JPS5937259B2 - Anti skid brake device for vehicles - Google Patents

Description

Detailed Description of the Invention The present invention provides a control hydraulic circuit that suppresses the braking action of a braking device when the braking force of the braking device is too large. The present invention relates to an anti-skid brake device for a vehicle that is provided with a safety valve so that the brake device can always perform its braking function normally even if the brake device fails in the same state.

When the brake system is activated to brake the rotation of the wheels while the vehicle is running, the braking force is too large and the wheels are knocked on their heads.
A so-called skidding condition occurs, which is extremely dangerous because not only the braking effect is reduced but also the directional stability and steering performance of the vehicle are deteriorated.

Therefore, an anti-skid brake device for a vehicle is being considered that is equipped with a control device that controls the operation of the brake device so as to suppress the braking action of the brake device when the braking force of the brake device is too large. If the control device fails while the braking operation of the braking device is inhibited, the braking device will no longer be able to perform braking. If a control hydraulic circuit that hydraulically controls the operation of the brake system is used as a control device to control the operation of the brake system, the anti-skid brake system can be easily installed, has a simple structure, and has relatively few failures. However, it is common for the control oil control circuit to include an electromagnetic switching valve, electrical devices that control the opening and closing operations of the electromagnetic switching valve, and various hydraulic devices. Technically, it is extremely difficult to completely eliminate failures in equipment and equipment.

The optimal braking force is greatly influenced by the condition of the surface on which the vehicle is running, but while the anti-skid brake system is operating normally, if the braking force is too large, the brake system will not operate properly. The braking action and the braking inhibiting action by the control device occur alternately as the vehicle decelerates, and the control device does not continuously inhibit the braking action of the braking device.

At this time, the level of braking inhibiting force provided by the control device is greatly influenced by the state of the running surface. However, if the anti-skid brake device fails while the braking action of the braking device is being inhibited, the braking inhibiting action by the control device continues to persist for more than a certain period of time regardless of the state of the running surface.
Therefore, a failure of the anti-skid brake device can be detected when the braking inhibiting effect continues for more than a certain period of time, but in this state, braking by the brake device is impossible. This is extremely dangerous for moving vehicles. In view of the above points, the main object of the present invention is to provide an anti-skid brake device for a vehicle, which includes a safety device for a control device that controls the braking operation of the brake device.

Another object of the present invention is to provide a control hydraulic circuit for hydraulically controlling the operation of the braking device as a control device for controlling the braking operation of the braking device, and to prevent any equipment or equipment related to the control hydraulic circuit from malfunctioning. To provide an anti-skid brake device for a vehicle, which is equipped with a safety device that can ensure the normal braking operation of the braking device by reliably exhibiting its safety function. According to the present invention, an anti-skid brake device for a vehicle is provided with a safety valve that releases the control hydraulic pressure to the outside of the control system when the control oil field circuit continues to supply the oil field as output for a certain period of time or more. is obtained.

Hereinafter, embodiments of the present invention will be described according to the drawings. First, in FIG. It communicates with the input section of the wheel cylinder 1 that constitutes the braking device 6 via the input section.

A pair of pistons 8 and 9 slidingly contact each other while facing each other in the wheel cylinder 7 have rods 10 and 11, respectively.
Brake shoes 12 and 13 are connected via
By introducing royal oil into the oil chamber formed between the opposing surfaces of each piston 8, 9, each brake shoe 12, 1
3 is pushed toward the outside and frictionally engages with a brake liner of a wheel (not shown) to brake the rotation of the wheel. The casing 14 of the brake hydraulic control device 4 includes a valve chamber 15 that communicates with the oil passage 3 through an opening 18, a cylinder chamber 16, and a cylinder chamber 16 that penetrates between the valve chamber 15 and the cylinder chamber 16 and has an opening 19. Through hole 1 communicating with oil passage 5 through
7 is formed, and a piston 23 that operates integrally with a valve ball 22 in the valve chamber 15 is slidably fitted into the cylinder chamber 16 via a connecting rod 21 passing through the through hole 17. has been done.

The outer diameter of the connecting rod 21 is suitably smaller than the inner diameter of the through hole 17, and the connecting rod 21 slides onto the inner wall surface of the through hole 17 via the sealing member at a position between the opening 19 and the cylinder chamber 16. It is supported in a freely accessible manner. Further, the valve ball 22 is always elastically pressed toward the cylinder chamber 16 by an Oshida spring 24 in the valve chamber 15, and the piston 23 is always elastically pressed toward the valve chamber 15 by a pusher spring 25 in the cylinder chamber 16. It is being pushed. The pressing force of the Oshida spring 25 is sufficiently larger than the pressing force of the Oshida spring 24, and normally the piston 2
3 is located in the cylinder chamber 16 at a position close to the end wall on the valve chamber 15 side, and the valve ball 22 is spaced apart from the opening end of the through hole 17 and connects the valve chamber 15 to the oil passage 5 through the opening 19.
is connected to. The pinuton 23 is the valve chamber 1 of the cylinder 16
Even when the piston 2 is closest to the end wall on the 5 side,
3 and the end wall of the cylinder 16 on the valve chamber 15 side. It has an opening 20 so as to communicate with the output section.

In the control hydraulic circuit 26, the hydraulic oil sucked and pressurized from the oil tank T by the pump P is passed through check valves 27 and 28.
The oil is sent to the storage vessel 29 through an oil passage 31 equipped with a.

An on-off valve 30 is disposed in the middle of the oil passage 31 between the pressure accumulator 29 and the opening 20, and an on-off valve 33 is disposed on the way from the oil passage 31 between the on-off valve 30 and the opening 20. The oil passage 32 which has an oil tank T and communicates with the oil tank T is branched. Each on-off valve 30, 33 is electromagnetically operated in response to an output signal from the computer 34. this computer 3
4 determines whether there is a risk of wheel locking based on the output of the wheel angular velocity sensor 35, and opens the on-off valve 30 when the braking force is too large, that is, when there is a risk of wheel locking. At the same time, the on-off valves 30, 33 are switched to the closed state, and when the braking force is acting properly, the on-off valves 30 and 33 are kept in the closed state, and the on-off valves 33 are kept in the open state. control. Thus, while the braking force from the braking device 6 is properly acting on the wheels, the oil chamber A is isolated from the pressure accumulator 29 by the on-off valve 30 and communicated with the oil tank T through the on-off valve 33. and
Since the piston 23 is pressed and moved toward the valve chamber 15 by the pushing spring 25, the braking oil field generated by the master cylinder 2 passes through the valve chamber 15 and is transferred to the wheel cylinder 7.
transmitted to.

Also, if the braking force by the first movement device 6 is too large, the oil chamber A
Since the on-off valve 33 is closed and disconnected from the oil tank T, and the on-off valve 30 is open, the pressure oil that has passed through the storage device 29 passes through the on-off valve 30 and the opening 20 into the oil chamber A. As a result, the valve ball 22 closes the opening of the through hole 17 and flows into the wheel cylinder 7, pushing the piston 23 toward the opposite side of the valve chamber 15 against the pressing force of the Oshida spring 25. In addition to preventing further inflow of braking oil from the master cylinder 2, pressure oil also flows into the oil chamber A from the pressure accumulator 29, so that the piston 23 and the connecting rod 21 integrally formed therewith are prevented. further retreats, connecting rod 2
1 is retreated within the through hole 17, the volume of the portion communicating with the wheel cylinder 7 increases, and accordingly, the braking oil pressure decreases, and therefore the braking force decreases.
Wheel locking is prevented. As a result, if the risk of wheel locking is reduced, the computer 34 determines this;
Each on-off valve 30, 33 is returned to its initial state again, and the braking force increases again. By the way, the on-off valve 30
If a failure occurs in any part of the control hydraulic circuit 26, the sensor 35, or the computer 34 while the on-off valve 33 is in the open state and the on-off valve 33 is in the closed state, and switching between the on-off valves 30 and 33 becomes impossible. , the piston 23 remains pressed and moved to the side opposite to the valve chamber 15 against the pressing force of the pressing spring 25, and the braking device 6 no longer functions normally.

In order to avoid such a dangerous situation, an oil passage 36 is branched from an oil passage 31 between the on-off valve 30 and the opening 20 to a safety valve 37 that communicates with the oil tank T via an oil passage 38. There is. The detailed structure of this safety valve 37 will be described later.
FIG. 2 illustrates a different type of anti-skid brake device from that shown in FIG.

A master cylinder 2'' operated by a brake pedal 1'' has a pair of pistons 8'' and 9 facing each other in a wheel cylinder 7' of a braking device 6' via an oil passage 3''.
' are fitted in such a way that they can be slid into contact with each other, and each piston 8', 9'
Brake shoes 12' and 13' are connected to the brake shoes 12' and 13' through rods 10' and 1'', respectively.The principle of braking the wheels by these brake shoes 12' and 13' is as follows.
The principle of braking the wheels by the brake shoes 12 and 13 in the figure is similar. Oil chambers A'' and N are formed on the back pressure side of each piston 8'' and 9b, respectively, and these oil chambers N and N are connected to a control hydraulic circuit 26 via an oil passage 39, respectively.
6 oil passage 31'.

In the control hydraulic circuit 26', the hydraulic oil sucked from the oil tank T'' by the pump P' and pressurized is passed through the check valve 27.
The oil is sent to the pressure accumulator 29' through an oil passage 31' having pressure accumulators 29'' and 28''.In the middle of the oil passage 31' between the pressure accumulator 29'' and the oil passage 39, there is an on-off valve 30. ', and from the oil passage 31' between the on-off valve 30' and the oil passage 39, there is an oil passage 32'' which has an on-off valve 33' in the middle and communicates with the oil tank T'. The computer 34' receives the output of the wheel angular velocity sensor 35'', and when the braking force is too large, opens the on-off valve 30'' and switches the on-off valve 33'' to the closed state.
Also, when the braking force is working properly, the on-off valve 305
The on-off valves 30' and 33'' are controlled to keep the on-off valve 33' closed and the on-off valve 33' open.Thus, while the braking force from the braking device 6' is properly acting on the wheels, The braking hydraulic pressure generated by the master cylinder 2' is transmitted to the wheel cylinder 7'' and each piston 8''
, 91 are moved in the direction of force away from each other, and the hydraulic oil in each oil chamber N, N is discharged from the oil tank Tk via the oil passage 39, oil passage 31', oil passage 32' and on-off valve 33'. Also, if the braking force of the braking device 61 is too large, the pressure accumulator 2
The pressure oil that has passed through 95 passes through an on-off valve 30'' and an oil passage 39,
The oil flows into each oil chamber A', N and presses each piston 8'', 9'' from the rear side to counter the pressing force of the pressure oil sent from the master cylinder 2θ). At this time, the control oil king circuit 26'
．． If a failure occurs in any part of the sensor 35 (or the computer 34') and switching of the on-off valves 30'', 33'0 becomes impossible, the pistons 8', 9' are pushed toward each other. In order to avoid such a dangerous situation, the oil passage 39 is connected to the safety valve 37' which communicates with the oil tank T' via the oil passage 385. The oil passage 36'' is branched.The structure of the safety valve 37'' is exactly the same as that of the safety valve 37 shown in FIG.

Therefore, the safety valve 37 shown in FIG. 1 will be explained in detail below. In FIG. 3, the casing 40 of the safety valve 37
Inside, a large-diameter cylinder part 41, a large-diameter relief part 42, a small-diameter cylinder part 43, and a small-diameter relief part 44 are formed in order in the axial direction, and on the inner surface side of the end wall near the large-diameter cylinder part 41. A protrusion 45 is formed.

The spool 46 includes a large diameter portion 47 that slides on the inner circumferential surface of the large diameter cylinder portion 41 in the axial direction, a small diameter portion 49 that slides on the inner circumferential surface of the small diameter cylinder portion 43 in the axial direction, and a large diameter portion. The spool 46 has a constricted portion 48 connecting the small diameter portion 47 and the small diameter portion 49, and the spool 46 is normally pressed toward the projection 45 by a pressing spring 53 within the small diameter relief portion 44. The end wall of the casing 40 near the large diameter cylinder portion 41 and the large diameter portion 4 of the spool 46
The opening 54 communicating with the oil chamber 50 between the check valve 58 and the
The opening communicates with the oil chamber A in FIG. 55 is connected to the orifice 5 via the oil passage 60.
7 and an oil passage 36 between the oil chamber A and the oil chamber A.

Further, an oil chamber 52 between the large diameter relief portion 42 and the constriction portion 48
The opening 56 that communicates with the oil tank T via the oil passage 38 communicates with the oil tank T. When the braking force is too large and the hydraulic circuit 26 is activated and royal oil flows into the oil chamber A, pressure oil also flows into the oil chamber 50 through the orifice 57 and flows through the oil path 60. Pressure oil also flows into the oil chamber 51.

At this time, each receiving field area of the large diameter part 47 and the small diameter part 49,
By appropriately selecting the pressing force of the pressing spring 53, the spool 46 moves toward the oil chamber 51, but since the royal oil flowing into the oil chamber 50 flows through the orifice 57,
Its inflow speed is considerably slower than the inflow speed of royal oil flowing into the oil chamber A. Therefore, while the piston 23 of the brake hydraulic control device 4 moves quickly, the spool 46 moves relatively slowly. Move with speed. During this time, the hydraulic oil in the oil chamber 52 is discharged to the oil tank T through the opening 56 and the oil passage 38. When the control hydraulic circuit 26 returns to normal state and the supply of royal oil into the oil chamber A is stopped and the oil chamber A communicates with the oil tank T, the supply of royal oil into the oil chamber 50 is also stopped at the same time, and the spool 4
6 is moved toward the oil chamber 50 by the pushing force of the spring 53.

During this time, part of the hydraulic oil in the oil chamber 50 flows into the oil chamber 51 through the check valve 58, and the remaining portion is returned to the oil tank T through the on-off valve 33. From then on, as long as the spool 1 power is too large, based on the operation of the control oil field circuit 26, the spool 4
The reciprocating motion of 6 is manipulated back. If the control hydraulic circuit 26 fails while supplying oil to the oil chamber A, the spool 4
6 continues to move beyond the amount of movement under normal operating conditions, until the large diameter portion 47 is finally pushed into the large diameter relief portion 42 and the small diameter portion 49 is pushed into the small diameter relief portion 44 at the same time.

As a result, the oil chamber 50 communicates with the oil chamber 52, and the oil chamber 51 also communicates with the oil chamber 52, and the oil in the oil chamber A flows through the oil passage 36.
, the oil chamber 50, the oil chamber 52, and the oil passage 38, and is discharged to the oil tank T via the oil passage 60, the oil chamber 51, the oil chamber 52, and the oil passage 38. That is, the safety valve 37 compensates for the failure of the control oil pressure circuit 26 and provides a safety function for the braking device 6. When the safety valve 37 shown in FIG. 3 is applied to the safety valve 37'0) position in FIG. 2, the oil passage 36 in FIG. 3 is communicated with the oil passage 39 in FIG.
The oil passage 38 shown in the figure communicates with the oil tank T'' shown in FIG.

Therefore, the spool 46 operates under the influence of the oil bottles in the oil chamber A5 and the oil chamber N. If the control oil field circuit 26' fails while a substantially constant amount of oil is being supplied to the oil chamber N and the oil chamber Since the oil pressures become equal, after a certain period of time, the large diameter part 41 is pushed into the large diameter relief part 42 and the small diameter part 49 is pushed into the small diameter relief part 44,
The oil chamber N and the oil chamber N are connected to an oil passage 39, a safety valve 37, and an oil passage 3.
8 and communicates with the oil tank T'.

Thus, the safety valve 37 compensates for a failure of the control oil pressure circuit 26' and provides a safety function for the brake system 6'. As described above, according to the anti-skid brake device for a vehicle of the present invention, when the control hydraulic pressure of the control hydraulic circuit is continuously supplied to the oil pressure output section of the control oil pressure circuit for a certain period of time or more, the control oil pressure Since the safety valve is connected to the outside of the control system, even if any device or equipment in the anti-skid device fails, the safety valve will surely perform its safety function and the braking device will be able to perform its normal braking action. can be guaranteed.

Furthermore, the safety valve is configured to include first, second, and third oil chambers, and a spool that is operated by the pressure force of the oil king and push king spring in the first and second oil chambers. It has a simple structure and can be operated reliably by hydraulic pressure. Furthermore, on the pressure-receiving surface side of the safety valve spool, which has a relatively small area, the same hydraulic pressure as in an oil field that acts on the relatively large-area receiving surface side acts in cooperation with the pressure force of the pressure spring. Even if the output oil pressure of the control oil field circuit fluctuates at a high level, as long as the anti-skid brake device is operating normally, the output oil field of the control oil field circuit will not be accidentally released outside the control system. There is no risk of damage.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the main parts showing one embodiment of the anti-skid brake device for a vehicle of the present invention, FIG. 2 is a schematic explanatory diagram of the main parts similar to FIG. 1 showing another embodiment of the present invention, Third
The figure is a longitudinal cross-sectional view showing an example of a safety valve used in the anti-skid brake device for a vehicle according to the present invention. 6, 6'... Braking device, 26, 26'...
-・Control oil king circuit, 37, 37′-・・Installation valve, 4
6...Spool, 50...First oil chamber, 51...Second oil chamber, 52...Third
Oil chamber, 53... Pressing spring, 57...
Orifice.

Claims (1)

[Claims] 1 The braking devices 6, 6' are operated by the braking hydraulic pressure generated in response to the braking input, and when the braking force of the braking devices 6, 6' is too large, the braking action of the braking devices 6, 6' is inhibited. The control hydraulic circuits 26, 26' which hydraulically control the operation of the braking devices 6, 6' include safety valves 37, 3.
7', the safety valves 37, 37' include a spool 46 which has a pressure receiving surface with a relatively large area on one end side and a pressure receiving surface with a relatively small area on the other end side, and a A first for applying the hydraulic pressure of the output pressure oil of the control hydraulic circuits 26, 26' to the relatively large pressure receiving surface to press the spool 46 in one direction.
The hydraulic pressure of the output pressure oil from the oil chamber 50 and the control hydraulic circuits 26 and 26' is applied directly to the pressure receiving surface of the relatively small area, and cooperates with the pressing force of the pressing spring 53 to push the spool 46. When the output pressure oil of the control hydraulic circuits 26 and 26' is continuously supplied to the second oil chamber 51 for pressing by other force, the spool 46 is moved to the second oil chamber 51 for pressing by another force.
1 side and a third oil chamber 52 for discharging the output pressure oil of the control hydraulic circuits 26, 26' to the outside of the control system.