JPS61155046A - Brake system for automobile - Google Patents

Abstract

PURPOSE:To improve vehicle running safety, according to a method wherein an automobile braking system consists of 3 systems including systems making automatic servo braking for controlling a control valve in an oil pressure circuit in accordance with treading force and vehicle speed respectively and a system obtaining an optimum deceleration immediately in response to treading force at the malfunction of an electric system. CONSTITUTION:A booster 2 operated by means of a brake pedal 5 through a main rod 3 and a sub rod 4, consists of a braking force transmitting cylinder 8 on the base side, a master cylinder 9 mounted on the front portion of the cylinder 8, and a treading force cylinder 10 integrally mounted on the lower side of the cylinder 8. the two reservoir chambers of the braking force transmitting cylinder 8 are respectively connected to a pair of control valves 44 and 45 interposed in parallel in an oil pressure circuit including an oil pressure pump 41 and an accumulator 43. Each of the valves 44 and 45 is respectively used for the control of a power and a spool pistons in the cylinder 8, and the control valve 44 is opened by means of a spring and the control valve 45 is closed when the malfunction of a computer 7 or the like is generated.

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology is a technical field of a system that enables the braking of an automobile to exhibit stable control performance regardless of variations in the loaded weight or brake mechanism, etc. belongs to

In this invention, a brake pedal provided on the driver's seat of an automobile is linked to a master cylinder, and a control valve for a hydraulic circuit connected to the master cylinder is connected to a vehicle speed sensor and a depression force provided on the brake pedal. This invention relates to a brake system that is optimally controlled by a computer based on data from a detection mechanism, and in particular,
Regarding the braking force transmission system for the power piston that transmits braking force to the front and rear wheel brakes of the master cylinder, when the electrical system is in good condition, hydraulic pressure is controlled by one control valve attached to the hydraulic circuit. A system that uses only hydraulic pressure, and a system that uses hydraulic pressure to control hydraulic pressure using the pedal force from the brake pedal via another control valve if one control valve in the hydraulic circuit does not operate due to a failure or trouble in the electrical system. In addition, in the event of a failure in the hydraulic system, there are three systems in which the braking force is transmitted to the power brake only by the pressing force of the brake pedal. , the two systems, or the three
This invention relates to a multi-system type brake system for automobiles that can perform various types of braking through mode conversion in which systems are automatically and mutually exclusive selected.

<Prior Art> As is well known, automobiles have a brake system as one of the safety devices, but the basic aspects of the brake system, such as deceleration and stopping functions, are already basically sufficient as functional technology. In order to respond to the diversification of usage patterns and further improve safety, research has been conducted on technologies to prevent slips caused by boost braking and excessive braking. For the latter brake system, so-called anti-skid systems were being developed and adopted.

<Problems to be solved by the invention> However, in these already developed brake systems, the system itself has been fixed as a single setting system and researched and developed, so the number of occupants and carrying load of the vehicle cannot be adjusted. For example, changes in brake deceleration in response to changes in weight due to fluctuations in brake pressure, and various decelerations that vary depending on the driver's physique, strength, habits, senses, etc. Even if the pedal force is applied, the expected deceleration cannot be obtained, and the actual braking that is performed does not work as designed due to the wide variety of decelerations that are related to each other. , there actually exists an imbalance in deceleration due to various changes in driving conditions over time on rough roads,
In addition, deceleration performance is not constant due to changes in deceleration due to changes in the friction coefficient of the friction material of the brake mechanism, for example, the friction material of the brake pad, and changes in shoe clearance.
The reality behind this situation is that stability cannot be achieved and dangerous situations occur due to delays in brake operation, etc.

Nevertheless, as mentioned above, the mechanical part of the brake system installed in actual vehicles adopts an average target design or a fixed mechanism based on a theoretical standard design.
It has the disadvantage of not being able to accommodate a variety of different deceleration rates, and it is an ergonomic demand that the driver expects the deceleration to correspond to the force applied to the brake pedal when driving the vehicle while actually operating the vehicle. There was also the difficulty of not being able to respond immediately.

In addition, the use of microcomputer-based electronic control systems such as the above-mentioned anti-skid system may cause troubles in the electronic mechanism due to radio wave interference, and unavoidable damage to the electronic components due to vibrations and vibrations that are applied frequently and over a long period of time. IC of
A high-precision brake system may not be able to perform its initial function due to troubles such as circuit shorts, so it is necessary to convert the braking mode so that the brake can reliably perform its braking function with just the master cylinder's hydraulic pressure based on the basic pedal force. There was also the drawback that it was not always what we expected.

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

The object of the present invention is to improve the system performance based on the above-mentioned prior art, regardless of changes in the loaded weight of the vehicle body, regardless of road conditions, and also regardless of wear of the friction material of the brakes or changes in shoe clearance. Even in the event of trouble, the basic safety braking function is maintained using only the optimum pedal force, and on top of that, the braking mode is smoothly changed according to the driver's applied pedal force, regardless of the conditions of the vehicle in question. It is an object of the present invention to provide an excellent braking system for automobiles that will benefit the field of safety technology application in the automobile industry by ensuring that the expected deceleration is obtained and that the advanced braking mechanism is able to fully demonstrate its performance.

<Means/effects for solving the problem> In accordance with the above-mentioned object, 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;
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 detected signal to the computer. The optimum deceleration according to the pedal force is calculated and a predetermined control signal is sent to one control valve in the hydraulic circuit to operate the spool piston of the master cylinder, and the hydraulic pressure from the hydraulic circuit is mastered via the other control valve. The power is applied to the power piston of the cylinder, and 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 Feedback is sent to the computer via the vehicle speed sensor, whereby the other control valves are controlled to close, and the power piston of the master cylinder is controlled to be in the front and
The hydraulic braking pressure on the rear wheel brake is released, and this repetitive control causes deceleration to occur as set. During this time, the pedal force applied to the brake pedal is only affected by the resistance of the elastic spring installed in the booster. This ensures that a linear pedal force input is sent to the computer to ensure that deceleration in accordance with the pedal force is expected as expected. If a short circuit or other malfunction occurs due to repeated vibrations applied to the wiring of parts, etc., the spring set in one of the control valves and the other control valve will automatically close the former, and the intruder will be shut off. The main bushing rod installed on the brake pedal controls the spool piston and applies the hydraulic pressure from the other υ control valve to the power piston, which brakes the front and rear wheels. The control force applied by the main bushing rod to the spool piston moves linearly to the compression spring of the sub bushing rod, so that the power piston applies hydraulic pressure to the front and rear wheels. It operates in the same way as a normal hydraulic brake system to mechanically give the optimum deceleration according to the pedal force, and for the two systems of braking, fully automatic and semi-automatic mentioned above, the hydraulic system In the event of a problem such as a breakage, the sub-button rod will not operate due to zero oil pressure, and only the main bush rod will push the power piston of the master cylinder forward, allowing the front and one wheel to be moved with only pedal effort. Alternatively, the braking mode can be smoothly switched by applying non-boosted braking force to both systems to ensure braking in a third system that can perform the minimum safety function as a brake. This is achieved by taking technical measures to make it possible.

<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.

In addition, vehicle speed sensors 6, 6, etc. provided for the front and rear left and right axles are electrically connected to the computer 7, transmit their detected vehicle speeds, and determine the fastest vehicle speed. has been detected.

As shown in detail in FIG. 1, the booster 2 includes a braking force transmission cylinder 8 on the base side, a master cylinder 9 provided integrally in front of the brake force transmission cylinder 8, and a master cylinder 9 integrally provided on the lower side. The master cylinder 9 has a control piston 11 which forms a front hydraulic chamber 13 in which a return spring 12 is inserted, and a reservoir chamber connected to a reservoir tank (not shown). 14 and the front wheel brake 15. A rear hydraulic chamber 16 formed at the rear also communicates with a reservoir chamber 11 connected to a reservoir tank (not shown), and as shown in FIG. It is connected to a rear wheel brake 19 via a steering valve 18.

Further, as described above, the braking force transmission cylinder 8, which is provided integrally with the master cylinder 9, has a power piston 21, which is provided on the control piston 11 via a return spring 20, between the front and rear of the brake force transmission cylinder 8. Reservoir chambers 22 and 23 are defined and communicated with the reservoir chambers 11 and 24, respectively, and the power piston 21
A return spring 25 is interposed inside the power piston 21 with respect to the reservoir chamber 22.23.
A spool piston 29 having a port 28 in the longitudinal direction that communicates with the radial port 26 of the Return spring 30 at the end. The main bushing rod 3 is attached to the hook 31 via a fitting part 32, and its rear end forms a slight play of a set length with respect to the upper part of the brake pedal 5. It is connected to the elongated hole 33 by a pin 34, and its front end and the power piston 2
1 is in communication with the port 28 in the spool piston 29 sliding relative to the power piston 21 via ports 36, 37,
Therefore, in the relative sliding state posture of the two, in which the port 27 of the spool piston 29 and the port 26 of the power piston 21 coincide, the pressurizing chamber 35 is communicated with the reservoir chamber 24 of the pedal force transmitting cylinder 8.

Moreover, the port 3 provided in the sub-button rod 32
8 is connected to a pressurizing chamber 39 at the front thereof, and communicates with a reservoir chamber 40.

Thus, the reservoir chamber 24.4 of the braking force transmission cylinder 8
0 are independently connected to a pair of control valves 44 and 45 which are connected in parallel to a hydraulic circuit having a hydraulic pump 41, an oil tank 42, and an accumulator 43, as shown in FIG. .

The pair of control valves 44 and 45 have substantially the same structure, but their function is exclusively for controlling the power piston 21 and the spool piston 29, and they are electrically connected to the computer 1 and configured to receive radio waves. In an unexpected situation such as a failure or a short circuit in the IC or printed circuit board of the computer 7 due to vehicle vibration, one control valve 44 is kept open by a spring and the braking force is transmitted to the power piston 21 via the reservoir chamber 24. The other control valve 45 is always closed and does not control the spool piston 29.

The front chamber 46 of each control valve 44, 45 is connected to the return circuit for the oil tank 41, and the middle valve 47 is neutral to maintain the applied oil pressure, and the rear chamber 4
8 supplies hydraulic pressure from a hydraulic pump 41 or an accumulator 43 to a reservoir chamber 24.4 of the braking force transmission cylinder 8.
0 is applied.

In this way, each IIIO valve 44,45 is independently dedicated to the control of the power piston 21 and the spool piston 29, thereby ensuring their respective functions and contributing to the activation of the brake system. are doing.

Further, a 21 control valve 49 is provided in the casing below the braking force transmission cylinder 8, and is connected to the pressurizing chamber 51 formed between the casing and the pressure chamber 51 on the rear side via the return spring 50. A port 52 communicates with a reservoir chamber 23 formed in the power transmission cylinder 8, and also communicates with another reservoir chamber 22 of the braking force transmission cylinder 8.
The port 53 communicating with the control piston 49
The neck-shaped front communication portion of the control pulp 49 communicates with the front chamber formed through a port (not shown) through a cup-shaped seal lip 54 with a U-shaped cross section provided on the outside of the control pulp 49. It is like that.

Further, a control piston 55 is inserted into the pedal force cylinder 10 which is integrally formed below the braking force transmission cylinder 8 via the casing of the control valve 49 so as to be slidable back and forth via an elastic spring 56. At the rear thereof, a pedal force piston 57 is provided via a pressurizing chamber 59 having a return spring 58.

The oil in the pressurizing chamber 59 is connected to the neck-shaped communication portion of the control valve 49 through the port 60, and the oil in the pressurizing 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 and the seal lip 54 is bent. 53, and further communicates with the reservoir chamber 11 through the 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-butch rod 3 which is connected to the brake pedal 5 via a pin 62 via a well-known load cell 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.

Note that 62 is a pressure detection switch, which is interposed in the accumulator 43 and the hydraulic circuit, and is electrically connected to the computer 7.

<Embodiment - Effect> In the above configuration, when applying braking to a running vehicle to decelerate or decelerate to a stop, the computer
7 is always front and rear vehicle speed sensor 6.6...
・Detects vehicle speed and measures the fastest speed of any of them.

During the driving process, various loads such as people and cargo are applied to the vehicle, 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 braking are different.

Then, 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 sub-button rod 4 and input to the computer 1, and the computer 1 calculates the reference vehicle speed at the vehicle speed. The optimum deceleration is calculated 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 shown as C'. It will be done.

Therefore, a control signal that provides the optimum deceleration for the pedal force is sent to the solenoids of the control valves 44 and 45 to open them and connect each rear chamber 48 to the hydraulic circuit.

Therefore, the hydraulic pump 41 of the hydraulic circuit is connected to the oil tank 42.
Alternatively, in cooperation with the accumulator 43, a predetermined hydraulic pressure is delivered to the reservoir chamber 24.40 of the corresponding braking force transmission cylinder 8 through each control valve 44.45.

At this time, the oil pressure applied to one reservoir chamber 24 is
Since the braking force is applied to the pressurizing chamber 51 of the control valve 49 on the lower side of the braking force application cylinder 8 through the port 52 through the reservoir chamber 23 communicating with the reservoir chamber 24,
The control valve 49 is pushed 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 corresponds appropriately and linearly to the pedal force by the pedal force piston 57. The set load of the elastic 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.

In this case, although the drag force of the elastic spring 56 is a dummy, the driver perceives it intuitively as a braking load.

Therefore, the pedal force applied by the driver to the brake pedal 5 is applied with a completely normal braking feeling, regardless of the change in the load or the unique changing situation of the car's brakes. .

On the other hand, in the main bushing rod 3 of the braking force transmission cylinder 8, the pedal force is reduced due to the loose engagement between the elongated hole 33 and the pin 34, which are provided above the brake pedal 5 at the base end and have a predetermined play. Nothing is applied.

Therefore, a predetermined hydraulic pressure from the hydraulic pump 41 applied to the reservoir chamber 40 of the braking force transmission cylinder 8 via the control valve 45 enters the pressurizing chamber 39 via the port 38, and moves the spool piston 29 to the return spring at its tip. 25, so that the port 27 of the spool piston 29 and the port 26 of the outer reservoir chamber 23 communicate with each other, so that the hydraulic pressure from the hydraulic pump 41 applied to the reservoir chamber 24 is transferred to the control valve. 44, the hydraulic pressure is transmitted to the reservoir chamber 24.23, the port 26.27, the port 28.31, and the pressurizing chamber 35 via the port 36. As a result, the power piston 21 is pressed. The hydraulic pressure from the reservoir chamber 14 of the front hydraulic chamber 13 is transmitted to the front wheel brake 15, while the hydraulic pressure from the reservoir chamber 17 of the hydraulic chamber 16 is transmitted to the rear wheel brake 19.
is applied to activate booster braking to provide the above-mentioned predetermined deceleration.

During this time, the tip of the spool piston 29 cuts off the port connection of the power piston 21 to the reservoir chamber 22, so that the hydraulic pressure for applying the braking force does not escape to the reservoir chamber 22 through the ports 36, 37, and 28, and the power is reliably maintained. - The braking force is continuously applied to the piston 21.

Although the power piston 21 moves forward in this state, the relative posture of the spool piston 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 v40 via the control valve 45 is applied to the port 28. In order to apply pressure to the spool piston 29 from its base side against the return spring 25 from the pressurizing chamber 39 through the spool piston 29, the spool piston 29 is inserted to the deepest point relative to the power piston 21. In addition, the hydraulic pressure by the hydraulic pump 41 is P, and the pressure in the pressurizing chamber 35 is
, and the set load of the end return spring 25 of the spool piston 29 is F, then P'A+F<P
A, therefore, the spool piston 29 is still in the back side with respect to the power piston 21, that is, the ports 26 and 21 are in the same position. Hydraulic pressure is still applied to the pressurizing chamber 35 to urge the power piston 21 into a position in which it is pushed forward.

During this time, the power piston 21 and the spool piston 29 are each independently controlled by the corresponding control valves 44 and 45.

As described above, the main bushing rod 3 is not applied with any pedal force from the brake pedal 5, and is merely moved forward through the hook 31 of the power piston 21 by a so-called dragging phenomenon.

When the vehicle speed is reduced in this way, the vehicle speed sensor 6 detects the deceleration state and inputs it to the computer 7, and as shown in FIG. When the vehicle speed C' is reduced by a set speed relative to the vehicle speed C, a control signal is sent to the solenoid of the control valve 44, 45 to
is connected to the reservoir chamber 24, and the front chamber 46 of the other control valve 45 is connected to the reservoir chamber 4o.

Therefore, the reservoir chamber 40 is connected to the oil tank 42 via the hydraulic circuit, and the pressurized chamber 3 is connected via the port 38.
9 is rapidly reduced, and as a result, the spool piston 29 is moved back relative to the power piston 21 by the return spring 25 at its tip, so that the port 26 of the power piston 21 and the spool piston 29
The port 27 will be displaced as shown in FIG.

Therefore, due to the neutral position of one control valve 44, the oil pressure in the reservoir chamber 24, 23 is maintained at the oil pressure that was decelerated immediately before, and therefore, the pressure in the pressurizing chamber 51 of the control valve 49 is reduced through the port 52. is maintained, and the control valve 49 still maintains the posture in which the predetermined deceleration is expressed. Therefore, the pedal force applied to the brake pedal 5 is applied to the pedal force cylinder 10, and the pressure force applied to the brake pedal 5 is applied to the pedal force cylinder 10, and the pressure force applied to the brake pedal 5 is applied to the pedal force cylinder 10. A linear pedal force application state can be maintained.

Then, the spool piston 29 retreats with respect to the power piston 21 and its tip is connected to the reservoir chamber 22, so that the reservoir chamber 22 and the pressurizing chamber 35 are connected to the port 2.
8.37.36, the previously high pressure hydraulic pressure will be communicated to the reservoir chamber 17 via the port 37.36.28 and will be rapidly depressurized, thus The power piston 21 moves back, and the main bushing rod 3 also moves back via the return spring 30.

However, since the base end of the main bushing rod 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 graph C' of the decelerated vehicle speed approaches or exceeds the graph C of the set vehicle speed in FIG.

During this time, the vehicle speed sensors 6, 6... actually measure the vehicle speed in the deceleration or deceleration maintenance state and send it to the computer 7, and when the vehicle speed exceeds the set reference vehicle speed C for the deceleration state in FIG. The computer 7 commands deceleration again, and the command signal causes one control valve 44 to return from the neutral state to the open state, then connects the chamber 48 to the reservoir chamber 24, and The control valve 45 is returned from the return position to the hydraulic circuit to the open position, thus connecting the chamber 48 to the reservoir chamber 40, so that hydraulic pressure is again applied to the pressurizing chamber 39 as described above and the spool piston 29 is moved. The port 21 is aligned with the port 26 of the power piston 21 again, and the hydraulic pressure from the hydraulic pump 41 in the reservoir chamber 24 is transferred from the reservoir chamber 23 to the port 26.
6.27, passes through ports 28.37.36, enters the pressurizing chamber 35, and applies braking force to the power piston 21.

In addition, when the spool piston 29 is in the forward movement state, the tip thereof blocks the port connection to the reservoir chamber 22, so that the deceleration braking force of the pressurizing chamber 35 is not reduced.

By repeating this process, the braking pressure in the reservoir chamber 23 is always maintained in the pressurizing chamber 51 of the control valve 49 via the port 52, so that the pedal force applied to the brake pedal 5 is controlled by the elastic spring of the pedal force cylinder 10. A linear application state with a set load of 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, such an operation is performed as shown in FIG.
The control valves 44 and 45 open and close independently and frequently in accordance with the frequency at which the graph C' of the vehicle speed during actual deceleration dynamically approaches and separates, so that the spool piston 29 and the power piston 21 move relatively back and forth. As a result, the pedal force applied to the brake pedal 5 changes to the pedal force cylinder 10.
With only a linear application state to the compression spring 56, regardless of changes in the live load or changes in brake pads or shoe clearance, the deceleration is simply set extremely linearly to the applied pedal force, as expected by the driver. Braking will appear.

Therefore, the computer performs the control.7
However, as is well known, if the computer 7 is subject to severe radio 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 during running, a proper operating signal will not be sent to each control valve 44, 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, the control valve 44 corresponding to the power piston 21 is immediately and automatically opened, that is, the rear chamber 48 is automatically connected to the reservoir chamber 24. On the other hand, the control valve 45 for the spool piston 29 is opened or returned to the return state, that is, the inside W47 or the front chamber 46 is connected to the reservoir chamber 39, so that the spool piston 29 is not connected to the reservoir chamber 39. Hydraulic pump 4 via chamber 39
Due to the hydraulic pressure from 1, forward movement is not possible.

When the driver performs predetermined braking in such a braking mode conversion state, when the driver applies a pedal force that corresponds to the feeling of braking to the brake pedal 5, hydraulic pressure is supplied to the reservoir chamber 24 via the open valve 44 as described above. Since the hydraulic pressure of the pump 41 is applied, the hydraulic pressure from the reservoir chamber 23 is transferred to the port 5.
2 to the pressurizing chamber 51 of the control valve 49, and the control valve 49 blocks the ports 60 and 53. Therefore, the pressing force applied to the brake pedal 5 is equal to the pressing force of the cylinder. The set load is applied linearly with respect to the resistance of the ten elastic springs 56, and a pedal force similar to the above-mentioned booster hydraulic servo braking operation is applied.

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 play allowance of 33, a small amount of pedal force is applied through the pin 34 to press the spool piston 29 integrally.

However, since the weight of the spool piston 29 and the main bushing rod 3 is extremely small, and the pushing force is also small, only a portion of the pedal force that pushes the main bushing rod 3 and the spool piston 29 is used. is substantially the same as the first and second pistons, and therefore, the driver hardly feels that the pedal force applied to the brake pedal 5 exceeds the resistance of the elastic spring 56 and feels a large operating force.

In this way, when the spool piston 29 is continued to be advanced after a slight idle advance, its port 21 will be mated and connected to the port 26 of the power piston 21, and the hydraulic pressure from the hydraulic pump 41 will be transferred to the control valve 44. , through the reservoir chamber 24, ports 26.27, and ports 28.37, and is applied to the pressurizing chamber 35 from the port 36 to advance the power piston 21 to a predetermined position, and the front hydraulic chamber 13 and the rear hydraulic chamber 16 are The hydraulic pressure is increased and a predetermined braking force is transmitted to the front wheel brake 15 and the rear wheel brake 19 to provide a deceleration corresponding to the pedal force similarly to the hydraulic servo braking mode described above.

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, the brake pedal by the driver may not be controlled by the computer 7 due to a problem with the electrical system. The servo function is enabled and the boost braking is activated by only linear operation of the pedal force applied to the elastic spring 56.

Then, without reducing the pressing force on the brake pedal 5,
The pushing force on the main bushing rod 3 is canceled, but at this time, the spool piston 29 is moved back by the return spring 25 at its tip, and the main bushing rod 3 is connected to the elongated hole 33 with an allowance of play at its base end. The port 26 of the power piston 21 and the port 21 of the spool piston 29 are slightly retracted through loose engagement with the pin 34 .
is displaced, and similarly to the above embodiment, the oil pressure in the pressurizing chamber 35 is transferred from the tip of the spool piston 29 through ports 36, 37 and 28 to the reservoir chamber 22.
17, the pressure is reduced, and deceleration is eliminated.

Also, when a pedal force is applied to the brake pedal 5, the ports 27 and 26 of the spool piston 29 are connected again, and the hydraulic pressure of the hydraulic pump 41 is applied to the pressurizing chamber 35 from the control valve 44, which is always open, and the power piston is activated again. 21 moves forward and braking force is applied.

Therefore, in this embodiment, the voltage is applied to the brake pedal 5 regardless of changes in the loaded weight, changes in the brake pad or shoe clearance, or even if there is a problem with the electrical system of the computer 7, etc. Great hydrolink braking can be obtained simply by linearly applying the pedal force to the compression spring 56 of the pedal force cylinder 10, and it is only semi-automatic servo braking that provides optimal deceleration that immediately responds to the pedal force applied by the driver. It will be done.

In addition, when the engine is stopped, the control valve 44.45 is connected to the return connection under the control of the computer 1, and the reservoir chamber 24.4 is
0 is connected to the oil tank 42, the brake oil pressure becomes zero, and the parking brake is used instead.

Therefore, the more automation and servo mechanisms are installed in the brake system, the more it becomes possible to convert the braking mode to manual braking using only pedal force as the minimum safety guarantee in the event that these complex mechanisms fail. However, in the present invention, if a hydraulic pressure loss unexpectedly occurs in the hydraulic circuit, the hydraulic pressure in the reservoir chamber 24 decreases, and therefore, the hydraulic pressure in the reservoir chamber 23 and the boat 52 decreases.
The hydraulic pressure in the pressurizing chamber 51 of the control valve 49 decreases through is the reservoir chamber 24,
That is, since the pressure becomes higher than the pressure in the pressurizing chamber 51 of the control valve 49, the pressure in the front chamber of the control valve increases via the boat 60 (not shown). The hydraulic pressure in the pressurizing chamber 59 causes the control valve 49 to retreat against the return spring 50, so that the hydraulic pressure in the pressurizing chamber 59 is directed to the reservoir chamber 17 via the boat 60.53.
Therefore, the hydraulic rigidity of the pressurizing chamber 59 is lost, and as a result, the pressing force applied to the brake pedal 5 is only slightly expended on the main bushing rod 3 due to the deflection of the return spring 58 of the pressurizing chamber 59. The upper part of the main bushing rod 3 is pushed through the pin 34 through a slight play in the elongated hole 33 with a play allowance, so that the main bushing rod 3 substantially immediately moves into the power piston 21.
The front hydraulic chamber 13 and the rear hydraulic chamber 1
6 is pressurized to apply braking force to the front brake 15 and rear wheel brake 16 in the same manner as a normal hydraulic brake system using mere pedal force without boosting, thereby decelerating the vehicle.

In this case, negative pressure is about to be generated in the pressurized chamber 35, but the pressure detection switch 62 is activated by the reservoir chamber 24 ports 26, 27.
28, 31, and 36, and the computer 1 connects the front chamber 44.44 of the control valve 44.45 to the feedback circuit to prevent the generation of negative pressure.

As described above, in the present invention, the first and second systems automatically and semi-automatically obtain the boosted hydraulic brake braking by the hydraulic pump 41, and the third system performs normal hydraulic braking using only the pedal force without boosting. It has three systems, and these three systems are in electrical control sound operating condition.
It is designed to automatically and immediately respond to three conditions, i.e., an electrical system failure condition and a hydraulic circuit failure condition, and to be switched in a mutually exclusive manner.

Control valves for controlling the power piston and spool piston are each independently and exclusively arranged to ensure reliable and smooth operation of each control.

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 the present invention, there is provided a brake system that has a hydraulic brake mechanism capable of producing an extremely strong braking force and is capable of performing boost braking. This makes it possible to obtain the optimum deceleration for the vehicle speed according to the applied pedal force, regardless of various conditions such as the load weight and changes in the brake pads and shoe clearance of the brake mechanism. The system is capable of automatic servo braking by controlling a control valve installed in the hydraulic circuit via hydraulic pressure based on detection signals of applied pedal force and vehicle speed, and boosts power when a failure occurs in the system and electrical system. By using three systems that can obtain the optimal deceleration that immediately responds to the pedal force applied in a non-servo manner, the effective operation of the brake is inherently different depending on the load weight conditions and brake mechanism parts. Regardless of various changes in speed, the optimum deceleration that immediately responds to the driver's sense of the actual speed is always achieved as expected and smoothly without any shock, thereby ensuring driver safety, which is the top priority. This provides an excellent effect in that the sensation is sufficiently guaranteed and the vehicle can reliably obtain safe running and driving conditions including deceleration and stopping.

In addition, a system that relies only on pedal force has been added, which guarantees normal hydraulic brake operation even if there is a failure in the electrical system or a loss in the hydraulic circuit.Moreover, these systems are automatically operated in their respective optimal conditions. By enabling the operation, the excellent effect of ensuring the above-mentioned safe driving optimum deceleration braking is achieved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a servo mechanism according to an embodiment of the present invention;
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. 9... Master cylinder, 5... Brake pedal, 61... Pedal force detection rock, 6... Vehicle speed sensor,
44.45...Control valve, 1...Computer, 21...Power piston

Claims (1)

[Claims] In a brake system in which a detection mechanism for detecting a pedal force applied to a brake pedal is connected to a master cylinder connected to a hydraulic circuit, and the pedal force detection mechanism and a vehicle speed sensor control a control valve of the hydraulic circuit via a computer. A system in which the braking force is transmitted to the power piston of the master cylinder by hydraulic pressure via control of a control valve attached to the hydraulic circuit, and a system in which braking force is transmitted to the power piston of the master cylinder by hydraulic pressure via control by pedal force from the brake pedal. and a system that is operated only by controlling the pedal force from the brake pedal, and the three systems are automatically and mutually selected. system.