JPS61157457A - Automobile brake system - Google Patents

Abstract

PURPOSE:To surely carry out braking operation even upon pressure failure, by carrying out braking operation with the use of pressure from a hydraulic source upon normal operation of the hydraulic source, and by carrying out braking operation upon abnormal operation of the hydraulic source such that, with the use of hydraulic pressure generated by depressing force by a foot, a change-over valve is switched to increase the pedal stroke so that braking operation is directly performed by the depressing force. CONSTITUTION:Upon normal operation of hydraulic sources 41, 43 and a hydraulic circuit 44, hydraulic pressure is fed to a booster 2 through a control valve 45. At this time the pressure from a circuit 44'' holds a control valve 49 in its inoperative condition, and a chamber 59 is held in its hydraulically rigid condition. When a pedal 5 is depressed in this consition, the control valve for the booster 2 is opened by means of a rod 3 so that hydraulic pressure is introduced into a pressure chamber to actuate a brake. When the pedal 5 is depressed upon abnormal operation of the hydraulic circuit 44, etc., the control valve 49 is changed over to relieve oil from the chamber 59 so that the hydraulic rigidity is loosed. Therefore, the stroke of a rod 4 is increased, and accordingly, the stroke of the rod 3 is also increased. This stroke causes a piston in a master cylinder 9 to directly actuate to perform braking.

Description

[Detailed Description of the Invention] Industrial Application Fields> The disclosed technology is capable of achieving stable control performance in braking an automobile regardless of the load weight or the unbalanced movement of the brake pedal. It belongs to the technical field of systems designed to ensure safety functions.

According to this invention, a brake pedal installed in the driver's seat of an automobile is linked to a master cylinder, and when the vehicle speed is sensed, a control valve installed in a hydraulic circuit connected to the master cylinder is connected to the brake pedal. This invention relates to a brake system in which optimal deceleration control is performed by a computer based on detection data from a pedal force detection mechanism provided, and in particular, the invention relates to a brake system that controls the front and rear wheels of the master cylinder. Regarding the braking force transmission system for the power piston that transmits power, when the electrical system is in good condition, the first system uses only the hydraulic pressure controlled by the control valve attached to the hydraulic indicator, and the first system operates only by hydraulic pressure controlled by the control valve attached to the hydraulic indicator, and troubles such as hydraulic pressure loss etc. If the hydraulic circuit does not operate due to reasons such as this, the hydraulic pressure is mechanically controlled only by the pressing force from the brake pedal, and a guaranteed second system that transmits the braking force by controlling the oil and pressure is automatically activated. Moreover, the invention relates to a multi-system type brake system for automobiles in which the ``1st and 20th systems are mutually and exclusively selected.''

<Prior art> As is well known, automobiles have a brake system as one of the driving safety devices, but basic functional technology has already been developed for the deceleration and stopping functions, which are the basic aspects of the brake system. The technology has reached a level that is fully satisfactory, and in order to respond to the diversification of usage patterns and further improve safety, research is being conducted into technologies to prevent slips caused by boost braking and excessive braking. Hydro brake systems were developed for the former, and so-called anti-skid systems were developed for the latter.

<Problem to be solved by the invention> However, in these existing brake systems, the system itself has been developed and researched with a fixed setting system. For example, changes in brake deceleration due to changes in weight due to changes in live load, etc., and various deceleration speeds that occur depending on the driver's physique, strength, habits, senses, etc. Even when applying force to the brake pedal, the expected deceleration cannot be obtained, and the actual braking that is performed does not go as planned due to various variations in deceleration, resulting in the widespread use of expressways. In reality, there is an unbalance in deceleration due to various changes in driving conditions over time, such as on rough roads or on rough roads. Furthermore, due to economical changes in shoe clearance, etc., deceleration performance is not constant, and stable constant deceleration cannot be obtained, leading to dangerous situations such as delays in brake operation. It's getting bigger.

Yawa. □、yo＊om＜＊＊cm□ゎ. 1. The mechanical part of the brake system is a fixed mechanism based on an average target design or a theoretical standard design. Therefore, there is a drawback that it is not possible to deal with the diversity of various decelerations, and when the driver actually operates the vehicle and drives the car, the driver expects the deceleration to correspond to the force applied to the brake pedal. Another drawback was that it was difficult to respond immediately to engineering requests.

In addition, the use of microcomputer-based electronic control systems such as the above-mentioned anti-skid system will inevitably cause troubles in the electronic mechanism due to unexpected radio wave interference, and unavoidable high frequency and long-term vibrations and photography that are applied in the roof. A high-precision brake system may not be able to fully demonstrate its designed function due to troubles such as short circuits in the IC circuits of electronic components or breakage of lead wires. Another drawback was that the brakes could not always be expected to perform their braking function.

Furthermore, if the brake system, which uses an extremely sophisticated mechanism, fails to operate due to some trouble, it may not function as a safety device.

Therefore, a brake system that makes full use of extremely high-tech mechatronic technology can respond flexibly and quickly to various changing conditions, and always maintain safe braking, which is the basic first condition of the brake system, and optimal control added on top of that. However, from the user's point of view, there was a disadvantage in that there were concerns that there were some parts that were not cost-effective.

The purpose of the present invention is to provide a system that is independent of changes in the load weight of the vehicle body based on the above-mentioned prior art, and is independent of road conditions.
Furthermore, regardless of wear of the brake friction material or changes in shoe clearance, the basic safety braking function based only on pedal force is always automatically switched and guaranteed even in the event of system trouble, and then the vehicle It is possible to obtain the expected deceleration according to the driver's applied pedal force regardless of the changing conditions of the vehicle, and the performance of the brake system is ensured by fully utilizing the advanced brake mechanism and ensuring minimum safety. It is an object of the present invention to provide an excellent automobile braking system that can be utilized in a manner that is beneficial to the field of safety technology application in the automobile industry.

<Means/effects for solving the problem> In accordance with the above-mentioned purpose, the structure of the present invention, which is summarized in the above-mentioned claims, is such that the equipped brake system operates normally in order to solve the above-mentioned problem. When braking while driving in
When a desired pedal force is applied to the brake pedal, a pedal force detection mechanism linked to the brake pedal detects the applied pedal force and inputs the detection signal to the computer;
Also, the vehicle speed sensors on the front and rear wheels detect the highest vehicle speed at any position and input the detection signal to the computer, so the computer calculates the reference vehicle speed at that speed and applies the The optimum deceleration according to the pedal force applied is calculated, and a predetermined control signal is sent to the control valve installed in the hydraulic circuit to operate the spool valve of the master cylinder, and the hydraulic pressure from the hydraulic circuit is converted to the power of the master cylinder. The master cylinder applies boosted braking pressure to each brake of the front and rear wheels to apply a predetermined deceleration and brake, and the momentary deceleration state is detected by the vehicle speed sensor. The control valve is controlled to close, and the power piston of the master cylinder releases the hydraulic braking pressure for the front and rear wheels.
deceleration is performed according to the setting, and during this time, the pedal force applied to the brake pedal is only subjected to the resistance of the elastic spring installed in the booster, ensuring that a linear input of the pedal force is sent to the computer. The first system described above ensures the deceleration according to the pedal force as expected, and prevents electromagnetic interference from occurring to the computer of this brake system, or from repeating wiring etc. of each electronic component. If a short circuit or other malfunction occurs due to rocking vibrations applied to the brake pedal, the above-mentioned l1lll valve will be automatically closed by the set spring, and the main button provided on the brake pedal will close due to the pedal force. Control the spool valve l111
Apply hydraulic pressure from the 1m valve to the power piston,
In order to apply the same boosted hydraulic pressure to the front and rear wheel brakes (the control force applied by the main bush rod to the spool valve is linearly applied to the return spring of the main bush rod as described above). By doing so, the power piston applies hydraulic pressure to the front and rear wheels in the same way as a normal hydraulic brake system, mechanically providing the optimum deceleration according to the pedal force, and furthermore, This technology enables the master cylinder to be operated by the brake pedal alone through its linked bushing rod, and provides a second system that performs normal hydraulic braking to ensure two systems of braking, the full servo and non-servo systems mentioned above. The measures taken were as follows.

<Embodiment - Configuration> Next, one embodiment of the present invention will be described below based on the drawings.

In FIG. 2, reference numeral 1 indicates the automobile brake system of the present invention, and its booster 2 is a main bushing rod 3.
, and is linked to a brake pedal 5 via a sub-button rod 4.

Further, suitably well-known vehicle speed sensors 6, 6, etc. provided for the front and rear left and right axles are electrically connected to the computer 7, and transmit their detected vehicle speeds. The faster vehicle speed is detected.

As shown in detail in FIG. 1, the booster 2 has a well-known aspect in which it is provided integrally with a braking force transmission cylinder 8 constituting a first braking force transmission system on the base side. It consists of a similar master cylinder 9 and a pedal force cylinder 10 that is integrally provided on the lower side, and the master cylinder 9 has a front hydraulic pressure chamber 13 in which a control piston 11 has a return spring 12 interposed in its front part. The rear hydraulic pressure chamber 1G formed at the rear is connected to a reservoir chamber 14 connected to a reservoir tank (not shown) and connected to the front wheel brake 15, and the rear hydraulic chamber 1G formed at the rear is connected to a reservoir chamber 17 connected to a reservoir tank (not shown). 2, and is connected to a rear wheel brake 19 via a proportioning valve 18, as shown in FIG.

Also 1. As mentioned above, there is a control provided integrally and rearwardly on the master cylinder 9. A power piston 21. The power piston 21 has reservoir chambers 22 and 23 formed between them, and communicates with the reservoir chambers 11 and 24, respectively, and a return spring 25 is provided inside the power piston 21. - A spool valve 29 having a φ boat 28 in the longitudinal direction that communicates with the reservoir chamber 22, 23 and the radial port 26 of the power piston 21 via the radial boat 21 is arranged relatively front and rear. The power piston 21 has a return spring 30 and a return spring 30 at the rear end of the power piston 21.
The main bushing rod 3 is mounted via a hook 31 through a mounting portion 32, and its rear end is connected to an elongated hole 33 forming a slight play of a set length with respect to the upper part of the brake pedal b. On the other hand, the pressurized chamber 35 formed between the front end of the bottle 34 and the first power piston 21 is connected to the other via the bottle 34, and the pressurized chamber 35 is connected to the other via the boat 36. The pressurized chamber is connected to the boat 28 in the spool valve 29, and when the boat 27 of the spool valve 29 and the boat 26 of the power piston 21 are in a relative sliding position, the pressure chamber 35 communicates with the reservoir chamber 24 of the pedal force transmission cylinder 8.

Further, an axial port 38 provided in the main bushing rod 3 is connected to a pressurizing chamber 39 at the front thereof, and
It communicates with the reservoir chamber 40.

Thus, the reservoir chamber 40 of the braking force transmission cylinder 8 is
As shown in FIG. 2, a hydraulic pump 41, an oil tank 42
, is connected to a control valve 45 interposed in a hydraulic circuit 44 having an accumulator 43.

The control valve 45 is electrically connected to the computer 1 to prevent radio wave interference and the computer's I/O.
In an unforeseen situation such as a short circuit due to shaking vibration of a car or printed circuit board, the return spring immediately closes the front chamber 46 of the control valve 45, which is connected to the hydraulic circuit 44 for the oil tank 42. The middle chamber 41 is connected to the return circuit 44' of the hydraulic pump 41, and the middle chamber 41 is neutral to maintain the applied hydraulic pressure, and the rear chamber 48 is connected to the hydraulic pump 41.
Alternatively, the hydraulic pressure from the accumulator 43 is applied to the reservoir chamber 40 of the braking force transmission cylinder 8.

Incidentally, a circuit 44' branched from the hydraulic circuit 44 is
The brake force transmission cylinder 8 is connected to the reservoir chamber 24 in a state where hydraulic pressure is constantly applied thereto, and a first system for switching between the first brake force control system for normal operation and the second brake force control system for unexpected situations is provided below the brake force transmission cylinder 8. A control valve 49 for detecting hydraulic inoperation is provided in the casing and is connected via a return spring 50.
A pressurizing chamber 51 formed between the rear side and the casing and a reservoir chamber 23 formed in the braking force transmission cylinder 8
A boat 52 is communicated between the boat 52 and the other reservoir chamber 22 of the braking force transmission cylinder 8.
3 is connected to a boat (not shown) through a neck-shaped front communication portion of the control valve 49 via a U-shaped cup-shaped seal lip 54 on the west side provided on the outside of the control valve 49. It communicates with the front chamber formed by the front chamber.

Further, the pedal force cylinder 10, which controls the function of a second braking force transmission system formed on the lower side of the braking force transmission cylinder 8 through the casing of the control valve 49, is provided with a control valve. A piston 55 is inserted through a compression spring 56 so as to be slidable back and forth, and a pedal force piston 51 is attached to a return spring 58 at the rear of the piston 55.
A pressurizing chamber 59 is provided therebetween.

The oil in the pressurizing chamber 59 is connected to the neck-shaped communication portion of the control valve 49 through the boat 60, and the oil in the pressurized chamber 59 is connected to the neck-shaped communication portion of the control valve 49 through the back and forth movement of the control valve 49. 53, and further communicates with the reservoir chamber 11 through a reservoir chamber 22 at the front of the braking force transmission cylinder 8.

The rear part of the pedal force piston 57 is linked to the sub-button rod 4 which is connected to the brake pedal 5 via a pin 62 via a well-known O-disel 61 as a pedal force detection mechanism.

The load cell 61 is electrically connected to the computer 7 and inputs the detected pedal force signal.

<Embodiment - Effect> In the above-described configuration, when applying braking to a running vehicle to decelerate or decelerate to a stop, the computer 7 always controls the front and rear vehicle speed sensors 6, 6, and 6.
The vehicle speed is detected by ... and the fastest speed of any of them is measured.

During the driving process, various loads such as people and cargo are applied to the automobile, and the degree of wear of friction materials such as brake pads may vary depending on the type of vehicle, aging, etc. There are changes in shoe clearance, etc., and the potential conditions for M disturbance are different.

Thus, the driver intuitively grasps the braking situation and applies a pedal force to the brake pedal 5 in anticipation of a deceleration corresponding to the pedal force applied to the brake pedal 5 operated by the driver.

Therefore, the pedal force applied to the brake pedal 5 is detected by the load cell 61 of the pedal force detection mechanism via the main bushing rod 3, and is input to the computer 7, where
The controller 7 calculates the reference vehicle speed at the vehicle speed, and also calculates the optimum deceleration according to the pedal force.・This relationship is shown in the graph of Figure 3, where the horizontal axis represents time t and the vertical axis represents vehicle speed S.The calculated vehicle speed corresponding to the set vehicle speed in graph C is expressed as C''. shown.

Therefore, a control signal that provides the optimum deceleration for the pedal force is sent to the solenoid of the control valve 45, and in normal normal operation, the control valve 45 is opened and the rear chamber 48 is connected to the hydraulic circuit 44.

Therefore, the hydraulic pump 41 of the hydraulic circuit 44 supplies oil from the oil tank 42 or from the accumulator 43.
A predetermined hydraulic pressure is delivered to the reservoir chamber 24, 40 of the braking force transmission cylinder 8 in cooperation with the braking force transmitting cylinder 8.

At this time, the hydraulic circuit 44 branched from the hydraulic circuit 44
The hydraulic pressure directly applied to one of the reservoir chambers 24 through ' is applied to the lower control valve 49 of the braking force application cylinder 8 by the boat 52 through the reservoir chamber 23 communicating with the reservoir chamber 24. Since the pressure is applied to the chamber 51, the control valve 49 is in a state of detecting normal oil pressure, and is pushed forward to the left in FIG. In order to seal the oil in the pressurizing chamber 59 and maintain hydraulic rigidity, the pedal force from the sub-button rod 4 via the brake pedal 5 is compressed by a pedal force piston 57 that appropriately linearly corresponds to the pedal force. The initial load of the spring 56 allows the driver to apply a braking force that produces the expected resistance of the applied pedal force to the brake pedal 5, that is, deceleration.

Of course, the action of the compression spring 56 is a dummy braking force.

Therefore, the pedal force applied by the driver to the brake pedal 5 is independent of the change in the load or the change in the brakes of the vehicle, which is unique to the vehicle, and the driver is not aware of this in advance. The pedal force is applied with a completely normal braking feeling regardless of whether the brake is hard or not.

On the other hand, the main bushing rod 3 in the braking force transmission cylinder 8 has a free play due to the free engagement between the long hole 33 and the pin 34 provided above the brake pedal 5 at the base end and having a predetermined free play. No pedaling force is applied in the range of the stroke that is only used as a substitute.

Therefore, a predetermined hydraulic pressure from the hydraulic pump 41 applied to the reservoir chamber 40 of the braking force transmission cylinder 8 enters the pressurizing chamber 39 via the boat 38, and moves the spool valve 29 against the return spring 25 at its tip. - As a result, the boat 27 of the spool valve 29 and the outer reservoir chamber 23 communicate via the boat 26 of the power piston 21, so that the hydraulic pressure applied to the spool valve chamber 24 is increased. Hydraulic pressure from 41 goes to reservoir chamber 24.2
3, and via boat 26.21, boat 28.37
The hydraulic pressure is transmitted to the pressurizing chamber 35 via the boat 36, and as a result, the power piston 21 is pressed and moves forward against the return spring 12, 20, and from the reservoir chamber 14 of the front hydraulic chamber 13. The oil from the reservoir chamber 11 of the -pressure chamber 16 is applied to the rear wheel brake 19 to operate the booster braking to achieve the above-mentioned predetermined deceleration. give: to give, to be given. '°゛'' During this time, the tip of the spool valve 29 is closed to the reservoir chamber 22.
and therefore the port connection to the boat 36.
．． 37 and 28', the hydraulic pressure for applying the braking force is not transferred to the reservoir chamber 22, and the application of the braking force to the power piston 21 is reliably maintained.

Although the power piston 21 moves forward in this state, the relative posture of the spool valve 29 with respect to the power piston 21 is independent of the posture of the power piston 21, and the hydraulic pressure from the reservoir '140 is applied to the spool valve via the boat 28. 29 is applied from the base side to the pressurizing chamber 39 against the return spring 25, the spool valve 29 is inserted into the deepest position relative to the power piston 21, and the hydraulic pressure is The hydraulic pressure from the pump 41 is P1, the pressure in the pressurizing chamber 35 is p +, and the spool valve 2 is
If the set load of the tip return spring 25 of 9 is F, then P'A+F<PA, so the spool valve 29 is still in the back side with respect to the power piston 21, that is, the boats 26 and 21 are aligned. Therefore, the hydraulic pressure from the hydraulic pump 41 from the reservoir 124 is still applied to the pressurizing chamber 35, and urges the power piston 21 into the pushing position.

Due to the play of the elongated hole 33, the main bushing rod 3 is not applied with any depressing force from the brake pedal 5 as described above, and the flag 3 is pushed forward by the power piston 21.
1, it is merely subjected to an advancing action in a so-called stagnation phenomenon.

In this way, when the vehicle speed is decelerated, the heavy speed sensor 6 detects the deceleration state and inputs it to the computer 7.
As shown in FIG. 3, when the vehicle speed C' in a predetermined deceleration state is decelerated relative to the set vehicle speed C, the computer 1 sends a control signal to the solenoid of the control valve 45 to control the vehicle speed C'. The front chamber 4G of the valve 45 is connected to the reservoir chamber 4.
It operates to connect to 0.

Therefore, the reservoir chamber 40 is connected to the oil tank 42 via the hydraulic circuit 44 and the return circuit 44'.
8, the hydraulic pressure in the pressurizing chamber 39 is rapidly reduced, and as a result, the spool valve 29 is moved back relative to the power piston 21 by the return spring 25 at its tip, so that the boat 26 of the power piston 21 As shown in FIG. 1, the boat 21 of the spool valve 29 will be displaced.

Therefore, the hydraulic pressure in the reservoir chamber 24, 23 is maintained at the same hydraulic pressure that was decelerated immediately before by the circuit 44' branched from the hydraulic circuit 44, and therefore the control valve 49 is pressurized via the boat 52. The pressure in the chamber 51 is maintained, and the control valve 49 still maintains the posture in which the predetermined deceleration is produced while detecting the oil pressure.
A linear pedal force application state can be maintained due to the set load of the elastic spring 56.

Therefore, the spool valve 2 is connected to the power piston 21.
9 is retracted and its tip is connected to the reservoir chamber 22 via the boat of the power piston 21, thereby connecting the reservoir chamber 22 and the pressurizing chamber 35 via the boats 28, 37, and 36. , the previously high hydraulic pressure is communicated from the reservoir chamber 11 to the return circuit via the boat 37, 36, 28, and is rapidly reduced in pressure.
The main bushing rod 3 is also moved back via the return spring 30.

However, since the base end of the main bush 3 is loosely engaged with the pin 34 in the elongated hole 33 having an allowance for play, no interference with the brake pedal 5 occurs.

Therefore, as the power piston 21 moves backward, the hydraulic pressure in the front hydraulic chamber 13 and the rear hydraulic chamber 16 is reduced, so that the braking applied to the front wheel brake 15 and the rear wheel brake 19 is lost, and the previous reduction is reduced. The speed is lost and the set vehicle speed graph C shown in Figure 3
On the other hand, the graph C' of the decelerated vehicle speed is close to or exceeds this.

During this time, the vehicle speed sensors 6, 6... are actually measuring the vehicle speed in the deceleration state or in the deceleration maintenance state and transmitting the measured value to the computer 1. , Computer 1 commands deceleration again,
The command signal returns the control valve 45 from the return position relative to the hydraulic circuit 44 to the open position, as described above, thereby reconnecting the chamber 48 to the reservoir chamber 40;
Therefore, as described above, hydraulic pressure is applied to the pressurizing chamber 39 again, the spool valve 29 moves forward, the boat 27 is again aligned with the boat 26 of the power piston 21, and the reservoir chamber 24 is moved forward.
Hydraulic pressure from the hydraulic pump 41 passes from the reservoir chamber 23 through the boat 26.27, through the boat 28.37.36,
It enters the pressurizing chamber 35 and applies boost braking force to the power piston 21.

In addition, when the spool valve 29 is in the forward state, its tip cuts off the boat connection to the reservoir chamber 22.
The deceleration braking force of the pressurizing chamber 35 is not reduced.

By repeating such a process, the braking pressure in the reservoir chamber 23 is always maintained in the pressurizing chamber 51 of the control valve 49 via the boat 52, so that the pedal force applied to the brake pedal 5 is equal to that of the pedal force cylinder 10. A linear applied state due to the set load of the elastic spring 56 is always maintained.

In order to constantly detect the actual vehicle speed by the vehicle speed sensor 6, 6, and send it to the computer 1, the above-mentioned operation is performed based on the measured deceleration as shown in FIG. As the control valve 45 opens and closes frequently in accordance with the frequency with which the vehicle speed C' approaches and departs dynamically, the spool valve 29 and the power piston 21 move relatively back and forth, thereby causing almost no shock to the brake pedal 5. In addition, the applied state of the pedal force is a linear application state to the elastic spring 56 of the pedal force cylinder 10. Therefore, regardless of changes in the live load or changes in the brake pad or shoe clearance, the applied pedal force is simply applied extremely. Stable and smooth braking is achieved with linear deceleration as expected by the driver.

Therefore, the computer performs the control.1
However, as is well known, if the computer 1 is subjected to severe radio wave interference, its control functions may malfunction or become inoperable, or the IC printed circuit board wiring of the computer 7 or its surroundings may be damaged. If a short circuit or disconnection occurs in the lead wire wiring due to severe vibration over time while running, a proper operating signal will not be sent to the control valve 45, and therefore the boosted hydraulic servo as described above will not be sent. There is a risk that brake control may become impossible.

To deal with this, when such an electrical system trouble occurs, a predetermined computer emergency program immediately and automatically shuts down the control valve 45.
is in a closed or return state, that is, its middle chamber 47 or front chamber 46 is connected to the reservoir chamber 40, and therefore, hydraulic pressure is not applied to the reservoir chamber 24 from the hydraulic circuit 441. However, the spool valve 29 is not moved forward by the hydraulic pressure from the hydraulic pump 41 via the reservoir chamber 40.

When the driver performs predetermined braking in such a state, when the driver applies a pedal force that corresponds to the braking sensation to the brake pedal 5, the hydraulic pump 41 is supplied to the reservoir g24 via the normally open hydraulic circuit 441, as described above. Since the oil pressure is being applied, the oil pressure from the reservoir chamber 23 is applied to the pressurizing chamber 51 of the control valve 49 via the boat 52, and the control valve 49 detects oil in a normal state. and blocked boats 60 and 53.
Therefore, the pedal force applied to the brake pedal 5 is linearly applied in balance with the set load against the resistance of the elastic spring 56 of the pedal force cylinder 10, and a pedal force similar to the mode of the above-mentioned double carbide 0 lick servo braking operation is applied. will be done.

Therefore, when the brake pedal 5 is depressed, a pedal force corresponding to the elastic spring 56 is applied to the sub-button rod 4 in the same way as in the above-mentioned embodiment, but the main bush rod 3 with respect to the braking force transmission cylinder 8 has an elongated hole. After a slight play through the free play of 33, a small portion of the pedal force through the pin 34 will be applied to the mark 7708 and press the spool valve 29 integrally.

However, since the weight of the spool valve 29 and the main bush rod 3 is extremely small, and the sliding resistance is also small, the main bush 3 and the main bush rod 3 are A portion of the pedal force that pushes the spool valve 29 is substantially equal to almost zero, and therefore, the pedal force that the driver applies to the brake pedal 5 exceeds the resistance of the elastic spring 56, and the driver feels a large operating force. Very rarely.

In this way, when the spool valve 29 is moved forward by a small amount of free stroke and then moved forward by MIFAL, the boat 21 is moved forward by the boat 26 of the power piston 21.
The hydraulic pressure from the hydraulic pump 41 is connected to the reservoir chamber 24, the boat 26, 27, and the port 28.
37, the power is applied from the boat 36 to the pressurizing chamber 35 to advance the power piston 21 to a predetermined value, and the hydraulic pressure in the front hydraulic chamber 13 and rear hydraulic chamber 16 is increased to apply pressure to the front wheel brake 15 and rear wheel brake 19. A predetermined braking force is transmitted to provide deceleration corresponding to the pedal force, similar to the hydraulic servo braking mode described above.

The servo ratio in this state is the cross-sectional area πD+2/4 of the main bushing rod 3, and the cross-sectional area πD22 of the braking force transmission cylinder 8.
/4, it becomes 02”/DI・2.

During this time, each vehicle speed sensor 6.6 detects the decelerated vehicle speed.
Even if ... detects the signal and sends the signal to the computer 7, as described above, in this case, the control valve 45 is not controlled by the computer 1 due to a problem with the electrical system, but the brake pedal 5 is not controlled by the driver. Only a linear operation of the applied pedal force to the elastic spring 56 is performed, the servo function is in an effective state, and the booster braking operates in a state that is substantially the same as in a state where there is no trouble in the electrical system.

Yes, 7 woo$<1.5□1□ka. A (Then, the pushing force on the main bushing rod 3 is canceled, but
At this time, the spool valve 29 is moved back by the return spring 25 at its tip, and the main bushing rod 3 is slightly pushed back through loose engagement with the elongated hole 33 and pin 34 at its base end. Therefore, power piston 2
The boat 26 of the spool valve 29 and the boat 27 of the spool valve 29 are misaligned, and the hydraulic pressure in the pressurizing chamber 35 is transferred to the spool valve 2 through the boats 36, 31 and 28, as in the above-mentioned embodiment.
9 is connected to the reservoir chamber 22.1γ via a boat connection, and the pressure is reduced through the feedback circuit 11' to the oil tank 42, and deceleration is eliminated.

Also, if -1 pedal force is applied to the brake pedal 5,
The boats 27 and 26 of the spool valve 29 are connected again, and the hydraulic pressure of the hydraulic pump 41, which is constantly in communication, is applied to the pressurizing chamber 35.
As a result, the power piston 21 moves forward again, and a braking force is applied.

Therefore, in this embodiment, the depressing force applied to the brake pedal 5 remains the same regardless of changes in the loaded weight, changes in brake pads or shoe clearance, or even if there is a problem with the electrical system of the computer 1, etc. Large heid O-lick braking can be obtained simply by applying linear pressure to the elastic spring 56 of the cylinder 10, and optimal deceleration can be obtained in response to the pedal force applied by the driver even though it is only semi-automatic servo braking. become.

Incidentally, when the engine is stopped, the control valve 45 is connected to the return connection by the braking of the computer 1, the reservoir chamber 40 is connected to the oil dunk 42, the brake oil pressure becomes zero, and the parking brake is activated.

Therefore, the more automation and servo mechanisms are installed in brake systems, the more likely it is that in the event of a failure of these complex mechanisms, human-powered mechanical mechanisms must be able to perform braking using only pedal force as a minimum safety guarantee. In this invention, if a hydraulic pressure loss occurs unexpectedly in the hydraulic circuit 44 due to a failure of the hydraulic pump 41, the hydraulic pressure in the reservoir chamber 24 decreases, and therefore, the hydraulic pressure is The oil pressure in the pressurizing chamber 51 of the control valve 49 will decrease,
When the pedal force applied to the brake pedal 5 presses the sub-button rod 4, the pressure chamber 5 of the pedal cylinder 2 is
9 becomes larger than the pressure in the reservoir chamber 24, that is, the pressure chamber 51 of the control valve 49, the pressure in the front chamber increases via the port 60 and the boat (not shown). The hydraulic pressure in the pressurizing chamber 59 through the port 60.53 causes the control valve 49 to retreat against the return spring 50, so that the oil pressure drop is automatically detected, and the hydraulic pressure in the pressurizing chamber 59 is controlled via the port 60.53. , toward the reservoir chamber 11. Therefore, the hydraulic rigidity of the pressurizing chamber 5 is also lost, and the second system functions, and as a result, the depression force applied to the brake pedal 5 is reduced to the subbutton. For the rod 4, only a small amount is used for the deflection of the return spring 58 of the pressurizing chamber 50, and the main bushing rod 3 on the upper part is moved through the slight play of the elongated hole 33 with play. As a result, the main bushing rod 3 substantially immediately pushes the power piston 21 and mechanically pressurizes the front hydraulic chamber 13 and the rear hydraulic chamber 16. Hydraulic braking force is applied to the front oil brake 15 and the rear wheel brake 16 to perform deceleration in the same manner as in a normal hydraulic oil brake system using mere pedal force without boosting.

As described above, in this invention, there are two systems: a first system that automatically and semi-automatically applies the braking of the boosted hydraulic brake by the hydraulic pump 41, and a second system that performs normal hydraulic braking using pedal force in an unexpected situation. It has
In addition, these two systems are designed to automatically and immediately respond to two conditions, i.e., a healthy electrical control operating condition and a troubled condition due to oil pressure deficiency, and are switched over in a mutually exclusive manner.

It is needless to say that the embodiments of the present invention are not limited to the above-mentioned embodiments. For example, various embodiments may be adopted in which different warning devices are provided in the event of electrical system trouble or hydraulic pressure loss. be. −゛〈Effects of the Invention〉゛As described above, according to Baimei, in a brake system that has a hydraulic brake mechanism capable of producing an extremely strong braking force and is capable of performing boost braking. Basically, depending on the applied pedal force, the optimum deceleration for the vehicle speed is obtained, regardless of various conditions such as the load weight and changes in the brake pad and shoe clearance of the brake mechanism. This is a system that enables automatic servo braking by controlling a 1 illtll valve installed in the hydraulic circuit via hydraulic pressure based on detection signals of applied pedal force and vehicle speed, and a system that can perform automatic servo braking by controlling a 1 illtll valve installed in the hydraulic circuit. There are two systems, one in which deceleration is obtained only by the pedal force applied servo-wise when a failure occurs. Firstly, the effective operation of the brake is essentially the optimum deceleration that always responds to the driver's sense of the actual speed applied, regardless of load weight conditions or various changes in the brake mechanism. This is usually achieved as expected, and as a result, the driver's sense of safety, which is given the highest priority, is sufficiently guaranteed, and the excellent effect is achieved that the vehicle can reliably obtain safe running and driving conditions, including deceleration and stopping. .

Since the hydraulic pressure control by the control valve is performed automatically and frequently, there is no shock to the brake pedal, and the excellent effect of maintaining good responsiveness is achieved.

In addition, even if a problem such as a hydraulic pump failure occurs, normal hydraulic brake operation is mechanically guaranteed using only pedal force, and furthermore, these systems can be operated completely automatically in their optimal conditions. This provides the excellent effect of ensuring the above-mentioned safe driving optimum deceleration braking.・

[Brief explanation of drawings]

First lashing A plan view of the servo structure according to an embodiment of the present invention, Second lashing
The figure is an overall schematic system diagram of one embodiment, and FIG. 3 is a graph showing the correspondence between the reference vehicle speed and the actually measured vehicle speed. 44... Hydraulic circuit, 9... Master cylinder, 5
...brake pedal, 61...treading force detection mechanism, 7
...computer, 21...power piston, 1
0...Control valve

Claims (1)

[Claims] A detection mechanism for detecting the pedal force applied to the brake pedal is connected to a master cylinder connected to the hydraulic circuit, and the pedal force detection mechanism and the vehicle speed sensor control a control valve connected to the hydraulic circuit via a computer. The brake system includes a first system in which braking force transmission to the power piston to the master cylinder is performed by hydraulic pressure via hydraulic control of a control valve attached to the hydraulic circuit, and a first system in which braking force is transmitted to the power piston to the master cylinder by hydraulic pressure via hydraulic control of a control valve attached to the hydraulic circuit; 2 with a second system carried out by hydraulic pressure through
A control valve for detecting hydraulic inoperation of the first system is interposed between the first and second systems so that the two systems are automatically selected to be mutually exclusive with respect to the first system. An automobile brake system characterized by: