JPS6078853A - Antiskid device for automobile - Google Patents

Abstract

PURPOSE:To check a sudden rise in pressure in time of reopening a cut valve which has once closed, and prevent any operating delay from occurring, by constituting a piston, forming a valve seat of the cut valve, with a stepped piston making the side of a master cylinder into a small diameter but a large diameter in the side of a wheel cylinder, respectively. CONSTITUTION:A valve seat 157 of a cut valve 44 is formed with a stepped piston 147, while its large diametral part 149 is set up at the side of a wheel cylinder and its small diametral part 150 at the side of a master cylinder, respectively. When a brake fluid pressure regulating piston 46 is shifted to the left by skid generation, the cut valve 44 closes. When the cut valve 44 is reopened by skid solution, hydraulic pressure at the wheel cylinder side is held down to being lower than that of the master cylinder side. Therefore, in time of reopening the cut valve 44, a sudden rise in brake pressure is checked. In addition, a stroke of the stepped piston 147 is as well held down to the specified extent whereby at normal time, the cut valve opens with certainty, thus any operating delay is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an anti-skid device that prevents wheels from locking and skidding against the road surface when a hydraulic brake system for an automobile is activated.

One type of conventional anti-skid device is a cut valve that is provided in a liquid passage connecting a mask cylinder and a wheel cylinder and that divides the liquid passage into a mask cylinder side liquid passage and a wheel cylinder side liquid passage, and the cut valve. Some systems include a brake fluid pressure adjusting piston that opens and closes the cut valve and adjusts the braking fluid pressure on the wheel cylinder side, and a power fluid pressure control device that controls the power fluid pressure for operating the piston. The brake fluid pressure adjusting piston communicates with the wheel cylinder side fluid passage, and is fluid-tightly and slidably provided in the housing. The wheel cylinder is configured to receive the brake fluid pressure in the pressure chamber and to receive the power fluid pressure in the power fluid pressure chamber on the second pressure receiving surface. T: Monitors the skid state of the wheels, and when the wheels are not in the skid state, supplies the hydraulic pressure generated by the power to the power hydraulic pressure chamber, detects the skid state, and when the wheel is not in the skid state, the power hydraulic pressure chamber is activated. When the hydraulic pressure in the power hydraulic pressure chamber is decreased, the brake hydraulic pressure adjusting piston moves back toward the power hydraulic pressure chamber to increase the volume of the brake hydraulic chamber, and also increases the volume of the brake hydraulic pressure chamber. Close, open, when the hydraulic pressure in the power hydraulic pressure chamber is increased, advance toward the flake hydraulic pressure chamber to reduce the volume of the brake hydraulic chamber, and cut 5.
Open F.

In this way, the brake fluid pressure in the wheel cylinder is controlled by opening and closing the cut valve by the brake fluid pressure regulating piston and by increasing and decreasing the volume of the brake fluid pressure chamber that communicates with the wheel cylinder side fluid passage. In the unlikely event that you fall into a skid situation,
Even in this case, the skid condition will be resolved quickly. Note that the skid condition here does not necessarily refer to a condition where the wheels have completely stopped and are slipping between them and the road surface. It does not refer to a specific term, but rather indicates that the slippage between the wheels and the road surface has reached a predetermined value (fLf) or higher, resulting in failure.

Such an anti-skid device monitors whether a skid condition actually occurs and controls the wheel cylinder hydraulic pressure. It is possible to efficiently decelerate or stop each vehicle one by one, preventing any vehicle from becoming incapacitated.

However, in the conventional anti-skid device, there is a risk that the skid state will occur again as soon as the cut valve is opened once the skid state occurs and the cut valve is opened. After the cut valve is closed, if the driver depresses the brake pedal further, high pressure brake fluid is supplied to the wheel cylinder at the same time as the cut valve opens.1. This kind of problem can be solved by reducing the liquid passage area, but in this case, the valve 1/-
Even at the time when a large needle of brake fluid is required at the beginning of the brake operation, the flow of brake fluid is restricted, causing a delay in the operation of the brake ↓.

OBJECTS OF THE INVENTION In order to solve these problems, the present invention is capable of preventing as much as possible an undesirable increase in wheel cylinder hydraulic pressure when the cut valve is once closed and opened.
The purpose of this invention is to provide an anti-skid device equipped with a cut valve that allows a sufficient flow of brake fluid to pass through during normal brake operation.

Structure of the Invention The present invention is characterized in that, as described above, in an anti-skid device including a cut valve, a brake fluid pressure regulating piston, and a power fluid pressure control device, the cut valve is The large diameter part and the small diameter part have a large diameter hole on the brake fluid pressure adjusting piston side and a small diameter hole on the mask cylinder side liquid passage side. The space inside the stepped hole is fluid-tightly fitted into the large-diameter hole and the small-diameter hole, and the space within the stepped hole is communicated with the mask cylinder side liquid passage, and the first hydraulic pressure chamber and the brake hydraulic pressure chamber are communicated with each other. It is divided into a second hydraulic pressure chamber and an intermediate air chamber,
a stepped piston that is movable within a certain stroke range in a direction parallel to the axis of the brake fluid pressure adjusting piston;
3) a through hole formed in the stepped piston to communicate the first hydraulic pressure chamber and the second hydraulic chamber, and (C) a through hole around the opening of the through hole on the first hydraulic pressure chamber side. (d) a valve element which is normally seated on the valve seat by a spring but is moved away from the valve seat by the advancement of the brake fluid pressure regulating piston; This includes: 1.

Effects of the Invention When the anti-skid device is equipped with such a cut valve, the skid state is stopped and the brake fluid pressure regulating piston is moved forward. When the valve element of the cut valve is formed in the stepped piston and is separated from the valve seat, the first hydraulic pressure chamber and the second hydraulic pressure chamber are communicated with each other. The hydraulic pressure in the two liquid ratio chambers is increased, but the stepped piston lowers the liquid pressure in the second hydraulic pressure chamber to be higher than the hydraulic pressure in the first hydraulic pressure chamber based on the difference in pressure receiving area between its large diameter part and small diameter part. The valve moves at a predetermined rate (t) to maintain a very low value.Second, the valve is seated again on the valve seat of the stepped piston, and the rise in wheel cylinder hydraulic pressure is kept relatively low. At the same time, the rapid increase in wheel cylinder hydraulic pressure is alleviated due to the slow propagation of hydraulic pressure from the second hydraulic pressure chamber to the wheel cylinder, the elastic deformation of the brake components, and the movement of the service piston. 1. Therefore, even if a skid condition occurs or the operation of the brake fluid pressure adjusting piston is delayed due to the condition of the road surface or hydraulic system, etc., an undesirable increase in wheel cylinder fluid pressure is prevented. ξ is possible.

In addition, when the brake fluid pressure adjustment piston moves forward,
When the hydraulic pressure difference between the hydraulic pressure chamber and the second hydraulic pressure chamber is small, the hydraulic pressure in the brake hydraulic pressure chamber increases as the brake hydraulic pressure adjusting piston moves forward, causing the brake hydraulic pressure adjusting piston to move the valve away from the valve seat. Before they are separated, the stepped piston starts to move, and the hydraulic pressure in the second hydraulic pressure chamber is maintained at a substantially constant value by a predetermined ratio t If (13) from 'ri, lf in the first hydraulic pressure chamber. Therefore, even if a skid condition occurs or the operation of the brake fluid pressure adjusting screw/ is delayed as in LI:j', an undesirable increase in the wheel cylinder fluid pressure is prevented.

Such movement of the stepped piston is possible only within a certain stroke range, and when the brake fluid pressure regulating piston is at the forward end position, the valve element is completely separated from the valve seat. Therefore, under normal conditions where a sufficient flow of brake fluid is allowed between the valve element and the valve seat and there is no risk of skidding, there is a risk of a delay in brake operation. There is no such thing.

EXAMPLE Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 denotes a master cylinder, which is equipped with two independent pressurizing chambers, in which the depression force of the brake pedal 12 is boosted by the booster 14, and the hydraulic pressure is boosted by the booster 14. Generates in the mouth and pressure chambers.

The rcohydraulic pressure generated in one pressurizing chamber is transmitted to the front wheel cylinder 18, that is, the wheel cylinder of the brake of the first wheel 19, through the pipe line 16. On the other hand,
The hydraulic pressure generated in the other force chamber 1IIf is transmitted by a line 20 to an anti-skid device 22 and further by a line 24 to a rear wheel cylinder 26, that is to say a wheel cylinder of the brake of the rear wheel 27.

The main part of the anti-skid device 22 is built into the l\Uzinog 28. This housing 28 is divided into several parts for convenience of processing and assembly, but after being assembled, it functions as an integrated housing 28. It shall be called. In addition, in FIG. 1, the housing 28 drawn in the lower left part and the housing 28 drawn in the center part
Although the two are integral, for convenience of illustration, they are shown divided into two parts. The housing 28 has a port 30
Hole 82. Valve chamber 84. Brake hydraulic chamber 86. A liquid passage is formed that passes through the hole 88 and the valve chamber 40 and reaches the port 42, and together with the pipes 20 and 24, constitutes a liquid passage that transmits the mask cylinder hydraulic pressure to the rear wheel cylinder 26. This liquid passage is provided in the valve chamber 84 and communicated with and shut off by the cut valve 44. The cut valve 44 is opened and closed by a brake fluid pressure adjustment piston 46, and this piston 46 controls the power fluid pressure supplied to the power fluid pressure chamber 48 and the brake fluid pressure chamber 8.
It operates in response to the brake fluid pressure in 6. The hydraulic pressure supplied to the power hydraulic chamber 48 is generated by the pump 50;
It is controlled by a regulator valve 52 and a power hydraulic supply/discharge valve 54 until the hydraulic pressure is supplied to the pump. The power hydraulic supply/discharge valve 54 switches the flow direction of the hydraulic fluid.
It is equipped with a switching valve 56 and an electromagnetic switching valve 58 that has an orifice 60 and switches the speed of the flow of the hydraulic fluid. The supply and discharge of the working fluid to the pressure chamber 48 and the speed of supply and discharge thereof are controlled.

Additionally, a bypass 664 is provided within the valve chamber 40,
The brake fluid supplied to the port 80 can be bypassed to the port 42 without passing through the cut valve 44.

The pump 50 pumps up the hydraulic fluid from the tank 66 and sends it to the power steering device 72 via pipes 68 and 70.
The regulator cell 52 is connected between the conduit 68 and the conduit 70. The regulator yi-52 connects the pump 50 to the power hydraulic chamber 48.
The power hydraulic pressure supplied to the is controlled by the mask cylinder hydraulic pressure.
The piston 74. 1st Benko 76
and a second valve 78. The piston 74 and the first valve element 76 are sealed with an O-ring and are fitted into the housing 28 so as to be slidable in the axial direction. The second valve element 78 has an annular projection 80 on the surface facing the first hexagon 76, and an annular projection 82 on the opposite surface, and is brought into close contact with the shoulder surface 86 of the housing 28 by a compression coil spring 84. It is energized as follows. The piston 74 is pushed to the left in FIG. It comes into contact with the valve element 76 and acts to push the element into close contact with the annular protrusion 80 of the second valve element 78. On the other hand, the first valve element 76 and the second valve element 78 are pushed to the right by the hydraulic pressure of the hydraulic pressure chamber 94, and the first valve element 76 is pushed against the pressing force of the piston 74. Either the second valve 78 moves away from the second valve 78 or the second valve 78 moves away from the first valve 7.
6 and moves away from the shoulder surface 88 against the pressing force of the piston 74 and the biasing force of the spring 84, so that the hydraulic fluid in the hydraulic chamber 94 flows through the hydraulic chamber 96 and the port 98 into the pipe line. Allow it to flow to 70-
ing.

That is, the hydraulic pressure in the hydraulic chamber 94 is transmitted to the hydraulic chamber 90.
It will change in relation to the master cylinder hydraulic pressure.

If the power liquid l in the hydraulic pressure chamber 94 is expressed by p, and the mask cylinder hydraulic pressure in the hydraulic pressure chamber 90 is expressed by P, the relationship between the two can be expressed by the following equation. 1 valve 76 is the hydraulic pressure chamber 96
Pressure-receiving area S2 when receiving hydraulic pressure: Pressure-receiving area S3 of the piston 74: Area of T circles surrounded by the inner periphery of the tip of the annular projection 80 S4: Area of f2 circles surrounded by the inner periphery of the tip of the annular projection 82 Biasing force Po of the F spring 84: The hydraulic pressure generated in the hydraulic pressure chamber 96 based on the flow resistance of the pipes 70, 100, etc.

(1) When the first valve 76 separates from the second valve 78 (2) When the second valve 78 separates from the shoulder surface 86
The relationship expressed by the equation and the second equation is illustrated in FIG. 2. In this figure (1).

(2) shows the straight lines expressed by the first equation and the second equation, respectively, and p2 is the 1-ni relief valve 102 provided in the pipe line 68.
It is a relief village. As is clear from FIG. 2, when the mask cylinder hydraulic pressure P75 is %<low, the first valve element 76 pushes the piston 74 toward the hydraulic pressure chamber 90 side by the hydraulic pressure in the hydraulic pressure chamber 96 and moves away from the annular protrusion 80. , in order to allow free flow of the working fluid from the hydraulic pressure chamber 94 side to the hydraulic pressure chamber 96 side, the power hydraulic pressure is a constant value p. can be maintained. However, the mask cylinder hydraulic pressure P is P. When reaching r, the piston 74 moves the first caster 76 closer to the annular projection 8° against the hydraulic pressure in the hydraulic pressure chamber 96. As a result, a throttling action occurs in the gap between the annular protrusion 80 and the first valve element 76, the hydraulic pressure in the hydraulic pressure chamber 94 starts to rise, and the mask cylinder hydraulic pressure reaches P.

The power hydraulic pressure increases from p to Pl. It will rise from p□. And the mask cylinder hydraulic pressure P
When reaching the P position, the second dropper 78 releases the spring 84.
The annular protrusion 80 moves against the urging force of the @1 center piece 76, while the annular protrusion 82 moves from the shoulder surface 86 to the A
fllf, and the hydraulic fluid in the hydraulic pressure chamber 94 flows into the hydraulic pressure chamber 96 through the gap between the annular projection 82 and the shoulder surface 86. In this state, when the mask cylinder hydraulic pressure P increases from P□ to P2, the power hydraulic pressure p increases from P□ to P, but when the hydraulic pressure in the hydraulic chamber 94 reaches p2 and f2, the relief valve 102 opens, and thereafter, even if the mask cylinder hydraulic pressure P increases, the power hydraulic pressure I) remains constant (direction 1).

Next, power hydraulic pressure supply ↑54 will be explained.

The hydraulic fluid in the hydraulic pressure chamber 94 is supplied to the holes 104, 106 and 10.
8 to the hole 110 of the electromagnetic switching valve 56, but since the valve element 112 of the electromagnetic switching valve 56 is urged downward by a spring, this hole 110 is normally open and the hydraulic fluid is supplied to the hole 110 of the electromagnetic switching valve 56. passes through the valve chamber 114 and hole 116 to the electromagnetic switching valve 5
8 to the valve chamber 118. Since the valve element 120 of the electromagnetic switching valve 58 is biased in the closing direction by a spring, the hydraulic fluid in the valve chamber 118 flows through the orifice 60 and the hole 12.
2 and flows into the power hydraulic pressure chamber 48. When the solenoid 124 of the electromagnetic switching valve 56 is energized, the valve element 112 is moved to a position where the hole 110 is closed and the hole 126 is opened. In this state, the valve chamber 114 is communicated with the tank 66 through the hole 126 and the conduit 128, and the hydraulic fluid in the power hydraulic pressure chamber 48 flows through the hole 122. Orifice 60. Valve chamber 118. hole 116, valve chamber 114. Hole 126 and conduit 1
28 and then returns to tank 66. Furthermore, the solenoid 180 of the electromagnetic switching valve 58 is energized, and the valve 120 opens the hole 182. In this state, the hydraulic fluid flows into the power hydraulic pressure chamber 48 and the power hydraulic pressure chamber 48
This allows the hydraulic fluid to flow out quickly.

Energization and deenergization of solenoids 124 and 130 are controlled by control computer 62. A rotation sensor 186 is connected to the control computer 62 to detect the rotary side of the output shaft of the automatic transmission 134. The rotation of the output shaft of the automatic transmission 134 corresponds to the rotation of the rear wheels 27. Second, the rotation speed of the output shaft of the automatic transmission 184 drops significantly. This means that the rotational speed of the motor will drop significantly and the motor will stop. The control computers 62 can monitor the skid status of the rear wheels 27 based on the input signal from the rotation sensor 136, and adjust the solenoid 124 of the electromagnetic switching valve 56 and the electromagnetic switching valve accordingly. -jP58 solenoid 180
and thereby control the supply of power to the power hydraulic chamber 4
This allows the hydraulic pressure within the 8 to be controlled.

The power hydraulic pressure within the power hydraulic pressure chamber 48, which is controlled in the manner described above, acts on the brake hydraulic pressure adjusting piston 46. This piston 46 consists of two parts, a large diameter piston 188 and a small diameter piston 140, which are arranged concentrically and can abut each other within the atmospheric pressure chamber 142. ■I'm here. This atmospheric pressure chamber 142 is connected to the atmospheric pressure chamber 9 of the regulator valve 52 by a hole (not shown).
It is connected to 2. The large-diameter piston 188 receives power hydraulic pressure from the power hydraulic chamber 48, and the small-diameter piston 140 operates upon receiving brake hydraulic pressure from the brake hydraulic pressure chamber 86. In this position, the cut valve 44 is opened by a protrusion 144 formed by a pin press-fitted into the end surface of the small diameter piston 140.

As shown in an enlarged view in FIG. 8, the cut valve 44 has a stepped piston 147 in the shape of a cylindrical cylinder with a rounded bottom, and a through hole 146 having an inner diameter that allows the protrusion 144 to fit therein with play is formed at the bottom thereof. and a ball 148 which is accommodated in the cylindrical portion of the piston 147 and serves as a valve. The stepped piston 147 has a large diameter part 149 and a small diameter part 150, a large diameter hole 151 on the brake fluid pressure adjustment piston 46 side, a small diameter hole 152 on the pipe 2° side (see Figure 1), and the housing 28. It is screwed into the r nib lug 153 and is fluid-tightly and slidably fitted into the r nib lug 153 so that it can move in a direction parallel to the axial direction of the brake fluid pressure adjusting piston 46. Second, brake fluid pressure adjustment piston 46 of brake lug 158
A stopper 154 having a cylindrical bottom shape and having a through hole with an inner diameter that allows the protrusion 144 to fit therein with some play is provided on the side, and this stops the stepped piston 147.
The movement limit 1 (of the stepped piston 147 towards the small diameter part 150 side is regulated by the bottom surface 155 of the small diameter hole 152, and the movement is constant). It is specified within the stroke range.The bottom of the stopper 154 and the large diameter portion 14 of the stepped piston 147
A compression fill spring 156 is inserted between the 9 ll and 1 ll ends, so that the stepped piston 147 is always
The large diameter portion 149 of the stepped piston 147 is pushed in the direction of contact with the small diameter piston 140
It has a larger diameter than TL.

On the other hand, a tapered valve seat 157 is formed on the ball 148 side of the through hole 146, and the ball 148 is always urged in the direction of seating on the valve seat 157 by a compression coil spring 158. As the brake fluid pressure adjusting piston 46 retreats, the ball 148 is seated on the vent 157, so that the valve chamber 84 is connected to the first fluid pressure chamber 159 communicating with the pipe line 20 and the brake fluid pressure chamber 86. The pipe line 20 and the pipe line 24 are separated into a second hydraulic pressure chamber 160 which communicates with each other, and communication between the pipe line 20 and the pipe line 24 is cut off. Ma f2, spring 15
The biasing force of spring 8 is smaller than the biasing force of spring 156.

Note that the plug 153 has a plurality of radial through holes 161.
However, a plurality of notches 162 are formed at the end of the stepped piston 147 on the side that comes into contact with the bottom surface 155, respectively.
The pipe line 20 and the first hydraulic pressure chamber 159 are constantly communicated with each other. Mar2 168 is the plug 158 of the stepped piston 147
It is an f-th air chamber that allows relative movement to the air chamber.

The cut valve 44 is shown in FIG. 3. When the brake fluid pressure adjusting piston 46 is at the forward end position,
A ball 148 is separated from the valve seat 157 by the protrusion 144 and opened, and the first hydraulic pressure chamber 159 and the second hydraulic pressure chamber 160 are communicated with each other through the through hole 146 with a sufficient flow area. At this time, the hydraulic pressure PB of the second hydraulic pressure chamber 160
The relationship between this and the hydraulic pressure P of the first hydraulic pressure chamber 159 is expressed by the following formula (%) (3) On the other hand, as shown in FIG. In a state of retreating,
The ball 148 is seated on the valve seat 157, and 714 connections between the first hydraulic pressure chamber 159 and the second hydraulic pressure chamber 160 are shut off. At this moment, the relationship between the hydraulic pressures PB and FA is expressed by the third equation above, but if the brake hydraulic pressure adjustment piston 46 is then further retreated, that is, the power hydraulic pressure in itJ decreases, and the brake The hydraulic pressure adjusting piston 46 is moved backward by the hydraulic pressure PB in the brake hydraulic pressure chamber 36, but as this dredging occurs, the volume in the brake hydraulic pressure chamber 36 increases and the hydraulic pressure BE decreases. Then, when this hydraulic pressure PB becomes lower than the hydraulic pressure PA by a predetermined ratio, the stepped piston 147 moves toward the second hydraulic pressure chamber 160 side. This lowering rate is due to the small diameter portion 1 of the stepped piston 147.
50 side pressure receiving area Smu and large diameter ff! It is determined by the pressure receiving area 8B on the 149 side, and is expressed by the following formula (%) (4), and the stepped piston 147 moves until it comes into contact with the stopper 154 while maintaining this relationship. FIG. 5 shows this state.

Here, the pressure receiving area 8B is made larger than 8A and SA/5
Since n(1), the hydraulic pressure PE is lower than the hydraulic pressure PA by a predetermined percentage.Also, with regard to the fourth equation above, the force of the compression coil blinders 156° and 158 also acts, These biasing forces are extremely small compared to the hydraulic pressures PA and FB and can therefore be ignored.

Then, when the brake fluid pressure adjustment piston 46 is moved further backward, the volume inside the brake fluid pressure chamber 36 increases.
On the other hand, when the brake fluid pressure 61-section piston 46 is moved forward from this state, the volume of the brake fluid pressure chamber 36 is reduced and the fluid pressure PB is further reduced. The stepped piston 147 is moved to the first hydraulic pressure chamber 159t1111 while maintaining the relationship of the fourth equation above, but the behavior is that the hydraulic pressure Ph, l! : Varies depending on the pressure difference with PB.

In other words, when the hydraulic pressure P is considerably larger than FB,
In other words, if the static pressures PA and PB cannot satisfy the relationship expressed by the above equation 4 simply by increasing the hydraulic pressure PB as the brake hydraulic pressure 61-node piston 46 moves forward, the protrusion 144 in FIG. The valve seat 157 is brought into contact with the ball 148, and the first hydraulic pressure chamber 159 and the second hydraulic pressure chamber 160 are slightly communicated with each other. When EPB rises and the relationship between the hydraulic pressure, % P n , and the two people satisfies the relationship of the fourth equation above, the stepped piston 147 moves and the ball 148 seats on its valve seat 157, Communication between the first hydraulic pressure chamber 159 and the second hydraulic pressure chamber 160 will be igrfr again. At this time, the hydraulic pressure in the second hydraulic chamber 160 increases due to the inertia of the brake fluid in the conduit 24, the elastic deformation of brake components such as the wheel cylinder 26, etc. lags behind the rise. Therefore, once the relationship of equation 4 is satisfied, the fC hydraulic pressure PB will decrease slightly as the hydraulic pressure propagates to the wheel cylinder 26, but as the hydraulic pressure PB decreases, The stepped piston 147 is the stopper 1
Since the ball 148 is moved to the valve seat 15 side, the ball 148 is moved to the valve seat 15 again.
7, and the hydraulic pressure PB is increased until it satisfies the relationship of the fourth equation. Therefore, wheel cylinder 2
During this movement of the stepped piston 147 and repetition of the seating and seating of the ball 148, the hydraulic pressure in the second hydraulic pressure chamber 1 increases.
It will rise until it matches the hydraulic pressure PB of 60,
The upward slope is relatively gentle with small fluctuations. When the stepped piston 147 comes into contact with the bottom surface 155 and is prevented from moving further, the ball 148 is completely removed from the valve seat 157. The first hydraulic pressure chamber 159 and the second hydraulic pressure chamber 160 communicate with each other, and the hydraulic pressure PB and the hydraulic pressure FA are separated from each other.
The relationship of Eq.

On the other hand, when the hydraulic pressure PA is slightly higher than FB by +liQ, in other words, the hydraulic pressures PA and FB are adjusted according to the fourth equation only due to the increase in the hydraulic pressure PB accompanying the advance of the brake hydraulic pressure adjusting piston 46. If the relationship is reached, the protrusion 14 in FIG.
The stepped piston 147 starts moving before the ball 148 contacts the ball 148.

After that, the actual body 144 comes into contact with the ball 148 and the first hydraulic pressure chamber 1
59 and the second liquid chamber E 160, but at this time, the stepped piston 147 has already touched the bottom surface 155, and the hydraulic pressure PBt becomes the same value as the hydraulic pressure PA according to the third formula. However, if the stepped piston 147 has not yet come into contact with the bottom surface 155, the stepped piston 1
47 moves, and after contacting the bottom surface 155, the ball 148 is completely separated from the valve seat 157.

Finally, the bypass valve 64 will be explained based on FIG. 1. The bypass valve 64 is provided with a valve element 168, and when the valve element 168 is located on the right side in FIG.
While the hole 17fl is closed, the hole 17fl is opened.

In this state, the bypass 4 (= 64) is closed. On the other hand, if the valve element 168 moves to the left, the hole 170 is closed while the hole 32 is opened. In this state, the bypass valve 4 (= 64) is closed. 64 is opened, while the hole 38 and the valve chamber 4,
Communication with 0 is cut off. Valve element 168 is biased to the left by compression coil spring 172, but can be moved to the right by piston 174. The piston 174 consists of three parts, a large-diameter piston 176 and a small-diameter piston 178, and these three parts are arranged concentrically so that they can abut each other in an atmospheric pressure chamber 180 that communicates with the atmospheric pressure chamber 142. has been done. Piston 1744-1. It is operated by the brake fluid pressure applied to the fluid pressure chamber 182 and the power fluid pressure applied to the fluid pressure chamber 184, and opens and closes the piston valve 64.

However, the pressure receiving area of the large diameter piston 176 and the small diameter piston 178 is equal to the brake fluid pressure in the fluid pressure chamber 182 and the pressure in the fluid pressure chamber 184.
What is the relationship between power and hydraulic pressure? Since the piston 174 is selected to be maintained as shown by the broken line in FIG. 2, when the power hydraulic pressure is normally controlled by the regulator valve 52 as shown by the solid line in FIG. The bypass valve 64 is not opened by moving from the right position shown in FIG.

The construction of each part and their detailed operations have been explained above, and below, the operation of the entire device will be fully explained.

Since the pump 50 is driven by the car's engine, it continues to supply hydraulic fluid to the power steering device 72 through the full regulator valve 52 while the car is running, but the brake pedal 12 is not depressed. In this case, since the mask cylinder hydraulic pressure is not applied to the hydraulic pressure chamber 90 of the regulator valve 52, the second valve element 78 is separated from the second valve element 78, and the power hydraulic pressure chamber 48 and the hydraulic pressure are removed. A constant power hydraulic pressure, PO, is applied to the pressure chamber 184. In addition, when a skid condition is not occurring, the control computer 62 controls the solenoid 1 of the electromagnetic switching valve 56.
24 and the solenoid 130 of the electromagnetic switching valve 58, both electromagnetic switching valves 56 and 58 are in the state shown in FIG. I'm forced to. Therefore, the hydraulic pressure in the power hydraulic pressure chamber 48 is maintained at the same level as the hydraulic pressure in the hydraulic pressure chamber 94. Further, the hydraulic pressure in the hydraulic pressure chamber 184 is also maintained at po. Therefore, the brake fluid pressure adjusting piston 46 and the piston 174 are located at the forward end shown in the fourteenth position, the cut valve 44 is fully opened, and the bypass valve 64 is closed. However, since no hydraulic pressure is generated in the mask cylinder 10, no hydraulic pressure is applied to the front wheel cylinder 18 and the rear wheel cylinder 26.

If the brake pedal 12 is depressed from this state and the mask cylinder hydraulic pressure is increased, the power hydraulic pressure in the hydraulic pressure chamber 94 is increased as shown in FIG. 2 as the mask cylinder hydraulic pressure increases. Therefore, the hydraulic pressure in the power hydraulic pressure chamber 48 is also increased as shown by the solid line in FIG. 2, and the force pushing the player hydraulic pressure adjusting piston 46 to the right in FIG. 1 increases. on the other hand,
The mask cylinder hydraulic pressure is also transmitted from the mask cylinder 10 to the brake hydraulic pressure chamber 36 through the conduit 2 (1''5), and the brake hydraulic pressure adjusting piston 46 is pushed to the left by this brake hydraulic pressure. , the force pushing to the left is always smaller than the force pushing to the right mentioned above.This is determined by the pressure receiving area of the large diameter piston 138 and the small diameter piston 140.Therefore, the cut valve 44
is maintained in the open state f, -, and the mask cylinder hydraulic pressure is transmitted to the rear wheel cylinder 26.

Section 11 in FIG. 6 shows this state, and at this time the hydraulic pressures PA and FB rise while satisfying the relationship of the third equation.

When the rear wheels 27 begin to skid as a result of increasing the hydraulic pressure in the rear wheel cylinders 26 as described above, rBt is adjusted based on the output signal of the rotation sensor 136.
The control computer 62 detects this and both electromagnetic switching valves 5
The solenoids 124 and 180 of 6 and 58 are energized and communicated with the power hydraulic chamber 48 and the entire tank 66. Therefore, the hydraulic pressure within the power hydraulic pressure chamber 48 rapidly decreases, causing the brake hydraulic pressure adjustment piston 46 to close the retreat heel cut valve 44 and increase the volume of the brake hydraulic pressure chamber 36.

Therefore, the cut valve 44 cuts off the mask cylinder side liquid passage, and the volume of the chavoir cylinder side liquid passage increases, causing the hydraulic pressure in the rear wheel cylinder 26 to rapidly drop.

The t2 section in FIG. 6 shows this state of 0+.

Thereafter, the control computer 62 controls the electric m-switching valve 58.
When the solenoid 130 is demagnetized and the flow 4 of the hydraulic fluid flowing out from the power hydraulic pressure chamber 48 is throttled by the orifice 60, the decrease in the hydraulic pressure in the brake hydraulic pressure chamber 36 becomes slow. The t3 interval in FIG. 6 shows this state 9.

As described above, when the hydraulic pressure in the rear wheel cylinder 26 decreases and the skid condition of the rear wheel 27 is eliminated, the control computer 62 detects this condition based on the detection signal from the rotation sensor 136, and the electromagnetic switching valve 56 solenoid 12
At the same time, the solenoid 1 of the electromagnetic switching valve 58 is demagnetized.
'3 tl k P) and excite. As a result, the power hydraulic pressure chamber 48 is again communicated with the hydraulic pressure chamber 94 of the regulator valve 52, and hydraulic fluid is rapidly supplied, and the brake hydraulic pressure adjusting piston 46 is moved forward, so that the pressure inside the brake hydraulic pressure chamber 36 is increased. Fluid pressure increases. Section L4 in FIG. 6 shows this state.

Then, when the hydraulic pressure in the power hydraulic pressure chamber 48 rises to a certain extent, the control computer 62 demagnetizes the solenoid 130 of the electromagnetic switching valve 58, and the inflow of hydraulic fluid into the power hydraulic pressure chamber 48 is throttled by the orifice 6(). Do it like this. Therefore, from now on, the hydraulic pressure increasing force of the power hydraulic pressure chamber 48 and the brake hydraulic pressure chamber 36 will be increased.
Section a shows one line like this.

As shown in C, the hydraulic pressure in the rear wheel cylinder 26 is
When the front rear wheel 27 reaches almost the same hydraulic pressure as the one at which it started to skid, the rear wheel 27 usually starts to skid again, so the control computer 6
2 detects this and fully retreats the brake fluid pressure adjusting piston 46, thereby completely reducing the fluid pressure in the rear wheel cylinder 26 before the rear wheel 27 completely enters the skid state. Section 6 in FIG. 6 shows this state.

When the overall control computer 62 detects that the skid-like condition O of the rear wheel 27 has disappeared, the rear wheel cylinder 26'/) hydraulic pressure is increased again, and the above-mentioned operation is repeated, and the rear wheel cylinder The hydraulic pressure of 26 is always controlled to be optimal. Na2,
The control computer 62 supplies hydraulic fluid to the power hydraulic pressure chamber 48 by appropriately controlling the electromagnetic switching valves 56 and 58 depending on the occurrence of the skit condition in the rear @ 27.

The discharge, its supply, and the speed of discharge per liter are controlled, and the above is merely an example.

By the way, in the above explanation, regarding the 1S section in FIG. 6, the hydraulic pressure of the rear wheel cylinder 26 is
7 started to become a skid 1 When the hydraulic pressure reached the same as the H1 pressure, a skid again occurred.However, in reality, a skid state occurs due to road surface conditions, etc. The hydraulic pressure in the puller wheel cylinder 26 fluctuates somewhat. If the hydraulic pressure is lower than the hydraulic pressure at which the skid condition occurred before, the hydraulic pressure in the rear wheel cylinder 26 is lowered before a complete skid condition occurs, as described above.・F If the coefficient of friction between the road surface and the wheels 27 becomes large, O, even if the hydraulic pressure becomes the same as the one that caused the skid before, the skid will not occur, and the hydraulic pressure will be slightly higher than the previous one.・1. An iron skit condition will occur. Also, depending on the road surface condition and the condition of the hydraulic system controlled by the brake hydraulic pressure adjustment piston 46,
In some cases, skids may occur or the operation of the brake fluid pressure adjusting piston 4G may be delayed.

In such cases, conventional anti-skid devices open the cut valve when the hydraulic pressure in the rear wheel cylinder 26 reaches the same hydraulic pressure as the hydraulic pressure at which the skid condition previously occurred, and at this time the driver When the brake pedal 12 is strongly depressed, high-pressure brake fluid is supplied to the wheel cylinder 26, and the fluid pressure rises rapidly as shown by the broken line in FIG. Therefore, when the control computer 62 detects the skid-like f'fi7f and moves the brake fluid pressure adjusting piston 46 (i-backward),
There was a risk that the hydraulic pressure in the rear wheel cylinder 26 would already become high enough to cause the wheels 27 to skid.

On the other hand, according to the anti-skid device 22 of this embodiment, due to the operation of the cut valve 44 as described above, the hydraulic pressure in the rear wheel cylinder 26 increases relatively slowly as shown in FIG. , and is limited to a value lower than the hydraulic pressure of the mask cylinder 12 by a predetermined percentage, so that the hydraulic pressure that causes a skid state due to changes in the coefficient of friction between the road surface and the car @ 27 as described above is Even if a skid condition occurs or the operation of the brake fluid pressure adjustment piston 46 is delayed due to the road surface, control fluid pressure system conditions, etc., a sudden zero fluid pressure increase 1C will cause the wheel 27 This prevents the system from falling into a complete skid state. In addition,
Although FIG. 7 shows a case where a skid state does not occur in the hypothetical case, in reality, a transition to a skid state is detected at a portion corresponding to the initial stage of operation of the cuff valve 44 or before that. As a result, the hydraulic pressure is reduced.

Further, the broken line indicates the change in hydraulic pressure in the case of the conventional device, similar to FIG. 6.

FIG. 8 shows the wheel cylinder 2 when the hydraulic pressure of the mask cylinder 1 () is relatively low when the cut valve 44 is activated.
A) shows the change in hydraulic pressure in 6.

In this case, the stepped piston 147 moves without the cut valve 44 opening, and the rear throat well 44 opens and the hydraulic pressure of the rear wheel cylinder 26 matches the hydraulic pressure of the mask cylinder 10, but the rear wheel cylinder 26
Since the hydraulic pressure is maintained for a while at approximately the same hydraulic pressure as the one at which the skid condition occurred, even if a skid condition occurs or the operation of the brake hydraulic pressure opening 1 piston 46 is delayed as described above, the sudden Even though the wheels 27 would not be completely in a skid state due to a sudden increase in fluid pressure, FIG. 8 also shows changes in fluid pressure when no skid state occurs, similar to FIG. 7. , and the broken line is for the conventional device.

Above, we have explained all the operations under the condition where the power hydraulic pressure is normally supplied, but in the unlikely event that the pump 5o malfunctions or
．． If the power hydraulic pressure is no longer supplied due to a rupture such as '100', the cut valve 44 is closed, the bypass valve 64 is opened, and the hydraulic pressure of the L1 master cylinder 1o remains the same. /supplied to the cylinder 26.

As described above, according to this embodiment, when a skid condition occurs and the once closed cut valve 44 is opened, the rising gradient of the hydraulic pressure in the rear wheel cylinder 26 is made gentle; Since the fluid pressure is maintained at a constant level before the brake fluid pressure adjustment piston 44 is opened, even if the fluid pressure that occurs in a skid state fluctuates, or there is a delay in detecting a skid state or in the operation of the brake fluid pressure adjustment piston 46, the This prevents @27 from falling into a complete skid state. Moreover, when braking in a normal state, the ball 14 of the cut valve 44
8 and the valve seat 157 are wide open, allowing a sufficient amount of brake fluid to pass through, thereby preventing a delay in the operation of the rear wheel brakes.

In the above, explanation 1(+j) has been given regarding one embodiment of the present invention, but the present invention can be explained in detail in other aspects as well.

For example, the pressure receiving areas SA and Su of the second stage A" piston 147 in the above-mentioned embodiment should satisfy at least SB>SA, and the pressure receiving surface 4=i"JSd is smaller than the pressure receiving area of the small diameter piston 140. , 1].However, in this case, it goes without saying that the pressure of the stepped piston 147, that is, the fluctuation of the hydraulic pressure PBD, is affected by the pressure receiving area of the stepped piston 147. The compression coil spring 156 restricts the movement (rattling) of the stepped piston 147 when the brake pedal 12 is not depressed, that is, when brake fluid pressure is not generated, and is not necessarily provided. Also good.

It is also possible to completely insert a normal provisioning valve or a load-sensitive provisioning valve into the conduit 20 or 24, thereby controlling the hydraulic pressure of the rear wheel cylinder 26 more ideally. That will happen.

Further, in the above-described embodiments, the present invention is applied to an anti-skid device for preventing skidding of the rear wheels, but it can also be used to prevent skidding of the front wheels. Furthermore, as a means to fully detect skid conditions,
For example, various methods such as one that detects the difference between the deceleration of the vehicle body and the deceleration of the wheels can be adopted.

In addition, it goes without saying that the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an anti-skid device according to an embodiment of the present invention, and also serves as a front sectional view of the main parts. FIG. 2 is a graph showing the operating characteristics of the regulator valve in FIG. 11V. FIGS. 3 to 5 are enlarged views showing different operations of the cut valve in the anti-skid device of FIG. 1, respectively. Figures 6 to 8
The diagrams show the construction of the anti-skid device in Figure 1, respectively.
=G is a graph showing the relationship between wheel cylinder hydraulic pressure and time. 10: Mask cylinder 20, 24: Pipe line 22: Anti-skid device t 26: Rear wheel cylinder (wheel cylinder) 28
: Housing 36 Brake hydraulic chamber 44: Cut valve 46: Brake hydraulic pressure adjustment piston 48; Power hydraulic chamber 50 = Pump 52: Regulator valve 146: Through hole 147: Stepped piston 148: Ball (valve) 149: Large Diameter portion 150: Small diameter portion 151: Large diameter hole 152: Small diameter hole 153 Nibrader 157: Valve seat 158: Pressure m coil spring (spring table °) 159
:First hydraulic pressure chamber 160:Second hydraulic pressure chamber 163:Air chamber 1 person Toyota Motor Corporation

Claims (1)

[Scope of Claims] A cut valve that is provided in a liquid passage connecting a mask cylinder and a wheel cylinder of a hydraulic flake device for an automobile, and that divides the liquid passage into a mask cylinder side liquid passage and a wheel cylinder side liquid passage. , connected to the wheel cylinder side liquid passage f, is liquid-tightly and slidably provided in the housing, and connected to the wheel cylinder side liquid passage on the first pressure receiving surface.
While receiving the brake fluid pressure of this brake fluid pressure product, the second pressure receiving surface receives the power fluid pressure in the power fluid pressure chamber, and reduces the volume of the brake fluid pressure chamber when moving forward toward the brake fluid pressure chamber side. (1) Open the cut valve and close the cut valve when retreating toward the power hydraulic pressure chamber; (1) Increase the volume of the brake hydraulic chamber to increase the volume of the wheel cylinder side fluid passage. A brake fluid pressure adjustment piston that adjusts fluid pressure and the wheel cylinder are provided to monitor the skid state of one wheel, and when there is no skid state, the brake fluid pressure adjustment piston and the wheel cylinder are provided.
Power that is generated by power and supplies power hydraulic pressure to the power fluid chamber, detects a skid condition, and lowers the pressure in the power fluid pressure chamber to move the brake fluid pressure adjusting piston backward. An anti-skid device for an automobile including a hydraulic pressure control device, wherein the cut valve has a large diameter portion and a small diameter portion, and the large diameter portion and the small diameter portion have a large diameter hole on the side of the brake fluid pressure adjustment piston. , the liquid passage side of the mask cylinder side is a small-diameter hole, which is liquid-tightly fitted into the large-diameter hole and the small-diameter hole of the stepped hole, and the space inside the stepped hole is The first hydraulic pressure chamber is in communication with the master cylinder side fluid passage, and the first hydraulic pressure chamber is in communication with the flake hydraulic pressure chamber in B11, and is divided into a second hydraulic pressure chamber and an intermediate air chamber. Constant stroke in the direction parallel to the axis
a stepped piston that is movable within a range, a through hole formed in the cedar stepped piston to communicate the first hydraulic chamber and the second hydraulic chamber, and a through hole in the through hole, and a through hole in the through hole; A valve seat is formed around the opening on the side of the hydraulic pressure chamber, and although it is normally seated on the valve seat by a spring, it is separated from the valve seat as the brake fluid pressure adjusting piston moves forward. An anti-skid device for an automobile, characterized in that it includes a valve that can be moved.