JPS602222B2 - Anti-skid braking device for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid braking device for a vehicle, and particularly to an anti-skid braking device for rear wheels.

In order to safely stop the vehicle in the shortest possible distance during braking, it is preferable to apply a braking force equal to the maximum frictional force between the tires and the road surface. In such a case, the wheels may lock and the tires may skid, which impairs maneuverability and increases braking distance, which is dangerous.

Conventionally, when the wheels lock during braking, the braking force is weakened to release the lock, and then when the wheels lock again, the braking force is weakened again to achieve braking with a braking force as close as possible to the maximum frictional force. An anti-skid braking device for this purpose is known, as described in Samurai Publication No. 51-39367. This anti-skid braking device is equipped with a brake pressure control valve equipped with a piston consisting of a large diameter part and a small diameter part, and the cylinder chamber of the small diameter part of the piston is connected to the master cylinder, and the cylinder chamber of the large diameter part of the piston is connected to the wheel cylinder. It is connected.
When the wheels are locked, the brake hydraulic line that directly communicates between the master cylinder and the wheel cylinder is closed, and at the same time, the brake hydraulic line that connects the cylinder chamber of the piston's large section and the wheel cylinder is communicated, thereby reducing the pressure ratio at both ends of the piston. The braking oil in the wheel cylinder is sucked into the cylinder chamber of the piston's larger portion until the amount of braking oil becomes constant, thereby weakening the braking force and preventing the wheels from locking. However, if the braking oil in the wheel cylinder is sucked into the cylinder chamber of the piston's largest part until the pressure ratio at both ends of the piston becomes constant, it is impossible to avoid wheel locking when the wheel rotation speed is low. There is. That is, when the rotational speed of the wheels is high, the inertial force against the rotation of the wheels is large, so if the wheels lock and the braking force is weakened, the rotational speed of the wheels immediately increases, so skidding does not occur. However, when the rotational speed of the wheels is low, even a small braking force causes the wheels to lock, so even if the brake oil pressure in the wheel cylinder is lowered until the pressure ratio at both ends of the piston becomes constant when the wheels are locked, the brake oil pressure is low to begin with and the brakes are not activated. Oil pressure doesn't drop that much. When the rotational speed of the wheels is low, the inertial force against the rotation of the wheels is small, so the wheels continue to be locked even if the braking oil pressure decreases to some extent, making it difficult to avoid skids. SUMMARY OF THE INVENTION An object of the present invention is to provide an anti-skid braking system that can avoid skids regardless of the driving condition of the vehicle.

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

Referring to FIG. 1, 1 is a front wheel, 2 is a disc brake device, 3 is a rear wheel, 4 is a brake wheel cylinder, 5 is a master cylinder connected to a foot brake pedal 6 provided in the driver's cabin, 7 8 indicates a brake hydraulic pressure line connecting the master cylinder 5 and the front wheel disc brake device 2, and 8 indicates a brake hydraulic line connecting the master cylinder 5 and the rear wheel cylinder 4. A sliding control valve arrangement 9 according to the invention is provided.

The slide control valve device 9 has a cylinder bore 11 in its housing 10, and a piston 12 constituting the slide valve is inserted into the cylinder bore 11 so as to be able to reciprocate. A stopper 1 having a ventilation hole 13 at the open end of the cylinder bore 11
4 is attacked by a fly. A compression spring 15 is inserted between the stopper 14 and the piston 12, and the spring force of the compression spring 15 constantly urges the piston 12 toward the right.
On the other hand, a decompression chamber 16 is formed between the closed end of the cylinder bore 11 and the end surface of the piston 12. When hydraulic pressure is applied in the decompression chamber 16, the piston 12 moves by a certain stroke until it comes into contact with the stopper 4. Also cylinder bore 11
In the piston 12 on the closed end side, there are formed a large cylinder bore 17 that is always open into the decompression chamber 16 and a four-cylinder cylinder bore 18 that is coaxially bored at the end thereof. Inside these cylinder bores 17 and 18 is a large diameter cylinder bore 17.
A sub-piston 21 is iron-bonded to the piston 21, which is integrally formed with a large concave portion 19 that slides therein and a small recessed portion 20 that slides within the small-diameter cylinder bore 18. Further, a spring seat 23 having a large number of through holes is fixedly installed in the large diameter cylinder bore 17. This Panesa 2
A compression spring 24 is installed between the piston 3 and the sub-piston 21, and the spring force of the compression spring 24 constantly presses the sub-piston 21 toward the left. Therefore, as shown in FIG. 1, the sub-piston 21 normally abuts on a shoulder 25 formed between the large-diameter cylinder bore 17 and the small-diameter cylinder bore 18. Further, when the secondary piston 21 moves to the right, the space formed between the shoulder portion 25 and the secondary piston 21 is formed by a ventilation hole 26 shown by a broken line drilled in the piston 12 and a ventilation hole formed in the stopper 14. 13 to the atmosphere. Furthermore, the piston 12 has a pair of annular grooves 27 and 28 cut on its outer peripheral wall surface at a distance from each other. The annular groove 27 has a tapered portion 29 formed at its left end so that the groove depth gradually decreases toward the left, while the annular groove 28 has a taper portion 29 formed at its right end so that the groove depth gradually decreases toward the right. It has a tapered portion 30 formed to taper off. As shown in FIG. 1, a hydraulic chamber 31 is defined within the small-diameter cylinder bore 18 by an auxiliary piston 21, and this hydraulic chamber 31 is connected to the annular groove 28 via a passage 32. On the other hand, a brake oil passage 33 consisting of passage portions 33a and 33b and a brake oil passage 34 consisting of passage portions 34a and 34b are formed within the housing 10.

The brake oil passage 33 is connected to the cylinder bore 11 through three branch passages 35, 36, and 37, while the brake oil passage 44 is connected to the cylinder bore 11 through three branch passages 38, 39, and 40. be done. A pair of branch passages 35, 38
are aligned with each other and are positioned so as to face the tapered portion 29 of the annular groove 27 when the piston 12 is in the rightmost position shown in FIG. On the other hand, the branch passages 36 and 39 are arranged in alignment with each other and are arranged so that when the piston 12 reaches the left end position against the spring force of the compression spring 15, three tapered portions of the annular groove 28 face each other. . Also, branch passage 3
7 and 40 are arranged in alignment with each other and are always closed to the decompression chamber 16. In the branch pilgrimage 38, there is a tapered part 2 of the annular groove 27.
A first on-off valve 41 that can be engaged with the valve 9 is provided.
The on-off valve 41 is always pressed upward by a compression spring 43 installed between the first on-off valve 41 and a spring seat 42 screwed into the housing. As shown in FIG. 1, this first opening/closing valve 41 is opened by the annular groove 2
The tapered portion 29 of the holder is engaged with the tapered portion 29 of the holder. Further, the brake oil circuit 34 is always connected to the master cylinder 5 through a hole 44 formed in the spring seat 42. On the other hand, a second on-off valve 45 that can engage with the tapered portion 30 of the annular groove 28 is provided in the branch passage 39, and this second on-off valve 45 is connected to a spring seat 46 screwed onto the housing 10, valve 45
It is constantly pressed upward by a compression spring 47 installed between the two. This second on-off valve 45 closes the branch passage 39 when the piston 12 is at the right end position, as shown in FIG. 1, and on the other hand, when the piston 12 moves to the left end position, the second on-off valve 4
5 engages with the tapered portion 30 of the annular groove 28, thereby making a connection. Further, the passage portion 34b and the branch passage are blocked by four river bolts 48. On the other hand, both ends of the brake oil passage 33 are closed by a pair of bolts 49 and 50.
Further, this brake oil passage 33 is connected to the rear wheel cylinder 4 via a brake oil pressure line 8.

The branch passage 36 is closed by a bolt 51, which is screwed on. The bolt 51 has a constricted portion 52 so that the passage portions 33a and 33b can communicate with each other when the passage portions 33a and 33b are opened. Furthermore, the sliding control valve device 9 according to the invention includes an electromagnetic device 5.
It has 3. This electromagnet device 53 includes a solenoid 54 and a movable plunger 55, and a valve head 57 is fixed to the lower end of a rod 56 extending downward from the movable plunger 65. The valve head 57 is constantly biased downwardly by the spring force of the compression spring 58 and normally closes the passageway 37 as shown in FIG. Further, in FIG. 1, reference numeral 59 is a rotation speed detector for detecting the rotation speed of the rear wheels, and 60
1. A brake pedal operation detector 61 detects the operation of the foot brake pedal 6, and detects the deceleration of the rear wheel during braking operation based on the output signals of the rotation speed detector 59 and the brake pedal operation detector 60. A control circuit is shown configured to energize solenoid 54 when the rear wheels are locked.

When no braking action is being performed, the piston 12 is located at the right end position due to the spring force of the compression spring 15, as shown in FIG.

Therefore, at this time, as described above, the first on-off valve 41 is open and the second on-off valve 45 is open. Therefore, the rear wheel cylinder 4 is connected to the master cylinder 5 via the brake hydraulic line 8, the brake oil passage 33, the branch passage 35, the annular groove 27, the branch passage 38, the hole 44, and the brake hydraulic line 8. There is. Next, when the foot brake pedal 6 is operated, as described above, the master cylinder 5 is directly connected to the rear wheel cylinder 4, so as shown in FIG. As a result, the brake hydraulic pressure in the rear wheel cylinder 4 also increases, and a brake hydraulic pressure equal to the brake hydraulic pressure in the master cylinder 5 is generated in the wheel cylinder 4. In addition, in FIG. 2, the vertical axis P represents the braking oil pressure in the rear cylinder wheel 4, and the machine axis Q
indicate the braking oil pressure in the master cylinder 5, respectively. Next, if the foot brake pedal 6 is further depressed, thereby increasing the braking oil pressure in the wheel cylinder 4, and as a result, the rear wheel is locked, this locked state is detected by the control circuit 61 and the solenoid 54 is activated as described above. is energized. As a result, the movable plunger 55 is attracted by the solenoid 54 and rises, and the on-off valve 57 closes the branch passage 37. Therefore, at this time, the pressurized brake oil in the wheel cylinder 4 is transferred to the brake oil pipe 8 and the brake oil passage 33.
It also flows into the decompression chamber 16 via the branch passage 37 .
As a result, the piston 12 moves to the left against the spring force of the compression spring 15 until the piston end abuts against the stopper 14. As soon as the piston 12 starts moving leftward, the engagement between the first on-off valve 41 and the taber portion 29 is released, so the first on-off valve 41 is raised by the spring force of the compression spring 43. Then, the dividing skin passage 28 is closed. When the rear wheels lock in this way, the connection between the master cylinder 5 and the wheel cylinders 4 is severed, and the pressurized brake oil in the wheel cylinders 4 escapes into the decompression chamber 16, as shown by the straight line portion ab in FIG. As a result, the brake oil pressure in the wheel cylinder 4 decreases, and as a result, the rear wheel is unlocked.
On the other hand, when the piston 12 reaches the left end position, the second on-off valve 4
5 and the tapered portion 30 of the annular groove 28 engage with each other, and as a result, the second on-off valve 45 becomes involved, and the pressurized brake oil pressure in the master cylinder 5 is transferred to the brake oil pressure passage 34, the branch passage 39, and the annular groove 28.
It is also added to the hydraulic working chamber 31 via the passage 32 .

Next, the foot brake pedal 6 is further depressed, thereby increasing the braking oil pressure in the master cylinder 5 and increasing the brake pressure in the second brake pedal.
When the brake oil pressure corresponding to point C in the figure is reached, the pressurized brake oil in the hydraulic chamber 31 is depressurized via the auxiliary piston 21, and the oil pressure in the decompression chamber 16 is transferred to the wheel cylinder 4 via the brake oil pressure passage 33. As a result, the braking oil pressure in the wheel cylinder 4 rises again as shown in FIG. At this time, the brake oil pressure increase rate, as shown by the straight line Cd in FIG. 2, is set lower than the brake oil pressure increase rate, shown by the straight line oa, before the rear wheels are locked. The braking oil pressure increase rate shown by the straight line Cd can be obtained by appropriately setting the dimensions of the small diameter cylinder bore 18, the dimensions of the large diameter cylinder bore 17, and the spring force of the compression spring 24. Next, when the foot brake pedal 6 is released, the braking oil pressure in the wheel cylinder 4 is transferred to the master cylinder 5.
As a result, the first on-off valve 41 is opened and the braking oil in the wheel cylinder 4 flows toward the master cylinder 5.

At the same time, the auxiliary piston 21 returns to the position shown in FIG. The piston 12 returns to the position shown in FIG.
The brake oil inside flows into the master cylinder 5 via the branch passage 37, the brake oil passage 33, the branch passage 35, the annular groove 27, and the first on-off valve 41. In this way, the initial state shown in FIG. 1 is returned. As shown in FIG. 1, the sliding control valve device 9 according to the present invention has a piston 12 and an auxiliary piston 21 in its housing 10, so that the braking oil pressure Q in the master cylinder 5 and the wheels as shown in FIG. A desirable relationship with the braking oil pressure P within the cylinder 4 can be obtained.

As described above, the sliding control valve device 9 according to the present invention is extremely compact and simple and consists of only one valve device, and is therefore of the 4-type type and inexpensive, and furthermore has extremely high reliability. have Furthermore, according to the present invention, when the wheels are locked, the sliding valve consisting of the piston 12 moves by a certain stroke, so that a certain amount of braking oil is pumped into the wheel cylinder 4.
and flows into the decompression chamber 16, resulting in a decrease in the braking oil pressure in the wheel cylinder 4. When the wheels are rotating at high speeds, this reduction in brake hydraulic pressure immediately increases the rotational speed of the wheels, thus avoiding skids. On the other hand, when the wheels are rotating at a low speed, the wheels are locked with low braking oil pressure, so the amount of braking oil stored in the wheel cylinders 4 at this time is small. However, even if the amount of brake oil integrated in the wheel cylinder 4 is small, the amount of brake oil flowing into the decompression chamber 16 when the wheels are locked is constant, so the brake oil pressure in the wheel cylinder 4 is The rate of decrease is considerably larger than when the wheels are rotating at high speed. Therefore, the inertial force against the rotation of the wheels is 4 mm, and even when the wheels are rotating at low speeds, the braking force is greatly weakened, so the rotation speed of the wheels immediately increases, thus making it possible to avoid skids. . As described above, the present invention has the advantage that skids can be avoided regardless of the driving condition of the vehicle.

[Brief explanation of drawings]

FIG. 1 is an overall view of the anti-skid device according to the present invention, showing a sliding control valve device in cross section, and FIG. 2 is a plug showing the relationship between the brake hydraulic pressure in the master cylinder and the brake hydraulic pressure in the wheel cylinder. 1...Front wheel, 3...Rear wheel, 4...
...Wheel cylinder, 5...Master cylinder, 6...
Foot brake pedal, 9...Sliding control valve device, 12...Piston, 16...Decompression chamber, 21...Sub-piston, 27, 28.・・・・・・
・Annular groove, 31... Hydraulic brake chamber, 33, 34.
...Brake hydraulic passage, 35, 36, 37, 38, 3
9, 40... Branch passage, 41... First on-off valve, 45... Second on-off valve, 53... Electromagnet device, 57... On-off valve, 59... Rotation speed detector, 60... Brake pedal operation detector. Figure 1 Figure 2・

Claims (1)

[Claims] 1. A sliding control valve device is arranged on the brake hydraulic pipe connecting the master cylinder and the wheel cylinder, and a sliding valve regulated to a certain stroke is inserted into the sliding control valve device, and one end of the sliding valve is inserted into the sliding control valve device. A decompression chamber is formed in the sliding valve, and a sub-piston consisting of a large diameter part and a small diameter part is inserted into the cylinder bore formed inside the slide valve, and the cylinder bore of the large diameter part of the piston is communicated with the decompression chamber, thereby detecting wheel lock. The pressure reducing chamber is connected to the wheel cylinder via a solenoid valve that opens when the wheels are locked in response to a signal, and the sliding valve is configured to communicate with the brake hydraulic pressure line under normal conditions, and the solenoid valve opens when the wheels are locked. By connecting the decompression chamber to the wheel cylinder through the cylinder, the sliding valve is moved by a certain stroke to cut off the brake hydraulic line, and at the same time, the hydraulic chamber formed in the cylinder bore of the small diameter part of the piston is communicated with the master cylinder. Anti skid braking device for vehicles.