Vehicle brake system having a foldable actuation pedal and method for actuating the brake system upon impact

Abstract

A brake system (4) for a vehicle with a foldable actuation pedal includes an actuation pedal (8) operatively connected to a hydraulic pump (12) having a delivery circuit (16) fluidly connected to an accumulator device (20). The delivery circuit (16) includes a hydraulic branch (24) with at least one normally closed control valve (28). The control valve (28) is connected to a control actuator (32) that commands its opening upon detection of an impact or accident by a suitable detector (36), or is connected to the accumulator device (20) that is calibrated to automatically open when a threshold pressure and / or flow value is reached in the hydraulic branch (24) following depression of the actuation pedal (8).

Description

[Technical Field]

[0001] The present invention relates to a vehicle brake system having a collapsible actuation pedal and a method for actuating the brake system during an impact. [Background technology]

[0002] The invention finds application in the technical field of automotive braking systems using a brake pedal connected to a lever.

[0003] The brake pedal lever is held in an idle position under normal driving conditions, and in this position the braking system does not apply any braking force.

[0004] However, in the event of an accident, the pedal lever is a potential hazard to the driver, who risks physical injury (e.g., typically a broken leg and / or foot bone) if struck by the pedal lever.

[0005] To solve this problem, conventional pedal solutions consist of mechanically collapsible components. However, these solutions are difficult to implement because the components can collapse due to stresses caused by external forces present in normal use conditions, such as road irregularities. These solutions are prone to unintentional collapse, unable to distinguish between stresses due to accidental impacts and stresses due to normal use conditions (uneven asphalt, potholes, off-road driving).

[0006] Furthermore, they do not always guarantee immediate collapse of the lever and therefore cannot always avoid the risk of physical injury to the driver, since for collapse to occur a threshold impact force between the limb and the pedal itself must be exceeded. Obviously, for safety reasons, such a threshold cannot be made low, otherwise there is a risk of dangerous "false activation" in the event of, for example, uneven ground, holes, stones, etc.

[0007] Therefore, a need is felt to overcome the drawbacks and limitations discussed above with reference to the prior art. Summary of the Invention

[0008] Such a need is met by a brake system for a vehicle with a foldable actuation pedal according to claim 1 and a method for actuating a brake system in the event of an impact according to claim 8.

[0009] In particular, such a need is met by a brake system for a vehicle with a foldable actuation pedal, An actuation pedal operatively connected to a hydraulic master cylinder having a delivery circuit fluidly connected to an accumulator device, the actuation pedal characterized by: the delivery circuit has a hydraulic branch with at least one normally closed control valve; The control valve is connected to a control actuator which commands its opening when an impact or accident is detected by a suitable detector, or is calibrated to open automatically when a limit pressure and / or limit flow value is reached in the hydraulic branch after the actuation pedal is lowered.

[0010] According to a possible embodiment, the detector is, for example, an airbag controller that oversees the deployment of at least one airbag, and the control actuator is operatively connected to the controller for actuating the control valve to open when the airbag controller commands deployment of the airbag.

[0011] According to a possible embodiment, the airbag controller is connected to an explosive that acts as an actuator for the control valve, such that the explosive can directly actuate the opening of the control valve.

[0012] According to a possible embodiment, the hydraulic branch is arranged in series and downstream with respect to the accumulator device.

[0013] According to a possible embodiment, the control valve is a pressure relief valve and the control actuator consists of a second accumulator device arranged in series and downstream relative to said accumulator device.

[0014] According to a possible embodiment, the braking system comprises at least one electrohydraulic or electromechanical actuator connected to at least one braking device, which actuator controls the actuation of the braking device as a function of the actuation pedal stroke.

[0015] According to a possible embodiment, the braking system comprises a safety valve which fluidly connects the delivery circuit with at least one braking device in the event of an electrical failure of said electrohydraulic or electromechanical actuator.

[0016] The present invention also relates to a method for operating a braking system in the event of an impact, comprising the steps of: providing a brake system for a vehicle having a foldable actuation pedal, the actuation pedal operatively connected to a hydraulic pump having a delivery circuit fluidly connected to an accumulator device; and depressurizing the delivery circuit when an impact of a vehicle in which the brake system is installed is detected and / or when pressure and / or flow limits in the delivery circuit are exceeded.

[0017] According to a possible embodiment, the actuation method comprises the step of providing in the delivery circuit a hydraulic branch with at least one normally closed control valve, said control valve being connected to a control actuator which commands its opening when an impact or accident is detected by a suitable detector, or which is calibrated to open automatically when a limit pressure and / or flow value is reached in the hydraulic branch after the actuation pedal is lowered.

[0018] Further features and advantages of the invention will be better understood from the following description of preferred embodiments given by way of non-limiting example. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of a prior art vehicle brake system. [Figure 2] FIG. 2 is a perspective view of a braking system according to a first embodiment of the device of the invention. [Figure 3] FIG. 3 is a perspective view of a braking system according to an embodiment of the device of the present invention. [Figure 4] FIG. 4 is a perspective view of a braking system according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Elements or parts common to the described embodiments will be designated hereinafter using the same reference numerals.

[0021] Referring to the aforementioned figures, reference numeral 4 globally indicates a braking system, as will be explained in more detail below.

[0022] The braking system is preferably, but not necessarily, of the brake-by-wire type.

[0023] For purposes of the present invention, the particular type of braking equipment (not shown) employed in the braking system will typically, but not necessarily, comprise disc brakes or drum brakes.

[0024] The braking system 4 comprises a collapsible actuation pedal 8 operatively connected to a hydraulic master cylinder 12 having a delivery circuit 16 fluidly connected to an accumulator device 20 .

[0025] The accumulator device 20 is a device configured to simulate the pedal resistance provided by a conventional hydraulic brake system. The accumulator device 20 may also be a reservoir or a pressure fluid accumulator.

[0026] Advantageously, the delivery circuit 16 consists of a hydraulic branch 24 equipped with at least one normally closed control valve 28 .

[0027] According to an embodiment, the control valve 28 is connected to a control actuator 32 which controls its opening upon detection of an impact or collision by a suitable detector 36 (trigger). Preferably, the detector 36 is an airbag controller which oversees the operation of at least one airbag, and when the airbag controller commands the deployment of the airbag, the control actuator 32 is in turn operatively connected to the airbag controller 36 and operates the control valve 28 to open.

[0028] In this way, when the airbag controller 36 detects an impact of a predetermined strength, it commands the control actuator 32 to open the control valve 28, thereby relieving pressure, i.e., depressurizing the delivery circuit. In this way, if the driver's foot strikes the actuation pedal 8, the pedal will not offer any resistance and will collapse, i.e., will collapse without injuring the driver.

[0029] According to a further possible embodiment (FIG. 3), the airbag controller 36 is provided with an explosive 40 which acts as the control actuator 32 of the control valve 28, such that the explosive can directly actuate the opening of the control valve 28. In this embodiment, the decompression of the pressure circuit 16 is particularly rapid.

[0030] According to a further embodiment (FIG. 4), the control valve 28 is calibrated to open automatically when a pressure and / or flow limit is reached in the hydraulic branch 24 following depression of the actuation pedal 8 .

[0031] In other words, if the user's foot or leg accidentally hits the actuating pedal 8, causing the pedal to suddenly lower and thus increasing the delivery pressure of the hydraulic master cylinder 12 in the delivery circuit 16, the control valve 28 will automatically open when said pressure and / or flow limit is reached, in which case the actuating pedal 8 will suddenly lower and no longer offer resistance, thus preventing damage to the user's foot or leg.

[0032] According to a possible embodiment, the hydraulic branch 24 is arranged in series with and downstream of the accumulator device 20. Furthermore, the control valve 28 is a pressure relief valve and the control actuator 32 consists of a second accumulator device 44 arranged in series with and downstream of said accumulator device 20.

[0033] In this way, the second accumulator device 44 acts as a pressure limiter for the pressure circuit 16 and, again, if the user's foot or leg accidentally strikes the operating pedal 8 causing the pedal to suddenly drop, thus increasing the pressure in the pressure circuit 16, the second accumulator device, acting as a control valve 28, will suddenly reduce the pressure downstream of the hydraulic master cylinder causing the operating pedal 8 to drop.

[0034] As mentioned above, the brake system 4 is preferably of the brake-by-wire type.

[0035] Furthermore, the braking system 4 comprises at least one electrohydraulic or electromechanical actuator connected to at least one braking device (not shown), which actuator controls the actuation of the braking device as a function of the stroke of the actuation pedal.

[0036] According to a possible embodiment, the braking system 4 includes a safety valve (not shown) that fluidly connects the delivery circuit with at least one braking device in the event of an electrical failure of said electrohydraulic or electromechanical actuator. In this way, it is ensured that in the event of an electrical failure the user can brake by directly actuating at least one braking device by means of hydraulic fluid pressurized by a hydraulic master cylinder.

[0037] Next, the operation of the brake system according to the present invention will be described.

[0038] The way the braking system operates in case of an impact is: A vehicle having a foldable actuation pedal (8) including an actuation pedal operatively connected to a hydraulic master cylinder (12) having a delivery circuit (16) fluidly connected to an accumulator device (20). The brake system is characterized in that the delivery circuit (16) is depressurized when an impact of a vehicle equipped with the brake system is detected and / or when pressure and / or flow limits within the delivery circuit (16) are exceeded.

[0039] In detail, the operating principle is based on the fact that in the event of an accidental impact of the user's foot or leg against the actuation pedal 8, the pedal offers a great resistance, as the actuation pedal 8 increases the delivery pressure in the delivery circuit 16 to which it is connected by the hydraulic master cylinder 12. If the resistance offered by the actuation pedal 8 exceeds a certain threshold, the pedal constitutes a dangerous obstacle for the user's foot / leg, and the user may suffer serious injuries.

[0040] On the other hand, the braking system 4 according to the invention provides for depressurizing the delivery circuit 16 in order to obtain a rapid lowering of the actuation pedal 8 upon impact against the user's foot and / or leg.

[0041] In this way, the brake pedal lever can be depressurized in the event of an accident, reducing the potential danger to the driver.

[0042] In this way, in the event of an accidental impact of the leg against the brake pedal in a stationary position, the pressure in the system downstream of the pedal is significantly reduced so that the pedal offers virtually no resistance and therefore sinks under the thrust of the leg, without causing injury or fracture.

[0043] The reduced pressure may be active or passive.

[0044] In the first case (FIGS. 2-3), a detector 36 can be utilized that actively detects a potential danger from an impact that would require the deployment of an airbag. Such activation is simultaneous with the activation of a control valve 28 that discharges the delivered pressure downstream of the hydraulic master cylinder 12. Furthermore, as can be seen, activation can consist of using a control actuator 28 that acts on the control valve 28 to at least partially open it.

[0045] For rapid activation, it is also possible to provide the detector 36 with an explosive charge to at least partially open the control valve 28 .

[0046] The reduced pressure can also be passive.

[0047] In such a case (FIG. 4), the control valve 28 opens automatically as soon as a predetermined threshold pressure is reached in the flow circuit 16 following depression of the actuation pedal 8 .

[0048] As can be seen from the above description, the present invention makes it possible to overcome the drawbacks presented in the prior art.

[0049] In fact, the proposed solution provides for the decompression of the brake pedal lever as soon as it is recognized that the vehicle is involved in a traffic accident. In this way, the brake lever does not face resistance to pressure and is free to move from its rest position in the event of an accidental impact by the driver. Therefore, the implementation of the invention significantly reduces the risk of injury due to an accidental impact on the brake pedal lever by the driver.

[0050] Those skilled in the art can make numerous modifications and variations to the above solution to meet their fortuitous specific needs, which fall within the protection scope of the invention as defined by the following claims.

Claims

1. A vehicle brake system (4) with a foldable actuation pedal, an actuation pedal (8) operatively connected to a hydraulic pump (12) having a delivery circuit (16) fluidly connected to an accumulator device (20); the delivery circuit (16) having a hydraulic branch (24) with at least one normally closed control valve (28); The control valve (28) is connected to a control actuator (32) that commands the opening of the control valve (28) when an impact or collision is detected by a detector (36); the detector (36) comprises an explosive (40) acting as a control actuator (32) for the control valve (28); A vehicle brake system (4) with a foldable actuation pedal, which allows the explosive (40) to directly actuate the opening of the control valve (28).

2. the detector (36) is an airbag controller (36) that oversees the deployment of at least one airbag; 2. The vehicle brake system (4) with a foldable actuation pedal as recited in claim 1, wherein the control actuator (32) is operatively connected to the airbag controller (36) to open the control valve (28) when the airbag controller (36) commands activation of the airbag.

3. The vehicle brake system (4) comprises at least one electrohydraulic or electromechanical actuator connected to at least one braking device; 3. A vehicle brake system (4) with a foldable actuation pedal according to claim 1 or 2, wherein the electrohydraulic or electromechanical actuator controls the actuation of the braking device according to the stroke (8) of the actuation pedal.

4. The vehicle brake system (4) has a safety valve, 4. A vehicle brake system (4) with a foldable actuation pedal as claimed in claim 3, wherein the safety valve fluidly connects the delivery circuit (16) to at least one of the braking devices in the event of an electrical failure of the electrohydraulic or electromechanical actuator.

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