Lock nut

Abstract

A longitudinal end of the nut has: at least one blocking face forming a means for blocking a rotation of the nut along a longitudinal axis of the nut, and at least one transmission face forming a means for transmitting a force directed along the axis. The blocking face or at least one of the blocking faces and the transmission face or at least one of the transmission faces have at least one common edge, and the blocking face or at least one of the blocking faces is concave.

Claims

1. Nut, wherein one longitudinal end of the nut has: at least one blocking face forming a means for blocking a rotation of the nut along a longitudinal axis of the nut, and at least one transmission face forming a means for transmitting a force directed along the axis, the at least one blocking face and the at least one transmission face having at least one common edge, and the at least one blocking face being concave, the nut comprising at least one groove crossing the at least one blocking face, wherein the at least one groove opens out onto a longitudinal orifice of the nut, wherein the at least one groove forms a bearing surface perpendicular to the axis.

2. Nut according to claim 1, wherein the groove is curved along its length.

3. Nut according to claim 1, wherein a contour of the bearing surface has at least one curved edge.

4. Nut according to claim 1 comprising several grooves, identical to each other.

5. Nut according to claim 4, wherein there are four grooves arranged in a cross pattern in a plane perpendicular to the axis.

6. Nut according to claim 1, wherein another longitudinal end of the nut has at least one other blocking face forming at least one other means for blocking the rotation of the nut with respect to a screw along the longitudinal axis.

7. Brake caliper comprising a nut according to claim 1.

8. Brake caliper according to claim 7 comprising: a piston, a screw, and the screw crossing the nut and the nut being inserted in the piston.

9. Braking device comprising a brake caliper according to claim 7.

10. Nut, wherein one longitudinal end of the nut has: at least one blocking face forming a means for blocking a rotation of the nut along a longitudinal axis of the nut, and at least one transmission face forming a means for transmitting a force directed along the axis, the at least one blocking face and the at least one transmission face having at least one common edge, and the at least one blocking face being concave, the nut comprising at least one groove crossing the at least one blocking face, wherein the at least one groove opens out onto a longitudinal orifice of the nut, wherein the at least one groove forms a bearing surface perpendicular to the axis, the at least one transmission face comprising a spherical part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) We will now describe one embodiment of the invention given as a non-limiting example referring to the attached figures, on which:

(2) FIG. 1 is a perspective view of a nut according to the invention,

(3) FIG. 2 is a front view of the nut,

(4) FIG. 3 is another perspective view of the nut,

(5) FIG. 4 is a cross-sectional view of the nut, a screw and a piston according to the invention,

(6) FIG. 5 is a transverse view of a piston according to the invention,

(7) FIG. 6a is a transverse view of a brake caliper according to the invention.

(8) FIG. 6b is a diagram of the brake caliper comprising a nut, a screw and a piston according to the invention,

(9) FIG. 6c is a diagram of a braking device according to the invention comprising the brake caliper,

(10) FIG. 7 is a cross-sectional view of the piston, and

(11) FIG. 8 is a transverse view of the piston along the plane VII-VII of FIG. 7.

(12) FIG. 9 is a front view of the nut.

MORE DETAILED DESCRIPTION

(13) As shown on FIGS. 1 and 3, the nut 1 comprises two parts: a body C on most of its length and an end head T. The body has an external face having the shape of a straight circular cylinder of longitudinal axis 10. As shown on FIG. 2, the nut is provided with an internal duct 8 opening out at each end 1a and 1b. It is therefore hollow. The duct also has the shape of a straight circular cylinder of longitudinal axis 10.

(14) The end head T comprises several lateral faces 1a.sub.1 and several extremal faces 1a.sub.2.

(15) The lateral faces 1a.sub.1 form an octagon around the axis 10. They can be flat, concave or convex. In this case, half of the faces 1a.sub.1 are flat and the other half are concave according to an alternate arrangement between the flat faces and the concave faces.

(16) The extremal faces 1a.sub.2 form a pyramid with spherical faces of truncated octagonal base of height equal to the longitudinal axis 10. In other words, the extremal faces are partially spherical since they are part of a spherical cap. A spherical cap is in fact a spherical surface formed by the intersection of a sphere and a plane. In this case, the spherical cap forming the extremal faces 1a.sub.2 is formed by the intersection of a sphere whose centre belongs to the axis 10 and the plane containing the edges 12.

(17) The extremal faces 1a.sub.2 are divided into two groups: a first group 1a.sub.21 and a second group 1a.sub.22. The set of extremal faces 1a.sub.2 is partially spherical, however the extremal faces 1a.sub.2 may be concave or convex. In this case, the faces 1a.sub.21 of the first group are concave and the faces 1a.sub.22 of the second group are convex. In the embodiment shown on FIGS. 1 to 3, half of the extremal faces are convex and the other half are concave according to an alternate arrangement between the convex faces and the concave faces. Thus, the faces 1a.sub.22 are hollow unlike the faces 1a.sub.21 which are in relief.

(18) As shown on FIG. 1, the lateral and extremal faces have a common edge 12. In other words, the extremal 1a.sub.2 and lateral 1a.sub.1 faces are adjacent or contiguous. In addition, the flat lateral faces have an edge in common with the convex extremal faces while the concave lateral faces have an edge in common with the concave lateral faces.

(19) The end head T is provided with several grooves 6. The grooves 6 open out onto the orifice forming the end of the duct 8 and each form a bearing surface 14 perpendicular to the axis 10. The grooves 6 are directed longitudinally along a first radius of longitudinal curvature. A radius of curvature of a curve is the radius of the curve osculating circle, also called the circle of curvature. This means that the radius of curvature is the radius of a circle following the curve as closely as possible. In this case, the radius of longitudinal curvature of the groove 6 has the same centre as the radius of curvature of the spherical cap. In addition, this radius is contained in the axis 10. In other words, the circle of curvature of the spherical cap and that of the longitudinal curvature of the groove are homothetic: one is the image of the other according to a homothety having a centre belonging to the axis 10. Furthermore, the grooves 6 are also directed longitudinally along a second radius of lateral curvature.

(20) The number of grooves 6 is arbitrary. In this case, the end head T of the nut comprises four grooves, all identical to each other and arranged in a cross pattern as shown on FIG. 2. Similarly, the radii of longitudinal curvature and the radii of lateral curvature are chosen depending on the circumstances. For example, the grooves 6 may each have identical radii of longitudinal curvature and different radii of lateral curvature, or vice versa. All the radii of curvature may also be identical from one groove to another, whether for the longitudinal curvatures or the lateral curvatures of the grooves 6. Furthermore, the radius of lateral or longitudinal curvature of a groove 6 may also vary along its length.

(21) In this case, the grooves 6 are located on the convex faces 1a.sub.22. In other words, the faces 1a.sub.22 comprise the grooves 6, however, the grooves could be arranged on the concave faces 1a.sub.21. The grooves can be arranged according to other patterns: for example, they may be arranged according to the vertices of a regular polygon. Lastly, the curve defined by the points of the groove 6 having the smallest radial radius with respect to the axis 10 is a straight line according to this embodiment. This curve defines the path of the groove. Its geometry is generally arbitrary.

(22) The other end 1b of the nut 1 comprises a notch 18 in the body C of the nut. The notch has a main face 1b extending in a plane radial to the axis 10.

(23) The nut comprises a thread on the internal face 20 of the duct 8.

(24) As shown on FIG. 4, the nut is intended to receive a screw 3 in the duct 8. In addition, the nut 1 is intended to be inserted in a piston 2. The piston 2 is provided with a longitudinal internal duct 22 and, at one end, longitudinal 22a and extremal 22b internal faces having a common edge 26. The piston duct 22 is cylindrical with a circular cross-section. As shown on FIG. 5, the orifice has a frustoconical shape at the closed end 28 of the piston, located on the right on FIGS. 4 and 5. As shown on FIGS. 5 and 6, the edge of the piston forming the entry of the orifice 22 is provided with an internal chamfer 32 at the other end 30. The screw 3 comprises an external thread adapted to cooperate with the internal thread of the nut 1. It comprises a frustoconical screw head of which an angle at the top of a head generation cone is equal to the angle of inclination of the internal chamfer of the edge of the piston.

(25) As shown on FIG. 4, the screw 3, the nut 1 and the piston 2 are arranged so that the common edge 12 of the lateral 1a.sub.1 and extremal 1a.sub.2 lateral faces is opposite the common edge 26 of the faces 22a and 22b of the piston. Thus, the extremal faces 1a.sub.2 of the nut 1 provide a sphere/cone support between the nut 1 and the piston 2.

(26) In addition, the internal chamfer 32 of the edge of the piston is opposite the screw head 2 since the angles of inclination of the chamfer and of the truncated cone of the screw head are equal.

(27) According to the invention, a brake caliper 16 shown on FIG. 6a receives the screw 3, the nut 1 and the piston 2 in the same configuration as on FIG. 4.

(28) According to the invention, a braking device 4 shown on FIG. 6c comprises the brake caliper 16.

(29) We will now describe the operation of such a nut.

(30) Once the nut 1 is inserted in the piston 2 as shown on FIG. 4, the common edges 34 of the lateral faces 1a.sub.1 prevent the rotation of the nut 1 about the axis 10 relative to the piston 2. The lateral faces form a means of blocking the rotation of the nut 1 about the axis 10. The lateral faces 1a.sub.1 are therefore blocking faces. This blocking connects the piston 2 and the nut 1 together.

(31) Thus, the rotation of the screw 3 relative to the caliper moves the nut 1 due to the shape complementarity between the external thread of the screw 3 and the internal thread of the nut 1. Since the nut 1 is connected to the piston 2, its translation causes the translation of the piston 2 by means of the extremal faces 1a.sub.2. The extremal faces 1a.sub.2 therefore form means for transmitting a linear force along the axis 10. This force transmission allows the transmission of a linear movement along the axis 10: the linear movement of the nut 1 along the axis 10 causes the linear movement of the piston 2 along the axis 10.

(32) The grooves 6 form passages. They therefore favor the flow of brake fluid inside the piston.

(33) We will now describe the advantages provided by the nut 1.

(34) Since the transmission faces 1a.sub.2 and the blocking faces 1a.sub.1 have a common edge 12, the nut is smaller. For example, an outer diameter of the square of the nut is 26.05 mm instead of 29.65 mm. A length of an outer square 36, shown on FIG. 9, of the nut is 23.05 mm (variation of 0.15 mm) instead of 26.65 mm (variation of 0.15 mm). The outer square is defined as being the square formed by the intersection, in a plane orthogonal to the axis 10, of straight lines tangential to the flat faces 1a.sub.1, as shown on FIG. 9.

(35) Such a nut therefore adapts to pistons of smaller dimensions. For example, a diameter of the bearing area between the means for blocking the rotation of the nut 1, in this case the lateral faces 1a1, and the piston 2 is 26 mm instead of 28 mm. Due to this space saving, the inner diameter of the piston square is 28.5 mm (possible variation of 0.2 mm) instead of 32.1 mm (same variation). Similarly, the diameter of the nut/piston bearing cone is 16.2 mm instead of 19.8 mm. Lastly, the diameter of the nut sphere formed by the extremal faces 1a.sub.2 is 16.2 mm instead of 19.8 mm.

(36) Such a nut can be used with a smaller screw and piston without having to modify their geometries.

(37) The nut is easier to machine. Since there is no collar, the number of manufacturing steps is reduced. In addition, the bearing areas 14 formed by the grooves make the nut easier to machine since they cooperate more easily with machining claws. Lastly, they allow manufacture using a stamping method.

(38) The invention is not limited to the embodiments described and other embodiments will be clearly apparent to those skilled in the art. 1—nut 1a—end of the nut 1a.sub.1—lateral faces of the end head of the nut 1a.sub.2—extremal faces of the end head of the nut 1a.sub.21—concave extremal faces 1a.sub.22—convex extremal faces 1b—other end of the nut 1b.sub.1—face of the notch at the other end of the nut 2—piston 3—screw 4—braking device 6—groove 8—longitudinal orifice of the nut 10—longitudinal axis of the nut 12—common edge of the lateral and extremal faces of the nut 14—bearing area 16—brake caliper 18—notch 20—face of the internal orifice of the nut 22—longitudinal orifice of the piston 22a—longitudinal faces of the longitudinal orifice of the piston 22b—extremal faces of the longitudinal orifice of the piston 24—contour of the bearing area 26—common edge of the longitudinal and extremal faces of the piston 28—closed end of the piston 30—open end of the piston 32—internal chamfer of the edge of the piston 34—common edge of the lateral faces of the end head of the nut 36—outer square of the nut C—body of the nut T—end head of the nut