Vehicle brake mechanism with pedal-jam detection capability

A vehicle brake mechanism that includes a pedal, a piston attached to the pedal, a spring associated with the piston and exerting a longitudinal force on the piston in a direction opposite the braking direction in order to bring the pedal to a resting position, and an autonomous brake module. A manual braking force on the pedal causes a longitudinal movement of the piston and displaces a transmitter element integrally joined to the piston. The autonomous brake module causes a movement of an intermediate plate that displaces the transmitter element and the piston, exerting a longitudinal force on the piston in the braking direction. The brake mechanism determines the force in the direction opposite the braking direction using a sensor situated on or in the intermediate plate and/or the transmitter element.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to ES 201730804, filed in Spain on Jun. 16, 2017, the content of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

In the automotive field, there are different types of mechanisms for acting in a vehicle. Specifically, present-day vehicles have automatic driving-assistance mechanisms and manual driving mechanisms. These mechanisms currently coexist in the vehicle, with the manual mechanisms taking precedence with regard to driving.

Consequently, it is important to identify failures of the manual mechanisms or the occurrence of anomalous situations that go unnoticed by, or escape the control of, the driver.

SUMMARY

The present invention relates to a mechanism for the detection of a jammed pedal, such that a determination can be made, for example, as to whether the mechanism has been blocked, either by damage to the vehicle or because an obstruction is present in the pedal path. This problem is magnified even further when the autonomous brake mechanism is in operation, because the user may believe that the mechanism will brake, whereas in reality the mechanism is jammed.

According to an example embodiment, a vehicle brake mechanism that includes: a pedal for exerting a manual braking force in a braking direction; a piston attached to the pedal; a spring associated with the piston, with the spring exerting a longitudinal force on the piston in a direction opposite the braking direction in order to bring the pedal to a resting position; and an autonomous brake module; where a manual braking force on the pedal causes a longitudinal movement of the piston and displaces a transmitter element integrally joined to the piston, and where the autonomous brake module causes a movement of an intermediate plate that displaces the transmitter element and the piston, exerting a longitudinal force on the piston in the braking direction, the brake mechanism having a component for determining the force in the direction opposite the braking direction, which component is situated in the intermediate plate and/or in the transmitter element.

In the context of the present invention, the term “manual” refers to an action that is carried out and/or caused by the user. Consequently, “manual braking force” refers to any type of force exerted by the user on a mechanism that is suitable for receiving the force, for example, a pedal.

In an example embodiment, the determination of the force in the direction of the resting position is made using an elastic part. The elastic part can be, for example, an elastic lug of an intermediate plate, such as an anti-rotation plate (ARP).

Specifically, the elastic part can be used to define the size of a gap between the transmitter element and the intermediate plate, and, in an example, a sensor determines the force in the direction opposite the braking direction based on a detected size of the gap. The sensor preferably includes a Hall-effect sensor attached to the intermediate plate and a magnet attached to the transmitter element in order to determine the distance between them, so as to enable the calculation of any relative displacement between them that is indicative of a blockage of the brake pedal. Alternatively, the sensor includes a Hall-effect sensor attached to the transmitter element and a magnet attached to the intermediate plate in order to determine the distance between them.

In a particularly preferred embodiment, the mechanism correlates the distance between the plate and the transmitter element with a detection of a jammed-pedal event, for example, through the use of a processor. The correlation can include comparing the distance between the plate and the transmitter element against a given threshold in which the distances below the threshold define a jammed-pedal event.

In another example, the mechanism includes a microswitch for determining the force in the direction opposite the braking direction. The microswitch can be attached to the intermediate plate or to the transmitter element in such a way that a force, in the direction opposite the braking direction, exerted on the transmitter element deforms the elastic part and activates the microswitch.

Furthermore, the transmitter element can include a first support connected to the elastic lug of the intermediate plate and a second, shorter support that defines the maximum deformation of the elastic part and that is configured so as to abut the intermediate plate. The second support is preferably stiffer than the first support, so as to prevent the plastic deformation of the elastic elements, such as the lugs.

In an especially preferred embodiment, the brake module is a hydraulically assisted module.

The present invention is described in greater detail with reference to the following figures, which should be understood as an illustrative and non-limitative example of the invention.

DETAILED DESCRIPTION

FIG. 1shows a brake mechanism according to an example embodiment of the present invention. In this embodiment, the mechanism includes a pedal that is coupled to a brake connection element101. Brake connection element101is associated with a pedal intended to be actuated by the user, and from an initial resting position moves along a braking path to a stop. In order to bring the pedal to the resting position after a braking maneuver has been executed, the mechanism has a spring11whose function is to apply a longitudinal force to piston10in the direction of the resting position of the pedal, which resting direction is opposite the braking direction.

The mechanism also includes an intermediate plate for the guidance and transmission of force. In this particular example it is an ARP12. The intermediate plate can have a plurality of openings121that serve as guides and into which a plurality of guide elements are inserted that run along a plurality of guide columns arranged perpendicular to frontal surfaces and to the plane of the central region of the intermediate plate.

The brake mechanism also has a transmitter element13that includes a magnet14whose purpose is to define, in conjunction with a Hall-effect sensor, the relative displacement between transmitter element13and a reference element of the braking system in order to detect a possible jam, as will be explained in greater detail with reference toFIG. 3. Furthermore, transmitter element13preferably includes four contact blocks having a first support131and a second support132with a predefined height difference between the two of them.

When a user carries out a manual braking maneuver, a braking force is exerted on the pedal, which moves brake connection element101in a braking direction and, in turn, moves a piston10that is integrally joined to brake connection element101, applying a substantially longitudinal force in the braking direction. The force is transferred to transmitter element13by piston10and causes a displacement thereof. Transmitter element13activates a brake module having a hydraulic output, with the brake module being the one that ultimately exerts a braking force on the wheels and/or axles of the vehicle in which the mechanism is installed. The brake module can also have a mechanical, pneumatic, hydraulic, or electrical assistance function, or a combination thereof, in order to apply the braking action to the vehicle.

The brake mechanism also has an autonomous brake module that, unlike manual braking, transmits an automatic braking force via a spindle15to the intermediate plate (in this case, ARP12) and through it to body21, which in turn transmits it to the hydraulic output cylinder, thereby achieving braking with no interaction by the user.

From one side, braking forces are exerted between transmitter element13and the intermediate plate12, and that, from the other side, in the case of automatic braking, a force in the direction opposite the braking (i.e., toward the resting position of piston10) is exerted, with the force in the direction opposite the braking being exerted, under normal conditions, principally by spring11. If a jammed-pedal event occurs while an automatic braking maneuver is being executed, spindle15moves the intermediate plate12in the braking direction, and this action in turn displaces transmitter element13. However, because transmitter element13is integrally joined to piston10, transmitter element13would be subjected to a force in the direction opposite the braking, as exerted by spring11, as well as to an additional force due to the jamming of the pedal.

In an example embodiment of the present invention, intermediate plate12can be made of a material that allows an elastic deformation, in the longitudinal direction of piston10, of a pair of lugs122arranged, for example, symmetrically, which define separation gaps100with supports131of transmitter element13, and a reference element in which a Hall-effect sensor16is provided to detect the relative displacement between them. In the example shown inFIG. 1, Hall-effect sensor16is attached to body21, although in certain embodiments of the present invention it can be attached, for example, to the piston or the brake module.

With reference toFIG. 2, it can be seen that the mechanism has, in its resting position (i.e., with no execution of autonomous or manual braking maneuvers), a gap100between supports131of transmitter element13and intermediate plate12. The purpose of gap100is to provide a measurement of the level of deformation of the elastic part, because the level of deformation of the elastic part is an indirect measurement of the force exerted by spindle15on the brake module. In short, the force in the counter-braking direction can be determined by measuring the distance between transmitter element13and intermediate plate12, i.e., gap100. If the force in the counter-braking direction is sufficient to deform the elastic part and reduce the size of gap100to below a threshold distance, it can then be determined that a jammed-pedal event has occurred.

FIG. 3shows an embodiment of the present invention in which the device is executing a braking maneuver in autonomous mode. Specifically, if the forces in ARP12are analyzed, it will be seen that, on the one hand, there is a force FBRK, which is the autonomous braking force exerted by spindle15on ARP12, and that, on the other hand, there is a force FEET in the counter-braking direction that is exerted by spring11on piston10in order to return it to the resting position.

FIGS. 4aand 4bshow the mode of operation of the present invention in the case of automatic braking without a jammed pedal (FIG. 4a) and with the pedal partially jammed (FIG. 4b).

With reference toFIG. 4a, an example of an elastic part is shown. In this case, it is an elastic lug122of intermediate plate12. This figure also shows part of transmitter element13, which has a plurality of contact blocks that have a first support131and a second support132, in which the height of the first support is greater than the height of the second support. When a braking maneuver is executed via the autonomous brake module, ARP12is displaced by spindle15, causing the first support131to come into contact with ARP12and to be displaced along with it, thereby activating the brake module. If the pedal is not jammed, the force in FDET (i.e., in the counter-braking direction) is low, because the only element exerting force in this direction is spring11. Consequently, this force either is insufficient to deform elastic lug122, or else deforms it in such a way that gap100is not modified to a degree sufficient to generate a jammed-pedal event. That is, the distance between transmitter element13and the plate remains above a threshold distance that determines the generation of the jammed-pedal event.

With reference toFIG. 4b, the case can be seen in which the pedal becomes jammed, for example, due to an obstruction in the pedal. In this case, the movement of piston10and of transmitter element13is restricted by the obstruction, and consequently piston10exerts a force FDET in the direction opposite the braking direction FBRK in addition to the force exerted by spring11. The force FDET causes transmitter element13, acting through the first support131, to deform elastic lug122, thereby reducing gap100, i.e., the distance between intermediate plate12and transmitter element13. In this case, the function of the second support132is to make contact with a stop surface123of the intermediate plate12in order to prevent the plastic deformation of elastic lug122.

The present invention contemplates the detection of the jamming of the brake pedal, doing so by detecting the force exerted on elastic part12, for example, by measuring the size of gap100.

This measurement is preferably done by placing a Hall-effect sensor in the brake module or in intermediate plate12, in such a way as to enable the determination of the distance from the intermediate plate12to a magnetic element, e.g., a magnet14, associated with transmitter element13.

In other examples of embodiments, the elastic part can have a microswitch, for example, in the second support132, so that when the gap100is below a threshold value, the ARP actuates a switch that detects the jamming of the pedal.

Another embodiment includes the placement of a load cell between transmitter element13and intermediate plate12in order to detect the force that is being applied at any time to the block of the elastic part that has the supports. If the force exceeds a threshold value, a jammed-pedal alarm is issued.