately, and by applying a bidirectional check valve 30 provided as one assembly, The configuration is simplified.

The anti-lock brake system having such a configuration is generally composed of a box-shaped modulator block 50 (FIG. 3) having a plurality of flow paths formed therein, and the first and second bypass flow paths 27 and 28 described above are modulator blocks ( A structure disposed within 50) and a seal application example of the bidirectional check valve 30 will be described with reference to FIGS. 3 and 4.

One surface of the modulator block 50 is formed with a plurality of valve coupling grooves 51a and 51b recessed to a predetermined depth so that the aforementioned NC type solenoid valves 23a and 23b can be press-fitted and fixed. In addition, the valve engagement grooves 51a and 51b are formed in communication with the flow passage 53 branched from the inlet flow passage 52 of the low pressure accumulator 25a. In addition, the above-described first bypass passage 27 is formed to extend in the transverse direction on the side of the modulator block 50 so that two adjacent valve coupling grooves 51a and 51b pass through the second bypass passage 28. Is formed in the vertical direction in the drawing so as to intersect with the first bypass passage 27 between the two valve coupling grooves 51a and 51b. At this time, the second bypass passage 28 communicates with the inlet side flow passage 52 of the low pressure accumulator 52a.

The bidirectional check valve 30 is press-fitted and fixed to a branch point where the first bypass passage 27 and the second bypass passage 28 intersect, and both ends penetrate inside the valve housing 31 of the check valve 30. Through passages 32 are formed, and two opening and closing balls 33a and 33b are installed at both ends of the valve housing 31 to be moved forward and backward to open and close both ends of the passage passage 32. At this time, the ball housing grooves 34a and 34b of a predetermined depth are formed at both ends of the valve housing 31 so that the two opening and closing balls 33a and 33b can be retractably received. The openings of the ball housing grooves 34a and 34b are opened and closed. Ball support members 35 and 36 are provided to support the opening and closing balls 33a and 33b to prevent separation of the balls 33a and 33b and have first through holes 35a and 36a formed therein for the flow of fluid. A second through hole 37 is formed around the valve housing 31 so that the inside of the through passage 32 and the second bypass passage 28 communicate with each other.

Meanwhile, the bidirectional check valve 30 having such a configuration is press-fitted from one end of the first bypass passage 27 and fixed to a point at which the second bypass passage 28 branches, which is press-fitted into the first bypass passage 27. At this time, the valve housing 31 is fixed in position so that the second through hole 37 maintains the communication state with the second bypass passage 28 so that both inner diameters d1 and d2 of the first bypass passage 27 are maintained. ) Is formed differently based on the branch point. That is, the first bypass passage 27 has a larger inner diameter d1 at which the valve housing 31 enters, so that the valve housing 31 is caught at the branch point when the valve housing 31 is press-fitted to stop at the correct position. In addition, the outer surface of the valve housing 31 is formed with a groove 38 and the jaw 39 to be fixed through the deformation of the inner surface of the first bypass passage (27). In FIG. 3, reference numerals 54a, 54b, and 54c denote caps for blocking the openings of the flow paths 27, 28, and 53 communicating with the outer surface of the modulator block 50, and 55a and 55b denote wheel cylinders 21a and 21b on each wheel side. ) Is a flow path to communicate with.

The following describes the overall operation of the anti-lock brake system in which the bidirectional check valve of this configuration is applied.

When the driver presses the brake pedal 20a, the back pressure is generated by the pressure difference in the power supply device 20b, and the braking hydraulic pressure is formed by receiving the amplified force from the master cylinder 20, and the hydraulic pressure is each NO-type solenoid. The valves 22a, 22b, 22c, and 22d are supplied to the wheel cylinders 21a, 21b, 21c, and 21d on each wheel side to exert braking force. At this time, when excessive braking pressure is transmitted, a slip phenomenon occurs that the tire of the vehicle stops rotating and slips on the road surface. The slip phenomenon is detected through a wheel sensor (not shown) mounted on the wheel side of the vehicle, and the detected information is detected. It is delivered to an ECU (not shown). At this time, the ECU opens the respective NC solenoid valves 23a, 23b, 23c, and 23d to release the oil in the wheel cylinders 21a, 21b, 21c, and 21d to release the temporary braking to prevent wheel slippage. do.

In addition, the oil drained out through the NC type solenoid valves 23a, 23b, 23c, and 23d is moved to the low pressure accumulators 25a and 25b and stored for a while, and the oil of the low pressure accumulators 25a and 25b is hydraulic pumps 24a and 24b. The pressure of the high pressure accumulator 26a, 26b is again supplied to the upstream side of each of the NO solenoid valves 22a, 22b, 22c, and 22d. To form a braking pressure. That is, the vehicle anti-lock brake system continuously controls such an operation by the ECU, thereby applying an intermittent braking pressure to the wheel cylinders 21a, 21b, 21c, and 21d so that the vehicle can be stably braked.

On the other hand, during this braking operation, the pressure of the oil supplied to the wheel cylinders 21a, 21b, 21c, and 21d via the NO solenoid valves 22a, 22b, 22c, and 22d is also applied to the first bypass passage 27. Will be added. However, in this case, since the two opening and closing balls 33a and 33b of the bidirectional check valve 30 close both ends of the through passage 32, the flow of fluid through the first and second bypass passages 27 and 28 is blocked. do.

When the brake operation is released, the brake pressure of the outlet side of the master cylinder 20 is released, so that the oil of each wheel cylinder 21a, 21b, 21c, 21d is NO solenoid valves 22a, 22b, 22c, 22d. Not only flows back toward the master cylinder 20, but also through the bypass passages 40a, 40b, 40c and 40d for the NO-type solenoid valves and through the check valves 41a, 41b, 41c and 41d. As a result, the braking operation is released quickly.

In this case, the oil remaining in the low pressure accumulators 25a and 25b flows back through the second bypass passage 28 and the first bypass passage 27 to be quickly returned to the master cylinder 20. That is, when the pressure in the first bypass passage 27 decreases due to the release of the braking operation, the two opening and closing balls 33a and 33b of the bidirectional check valve 30 are pushed by the pressure of the second bypass passage 28 and the passage passage 32 Since both ends are open, residual oil of the low pressure accumulators 25a and 25b can flow back through the first and second bypass passages 27 and 28. The residual oil inside the low pressure accumulators 25a and 25b is reversed to prevent unnecessary operation of the hydraulic pumps 24a and 24b which have been operated to discharge the residual oil of the low pressure accumulators 25a and 25b after the braking operation ends. Can be.

As described in detail above, the anti-lock brake system according to the present invention includes a first bypass passage formed between two NC-type solenoid valves adjacent to each other, and a first bypass passage connected to an inlet side of the low pressure accumulator in the middle of the first bypass passage. By providing two bypass flow paths and a bidirectional check valve shared by the two NC-type solenoid valves at the branch points of the first bypass flow path and the second bypass flow path, the configuration inside the modulator block is simplified and the check valve can be easily installed. Instead, the volume of the modulator block is reduced.

Claims (4)

A master cylinder for generating braking pressure, a wheel cylinder provided at each wheel to exert a braking force by brake fluid pressure, a plurality of NO solenoid valves installed in the middle of a flow path in which oil is supplied from the master cylinder to each wheel cylinder; And a plurality of NC type solenoid valves installed in the middle of the flow path for returning oil from the wheel cylinder to the master cylinder, and installed in the middle of a return flow path connecting the NC type solenoid valve and the master cylinder to pump oil. In the vehicle anti-lock brake system including a hydraulic pump, a low pressure accumulator which is installed in the middle of the flow path connecting the NC-type solenoid valve and the hydraulic pump to accumulate oil, A first bypass passage connecting the two NC-type solenoid valve outlet side passages adjacent to each other among the NC solenoid valves, a second bypass passage branched at the middle of the first bypass passage and connected to the low pressure accumulator, and And a bidirectional check valve installed at a branch point of the first bypass passage and the second bypass passage such that oil flows only from the low pressure accumulator to the inlet of the two NC type solenoid valves through the second bypass passage and the first bypass passage. Vehicle anti-lock brake system, characterized in that. The method of claim 1, The NC-type solenoid valve is fixed to the box-shaped modulator block formed with a plurality of passages therein, A plurality of valve coupling grooves recessed for coupling the NC solenoid valve is formed on one surface of the modulator block, and the first bypass passage passes through two valve coupling grooves adjacent to each other at the side of the modulator block. The second bypass flow path is formed in a direction crossing the first bypass flow path between the two valve coupling grooves, and the bidirectional check valve is press-fitted into the second bypass flow path from one end of the first bypass flow path. Vehicle anti-lock brake system, characterized in that fixed to the branch point of the. The method of claim 2, The bidirectional check valve includes a valve housing having a through flow passage through which both ends penetrate therein, and two opening and closing balls removably installed in ball receiving grooves formed at both ends of the valve housing to open and close both ends of the through flow passage. A ball support member fixed to an opening of each ball receiving groove to prevent separation of the ball support member, and having a first through hole formed at the center thereof, and formed around the valve housing so that the inside of the through passage and the second bypass passage communicate with each other. An antilock brake system for a vehicle comprising a second through hole. The method of claim 2, And the first bypass passage has a larger inner diameter at which the bidirectional check valve enters with respect to the branch point so as to be caught at the branch point when the bidirectional check valve is press-fitted.