JPS5937261B2 - 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 operating the brake system to brake the rotation of the wheels while the vehicle is running, if the braking force is too large, the wheels may be 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. As a control device for controlling the operation of the braking device, it is easy to control by using a control hydraulic circuit that uses hydraulic pressure to control the operation of the control device.
Although the anti-skid brake device has a simple structure and relatively few failures, the control hydraulic circuit includes an electromagnetic switching valve, electrical devices that control the opening and closing operations of this electromagnetic switching valve, and various other devices. Hydraulic equipment and the like are usually incorporated, and it is technically extremely difficult to completely eliminate failures in these various devices and devices.

The optimum braking force is greatly affected 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 braking force will not be used. The braking inhibiting action by the control device occurs alternately as the vehicle decelerates, and the control device does not continuously inhibit the braking action of the braking device.

The level of the braking inhibiting force exerted by the control device at this time is greatly influenced by the state of the running surface. However, if the anti-skid brake device fails while the braking action of the brake device is being inhibited, the braking inhibiting action by the control device continues to continue beyond a certain period of time regardless of the state of the running surface. Therefore, it is possible to detect a malfunction of the anti-slip brake system when the brake suppression effect continues for a certain period of time, but in this state, braking by the brake system is not possible. 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 braking device for a vehicle, which is provided with a safety device for a control device that controls the braking action of a braking device. be.

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. Another object of the present invention is to provide an anti-skid brake device for a vehicle, which is equipped with a safety device that can reliably exhibit its safety function and ensure normal braking operation of the brake device. 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 hydraulic circuit continues to supply the control hydraulic pressure as an output for a certain period of time or more. can get.

Hereinafter, embodiments of the present invention will be described according to the drawings. First, in FIG. The input portion of the wheel cylinder 7 constituting the braking device 6 is communicated via the input portion of the wheel cylinder 7 .

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 pressure oil into the oil chamber formed between the opposing surfaces of each piston 8, 9, each brake shoe 12, 1
3 is pressed outward 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 is in sliding contact with the inner wall surface of the through hole 17 via a sealing member at a position between the opening 19 and the cylinder chamber 16. freely supported. Further, the valve ball 22 is connected to the valve chamber 1
The piston 23 is always elastically pressed toward the cylinder chamber 16 by a pressing spring 24 in the cylinder chamber 16, and the piston 23 is always elastically pressed toward the valve chamber 15 by a pressing spring 25 inside the cylinder chamber 16. The pressing force of the pressing spring 25 is the pressing force of the pressing spring 2.
4, and is normally sufficiently larger than the pressing force of piston 23.
is located close to the end wall on the valve chamber 15 side within the cylinder chamber 16, and the valve ball 22 is spaced apart from the opening end of the through hole 17, communicating the valve chamber 15 with the oil passage 5 through the opening 19. are doing. The piston 23 is located in the valve chamber 1 of the cylinder chamber 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 section.

In the control hydraulic circuit 26, the hydraulic oil sucked from the oil tank T by the pump P and pressurized is supplied to the reverse city valves 27, 28.
It is designed to be sent to the pressure accumulator 29 through an oil path 31 equipped with.

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 and 33 are switched to the closed state, and the on-off valves 30 and 33 are kept in the closed state when the braking force is acting properly, 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. Since the piston 23 is pressed by the pressure spring 25 and moved toward the valve chamber 15, the braking oil pressure generated by the master cylinder 2 is transmitted to the wheel cylinder 7 via the valve chamber 15.

Also, if the braking force by the braking 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 pressure accumulator 29 enters the oil chamber A through the on-off valve 30 and the opening 20. The valve ball 22 closes the opening of the through hole 17 and prevents any further flow into the wheel cylinder 7. In addition to preventing the braking hydraulic pressure from flowing into the master cylinder 2, pressure oil also flows into the oil chamber A from the pressure accumulator 29. Retract, 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 valves 33 are in the open state and the on-off valves 33 are 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'' actuated by a brake pedal 1'' communicates with a wheel cylinder 7' of a braking device 6'' via an oil passage 3''. A pair of pistons 8'' and 9'' facing each other are fitted into the wheel cylinder 7' so as to be able to freely slide into contact with each other, and brake shoes are connected to each piston 8'' and 9'' via rods 1'' and 1'', respectively. 12″,
13" are connected. These brake shoes 12
The principle of braking the wheels by the brake shoes 12, 13 in FIG. 1 is the same as the principle of braking the wheels by the brake shoes 12, 13 in FIG. ″″ is formed, and these oil chambers A″
, A'' are connected to the control hydraulic circuit 26 via oil passages 39, respectively.
In the control hydraulic circuit 261, the hydraulic oil suctioned from the oil tank T' and pressurized by the pump P' is connected to the oil passage 3', which is provided with check valves 27' and 28''. The oil is sent to the pressure accumulator 29'' via oil line 3''. An on-off valve 3' is disposed in the middle of the oil passage 3' between the pressure accumulator 29' and the oil passage 39, and this on-off valve 3'
From the oil passage 31″ between the oil passage 39 and the oil passage 39, there is an on-off valve 3
An oil passage 32 having a diameter of 3" and communicating with an 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 3' and closes the on-off valve 33.
' is switched to the closed state, and when the braking force is working properly, the on-off valve 3' is kept in the closed state, and the on-off valve 3' is switched to the closed state.
Each on-off valve 3'', 33'' is controlled so as to keep valve 3'' open. Thus, while the braking force from the control device 6'' is properly acting on the wheels, the braking oil pressure generated by the master cylinder 2' is transmitted to the wheel cylinder 7'' to separate the pistons 8'' and 9'' from each other. At the same time, the hydraulic oil in each oil chamber A', A'' is discharged to the oil tank T'' through the oil passage 39, the oil passage 31', the oil passage 32', and the on-off valve 33''.

Furthermore, if the braking force of the braking device 6'' is too large, the pressure oil that has passed through the pressure accumulator 295 will flow into the oil chambers A'' and A'' through the on-off valve 3'' and the oil passage 39, and will flow into each piston 8''. ，
9'' from the back pressure side to counter the pressing force of the pressure oil sent from the master cylinder 2''. At this time, if a failure occurs in any part of the control hydraulic circuit 26'', sensor 35'' or computer 34'' and switching of the on-off valves 3'' and 33'' becomes impossible, the pistons 8' and 9'' will The braking device 6 remains pressed in the approaching direction.
' will no longer function properly. In order to avoid such a dangerous situation, an oil path 36'' branches from the oil path 39 to a safety valve 337' that communicates with the oil tank T/ via an oil path 38'.Structure of the safety valve 3U is the safety valve 37 in Figure 1.
It is acceptable if the structure is exactly the same as that of .

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
A large-diameter cylinder part 41 and a small-diameter cylinder part 42 are formed inside, and a large-diameter part 44 that slides in axial contact within the large-diameter cylinder part 41 and a small-diameter cylinder part 44 that slides in axial contact within the small-diameter cylinder part 42 are formed. The spool 43 having a portion 45 is pressed by a pressure spring 47 in an oil chamber 49 formed by the small diameter cylinder portion 42, and normally hits a shoulder portion 46 formed on the end wall on the large diameter cylinder portion 41 side. An oil chamber 48 is formed between the end wall and the end wall on the large diameter cylinder portion 41 side.

A valve hole 50 is provided in the end wall portion of the small diameter cylinder portion 42, and a pressing spring 51 interposed between the valve hole 50 and the lid member 54 is provided.
A check valve 71 is formed which has a valve ball 52 that is normally closed by the valve ball 52 that is pressed by the valve ball 52 .

The opening 65 that communicates with the oil chamber 48 communicates with the oil chamber A in FIG. 1 via an oil path φ that has an orifice 64 in the middle that includes an oil path 68 having a check valve 67 as a bypass path. Further, the opening 66 communicating with the oil chamber 49 communicates with the oil passage 36 between the orifice 64 and the oil chamber A via an oil passage 72. Furthermore, the opening 53 that communicates with the oil chamber 49 via the check valve 71 communicates with the oil tank T in FIG. 1 via the oil passage 38. A spool 4 is provided on the outside of the large diameter cylinder portion 41.
A return inhibiting device 55 is provided to restrict the movement of the switch 69.
switch boxes 59 are arranged in series.

A sliding rod 58 that is constantly pressed toward the large-diameter cylinder portion 41 by a pressing spring 57 is slidably fitted into a spring chamber 56 formed inside the return inhibiting device 55 . The inner end of the sliding rod 58 passes through the large diameter cylinder part 41 and normally comes into contact with the outer circumferential surface of the large diameter part 44 of the spool 43, and the outer end of the sliding rod 58 passes through the large diameter cylinder part 41. It protrudes inward, and a contact 61 connected to an electrical device 62 such as a computer that operates the switching valves 30 and 33 is provided at its tip. A contact 60 connected to a power source 63 is provided on the switch box 59 side at a position opposite to this contact 61, and normally both contacts 60 and 61 are in contact with each other. A protrusion 70 protrudes in the axial direction from the end face of the spool 43 on the small diameter portion 45 side, and when the spool 43 is pushed and moved over a certain distance toward the oil chamber 49 side against the pressing force of the pressing spring 47, the protrusion 70 70 penetrates the valve hole 50 to press and move the valve ball 52 against the pressing force of the pressing spring 51, thereby opening the check valve 71.

At this time, the large diameter portion 44 simultaneously passes the tip of the sliding rod 58, causing the sliding rod 58 to press against the pressing spring 5.
7 into the oil chamber 48, and as a result, the electrical equipment 62 is cut off from the power source 63. When the braking force is too large and the control hydraulic circuit 26 is activated and pressure oil flows into the oil chamber A, pressure oil simultaneously flows into the oil chamber 48 through the orifice 64 and also through the oil path 72. Pressure oil also flows into the oil chamber 49.

At this time, the pressing force of the pressing spring 51 is adjusted to such an extent that the reverse city valve 71 does not allow pressure oil to pass through only due to the pressure oil in the oil chamber 49. Furthermore, by appropriately selecting the pressure receiving areas of the large diameter portion 44 and the small diameter portion 45 and the pressing force of the pressing spring 47, the spool 43 can be moved toward the oil chamber 49.
Since the pressure oil flowing into the chamber 48 flows through the orifice 64, its inflow speed is considerably slower than the inflow speed of the pressure oil flowing into the oil chamber A. Therefore, the piston of the brake hydraulic control device 4 23 moves quickly, whereas spool 43 moves at a relatively slow speed. During this time, oil chamber 49
The pressure oil inside moves into the oil chamber 48 via the oil passages 72 and 36. When the control hydraulic circuit 26 returns to normal state and the supply of pressure oil to the hydraulic pressure A is stopped, and the oil chamber A communicates with the oil tank T, the supply of pressure oil to the oil chamber 48 is also stopped at the same time, and the spool 43 is moved toward the oil chamber 48 by the pressing force of the pressing spring 47.

During this time, a portion of the hydraulic oil in the oil chamber 48 flows into the oil chamber 49 through the check valve 67 and the oil passage 36, and the remainder is returned to the oil tank T through the on-off valve 33. Thereafter, as long as the braking force is too large, the reciprocating motion of the spool 43 is repeated based on the operation of the control hydraulic circuit 26. Control hydraulic circuit 2
6 fails while supplying pressure oil at a constant pressure to the oil chamber A, the pressure oil in the oil chamber 48 and the oil pressure in the oil chamber 49 will eventually become equal, and the spool 43 will not operate normally. The projection 70 presses the valve ball 52 to open the check valve 71, and the sliding rod 58 protrudes from the large-diameter cylinder portion 41 into the oil chamber 48 to open the spool. 43 from returning to the oil chamber 48 side.

As a result, the pressure oil in the oil chamber A is discharged to the oil tank T via the oil passage 36, the oil passage 72, the oil chamber 49, the check valve 71, and the oil passage 38, and the electrical equipment 62 is cut off from the power source 63. Ru. That is, the safety valve 37 compensates for a failure of the control hydraulic 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 position of the safety valve 375 in FIG. 2, the oil passage 36 in FIG. 3 is communicated with the oil passage 39 in FIG. Channel 38 communicates with oil tank T' in FIG. Therefore, spool 4
3 operates in response to the oil pressure in oil chambers A' and A''''. If the control hydraulic circuit 26' fails while constant pressure oil is still being supplied to the oil chamber A' and the oil chamber A/'', the protrusion 70 will close the valve ball 52 after a certain period of time. Press to open the reverse city valve 71, and the sliding rod 58 opens the oil chamber 4.
By protruding into 8, electrical equipment 62 is disconnected from power supply 63.

The oil chamber A'' and the oil chamber A''5 are connected to the oil passage 36 and the oil passage 7.
2. Oil tank T' via oil chamber 49, check valve 71, and oil passage 38
will be communicated to. Thus, the safety valve 37 is connected to the control hydraulic circuit 2.
6'' and provides a safety function for the braking device 6''. As described above, according to the vehicle anti-skid brake device of the present invention, the hydraulic output section of the control hydraulic circuit has
When the control hydraulic pressure of the control hydraulic circuit is supplied for a certain period of time or more, a safety valve is connected to release the control hydraulic pressure outside the control system, so there is no possibility that any device or equipment in the anti-skid system will malfunction. However, the safety valve can reliably perform its safety function and ensure the normal braking operation of the braking device.

Furthermore, the safety valve has a check valve that releases the output hydraulic pressure of the control hydraulic circuit to the outside of the control system in response to movement of the spool when the output hydraulic pressure of the control hydraulic circuit is continuously supplied for a certain period of time or more. Therefore, its simple structure allows it to perform its functions safely and reliably. Furthermore, the second spool
When the spool moves more than a certain amount to the side of the oil chamber, the
Since the safety valve has a return prevention device that prevents the oil from returning to the oil chamber side, the safety valve can reliably maintain its safety function.

[Brief explanation of the drawing]

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 hydraulic circuit, 37,3U...Safety valve, 4
3... Spool, 47... Pressing spring,
48...First oil chamber, 49...Second oil chamber, 55 Return prevention device.

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. In the anti-skid brake system for a vehicle, the control hydraulic circuits 26, 26' are equipped with safety valves 37, 37', which hydraulically control the operation of the braking devices 6, 6'. The safety valves 37, 37' include a spool 43 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 the control hydraulic pressure after passing through the orifice. a first oil chamber 48 for applying the hydraulic pressure of the output pressure oil of the circuits 26, 26' to the relatively large pressure receiving surface to press the spool 43 in one direction; and the control hydraulic circuits 26, 26'. a second oil chamber 49 for directly applying the hydraulic pressure of the output pressure oil to the pressure receiving surface of the relatively small area to press the spool 43 toward the other side in cooperation with the pressing force of the pressing spring 47; When the output pressure oil of the control hydraulic circuits 26, 26' is continuously supplied for a certain period of time or more and the spool 43 moves to the second oil chamber 49 side by a certain amount or more, the spool 43 responds to The control hydraulic circuit 2
Check valve 71 that releases the output hydraulic pressure of 6 and 26' to the outside of the control system.
At the same time as this check valve 71 opens, the spool 4
3. A vehicular anti-skid brake device comprising: a return prevention device 55 for inhibiting a return of No. 3 to the first oil chamber 48 side.