Clamping nut equipped with at least one anti-loosening locking tab

Abstract

The invention relates to a nut (200) intended to be screwed onto a threaded shaft (310) and comprising a main screwing body (210) having a threaded cylindrical bore designed to receive said threaded shaft (310) during the tightening of said nut (200); characterized in that it also comprises at least one elastically deformable locking tab (230) comprising a stop section (231) fixedly connected to said main screwing body (210) and projecting inside said threaded bore, said stop section (231) of each locking tab (230) being configured to be elastically folded by said threaded shaft (310) during the tightening phase so as to slide along the latter, and to insert at the end of the tightening process into an annular groove (311) formed in this threaded shaft (310) so as to prevent any Loosening the nut (200). Figure to be published with the abbreviation: Fig. 3C

Description

Title of the invention: Clamping nut equipped with at least one anti-loosening locking tab technical field

[0001] The present invention relates to the problem of loosening a nut intended to be screwed onto a threaded shaft in order to assemble by tightening this nut a first part to a second part. Previous technique

[0002] Such a nut classically comprises a main screwing body having a threaded cylindrical bore intended to receive the threaded shaft.

[0003] The use of locking means for such a nut on this threaded shaft to prevent it from loosening is often required, particularly when the assembly is subject to vibrations, as is the case, for example, with assemblies of motor vehicle wheel hubs on their axle spindle.

[0004] It is known for example to use a pin passing through two holes arranged diametrically opposite in the nut as well as a diametrical hole made in the threaded axis, so as to prevent any axial movement or rotation of this nut around this threaded axis, and thus its loosening.

[0005] Such a nut locking device is simple and effective, but has the disadvantage of requiring a significant amount of space around the threaded shaft. Indeed, there must be no obstruction within a radius at least equal to the height of the pin from the surface of the threaded shaft, so as to allow its insertion into the bore of the threaded shaft.

[0006] In some cases, the shape of the wheel hub is such that, once it is positioned on its respective axle spindle, the end of the threaded shaft of the latter is located inside a cylindrical cavity whose diameter is not sufficient to allow the mounting of a pin.

[0007] Moreover, the use of such locking pins generates a significant additional cost.

[0008] Other known solutions exist to prevent the nut from loosening over time.

[0009] One of these methods consists of achieving a locking effect by peening, through an operation in which at least one area of ​​the nut is plastically deformed in a localized manner, without crushing the material, in order to prevent its rotation. For this purpose, the threaded shaft of the spindle is provided with at least one axial groove, while the nut is provided with a kind of skirt that is peened opposite this groove.

[0010] This peening is carried out manually with a hammer, chisel, and punch, that is, with means likely to cause violent shocks and significant mechanical stresses on the axle stub. These shocks and mechanical stresses can have very damaging consequences for vehicle safety.

[0011] To limit these mechanical stresses, it is also known from document FR 2 957 991 to use a crimping tool comprising two articulated arms, each having a jaw at one end and a handle at the other. This tool also includes a guide sleeve located at its front end, designed to "cap" the skirt of the nut in order to position the tool on the nut-type component. This guide sleeve includes two radial openings for the passage of the two jaws.

[0012] Nevertheless, these peening operations waste valuable time on the vehicle assembly line (on the order of 30 seconds per nut, or 2 minutes per vehicle).

[0013] Furthermore, such peening greatly complicates dismantling operations during after-sales service, for example when replacing the driveshaft. Operators must manually straighten the nut skirts before they can be loosened, which can be a lengthy and tedious process. Description of the invention

[0014] The present invention therefore aims to improve the situation.

[0015] For this purpose, it provides a nut intended to be screwed onto a threaded shaft and comprising a main screwing body having a threaded cylindrical bore intended to accommodate said threaded shaft when screwing said nut; characterized in that it also comprises at least one elastically deformable locking tab including a stop section fixedly connected to said main screwing body and projecting inside said tapped bore, said stop section of each locking tab being configured to be elastically folded by said threaded shaft during the face phase so as to slide along the latter, and to come to be inserted at the end of screwing into an annular groove formed in this threaded shaft so as to prevent any loosening of the nut.

[0016] The presence of at least one such locking tab thus prevents the nut from loosening over time.

[0017] The invention also has the advantage of not requiring the use of any additional parts such as pins or other components, which reduces assembly time and contributes to cost reduction.

[0018] According to preferred characteristics of said nut according to the invention: - said stop section of each locking tab is configured so that, when folded, it fits entirely into a respective housing provided in said main screw body; - each said housing extends radially from said tapped bore and opens onto the outer face of said main body, each said locking tab also comprising a gripping section rooted at the inner end of said stop section and radially passing through a corresponding said housing; - the free end of said gripping section of each said protruding tab on the outer face of said main screwing body has an opening intended to allow its hooking; - each said housing, with an L-shaped cross-section, comprises an axial part opening onto said tapped bore and intended to house said stop section of a corresponding locking tab during the screwing phase, as well as a radial part opening onto the outer face of said main body; - said stop section of each said locking tab is fixedly connected to said main screwing body, at the level of the distal axial end of the axial part of a said corresponding housing, and extends diagonally radially towards the axis of said tapped bore and axially in the opposite direction of screwing; - each said locking tab is made by cutting and folding from a sheet of metal sheet; - the stopping section of each said locking tab is fixedly connected to said main screw body by welding; and / or - said nut includes several said locking tabs regularly distributed around the axis of said tapped bore.

[0019] The invention also relates, in a second aspect, to a screwing device comprising a threaded shaft having an annular groove and such a clamping nut. Brief description of the drawings

[0020] The description of the invention will now be continued by a detailed description of an example embodiment, given below by way of illustration but not limitation, with reference to the accompanying drawings, on which: - [Fig.1] represents a partial cross-sectional view of a wheel hub assembled on an axle spindle of a motor vehicle by means of a nut according to the invention screwed onto a threaded shaft of this spindle, said nut being locked by means of two anti-loosening devices according to the invention; - [Fig. 2] is a partial cross-sectional and perspective view of a nut according to the invention; and - [Fig.3A], [Fig.3B] and [Fig.3C] illustrate the steps of screwing a nut according to the invention onto the threaded shaft of the rocket. Description of the implementation methods

[0021] The [Fig. 1] is a partial cross-sectional view of a wheel hub 100 held by a nut 200 according to the invention screwed onto an end forming a threaded shaft 310 of a motor vehicle axle spindle 300.

[0022] As previously explained, to prevent this nut 200 from loosening over time, it is necessary to lock it against rotation on the axle spindle 300.

[0023] As illustrated by [Fig.2], the nut 200 conventionally comprises a main metal screwing body 210 having a threaded cylindrical bore 211 intended to receive the threaded shaft 310 of the axle spindle 300 when screwing this nut 200.

[0024] The nut 200 also advantageously comprises at its entry end, by which it comes to the free end of the threaded shaft 310, an annular collar forming a support base 220 and made of a single piece of metal with the main body 210.

[0025] The outer face 212 of the screw body 210 has on at least a portion of this body 210 a hexagonal shape allowing the nut 200 to be tightened using a suitable tool such as a wrench.

[0026] According to the invention, the nut 200 also includes at least one elastically deformable locking tab 230 comprising a stop section 231 fixedly connected to the main screwing body 210 and radially projecting inside the tapped bore 211.

[0027] In order to ensure optimal locking, this nut 200 will advantageously include several locking tabs regularly distributed around the axis of the tapped bore 211 of the main screw body 210.

[0028] In the embodiment illustrated by the figures, this nut 200 comprises in this case two tabs 230 arranged diametrically opposite to the tapped bore 211.

[0029] Advantageously made by cutting and bending from a sheet of metal preferably with a thickness between 0.3 and 0.5 millimeters, each tab 230 is partially housed in a respective through-hole 213 provided in the main screw body 210 and extending radially between its outer face 212 and the tapped bore 211.

[0030] Having an L-shaped cross-section, each housing 213 extends radially from the tapped bore 211 and opens onto the outer face 212 of the main body 210. More specifically, each of the housings 213 comprises an axial portion 213A giving on this tapped bore 211 and a radial part 213B opening onto this outer face 212 of the main body 210.

[0031] Fixedly connected by welding to the main screw body 210, at the level of the distal axial end (i.e. opposite the radial part 213B) of the axial part 213A of the corresponding housing 213, the stop section 231 of each locking tab 230 extends diagonally radially towards the axis of the tapped bore 211 and axially in the opposite direction of screwing.

[0032] Presenting in this case a section a shape of 7, each locking tab 230 also includes a gripping section 232 taking root at the inner end of the stop section 231 (that located housed inside the tapped bore 211) and radially passing through the corresponding housing 213.

[0033] As illustrated in this [Fig.2], the free end of this gripping section 232 protruding from the outer face 212 of the main screwing body 210 has an orifice 233 intended to ensure its hooking by a suitable tool not shown in order to allow the unlocking of the nut 200 as will be seen later.

[0034] Figures 3A, 3B and 3C illustrate the successive steps of screwing the nut 200 according to the invention onto the threaded shaft 310 of the axle spindle 300 after the positioning of the wheel hub 100.

[0035] Initially the operator presents the nut 200 by its entry end consisting of the annular collar 220 opposite the free end of the threaded shaft 310, then begins by screwing it onto the latter so as to cause the axial displacement of this nut 200 along this threaded shaft 310 as illustrated by [Fig.3A].

[0036] This first screwing step is carried out without resistance effort until the free end of this threaded shaft 310 comes simultaneously into contact with the stop sections 231 of the locking tabs 230.

[0037] The continued screwing of the nut 200 onto the threaded shaft 310 using a tightening tool such as a wrench will then cause the elastic pivoting folding of the stop sections 231, pushed by the free end of this threaded shaft 310, and which will come to fit entirely inside the axial parts 213A of the corresponding housings 213 as illustrated by [Fig.3B].

[0038] It will be noted with reference to this [Fig.3B] that this folding of the stop sections 231 will cause a slight lifting and a slanted inclination in the direction of screwing of the gripping sections 232. It will also be noted, again with reference to this [Fig.3B], that the axial depth of the radial part 213A of the housings 213 will be determined so as to be sufficient so as not to hinder the movement of the locking tabs 230.

[0039] After folding the stop sections 231, the operator must continue to screw the nut 200 onto the threaded shaft 310, until these stop sections 231 slide along of this threaded axis 310 come to position themselves, at the end of screwing, opposite an annular groove 311 made on the latter, which automatically causes them to return to their initial position, so that these stop sections 231 now fit partially inside this groove 311, preventing any loosening of this nut 200 (see [Fig.3C]).

[0040] It will be noted with reference to this [Fig.3C], that the operator will be able to visualize this return of the locking tabs 230 to the rest position signifying the attainment of the adequate tightening, thanks to the radial repositioning of the gripping sections 232.

[0041] The positioning of the groove 311 on the threaded shaft 310 will thus be determined according to the desired tightening torque.

[0042] In the event of needing to dismantle the wheel hub 100 in after-sales service, for example when replacing the drive shaft, the operator shall subject the locking tabs 230 to a radial tensile force directed outwards from the nut 200, in order to cause their stop sections 231 to fold back into the axial parts 213B of the corresponding housings 213, so as to allow the unscrewing of this nut 200.

[0043] To do this, this operator will use for example a tool comprising articulated arms equipped at their ends with hooks intended to be inserted into the holes 233 of these locking tabs 230.

[0044] According to alternative embodiments not shown, the locking tab(s) could be connected to the axial output end of the main screw body of the nut, thus avoiding the need to provide recesses such as 213 for these tabs in the main screw body. However, these tabs would be less well protected from external impacts, which could lead to their deformation and an increased risk of accidental loosening of the nut.

[0045] Many variants are conceivable and it is recalled in this regard that the present invention is not limited to the embodiments described and represented, but also encompasses all variants of execution within the reach of a person skilled in the art.

[0046] The invention could also find its application in fields other than automobiles.

Claims

1. Demands Nut (200) intended to be screwed onto a threaded shaft (310) and comprising a main screwing body (210) having a threaded cylindrical bore (211) provided to receive said threaded shaft (310) when screwing said nut (200); said nut also comprising at least one elastically deformable locking tab (230) comprising a stop section (231) fixedly connected to said main screwing body (210) and projecting inside said tapped bore (211), said stop section (231) of each locking tab (230) being configured to be elastically folded by said threaded shaft (310) during the screwing phase so as to slide along the latter, and to come to be inserted at the end of screwing into an annular groove (311) provided in this threaded shaft (310) so as to prevent any loosening of the nut (200); said nut being characterized in that said stop section (231) of each locking tab (230) is configured so as to fit entirely, when folded, into a respective recess (213) formed in said main screw body (210), in that each said recess (213) extends radially from said tapped bore (211) and opens onto the outer face (212) of said main body (210), each said locking tab (230) also comprising a gripping section (232) originating at the inner end of said stop section (231) and radially passing through a corresponding recess (213), in that each said recess (213), having an L-shaped cross-section, comprises an axial portion (213A) opening onto said tapped bore (211) and intended to house said stop section (231) of said tab corresponding locking (230) during the screwing phase,as well as a radial portion (213B) opening onto the outer face (212) of said main body (210), and in that said stop section (231) of each said locking tab (230) is fixedly connected to said main screw body (210), at the level of the distal axial end of the axial portion (213A) of a said corresponding housing (213), and extends diagonally radially towards the axis of said tapped bore (211) and axially in the opposite direction to the screwing direction.

2. Nut (200) according to claim 1, characterized in that the free end of said gripping section (231) of each said tab (230) projecting from the outer face of said main screwing body (210) has an orifice (233) intended to allow its hooking.

3. Nut (200) according to any one of claims 1 or 2, characterized in that each said locking tab (230) is made by cutting and bending from a sheet of metal.

4. Nut (200) according to any one of claims 1 to 3, characterized in that the stop section (231) of each said locking tab (230) is fixedly connected to said main screwing body (210) by welding.

5. Nut (200) according to any one of claims 1 to 4, characterized in that it comprises several said locking tabs (230) regularly distributed around the axis of said tapped bore (211).

6. Screwing device comprising a threaded shaft (310) having an annular groove (311) and a clamping nut (200) according to any one of claims 1 to 5.

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