FR3031780A1 - PEDAL RECALL REMOTE HYSTERESIS SPRING DEVICE AND OVERSPEED CHARACTERISTIC - Google Patents

Abstract

A spring device (16) for biasing a pedal (10) and having a spring member (20, 22) which contracts in the axial direction in a housing (18) supporting one end of the spring member the other against a support member (28) for transmitting the force to the lever (14) of the pedal. An overspeed spring (50) laterally projecting from the bearing member (28) extends axially on the spring member (20, 22). The housing (18) has an inner edge (60) against which the overspeed spring (50) engages in the overspeed position to exert additional spring force on the pedal lever (14) from the overspeed position.

Description

Field of the Invention The present invention relates to a spring device for biasing a pedal and having a spring element which contracts in the axial direction, a housing receiving the spring element and supporting one end of the spring. spring element, a support element on which the other end of the spring element bears to transmit the force generated by the spring device to the lever of the pedal.

STATE OF THE ART The pedals fitted on vehicles such as the clutch pedal or the accelerator pedal serve to control certain functions of the vehicle. These pedals generally have a spring device that exerts an opposite force (reaction) to the force exerted by the driver on the pedal to return the pedal in the rest position. In the case of the accelerator pedal which controls for example the fuel supply to the internal combustion engine or the power delivered by an electric motor, it is generally advantageous for the curve of the pedal force to have a positive effect. hysteresis, that is to say that, for example, the opposite force that must be overcome to drive the pedal is greater than the force that is exerted when releasing the pedal for the return stroke. It may also be advantageous to end the pedal stroke, when the pedal is fully depressed, the antagonistic force increases sharply, which is called overspeed or "kickdown". DE 10 2010 027 924 A1 describes a pedal comprising a spring device in which an electromagnet generates the hysteresis applied to the spring force as a function of the stroke. The overspeed or kickdown force is generated by a snap-in spring and a stop. DESCRIPTION AND ADVANTAGES OF THE INVENTION The subject of the present invention is a pedal return device of the type defined above, characterized in that it comprises an overspeed spring laterally projecting from the element and bearing in the axial direction on the spring member and the housing has an inner edge against which the overspeed spring engages in the overspeed position to exert an additional spring force on the pedal lever from the position of overspeed.

The lever device according to the invention has the advantage of developing in a simple manner a hysteresis characteristic and an overspeed characteristic. The pedal return spring device relates in particular to the clutch pedal, for example that of an electric clutch or to the accelerator pedal controlling the power supplied by an internal combustion engine, an engine electric or hybrid drive. According to the invention, the pedal device comprises a spring element which contracts in the axial direction while being housed in a housing against the bottom of which the spring element rests, a support element receiving the other end the spring member for transmitting the force of the spring device to the pedal lever. The housing, for example in the form of pot houses the spring element consisting of one or more coil springs, interleaved, bearing against the bottom of this form of pot. The pedal lever depresses the bearing member within the housing and thereby compresses the spring member. The spring device comprises as indicated above an overspeed spring coming laterally projecting relative to the support element. In the overspeed position, the overspeed spring abuts against the inner edge of the housing and from this overspeed position the spring device applies an additional spring force to the pedal lever. When the pedal lever acts on the bearing member, it pushes the bearing member into the housing and thereby compresses the spring device within the housing to generate the main component of the opposing force or counterforce exerting on the pedal lever. From a certain stroke corresponding to the overspeed position, the mechanical overspeed spring, which is next to the spring device inside the casing, meets at one end the inner edge and thus undergoes a contraction. additional power so that from this overspeed position the force exerted on the pedal lever increases. The invention thus makes it possible with simple mechanical means to generate an additional overspeed counterforce. As indicated, the overspeed spring and the spring device are housed in the same pot-shaped housing, which reduces the number of additional components of the housing. According to a development of the invention, the bearing element comprises a friction element for generating a friction force on the inner side of the housing when the bearing element moves into the housing. The friction element comprises for example a friction surface on its outer side which slides on the inner side of the housing. With the contraction of the spring element by the pedal lever, the friction element increases in diameter so that the friction surface is pressed more strongly against the inner side and thus increases the frictional force. Upon expansion of the spring member, i.e., as the force exerted by the pedal lever on the bearing member decreases, the diameter of the friction element decreases and thus reduces the surface area of the friction element. friction. Overall, the force generated by the spring device has hysteresis, which means that at the same point of the pedal lever stroke, the depression of the bearing element in the housing, the force is larger than the return produced by the spring device. The device as described above generates a hysteresis which, at the starting point which corresponds for example to the idle position of the pedal, generates a first force in a range between 7N and 23N and preferably in a range between 12N and 18N; when the maximum load point is reached, the spring device generates a second force in a range of 37N to 65N and preferably 45N to 55N. When releasing the pedal, to maintain the maximum load point, it is necessary to exert for example a third force which is in a range between 25N and 40N and preferably between 30N and 38N; when the idle point is reached, it is sufficient to exert a fourth force which lies in a range between 3N and 18N and which is preferably between 8N and 12N. The four end points that define the hysteresis and the plot of the curve of the force between the end points make it possible to easily adapt the spring device according to the invention to the criteria defined by the customer. This makes it possible to develop the hysteresis characteristic of the spring device with simple mechanical components. The hysteresis curve, that is to say the differential force in the direction of travel and / or the non-linear function of the stroke are adjusted by the adaptation of the axial contour of the inner surface of the housing. All the friction surfaces that generate the extra force for the hysteresis are inside the housing which is relatively compact.

According to one development, the support member has an expansion member having a first wedge-shaped surface abutting against a second wedge-shaped surface belonging to the friction element so that the thrust on the The expansion element by the pedal lever causes the expansion element with the first wedge-shaped surface to widen the friction element with its second wedge-shaped surface. In other words, when the support member is moved, it pushes the first wedge-shaped surface inwards against the second wedge-shaped surface and widens the support member, thereby increasing the force exerted by the friction element on the inner wall of the housing and therefore increases the frictional force between the friction element and the housing. When the support element disengages, it comes out of the friction element whose diameter decreases. The force exerted by the friction element on the inner wall of the housing thus decreases and therefore reduces the frictional force between the friction element and the housing. It should be noted that the size of the first wedge-shaped surface and the second wedge-shaped surface may be different. In section, each wedge-shaped surface has, at the axial ends, a diameter located on the axis of symmetry and orthogonal to this axis of symmetry. Due to the inclination of the wedge-shaped surfaces, the diameter at one end of the wedge-shaped surface is smaller than at the opposite end. The smaller diameter of the wedge-shaped surface is called "inside diameter" and the larger diameter is called "outside diameter". The wedge-shaped surfaces will be of different sizes in that for example the axial distance between the inner diameter and the outer diameter of the second wedge-shaped surface will be much smaller than the corresponding distance on the first wedge-shaped surface (Or conversely the axial distance between the inside diameter and the outside diameter of the first wedge-shaped surface will be considerably smaller than the corresponding distance for the second wedge-shaped surface). This axial distance may be small enough that the second wedge-shaped surface has a substantially linear shape (and vice versa for the first wedge-shaped surface). In other words, one can also choose a shape for the wedge-shaped surface so that one of the wedge-shaped surfaces has only a linear contact (or appearing in section, as a point contact) with the other wedge-shaped surface. The different implementations of the wedge-shaped surfaces make it possible to adjust the hysteresis evolution appropriately. According to a development of the invention, the first wedge-shaped surface is turned outwardly with respect to the axis of the spring device and the second wedge-shaped surface is turned inwardly. The friction element and / or the expansion element may comprise projecting portions which are in relief of the disc of each of the elements and which constitute the wedge-shaped surfaces. These protruding portions are for example protruding from the plane of the disc along the normal direction to the surface of the plane, that is to say that project in the axial direction.

According to another feature, the first wedge-shaped surface and the second wedge-shaped surface, i.e. the two protruding portions surround the axis of the spring device at least partially in an annular shape. The device according to the invention is of a particularly compact construction.

The shape of the corner surfaces facing each other is, for example, inclined at an angle of inclination with respect to the axis which makes it possible to adjust the hysteresis in a simple manner. For wedge-shaped surfaces that have an orientation parallel to the axis, that is, the smaller the angle between the axis and the wedge-shaped surface and the smaller the diameter of the element. friction will be enlarged by the expansion element. This makes it possible to easily adjust the hysteresis curves at the request of the customer by the only mechanical components. Such an arrangement is particularly robust and reliable.

According to a development of the invention, the friction element has a central opening through which the centering element of the expansion element passes. The centering element is for example a ring or a raised annular wall of the disk forming the expansion element and penetrating into the housing, for example in its axial direction. This ring is not necessarily closed. The centering element may have a stud shape which will advantageously facilitate the assembly of the device since this makes it possible to guide the spring element on the centering element and to stabilize it in the radial direction. In operation, this prevents the spring from bending to one side, thereby increasing the reliability and service life of the device. According to a development of the invention, the friction element has substantially an annular shape with a longitudinal slot allowing the variation of the diameter of the friction element. Even when the friction element is made of a relatively rigid material, the enlargement and reduction of the slot allows the friction element to deform by its side opposite the slot and thus increase or decrease the outer diameter of the friction element. This allows the friction element to deform by its opposite side to the slot.

According to a development of the invention, the friction element is elastic to automatically oppose the enlargement of its diameter. The friction element or the point of the friction element opposite the slot returns to the initial shape when the expansion element is more strongly deployed which guarantees the reliability and regularity of the behavior during the entire lifetime. According to a development of the invention, a friction enhancing material is inserted between the inner friction surface of the housing and the outer friction surface of the friction element. This material is for example Santoprene © applied on the housing or on the friction element. According to a development of the invention, the friction surface of the housing has at least two zones in the axial direction so that in the first zone the friction element generates a different friction force than the friction zone. generated in the second zone, for example the zones may have different diameters. It is also possible to have in one of the two zones a material increasing the frictional force without providing material in the other zone or having another material therein. This makes it easy and economical to adjust the hysteresis behavior at the customer's request without having to change the external shape of the device. It is thus possible to apply principles of modular manufacturing, which results in an economy. If the friction surface of the housing is parallel to the direction of movement of the support member, this frictional force is generally constant and in combination with the force developed by the spring element which is a function linear stroke, the force exerted on the pedal is a linear function. The rubbing force also depends on the inside diameter of the friction surface of the casing. Different inner diameters realize different friction forces. If the friction surface is not parallel but inclined with respect to the direction of movement, the friction force, i.e. the force exerted on the accelerator pedal, does not increase significantly. linear with the stroke, that is to say that it increases with a different slope in the direction going (that is to say during the depression in the case) compared to the force developed during the movement back. The housing is manufactured for example by injection of metal 35 or plastic. The friction surfaces of the housing can be obtained by using an interchangeable insert installed in the injection mold to thereby adapt the hysteresis to demand. According to a development of the invention, the over-speed spring consists of a leaf spring having an elastic tongue passing over the spring element. The spring blade is fixed at one end in the bearing member and then, bent for about 90 °, joins the resilient tongue which is substantially parallel to the inner surface of the housing by passing the spring device. The overspeed spring is thus of a particularly simple and compact manufacture; it is therefore particularly robust and very resistant to breakage. According to a development of the invention, the leaf spring has two opposite spring tongues protruding laterally from the bearing element. The two spring tabs cooperate symmetrically with the opposite inner edges from the overspeed position which prevents jamming during operation. In addition, the two spring tabs also ensure a certain redundancy in case of breakage of one of the tongues because then the operation will not stop abruptly, but there will remain at least one other tongue that will continue to work, which is an important point for the safety of the vehicle. According to a development of the invention, the support element (or expansion element) consists of two parts between which is fixed the middle part of the overspeed spring. The overspeed spring will thus have a U-shaped curved shape whose branches constitute the two spring tabs and the base portion or intermediate portion of this U-shaped form constitutes the median part which is housed between the two parts of the element. support. There is thus a particularly simple and economical overspeed production and assembly spring.

This structure also allows a modular design using for example the same overspeed spring for different support elements. According to a development of the invention, at least one elastic tongue or spring tongue has a curved spoon-shaped end away from the inner wall of the housing, that is, facing inwards, c that is, towards the axis. The inner edge may also have a suitable curvature so as to avoid during operation the jamming of the spring end within the housing.

According to a development of the invention, the housing has a lateral channel in which the overspeed spring moves, that is to say the tongue of the overspeed spring and next to the channel, the housing has internal friction surfaces. on which the friction element slides. Thus, advantageously, a single housing integrates both the hysteresis function and the function of the overspeeding point. The device is easy to carry out, requires little maintenance and the sensitive components are well protected against environmental influences in the same housing. The invention also relates to the pedal, for example the clutch pedal or the accelerator pedal comprising a pedal lever pivoting about an axis and a spring device generating the opposing variable force exerted on the pedal lever as has been described above. This pedal develops in a simple and economical way an opposing or opposing force with hysteresis and overspeed characteristic. Drawings The present invention will be described hereinafter in more detail with the aid of an exemplary hysteresis and overspeed pedal return spring device shown in the accompanying drawings in which: FIG. a schematic view of a first embodiment of a pedal according to the invention, Figure 2 is a longitudinal section of an embodiment of the spring device according to the invention, Figure 3 is a perspective view of components of the spring device of FIG. 2, FIG. 4 is an exploded view of the components of FIG. 3, FIG. 5 is another perspective view of the components of the spring device of FIG. 2, FIG. schematic very partial, longitudinal of an embodiment of the spring device of the invention, Figure 7 is a schematic section of an embodiment of the spring device according to the invention.

DESCRIPTION OF EMBODIMENTS FIG. 1 shows a pedal 10 such as an accelerator or clutch pedal that the driver actuates with his foot to push it from his rest position to his end position. race. The driver thus actuates the foot support 12 which pivots the pedal lever 14 about an axis. The spring device 16 produces a force opposite to the force developed by the driver and tends to return the pedal 10 in the rest position. The spring device 16 described hereinafter generates a different opposing force in a purely mechanical manner.

FIG. 2 is a longitudinal or axial section of a spring device 16 having a pot-shaped housing 18 housing two spring elements in the form of helical springs 20, 22 pressing against one end 24 of the housing 18, that is, at the bottom of the pot-shaped housing. The inner coil spring 20 or first spring member 20 is slightly longer than the outer coil spring 22 or second spring member 22; the end 24 of the housing 18 thus has two bearing surfaces 26 spaced axially and each receiving a spring 20, 22. A bearing element 28 at the other end 30 of the housing is guided by the inner walls of the housing 18; this support element consists of an expansion element 32 and a friction element 34. Depending on the end 24, the support element 28 or the friction element 34 comprise one or two bearing surfaces 40 spaced axially and each receiving support one of the helical springs 20, 22 or only the spring 22. Opposite the bearing surfaces 40, the friction element 34 has a second surface wedge shape 42, annular, inclined in relation to the axial direction, turned inwards, and sliding on the first wedge-shaped annular surface 44 of the expansion element 32. The first wedge-shaped surface 44 is at the same angle as the second wedge-shaped surface 42, being inclined relative to the axial direction, outwardly. Expansion member 32 has a second axially directed annular centering element 46, the central orifice 48 of which is engaged with friction element 34. When pedal lever 14 presses the support element 28, the expansion element 32 and the friction element 34 slide relative to each other; the first conical surface 44 and the second conical surface 42 slide over each other and the friction element 34 is enlarged by the expansion element, which increases the frictional force exerted between the surfaces 36, 38 Conversely, when the load exerted on the pedal lever 14 and thus on the support element 28 decreases, the expansion element 32 and the friction element 34 slide away from one another. other; the friction element 34 has its outer diameter decreasing so that the frictional force exerted between the surfaces 36, 38 decreases. This gives a force / stroke curve of the spring device 16 which has hysteresis. The bearing element 28 carries an overspeed spring 50 consisting of a U-shaped leaf spring whose middle part 52 comes between the two parts 54 of the expansion element 32. Two elastic tabs 56 form the arms of this U-shaped structure; these two resilient tongues pass next to the coil springs 20, 22 penetrating the housing 18. The resilient tongues 56 are each housed in a lateral slot 58 (or channel 58) of the housing passing between the hysteresis surface 38 of the housing 18 At the end of the channels 58, there is an inner edge 60 against which each of the resilient tongues 56 can abut in the overspeed position. The resilient tongues have a spoon-shaped end 62 that curves inwardly toward the axis. Thus, the leading surface prevents seizing of the resilient tongue 56 in operation, inside the housing 18. The inner edge 60 has a suitable curvature. When the support element 28 is pushed by the pedal lever 14 in the overspeed position, the elastic tabs 56 come against the inner edges 60 and from this position, the elastic tongues 56 are compressed in a complementary manner by the springs. 20, 22, which increases the counterforce exerted on the pedal lever 14. Figures 3 to 5 show further perspective views of components of the spring device of Figure 2. Figures 4 and 5 also show that the friction element 34 has a slot 64 in the radial direction. This slot allows the friction element 34 to enlarge or reduce its diameter. The slot 64 is on one side of the edge of the friction element 34 and passes through the bearing surfaces 40 on both sides of the opening 48.

Figure 6 shows a schematic sectional view of a spring device 16 whose inner surface 38 of the housing has a plurality of zones 66, 68 having different diameters. The different diameters generate different friction forces which give the non-linear behavior to the force as a function of the pedal stroke. Figure 7 shows schematically a partial section of the spring device 16 showing that between the housing 18 and the friction element 34 there is an additional material 70 which increases the friction between the housing 18 and the friction element 34 This material 70 may be attached to the housing 18 or the friction element 34. This material is for example a thermoplastic elastomer such as an elastomer based on polypropylene PP, Ethylene-Propylene Diene Rubber (EPDM). Santoprene e is particularly suitable for use.25 NOMENCLATURE OF MAIN ELEMENTS 10 Pedal 12 Pedal support 14 Pedal lever 16 Spring device 18 Pot-shaped housing 20 Coil spring 22 Coil spring 24 End of housing 26 Support surface 28 Element d 30 Housing end 32 Expansion element 34 Friction element 36 Outer surface 38 Inner surface 40 Support surface 42 Second annular wedge-shaped surface 44 First annular wedge-shaped surface 46 Centering element 48 Central opening 50 Overspeed Spring 52 Middle Region 54 Expansion Element Part 56 Spring Tab / Elastic Tongue 58 Side Slot 60 Inner Edge 62 Bent End of Elastic Tongue 64 Slot 66, 68 Enclosure Area 70 Additional Material35

Claims (4)

1) spring device (16) for biasing a pedal (10) and having a spring element (20, 22) which contracts in the axial direction, a housing (18) receiving the spring element (20, 22); ) and supporting one end of the spring element, a support element (28) on which the other end of the spring element (20, 22) bears to transmit the force generated by the spring device (16) to the lever (14) of the pedal, spring device characterized in that it comprises an overspeed spring (50) laterally projecting with respect to the bearing element (28) and which passes in the direction axial direction on the spring element (20, 22) and the housing (18) has an inner edge (60) against which the overspeed spring (50) abuts in the overspeed position to exert an additional spring force on the pedal lever (14) from the overspeed position. 2) spring device (16) according to claim 1, characterized in that the overspeed spring (50) comprises a leaf spring with at least one resilient tongue (56) passing next to the spring element (20). , 22). 3) spring device (16) according to claim 2, characterized in that the leaf spring has two spring tongues (56) facing each other and laterally projecting from the bearing element (28). . 4) A spring device (16) according to claim 2 or 3, characterized in that the spring tongue (56) has a curved spoon-shaped end (62) so as to deviate from the inner surface of the housing (18) and the inner edge of the housing (60) has a corresponding curvature.355 °) Spring device (16) according to claim 1, characterized in that the support element (28) comprises a friction element (34) for pressing against the inner side of the housing (18) and generating a frictional force as the bearing member moves in the housing (18), and contraction of the spring element (20). , 22) by the pedal lever (14), the friction element (34) increases in diameter to thereby increase the frictional force and upon expansion of the spring element (20, 22), friction element (34) decreases in diameter and thus reduces the frictional force so that the force acting on the lever of edale (14) has hysteresis. Spring device (16) according to claim 1, characterized in that the support element (28) comprises an expansion element (32) having a first wedge-shaped surface (44) supported by a second wedge-shaped surface (42) of the friction element (34) so that with a thrust exerted on the expansion element (32) by the pedal lever (14), the first shaped surface wedge (44) of the expansion element (32) widens the friction element (34) by the second wedge-shaped surface (42). 7 °) spring device (16) according to claim 1, characterized in that the housing (18) has at least one side channel (58) in which the overspeed spring (50) and the channel (58) the inner housing (18) has friction surfaces (38) on which the support element (28) slides. 8 °) spring device (16) according to claim 7, characterized in that the inner edge (60) is at the end of the lateral channel (58), edge against which abuts the overspeed spring (50) in position overspeed .359 °) Spring device (16) according to claim 1, characterized in that the support element (28) has two parts (54) between which is housed the middle portion (52) of the overspeed spring (50). Pedal (10) comprising - a pedal lever (14) pivotally mounted about an axis, and - a spring device (16) according to any one of claims 1 to 9 for generating an opposite, variable force exerting itself on the pedal lever (14).