JPS6071358A - Hydraulic braking device for automobile - Google Patents

Abstract

PURPOSE:To reduce the cost of production, by connecting a pressure chamber of a master cylinder to one side of front wheel brakes via a hydraulic regulating device as well as connecting rear wheel brakes situated in a diagonal position to the brake to the downstream side of the said regulating device via a proportioning valve. CONSTITUTION:A first pressure chamber 12 of a master cylinder is connected to a wheel cylinder 24 of a right front wheel 22 via first front passage 18. A hydraulic regulating device 20 is interposed in the passage 18. In addition, the downstream side of the hydraulic regulating device 20 is connected to a wheel cylinder 32 of a left rear wheel 30 with a first rear passage 26, while a proportioning valve (P valve) 28 is interposed in this passage 26. On the other hand, a second pressure chamber 14 of a master cylinder 10 is connectd to a wheel cylinder 38 of a left front wheel 36 with a second front passage 34. Furthermore, this passage 34 is connected to a wheel cylinder 44 of a right rear wheel 42 with a second rear passage, and a hydraulic control valve 46 is interposed in a passage 40. With this constitution, a set of front and rear brakes' hydraulic pressure can be regulated with one hydraulic regulating device alone, thus the cost of production is well reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a hydraulic brake system for automobiles, and in particular to a hydraulic brake system capable of preventing the occurrence of slippage, which occurs when wheels lock and cause slippage between them and the road surface. This relates to a brake device.

When the wheels of a prior art vehicle lock, cornering force is reduced and the vehicle loses its ability to maintain direction. Therefore, if the front wheels lock, the vehicle loses its steering ability, and if the rear wheels lock, the rear of the vehicle swings sideways, causing a spin. However, in order to avoid such a situation, if the hydraulic pressure of the brakes that brake each wheel is kept low, the THD power of the entire automobile will be insufficient.

For this reason, efforts have been made to avoid wheel locking as much as possible while increasing the braking force of the entire vehicle. Hydraulic pressure including an electromagnetic directional control valve that selectively communicates the cylinder with the mask cylinder and the reservoir, and a control device that controls the electromagnetic directional control valve while monitoring the skid state of wheels braked by the brake. It is practiced to provide a regulating device. This hydraulic pressure adjustment device adjusts the hydraulic pressure in the wheel cylinder while actually monitoring the skid condition of the wheels, so if it is installed on all wheels of a car, it will prevent any wheels from locking up. Furthermore, the vehicle can be braked efficiently.

However, since this hydraulic pressure adjustment device is expensive,
If it is provided for all wheels, it is inevitable that the cost of the entire hydraulic brake system will be extremely high.

OBJECTS OF THE INVENTION The present invention has been made against the background of the above-mentioned circumstances, and therefore, its purpose is to ensure the steering performance of a vehicle while keeping the manufacturing cost of a hydraulic brake device as low as possible. Another object of the present invention is to provide a hydraulic brake device for an automobile that can prevent the occurrence of spin.

Structure of the Invention The present application relates to two inventions that can achieve the above object, and both inventions are based on two systems of hydraulic pressure generated in two pressurizing chambers of a mask cylinder based on a driver's brake operation. The front wheel of the brake brakes the front wheels and rear wheels, which are diagonally positioned relative to each other, through mutually independent liquid passages. This is commonly used in automobile hydraulic pressure gearing devices of the type that are transmitted to the wheel cylinders of .

The feature of the first invention is that the front wheel cylinder is connected to the reservoir in the middle of the front passage connecting one of the pressurizing chambers of the mask cylinder and the front wheel cylinder of one of the left and right front wheels. A hydraulic pressure regulating device is provided that includes an electromagnetic directional switching valve that selectively communicates with one of the pressurizing chambers, and a control device that controls the electromagnetic directional switching valve while monitoring the skid state of the one front wheel. , the rear wheel cylinder of the rear wheel, which is diagonally positioned with respect to one of the front wheels, is connected to the portion between the electromagnetic directional control valve and the front wheel cylinder in the front passage through a rear passage, and the rear wheel cylinder is connected in the middle of the rear passage. In addition, a provisioning valve is provided that reduces the hydraulic pressure in the front wheel cylinder at a constant rate and transmits the reduced pressure to the rear wheel cylinder at least when the hydraulic pressure exceeds a certain level.

Further, the second invention is characterized in that the first system for transmitting hydraulic pressure to the first pair of wheel cylinders of the front wheels and rear wheels that are diagonally positioned relative to each other is the same as the first invention. The second system that transmits hydraulic pressure to the second set of wheel cylinders is not provided with a hydraulic pressure adjustment device, and the front wheel cylinders and rear wheel cylinders of the second set are connected to a separate pressurizing chamber of the mask cylinder. There is another front passage connected to the middle passage, and if the hydraulic pressure in the pressurizing chamber is increased to the planned maximum hydraulic pressure in the middle of the rear passage, dust will drop and the boiling cylinder hydraulic pressure The reason is that a hydraulic pressure suppression valve is provided to suppress the hydraulic pressure so that it does not exceed a certain upper limit value.

Effects of the Invention In the hydraulic brake system according to the first invention, the front wheel skid condition is monitored and the hydraulic pressure in the front wheel cylinder adjusted by the hydraulic pressure adjustment device is reduced by the provisioning hub. Since the hydraulic pressure is transmitted to the rear wheel cylinder, it is possible to adjust the hydraulic pressure between each of the front wheels diagonally to each other (multiple axles) using a single hydraulic pressure adjustment device. The number of adjustment devices installed can be reduced.

Further, in the hydraulic brake device according to the second invention, 1! which is diagonally positioned with respect to each other as in the first invention described above. J1
l transmitted to the wheel cylinders of the front axle and the rear wheels
While the fk pressure is regulated by the regulator of I II,
Of the front wheels and rear wheels, which are diagonally located in IMl, the mask cylinder hydraulic pressure is supplied as is to the front wheel cylinder, and the hydraulic pressure is controlled below a certain upper limit by the hydraulic pressure suppression valve to the rear wheel cylinder. A suppressed hydraulic pressure is provided.

In other words, if we look at the front cylinders that can obtain a large braking force, one side is supplied with the optimally adjusted hydraulic pressure by the hydraulic pressure adjustment device, and the other side is supplied with the mask cylinder hydraulic pressure as is, so the braking force is It can be ensured that there is no shortage and that one of the front wheels, ie the front wheel whose hydraulic pressure is regulated by the hydraulic pressure regulating device, does not run out. In addition, one of the two rear wheels, that is, the rear wheel to which the hydraulic pressure adjusted by the hydraulic pressure adjustment device is further reduced and supplied by the provisioning hub, has a uniform coefficient of friction on the road surface. (Usually, this condition is met), the lock will not occur, and the other rear wheel, that is, the rear wheel on the side to which the hydraulic pressure suppressed by the hydraulic pressure suppression valve is supplied, will reach the above-mentioned -chamber upper limit value. By appropriately determining , it is possible to prevent the vehicle from locking on a road surface with a friction coefficient greater than a desired one. After all, according to the hydraulic brake device according to the second aspect of the invention, it is possible to effectively achieve both the objectives of ensuring steering performance and preventing spin of the automobile by using only one hydraulic pressure adjusting device. 'Embodiment Fig. 1 is a schematic 1/8 view of a hydraulic brake system for an automobile; 6' which is an embodiment of the second invention, but it is also an embodiment of the first invention.

In the figure, 10 is a mask cylinder, and the first pressurizing chamber ■
2 and a second pressurizing chamber 14, and in response to depression of the brake pedal I6, hydraulic pressure of equal height is generated in the two pressurizing chambers 12 and 14.

The hydraulic pressure generated in the first pressurizing chamber 12 passes through the first front passage 18 and a hydraulic pressure adjustment device 20 provided in the middle thereof, and then passes through the first front passage, which is the wheel cylinder of the brake that brakes the right front wheel 22. wheel cylinder 24
supplied to Further, a first rear passage 26 is branched from the downstream side of the first front passage 18 from the hydraulic pressure adjustment device 2o, that is, from a portion of the first front oil cylinder 24, and passes through a proportioning valve 28 to the left rear wheel. 30 is transmitted to the first rear wheel cylinder 32, which is the wheel cylinder of the brake. For convenience, this system will be referred to as the first system.

On the other hand, the hydraulic pressure generated in the second pressurizing chamber 14 of the mask cylinder 10 is transmitted through the second front passage 34 to the second front wheel cylinder 38, which is a wheel cylinder of a brake that brakes the left front wheel 36. Ru. Then, from this second front passage 34 to the second rear passage 40
is branched off and connected to a second rear wheel cylinder 44 which is a brake wheel cylinder that brakes the right rear wheel 42. This system will be referred to as the second system.

As is clear from the following description, the wheel cylinders 24. are provided on the right front wheel 22 and the left rear wheel 30, which are diagonally positioned relative to each other. ．． 32 are subject to the first system, both of which are under the control of the hydraulic pressure regulator 20, while another set of wheels diagonally positioned and related to each other, namely the left front wheel. 36 and the wheel cylinders 38 and 44 of the right rear wheel 42 are subject to the second system, but the front passage of this second system is not provided with any means for controlling the hydraulic pressure, and the rear? The hydraulic pressure suppression valve 46 is provided only in iM'yIf1M&. Each element constituting the above circuit will be explained below.

First, the hydraulic pressure adjusting device 20 will be explained with reference to FIG. 2. The hydraulic pressure adjustment device 20 includes an electromagnetic directional switching valve 50 connected midway between the first floor 1 and the passage 18 . This electromagnetic directional switching valve 50 is a 3-boat, 3-position switching valve, and is normally in the first position shown in the figure, which communicates the wheel cylinder 24 with the mask cylinder 10 and cuts off communication 1ffl with the reservoir 52. Yes, when a small current is supplied to the solenoid 56 under the control of the microcomputer 54, it switches to the second position and cuts off all three boats, and when a large current is supplied to the solenoid 56, it switches to the third position. wheel cylinder 24
from the mask cylinder 1o and remove the reservoir 5.
Connect to 2. The size and control of the solenoid 56 by the microcomputer 54 is performed based on the output signal of the sensor 58. Sen-! ) 58 is provided near the right front wheel 22 to detect its rotational speed;
Based on this rotational speed, the computer 54 calculates the rotational deceleration or rotational acceleration of the wheel 22, and if the deceleration exceeds a preset deceleration, the right front wheel 22
It is determined that solenoid 2 has started to skid and solenoid 5 is activated.
When the deceleration becomes less than the set value or the acceleration becomes more than the set value, it is determined that the right front wheel 22 is coming out of the skid state, and the solenoid 56 is supplied with a small current or a large current. The current supplied to the device is reduced to a small current, or the current supplied to the device is reduced to a low current. therefore,
The wheel cylinder 24 is supplied with an appropriate hydraulic pressure that can brake the right front wheel 22 most effectively without locking it. A G filter 0 and a throttle 62 are provided in a portion of the first front passage 18 closer to the mask cylinder than the electromagnetic directional switching valve 5o, while a filter 64 is provided in a portion of the first front passage 18 closer to the front wheel cylinder 24 than the electromagnetic directional switching valve 50. There is. Further, a restrictor 68 is provided in a liquid passage 66 extending from the electromagnetic directional switching valve 50 to the reservoir 52 . A return passage 72 equipped with a check valve 70 is provided in parallel to the series circuit of the throttle 62 and the electromagnetic directional control valve 50, and when the brake pedal 16 is depressed or released, the wheel cylinder The brake fluid can quickly return from the mask cylinder 10 from the mask cylinder 10 through the return passage 72. Furthermore, reservoir 5
2, pump the brake l skin with the pump 74, and then pump the muff without returning to the cylinder 10, pump ii01+876
is provided. 78 is a check valve.

Next, the hydraulic pressure suppression valve 4G will be explained with reference to FIG. 3. The pressure suppression valve 11 is a combination of a limiting valve 80 and a provisioning valve 82. The limiting valve 80 includes a valve piston 86 slidably and fluid-tightly disposed within the housing 84, so that the space within the housing 84 is divided into a hydraulic chamber 88 and an atmospheric pressure chamber 90. It is being

The valve piston 86 is integrally equipped with a valve element 91 at the end facing the hydraulic chamber 8B, and the valve element 91 and a valve seat 92 formed in the housing 84 constitute a cut valve 94. This cut valve 94 is for cutting off the liquid passage from the boat 96 to the communication passage 98 via the hydraulic pressure chamber 88, but since the valve piston 86 is biased toward the hydraulic pressure chamber 88 by the compression coil spring 100. , usually open. On the other hand, Provocationing Harp 82
A valve piston 104 is slidably disposed within the housing 84 and has one end exposed outside the housing 84.
It is equipped with This valve piston 104 is integrally equipped with a valve element 106 at the end opposite to the exposed end, and this valve element 106 opens and closes in cooperation with a rubber valve seat member 10B held in the housing 84. It constitutes a valve 110.

The valve piston 104 is urged by a compression coil spring 112 in the direction in which the on-off valve 110 opens, and the two hydraulic chambers 1 formed with the on-off valve 110 sandwiched therebetween.
14 and 116 are always in communication.

Therefore, the hydraulic pressure transmitted to the communication passage 98 is transmitted to the hydraulic chamber 1.
14, 116 and the boat 118 to the second rear wheel cylinder 44 (see FIG. 1).

The pressure control characteristic at 71 of the hydraulic pressure suppression valve 46 is determined by the pressure control characteristic of the left front wheel 3.
The braking force distribution between the rear right wheel 42 and the rear right wheel 42 is set as shown in FIG. That is, while the mask cylinder liquid pressure (the liquid pressure in the second pressurizing chamber 14) is low, both the limiting valve 80 and the provisioning valve 82 are in an open state, and the mask cylinder liquid pressure remains almost the same as the wheel cylinder 44. The braking forces of both axles 36 and 42 maintain the relationship shown by the straight line OA in Fig. 4.
When the mask cylinder hydraulic pressure becomes high to a certain extent, the proportioning hub 82 starts a pressure reducing operation and the axles 36
．． The relationship between the braking forces of 42 is shown by the straight line AB, and when the master cylinder hydraulic pressure increases further, the misting valve 80 closes, and from then on, the mask cylinder hydraulic pressure increases as shown by the straight line BC. Despite the rise in
The hydraulic pressure in the wheel cylinder 44 is prevented from increasing and the braking force of the right rear wheel 42 is kept constant, and the hydraulic pressure at which this limiting valve 80 is closed is such that the friction coefficient μ of the road surface is 0. 3, the hydraulic pressure is set such that the right rear wheel 42 and the left front wheel 36 are locked at the same time.

Above, the hydraulic pressure adjustment device 20 and the hydraulic pressure suppression valve 46 have been explained in detail, but the provisioning valve 28 is
The provisioning hull 82 shown in the figure is similar, and the mask cylinder IO and each wheel cylinder 24, 32, 38, and 44 are well known, so detailed description thereof will be omitted.

Next, the operation will be explained.

First, a case where the friction coefficient of the entire road surface is uniform will be explained. The wheel cylinder 24 of the right front wheel 22 is always supplied with hydraulic pressure that is properly adjusted by the hydraulic pressure adjustment device 20. Then, this hydraulic pressure is reduced by the proportioning valve 28 and transmitted to the wheel cylinder 32 of the left rear wheel 30, but the pressure reduction characteristic of the proportioning valve 28 is adjusted so that this liquid pressure also becomes an appropriate hydraulic pressure. is set. Therefore, the right front wheel 22 and the left rear wheel 30 are always locked almost simultaneously, regardless of the road surface friction coefficient. On the other hand, the hydraulic pressure supplied to the wheel cylinder 44 of the right rear wheel 42 is
Since it is suppressed by G as described above, the right rear wheel 42 will not lock if the friction coefficient μ of the road surface is 0.3 or more. However, on road surfaces where the friction coefficient p is 0.3 or more, the hydraulic pressure supplied to the wheel cylinders 44 is suppressed too low, and the braking force that can be borne by the rear wheels is equal to that of the front wheels. Since it is originally small in comparison, the disadvantage to the automobile as a whole is small. Further, since the mask cylinder hydraulic pressure is directly transmitted to the wheel cylinder 38 of the left front wheel 3G, there is a possibility that this wheel 36 will lock, but as mentioned above, the right front wheel 22 will not lock, so the vehicle The steering performance is not lost. Further, the braking force of the left front wheel 36 is not suppressed too low, which is advantageous since the front wheel is originally capable of bearing a large braking force.

As is clear from the explanation below, the coefficient of friction of the road surface is 71
When is 0.3 or more, there is no possibility that the right front wheel 22 and the left and right rear wheels 30 and 42 will lock, and the purpose of ensuring steering performance and preventing spin of the automobile is completely achieved. Also,
When the coefficient of friction μ of the road surface is 0.3 or less, the front left wheel 36 and the rear right wheel 42 may lock, but the front right wheel 22 and the rear left wheel 30 do not lock, ensuring steering performance. The purpose of preventing spin is almost achieved.

Next, as a special case, a case will be described in which the coefficient of friction between the road surface on which the right wheel is riding and the road surface on which the left wheel is riding is different. First, if the friction coefficient on the right side is higher than the friction coefficient on the left side, there is a possibility that the left front wheel 36 and the left rear wheel 30 will lock, but the right front wheel 22 will not be locked no matter what the friction coefficient of the road surface is. , the right rear axle 42 will not lock if the friction coefficient μ is 0.3 J:) or above. Further, since the braking force of the right rear wheel 420 is kept relatively small, the difference in braking force between the left and right wheels is reduced, and the effect of reducing the spin moment can also be obtained. In addition, the friction coefficient μ is 0.3
If it is below, the right rear axle 42 may also lock, but the friction coefficient I! is 0.3 or less, which is a very special case and rarely causes any practical problems.

On the other hand, if the friction coefficient on the left side is larger than the friction coefficient on the right side, the right front wheel 22 and the left rear wheel 30 will not lock, and if the friction coefficient 71 of the right road surface is 0.3 or more, the right rear wheel 42 also does not lock. Therefore, the objectives of ensuring steerability and preventing spin are completely achieved. However, if the friction coefficient μ of the right road surface is 0.3 or less, the right rear wheel 4
However, at least the right front wheel 22 and the left rear wheel 30 do not lock, so the above objective is almost achieved.

As is clear from the above explanation, although the hydraulic brake system of this embodiment is equipped with only one expensive hydraulic pressure adjustment device 20, it can almost certainly ensure steering performance and prevent spin on road surfaces under all conditions. It is possible to achieve the purpose.

It should be noted that in the above embodiment, the hydraulic pressure suppression valve 46
Although it is a combination of a beam soting valve 8o and a proportioning valve 82, the present invention is not limited to this, and for example, a beam soting valve 8o and a proportioning valve 82 can be combined. Various types of provocation valves can be adopted, such as a combination of provocation valves.In short, even if the maximum hydraulic pressure that can be generated in the mask cylinder is generated, if the friction coefficient of the road surface is above a predetermined value, Any mechanism may be used as long as it can suppress the hydraulic pressure in the second rear wheel cylinder 44 so as not to lock the right rear wheel 42. Furthermore, it is possible to appropriately select the coefficient of friction of the road surface so that the right rear wheel 42 will not lock, but it should be selected so that the right rear wheel 42 will not lock when the wet paved road is 0, 4 or more. It is desirable that the resistance be selected in such a way that it does not break, and it is especially desirable that it be selected so as not to break.

Furthermore, the hydraulic pressure adjusting device 2o is also the same as that of the embodiment described above. Furthermore, the configuration of the above embodiment can be reversed, that is, the wheel spacing between the left front wheel 36 and the right rear wheel 42 is changed, and the hydraulic pressure suppression valve 46 is provided in another system, that is, the first system. It is also possible to do so.

It is also possible to However, although this is an embodiment of the first invention, it is not an embodiment of the second invention.

Although not illustrated individually, it is of course possible to implement the present invention in various modifications and improvements based on the knowledge of those skilled in the art without departing from the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit diagram of a hydraulic brake system for an automobile, which is an embodiment of the present invention. FIG. 2 is a detailed circuit diagram of the hydraulic pressure regulating device in FIG. 1. FIG. 3 is a front sectional view of the hydraulic pressure suppression valve in FIG. 1, and FIG. 4 is a graph showing the control status of braking force distribution between the left front wheel and the right rear wheel by the hydraulic pressure suppression valve. FIG. 5 is a graph showing the braking frequency for each deceleration of an automobile traveling on a normal road. 10: Master cylinder 12: First pressurizing chamber 14: Second pressurizing chamber 18: First front passage 20: Fluid pressure adjustment device 22: Right front wheel (first front wheel) 24: First front wheel cylinder 26: First front wheel 1st rear passage 28. 82: Provocation valve 30: Left rear wheel (first rear wheel) 32: First rear wheel cylinder 34: Second front passage 36: Left front wheel (second surface wheel) 38: Second front Wheel cylinder 40: Second rear passage 42: Right rear wheel (second rear axle) 44: Second rear wheel cylinder 46: Hydraulic pressure suppression valve 5o: Electromagnetic directional control valve 54: Microcomputer 58: Sensor 70: Check valve 72: Return path 74: Pump 76: Pon 13m path 80: Rimisotinghalb Applicant Toyota Motor Corporation

Claims (3)

[Claims] (1) The hydraulic pressure generated in the two pressurizing chambers of the mask cylinder based on the driver's brake operation is transmitted to the front wheels and rear wheels, which are diagonally positioned through two systems of mutually independent liquid passages. In a hydraulic brake system for an automobile, the hydraulic pressure is transmitted to the front and rear wheel cylinders of the brake, and the front passage connects one of the pressurizing chambers of the mask cylinder and the front wheel cylinder of one of the left and right front wheels. On the way, an electromagnetic directional switching valve selectively communicates the front wheel cylinder with the reservoir and the one pressurizing chamber, and control controlling the electromagnetic directional switching valve while monitoring the skid state of the one front wheel. a rear wheel cylinder of a rear wheel diagonally positioned with respect to the one front wheel is connected to the electromagnetic directional control valve of the front passage and the front wheel cylinder by means of a rear passage; A provocation halp is connected to the part between the front and rear passages, and is provided in the middle of the rear passage for reducing the hydraulic pressure of the front wheel cylinder at a fixed ratio at least when the hydraulic pressure is higher than a certain level and transmitting the reduced pressure to the rear wheel cylinder. A hydraulic brake device for automobiles characterized by the following. (2) Front wheels where the hydraulic pressure generated in the first and second pressurizing chambers of the mask cylinder based on the driver's brake operation is transmitted through two independent 11ν passages, each diagonally positioned relative to each other. In an automatic military hydraulic brake system, the first pressurizing chamber of the mask cylinder and the first front wheel cylinder of the first front wheel are transmitted to a front wheel cylinder and a rear wheel cylinder of a brake for braking a front wheel and a rear wheel. An electromagnetic directional control valve that selectively connects the first front wheel cylinder to the reservoir and the first pressurizing chamber is installed in the middle of the first front passage connecting the first front wheel to the first pressurizing chamber. and a control device for monitoring and controlling the electromagnetic directional switching valve; A rear passage connects to a portion of the first front passage between the electromagnetic directional control valve and the first front wheel cylinder, and the third front passage is connected to a portion of the first front passage between the electromagnetic directional control valve and the first front wheel cylinder, and the third front passage is connected to the first front passage at least at a certain hydraulic pressure or higher. 1. A provisioning valve is provided to reduce the hydraulic pressure of the wheel cylinder at a constant rate and transmit it to the rear wheel cylinder, while the second pressurizing chamber of the mask cylinder and the second front wheel of the second wheel are provided. A second rear wheel cylinder of a second rear wheel diagonally positioned with respect to the second part wheel is connected to the second pressurizing chamber by a second rear passage. and, even if the hydraulic pressure in the second pressurizing chamber is increased to a predetermined maximum hydraulic pressure in the middle of the second rear passage, the hydraulic pressure in the second rear wheel cylinder cannot exceed a certain upper limit value. A hydraulic brake device for an automobile, characterized in that it is provided with a hydraulic pressure suppression valve that suppresses the pressure from occurring. (3) If the upper limit value of the hydraulic pressure in the second rear wheel cylinder is such that the coefficient of friction of the road surface is at least 0.3, the hydraulic pressure in the second pressurizing chamber is increased to the maximum hydraulic pressure. 3. The hydraulic brake system for a motor vehicle according to claim 2, wherein the value is selected so that the second rear axle will not lock even if the brake force is applied.