Leaf spring with built-in stop

Abstract

The invention relates to a limit stop device (1) designed to equip a leaf spring (2) of a motor vehicle suspension, the spring (2) being of the type comprising two mounting shafts (4) and several damping leaves (5) extending between the mounting shafts (4) of the spring (2), the device (1) comprising two attachment heads (6), each designed to be fixed to a mounting shaft (4), the device (1) comprising a connecting element (7) linking the attachment heads (6) and designed to deform in order, on the one hand, to allow the mounting shafts (4) to move closer together and, on the other hand, to limit the separation of the mounting shafts (4) to a maximum distance, when the heads (6) of the device (1) are fixed to the shafts (4) of the spring (2) and the latter deforms to dampen a movement of the vehicle on which it is mounted. (Figure 1)

Description

Title of the invention: Leaf spring with integrated attack stop

[0001] The technical field relates to stop devices for leaf springs of motor vehicles, suspensions comprising such a device mounted on a leaf spring, and finally motor vehicles having at least such a suspension.

[0002] Some motor vehicles have, for one wheel, a suspension comprising a leaf spring capable of undergoing elastic deformation to dampen the wheel's movement. To prevent damage to the leaf spring and also to prevent the wheel from striking the vehicle body, the vehicle body has a stop designed to quickly stop the suspension's travel in the event of a significant impact, for example, from an obstacle. Such a stop is, for example, implemented by a buffer offset from the body against which the leaf springs bear.

[0003] Implementing such a stop complicates the design of the vehicle's suspension and requires an additional part. However, car manufacturers are seeking to simplify the design of their vehicles in a context of reducing development, production, and logistics costs.

[0004] Thus, there is a need for a solution that eliminates the need for an offset end stop.

[0005] The present invention aims to overcome the problems described above. In this technical context, one objective of the present invention is to provide a limit switch device for equipping a leaf spring and replacing an offset stop.

[0006] To this end, the present invention relates to a limit stop device designed to equip a suspension leaf spring of a motor vehicle, the spring being of the type comprising two fixing axes and several damping leaves extending between the fixing axes of the spring, the device comprising two attachment heads, each designed to be fixed to a fixing axis, the device comprising a linking element connecting the attachment heads and designed to deform in order, on the one hand, to allow the fixing axes to come closer together and, on the other hand, to limit the separation of the fixing axes to a maximum distance, when the heads of the device are fixed on the fixing axes of the spring and the latter deforms to dampen a movement of the vehicle on which it is mounted.

[0007] The invention also relates to a vehicle suspension comprising a leaf spring, having two fixing axes, allowing the spring to be fixed to the vehicle, and several damping blades extending between the fixing axes, the suspension further comprising a device according to the invention fixed on the spring, each attachment head being fixed on a fixing axis of the spring, the linking element being designed to deform to allow the fixing axes to come closer together and to limit the separation of the fixing axes to a maximum distance, corresponding to their distance at the end of the suspension stroke.

[0008] The invention finally relates to a motor vehicle comprising at least one suspension according to the invention.

[0009] Thus, the device according to the invention, thanks to the connecting element, makes it possible to control the distance between the spring's fixing axes by limiting the distance to the maximum separation distance. The stop device according to the invention therefore makes it possible to form a suspension according to the invention, in which the leaf spring is directly equipped with an end-of-stroke stop, which prevents excessive deformation of the leaf spring at the end of its stroke. The device according to the invention reduces manufacturing complexity and costs.

[0010] According to one embodiment of the device, the connecting element is formed of a strip of elastomeric material connecting the attachment heads.

[0011] Advantageously then, the maximum length of the live strip defines the maximum separation distance.

[0012] According to one possibility of the stop device, each fastening head is designed to surround at least part of a fastening axis.

[0013] According to one embodiment, each attachment head comes from the material with the connecting element.

[0014] According to one possibility of the suspension, when the connecting element is formed of a band of elastomeric material connecting the attachment heads, the band of elastomeric material has a length such that it is taut when the suspension is at the end of its travel.

[0015] The invention will be better understood upon reading the following detailed description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0016] [Fig-1] [Fig.1] represents a perspective view of a suspension according to the invention, in an intermediate position;

[0017] [Fig.2] [Fig.2] represents a side view of the suspension of [Fig.1] in a end-of-stroke attack position;

[0018] In these figures, the same references are used to designate the same elements.

[0019] A limit stop device 1 according to the invention, illustrated in the figures, is designed to equip a leaf spring 2 of a motor vehicle, also illustrated in the figures, to form a suspension 3 according to the invention.

[0020] The leaf spring 2 conventionally comprises two mounting pins 4, for attaching it to the vehicle, and several damping leaves 5 extending between the mounting pins 4 of the spring 2. The number and dimensions of the damping leaves 5 give the spring 2 its damping capacity. When the spring 2 is mounted on a vehicle to contribute to the vehicle's suspension, the mounting pins 4 move closer together or further apart. When the leaf spring 2, mounted on a vehicle, is subjected to an impact force, the distance between the mounting pins 4 increases.

[0021] The device 1 comprises two attachment heads 6, illustrated in the figures, each designed to be fixed to a fixing axis 4. Each attachment head 6 is designed to surround at least partially a fixing axis 4.

[0022] As illustrated in the figures, the device 1 further comprises a connecting element 7 linking the attachment heads 6. The connecting element 7 is designed to deform in order, firstly, to allow the attachment axes 4 to move closer together when the spring 2 is released. The connecting element 7 is also designed, secondly, to limit the separation of the attachment axes 4 to a maximum distance Dmax, illustrated in [Fig. 2], when the heads 6 of the device 1 are fixed to the attachment axes 4 of the spring 2 and the latter deforms to dampen a movement of the vehicle on which it is mounted.

[0023] In the example illustrated in the figures, the connecting element 7 is formed of a strip 8 made of elastomeric material. The thickness, width, and nature of the elastomeric strip 8 are chosen to ensure flexibility suitable for the functions of the connecting element 7 and sufficient strength to limit the separation of the fixing axes 4 to the maximum separation distance Dmax. The properties of the strip 8 are chosen so that the maximum length of the strip 8 defines the maximum separation distance Dmax. In particular, when the strip 8 is designed to prevent elastic elongation, the maximum length of the strip 8 corresponds to the length of the strip 8.

[0024] Advantageously, each attachment head 6 comes from material with the connecting element 7.

[0025] As illustrated in [Fig.1], when the suspension 3 is in the nominal position, i.e. deformed by the weight of the vehicle at rest or in an intermediate position (i.e. a position between the nominal position and the end-of-stroke position), the length of the band 8 of the connecting element 7 is such that the band 8 is unstretched, i.e. is bent, forming, for example, a chain.

[0026] In [Fig. 2], the suspension 3 is shown in its end-of-travel position. The connecting element 7 of the device 1 prevents the mounting axes 4 from moving beyond the maximum separation distance Dmax and forms an end-of-travel stop. The band 8 of the connecting element has a maximum length L such that the band 8 is taut when the suspension 3 is at the end of its travel.

[0027] Thus, device 1, thanks to the connecting element 7, allows control of the distance between the mounting axes 4 of spring 2 by limiting the distance to the maximum separation distance Dmax. The stop device 1 therefore makes it possible to form a suspension 3 in which the leaf spring 2 is directly equipped with an end-of-stroke stop, which prevents excessive deformation of the leaf spring 2 at the end of its stroke. Device 1 thus reduces manufacturing complexity and costs.

[0028] The invention is not limited to the embodiment of the stop device described above, only by way of example, but other embodiments may be designed by a person skilled in the art without departing from the scope and extent of the present invention.

Claims

Demands

1. A limit stop device (1) designed to equip a suspension leaf spring (2) of a motor vehicle, the spring (2) being of the type comprising two fixing pins (4) and several damping leaves (5) extending between the fixing pins (4) of the spring (2), the device (1) comprising two attachment heads (6), each designed to be fixed to a fixing pin (4), the device (1) comprising a linking element (7) connecting the attachment heads (6) and designed to deform in order, on the one hand, to allow the fixing pins (4) to move closer together and, on the other hand, to limit the separation of the fixing pins (4) to a maximum separation distance (Dmax), when the heads (6) of the device (1) are fixed to the fixing pins (4) of the spring (2) and the latter deforms to dampen a movement of the vehicle on which it is mounted.

2. Stop device (1) according to claim 1, characterized in that the connecting element (7) is formed of a strip (8) of elastomeric material connecting the attachment heads (6).

3. Stop device (1) according to claim 2, characterized in that the maximum length (L) of the band (8) under tension defines the maximum separation distance (Dmax).

4. Stop device (1) according to claim 1 or 2, characterized in that each attachment head (6) is designed to surround at least partially a fixing axis (4).

5. Stop device (1) according to any one of claims 1 to 4, characterized in that each attachment head (6) comes from the material with the connecting element (7).

6. Vehicle suspension (3) comprising a leaf spring (2) having two fixing pins (4) for fixing the spring (2) to the vehicle, and several damping leaves (5) extending between the fixing pins (4), the suspension (3) further comprising a device (1) according to any one of claims 1 to 5 fixed to the spring (2), each attachment head (6) being fixed to a fixing pin (4) of the spring (2), the connecting element (7) being designed to deform to allow the fixing pins (4) to move closer together and to limit the separation of the fixing pins (4) to a maximum separation distance (Dmax), corresponding to their separation distance at the end of the suspension (3) stroke.

7. Suspension (3) according to claim 6, in combination with claim 2, characterized in that the band (8) of elastomeric material has a length (L) such that it is taut when the suspension (3) is at the end of its stroke.

8. Motor vehicle comprising at least one suspension (3) according to claim 6 or 7.

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