Foot lever mechanism with lever kinematics

Abstract

Foot lever mechanism with a bearing block (1) for securing the foot lever mechanism to a device operable by means of the bearing block (1) and with at least one foot pedal (2), which consists of a pedal plate (4) and a pedal lever (3) and is mounted with one end of the pedal lever (3) on a pedal bearing (5) of the bearing block (1) so as to be pivotable about a pivot axis (6), characterized in that the pedal lever (3) is connected between its end mounted on the pedal bearing and its other end to the bearing block (1) via a deflection lever (7), which is formed from a first articulated lever (7') rotatably fixed to the pedal lever (3) and a second articulated lever (7''), which has a free end (17) and is fixed to the bearing block (1) so as to be displaceable with respect to its longitudinal axis (16), wherein the deflection lever (7) is located at one of its articulated levers (7',7'') interconnecting joint (8) on the bearing block (1) via a spring element (9) generating a restoring force for the foot pedal (2), the end (15) of which facing away from the joint (8) is rotatably mounted on the bearing block (1), and wherein a cam (11) arranged on the free end (17) of the articulated lever (7'') is guided in a guide track (12) of a guide element (10) inserted into the bearing block (1).

Description

The invention relates to a foot lever mechanism, preferably provided for use in motor vehicles, having at least one foot pedal, which has a special lever kinematics. It relates preferably in particular to a foot lever mechanism for a brake pedal, but the invention is not restricted to this, nor to use in a motor vehicle.FR 2 871 114 A1 discloses a foot lever mechanism with a pedal which can be actuated by the foot of a user and which is mounted on a frame such that it can pivot about a pedal axis, wherein a first spring exerts a force between a fixed bearing of the frame and a movable element connected to the pedal for holding the pedal in a raised position. In this case, means for modulating the restoring force are provided, comprising a cam and a finger which is mounted in a sliding manner on a finger carrier, the finger being held against the cam by pressure means, and the means for modulating are connected to the movable element for transmitting a modulating force to the pedal.DE 101 04 665 A1 describes a disengagement device having a master cylinder of a hydraulic system which can be actuated by a pedal and having an energy store which absorbs energy during engagement and releases the energy again during disengagement in the form of an assistance force and is articulated on the pedal or on a lever device connected to the pedal. In this case, means for influencing the profile of the assistance force for the actuating force of the pedal are arranged between the pedal and the energy store.When actuating a foot pedal, it is very important in many cases that a person who actuates the pedal with his foot receives feedback from the system operated by means of the foot pedal, which feedback enables him to dose the force respectively applied or to be applied for actuating the pedal. This applies in particular to foot lever mechanisms in motor vehicles and in this case to a particular extent to the foot lever mechanisms of brake pedals. In this respect, it is very important for a motorist, when actuating the brake pedal, to receive feedback from the brake system, which enables him to assess whether the braking force he applies is appropriate with regard to the respective traffic situation. In the hydraulic or pneumatic brake systems mostly used according to the prior art, it receives the corresponding information on the basis of the brake pressure that is respectively building up. According to the distance travelled by its actuation by the brake pedal, a quite specific brake pressure is established for the respective vehicle in the brake system. The relationship between the distance travelled by the pedal and the brake pressure, which in turn is in a relationship, dependent on the road conditions and the tyres of the vehicle, with the brake distance resulting for a braking operation, can be described by a force-distance characteristic curve or curve for the corresponding foot pedal. This force-path curve, the course of which in a respective vehicle, for example for its brake pedal, changes to a certain extent into the under-awareness of a driver who is regularly using the vehicle, provides the driver with an immediate feel as to how he must dose the braking force in an appropriate reaction to a respective traffic situation. As already explained, its course is determined decisively by the brake pressure that is established in the hydraulic or pneumatic brake system. By means of this brake pressure and any restoring springs present, a return of the brake pedal is also effected when the brake force is reduced and the return to the starting position is effected after the end of the braking process. The force-displacement curve of the foot pedal of a hydraulic or pneumatic brake already mentioned has a hysteresis with regard to the actuation of the pedal for triggering a braking process and the relief of the pedal upon a reduction of the braking force or upon termination of the braking process. This hysteresis can only be influenced to a very limited extent.In more recent motor vehicles, so-called brake-by-wire systems are already used in some cases. These are electromechanical or mechatronic brake systems, in which hydraulics or pneumatics are generally dispensed with. The foot lever mechanisms of brake pedals of corresponding brake systems accordingly do not have a hydraulic or pneumatic connection, but generally also no direct mechanical connection to the actual brake system. Thus, no resistance or no counterforce is generated by corresponding systems when the brake pedal is actuated, which gives the driver a feeling for the braking force he applies and resets the pedal when the braking force is reduced or when the braking process is ended.It is the object of the invention to provide a foot lever mechanism with at least one foot pedal, which provides an individual actuating the corresponding pedal with adequate feedback about the actuating force applied by it, resets the pedal when the actuating force is reduced or when the actuating process is ended, and furthermore opens up the possibility, during the production or installation of the foot lever mechanism, of realizing a force-path curve for the at least one foot pedal in accordance with the wishes of the customer or user.The object is achieved by a foot lever mechanism having the features of claim 1. Advantageous embodiments and further developments of the invention are given by the dependent claims. The foot lever mechanism that achieves the object consists essentially of a bearing block and of at least one foot pedal formed by a pedal lever and a pedal plate. The latter is mounted with one end of its pedal lever on a pedal bearing of the bearing block, pivotable about a pivot axis. By means of the bearing block, the foot lever mechanism is fixed to a device, preferably a motor vehicle, which can be operated with its aid.According to the invention, the pedal lever of the at least one foot pedal is additionally connected to the bearing block via a deflection lever at a position between its end mounted on the pedal bearing and its other end. The respective reversing lever consists of a first articulated lever rotatably fixed to the pedal lever and a second articulated lever which has a free end and is fixed to the bearing block so as to be displaceable with respect to its longitudinal axis. At a joint connecting its two articulated levers to one another, the deflection lever is supported on the bearing block via a spring element. This spring element generates a restoring force for the foot pedal. The end of the spring element facing away from the joint of the deflection lever is rotatably mounted on the bearing block.As already explained, one of the two articulated levers forming the deflecting lever, namely the articulated lever of the deflecting lever fixed axially displaceably on the bearing block, has a free end. At this free end of the articulated lever, a cam is arranged according to the invention, which is guided in a guide track of a guide element inserted into the bearing block. Due to the additional connection of the pedal lever and the bearing block by means of the deflection lever supported on the bearing block at its joint via the spring element, a lever kinematics is realized in cooperation with the cam of the deflection lever guided in the guide track, which makes it possible to set the force-displacement curve for a foot pedal of the foot lever assembly according to the invention in a very flexible manner according to the respective requirements of the customer, e.g. of a vehicle manufacturer. According to a particularly preferred embodiment, the already repeatedly discussed cam is formed at the free end of one of the articulated levers forming the deflection lever as a cam roller which rolls on the inner contour of the guide track of the guide element inserted into the bearing block.The axial displaceability of the articulated lever provided with the cam is ensured, in accordance with a possible embodiment of the foot lever mechanism according to the invention, in that the relevant articulated lever has an elongated hole. A bolt is guided through this elongated hole, by means of which the articulated lever is fixed axially displaceably on the bearing block.The already mentioned spring element for supporting the articulated lever or its joint has at least one helical spring according to a preferred embodiment. According to a practical embodiment of this embodiment, the spring element is formed by a helical spring which surrounds a support core made of two rod-shaped elements which can be pushed one inside the other. At the outer, i.e. the ends of the strand-shaped elements facing away from each other, a respective disk-shaped or cap-shaped limiting element is arranged. On their side facing the spiral spring, the named limiting elements each form a supporting surface for the spiral spring. In addition, on their side facing away from the spiral spring, they have means for connecting the spring element to the deflection lever on the one hand and to the bearing block on the other hand. In this embodiment, the prestress for the preferably prestressed spring of the spring system can advantageously be adjusted over the length, more precisely the ratio between the length of the helical spring and the spacing of the limiting elements forming the supporting surfaces for the spring and / or the spring rate of the helical spring. As the coil spring, standard springs or non-linearly wound springs can be used. By using non-linearly wound spiral springs, it is possible to have additional influence on the force-displacement curve of one or of the at least one foot pedal of the foot lever mechanism according to the invention via the type of winding of the spring.Alternatively, the spring element can also be realized by means of an elastomer spring. The foot lever mechanism according to the invention is preferably further developed in that above and below the pedal lever stops are arranged which limit the pivot path of the pedal lever. In this case, according to an embodiment of the invention, the lower stopper is arranged on the upper side of the guide element in which the guide curve for the cam is formed.The principle according to the invention for forming the foot lever mechanism can be used both for foot lever mechanisms in which the foot pedal equipped with the lever kinematics according to the invention is formed as a hanging pedal and for those in which the pedal is formed as a standing pedal. The pedal plate can be arranged at the free end of the pedal lever according to one possibility. However, it can also extend along the pedal lever on its upper side, the latter preferably being provided in the case of a foot pedal which is configured to be upright.An exemplary embodiment of the invention is to be explained below with reference to the associated drawings. The drawings show in detail: FIG. 1 shows a possible embodiment of the foot lever mechanism according to the invention in a three-dimensional representation, FIG. 2 shows a part of the foot lever mechanism according to FIG. 1, with enlargement of the detail X and with omission of the bearing block, FIG. 3 : a force-displacement curve which can be realized by means of the foot lever mechanism according to FIGS. 1 and 2, FIG. 4 : an enlargement of the section Y of the force-displacement curve according to FIG. 3.FIG. 1 shows a possible embodiment of the foot lever mechanism according to the invention in a three-dimensional representation. The foot lever mechanism is accordingly substantially formed by the bearing block 1 and a foot pedal 2, which is mounted on the bearing block 1 by means of the pedal bearing 5 such that it can be pivoted about a pivot axis 6. The foot pedal 2 consists in a manner known per se of the pedal lever 3, one end of which is mounted on the pedal bearing 5, and of a pedal plate 4 which is arranged on the free end 27 of the pedal lever 3. According to the invention, the pedal lever 3 is additionally connected to the bearing block 1 via the deflection lever 7. The deflection lever 7, which is formed from two articulated levers 7', 7" joined together at a joint 8, one of which is rotatably fixed to the pedal lever 3 and the other of which is fixed to the bearing block 1 in an axially displaceable manner (see FIG. 2 in this regard), is supported with its joint 8 on the bearing block 1 via the spring element 9. At the free end 17 of the articulated lever 7" fixed axially displaceably on the bearing block 1, a cam 11 is formed, which is guided in a guide track 12 of a guide element 10 (see FIG. 2 in this regard). By guiding the cam 11 formed on the articulated lever 7" in the guide track 12 on the one hand and the spring element 9 supporting the deflection lever 7 on the other hand, a special lever kinematics is formed, which enables a very largely free configuration of the force-path curve of the foot pedal 2 according to the customer or user specifications. This is illustrated by way of example by FIGS. 3 and 4, wherein FIG. 3 shows a force-displacement curve which can be realized by means of the foot lever mechanism according to the invention. FIG. 4 once again shows a detail Y of this force-displacement curve in an enlarged illustration.FIG. 2 once again shows a part of the foot lever mechanism with the foot pedal 2 according to FIG. 1 with an enlarged detail X, the illustration of the bearing block 1 having been omitted in this figure for the sake of better clarification. The elements of the lever kinematics according to the invention can be seen very well once again in the figure. It shows the deflection lever 7 with its two articulated levers 7', 7" joined together at the joint 8, of which one, namely the articulated lever 7" is fixed on the bearing block 1, not shown here, so as to be displaceable along its longitudinal axis 16. For this purpose, an elongated hole 13 is formed in the relevant articulated lever 7'', through which a bolt 14 serving for fixing to the bearing block 1 is guided. Corresponding to the longitudinal extension of this elongated hole 13, the articulated lever 7" is axially displaceable. The free end 17 of the cam 11 is formed, which in the exemplary embodiment shown is a cam roller which rolls in the guide track 12 of the guide element 10. The joint 8 of the reversing lever 7 is supported via the spring element 9 on the bearing block 1, not shown here. In this case, the end 15 of the spring element 9 to be connected to the bearing block 1 is rotatably mounted on the bearing block 1 after its connection to the latter. The spring element 9 consists of a helical spring 18 which surrounds a guide and support core which consists of two rod-shaped elements 19, 20 which can be pushed one inside the other. At their outer ends facing away from each other, the mentioned strand-shaped elements 19, 20 each have a plate-shaped or cap-shaped limiting element 21, 22. The limiting elements 21, 22 form a supporting surface for the helical spring 18 on their side facing the helical spring 18 and have means 23, 24 on their side facing away from the helical spring 18 for connection to the reversing lever 7 or its joint 8, on the one hand, and to the bearing block 1, on the other hand. The spiral spring 18 of the spring element 9 is prestressed, wherein the prestress is determined by the length of the spiral spring 18 in relation to the distance between the limiting elements 21, 22 and / or the spring rate of the spiral spring 18. For travel limitation for the foot pedal 2, a stopper 25, 26 is arranged below and above the pedal lever 3, the lower stopper 25 being formed on the upper side of the guide element 10 having the guide track 12.List of reference characters1 Bearing block 2 Foot pedal 3 Pedal lever 4 Pedal plate 5 Pedal bearing 6 Pivot axis 7 Deflection lever 7', 7" Articulated lever 8 Joint 9 Spring element 10 Guide element 11 Cam 12 Guide track 13 Slot 14 Bolt 15 End of the spring element 16 Longitudinal axis of the articulated lever 17 Free end of the articulated lever 18 Spiral spring 19, 20 Strand-shaped element 21, 22 Limiting element 23, 24 Means for connection 25, 26 Stopper 27 Free end of the pedal lever

Claims

Foot lever mechanism with a bearing block (1) for fixing the foot lever mechanism to a device which can be operated by means of it and with at least one foot pedal (2), which consists of a pedal plate (4) and a pedal lever (3) and is mounted with one end of the pedal lever (3) on a pedal bearing (5) of the bearing block (1) such that it can be pivoted about a pivot axis (6), characterized in that the pedal lever (3) is connected between its end mounted on the pedal bearing and its other end to the bearing block (1) via a deflection lever (7), which is formed from a first articulated lever (7') rotatably fixed to the pedal lever (3) and a second articulated lever (7"), which has a free end (17) and is fixed to the bearing block (1) such that it can be displaced with respect to its longitudinal axis (16), wherein the deflection lever (7) is supported on the bearing block (1) at a joint (8) connecting its joint levers (7', 7") to one another via a spring element (9) generating a restoring force for the foot pedal (2), the end (15) of which facing away from the joint (8) is rotatably mounted on the bearing block (1), and wherein a cam (11) arranged at the free end (17) of the joint lever (7") is guided in a guide track (12) of a guide element (10) inserted into the bearing block (1).Foot lever mechanism according to claim 1, characterised in that the spring of the spring element (9) is prestressed.Foot lever mechanism according to claim 1 or 2, characterised in that the cam (11) is formed as a cam roller rolling on the inner contour of the guide track (12) of the guide element (10).Foot lever mechanism according to one of Claims 1 to 3, characterized in that the articulated lever (7") is fixed to the bearing block (1) by means of a bolt (14) which is guided through an elongate hole (13) formed in this articulated lever (7").Foot lever mechanism according to one of Claims 1 to 4, characterized in that the spring element (9) has at least one helical spring (18).Foot lever mechanism according to claim 5, characterised in that the spring element (9) is formed by a helical spring (18) which surrounds a support core consisting of two rod-shaped elements (19, 20) which can be pushed one inside the other and at the outer ends of which are arranged plate-shaped or cap-shaped delimiting elements (21, 22) which form a respective supporting surface for the helical spring (18) on their side facing the helical spring (18) and have, on their side facing away from the helical spring (18), means (23) for connecting the element (19) to the joint (8) of the deflection lever (7) on the one hand and means (24) for connecting the element (20) to the bearing block (1) on the other hand.Foot lever mechanism according to claim 5 or 6, characterised in that the helical spring (18) of the spring element (9) is a non-linearly wound helical spring (18).Foot lever mechanism according to one of Claims 1 to 4, characterized in that the spring element (9) is realized by means of an elastomer spring.Foot lever mechanism according to one of Claims 1 to 8, characterized in that stoppers (25, 26) for limiting the pivot travel of the pedal lever (3) are arranged above and below the pedal lever (3), the lower stopper (25) being formed on the upper side of the guide element (10).Foot lever mechanism according to one of Claims 1 to 9, characterized in that the pedal plate (4) is arranged at the free end (27) of the pedal lever (3).Foot lever mechanism according to one of Claims 1 to 10, characterized in that the pedal plate (4) extends along the pedal lever (3) on the upper side thereof.

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