FR2968050A1 - Transmission joint for use in control apparatus for transmission of rotary motion between two non-aligned convergent shafts in aircraft, has rings, and outer surface of spherical form is mounted within concave housing of associated cover - Google Patents

Abstract

The joint has a brace (50) that is provided with four pivots (54). A set of covers (24) is connected by the brace. Each of the covers is provided with two cylindrical bores (34) that are arranged longitudinally in a direction of the pivots. A set of assembly rings (66) is provided radially between one of the pivots and the associated cover. The rings are provided with a boring (68) for forming path for a sliding bearing (60). An outer surface of spherical form is mounted within a concave housing (76) of the associated cover. An independent claim is also included for a control apparatus comprising a lever.

Description

B 10-2986EN 1 Universal transmission joint. The present invention relates to the field of universal transmission joints, conventionally called cardan joints, allowing in particular the transmission of a rotational movement between two non-aligned concurrent shafts. The present invention relates more particularly to a transmission joint of the type comprising a spider provided with four journals and two clevises each rotatably mounted on two opposite journals. A particularly interesting use of the invention relates to the mechanical transmission of the flight controls of an aircraft. Another interesting use of the invention may relate to the automotive field.

In this field, patent US-B2-6,520,859 discloses a transmission joint comprising a spider with four journals, cups or sleeves mounted on the journals, and plain bearings each mounted radially between one of the journals and the associated socket so to allow a relative rotational movement between these two elements. The transmission joint also comprises two clevises each provided with two bores adapted to receive the sleeves mounted on two opposite journals of the spider. The assembly of the transmission joint described in this document can be difficult to achieve given the misalignment that may exist between the axis of the bores of a yoke and the axis of the spigot journals. The bores of the screed may also not be perfectly coaxial. The present invention aims to remedy these disadvantages. More particularly, the present invention aims to provide an economical transmission joint, easy to manufacture and can accommodate the manufacturing defects of the various parts constituting it to facilitate assembly. In one embodiment, the transmission joint comprises a spider provided with four pins, two yokes interconnected by said spider and each comprising two bores arranged longitudinally in the direction of two opposite journals of the spider for mounting said journals, and bearings each mounted on one of the journals to allow relative rotational movement between each clevis and the two associated journals. The transmission joint further comprises mounting rings each arranged radially between one of the journals and the associated yoke. The rings are each provided with a bore or inner surface forming a raceway or sliding for the associated bearing and an outer surface of generally spherical shape mounted inside a concave housing of the associated yoke. During the assembly of the transmission joint, each mounting ring is angularly or pivotally movable relative to the associated yoke so that the axis of said ring and the axis of rotation of the trunnion can be tilted angularly relative to the axis of the associated bore of the screed. Thus, the swiveling capacity of the mounting rings makes it possible to accommodate, during assembly of the joint, manufacturing defects in the elements constituting it, and in particular the angular misalignment that may exist between the axis of the bores of a clevis and the axis of the two associated pins of the spider. After assembly, the mounting rings are fixed relative to the associated screeds. In one embodiment, the housings receiving the mounting rings are formed at least in part by the bores of the yokes.

The transmission joint may also comprise four covers each mounted in one of the bores of the yokes and delimiting at least in part the housing receiving the associated mounting ring. Advantageously, the covers comprise means for axially retaining the mounting rings relative to the yokes.

In one embodiment, each cover comprises a thread cooperating with the corresponding threaded portion of the associated bore of the yoke. In one embodiment, each cover comprises radially elastic rings bearing against the associated mounting ring and adapted to exert an axial force on said ring. The elastic rings are preferably mounted radially between the associated mounting ring and the cover. The covers can close an axial end of the associated bore of the yoke so as to form sealing caps. In one embodiment, the outer surface of each mounting ring comprises a coating adapted to limit sliding with the associated housing of the yoke. The bearings may include a plurality of rolling elements.

The invention also relates to an aircraft flight control device comprising a housing, a control lever movable relative to the housing, a transmission shaft connected to said lever and a transmission joint as defined above, in which one of the clevises is attached to the drive shaft and the other clevis is mounted on the housing. The present invention will be better understood on studying the detailed description of embodiments taken as non-limiting examples and illustrated by the appended drawings, in which: FIG. 1 is a schematic perspective view of a device FIGS. 2 and 3 are perspective views of clevises of a transmission joint of the device of FIG. 1; FIG. 4 is a sectional view of an assembly of FIG. connecting the transmission joint used in the device of Figure 1, - Figures 5 and 6 are partial sectional views of the transmission joint of Figures 2 to 4, and - Figures 7 to 12 are partial sectional views. transmission joints according to other embodiments. FIG. 1 is a diagrammatic illustration of an aircraft flight control device 10 comprising a control box 12 and a control lever 14 movable relative to the box about a roll axis 16 and a pitch axis. 18 to allow control of the rudder of the aircraft. The roll 16 and pitch 18 axes are perpendicular.

To ensure the mechanical transmission of the movement of the control lever 14, a transmission joint illustrated in FIGS. 2 to 4 is mounted inside the housing 12. The transmission joint comprises a first yoke 22 (FIG. 2) intended to be mounted on the control box, a second yoke 24 (FIG. 3) fixed to a transmission shaft (not shown) connected to the control lever and a connection assembly 26 (FIG. 4) mounted between the yokes so as to allow a swiveling of the yoke 24 relative to the yoke 22. As illustrated in Figure 3, the yoke 24 comprises a tubular base 28 provided with a bore 28a to allow mounting of the transmission shaft and two arms 30, 32 opposite s' extending from said base. Each arm 30, 32 comprises a cylindrical recess or bore 34, 36 arranged longitudinally along the roll axis 16. Referring now to FIG. 2, the yoke 22 comprises a cylindrical portion 40 enclosing inside which is intended to be mounted in part the yoke 24 and comprising two cylindrical recesses or bores 42, 44 extending along the pitch axis 18. At an upper axial end of the cylindrical portion 40 is provided a flat portion 46.

As illustrated in FIG. 4, the connection assembly 26 comprises a spider 50 provided with a central body 52 of generally cubic shape and four trunnion shafts 54, with an axis 56 extending outwards. from said body being circumferentially equally spaced. The journals 54 are arranged in a single plane and at right angles to each other. An annular radial shoulder 58 is formed between each trunnion 54 and the central body 52. In the illustrated embodiment, the trunnions 56 are made in one piece with the central body 52. In a variant, it is possible to provide journals on a body central. The link assembly 26 also comprises rolling bearings 60 each mounted on an outer cylindrical surface 62 of one of the journals 54 and identical to each other. Each rolling bearing 60 comprises rolling elements 64 constituted by a row of needles in the exemplary embodiment illustrated. The outer cylindrical surface 62 of each trunnion 54 forms a cylindrical track or raceway for the rolling elements 64 of the associated rolling bearing. An axial end of the row of rolling elements 64 is located axially in the vicinity of the shoulder 58 of the associated pin while remaining at a distance therefrom. The other axial end of the row of rolling elements 64 remains axially recessed with respect to an end surface 54a of the associated pin 54.

The connection assembly 26 further comprises a mounting ring 66 arranged radially around each pin 16 and provided with a cylindrical and concentric bore 62 with an outer cylindrical surface 62 of the associated pin 16. The bore 68 has an inside diameter greater than the outside diameter of said surface so as to leave between them an annular radial space inside which is mounted the rolling bearing 60. The bore 68 forms a track or raceway cylindrical for the rolling elements 64 of the rolling bearing. The bore 68 also allows the ring 66 to be centered on an outer cylindrical surface 70 of the central body 52 extending the large-diameter edge of the shoulder 58 axially on the opposite side to the cylindrical surface 62. In this embodiment the bore 68 is non-through or blind. An axial space 72 is provided between the axial end of the journal 54 and the ring 66. Each mounting ring 66 comprises a convex outer surface 74 delimiting a portion of a sphere whose center coincides with the axis 56 of the journal and in contact with a concave housing complementary to the associated screed as will be described in more detail later. The four mounting rings 66 are identical to each other.

5 illustrates in section the mounting of the ring 66 in the bore 34 formed at the arm 30 of the yoke 24. In the bore 34 is formed a concave housing 76 in shape matching and in contact with the outer surface 74 of the ring 66. The housing 76 opens at the outer end face of the arm 30. The mounting ring 66 is disposed within the housing 76 being introduced from the outside. The pin 54 is then mounted inside the ring 66 so as to contact the row of rolling elements 64 with the bore 68. FIG. 5 illustrates a mounting position in which the axis 16 of the bore 34 is coaxial with the axis 56 of the journal and the mounting ring 66. However, during the mounting of the ring 66 on the yoke 24, there may be an angular misalignment between the axis 16 of the bore 34 and the axis 56 of the pin in view of the machining operations of the spider 50 and the clevis 24. In this case, as shown in Figure 6, the housing 76 allows the angular tilting of the ring 66 and the pin 54 relative to the axis 16 of the bore 34 of the yoke so that the axis 56 of the pin is misaligned with respect to the axis of the bore. In Figure 6, the axis 56 is misaligned angularly with respect to the axis 16 in the counterclockwise direction while remaining in the same radial plane. Of course, a tilting of the ring 66 and the pin 54 can also occur in the clockwise direction. The angular tilting of the axis 56 relative to the axis 16 is for example less than 10 °. The ring 66 mounted in the housing 76 complementary can rotate inside thereof. The swiveling ability of the ring 66 relative to the arm 30, and more generally relative to the yoke 24, angularly aligns the axis 56 of the pin 54 and the axis of the ring 66 and accommodate misalignment angular between the axis 56 and the axis 16. The outer surface of each mounting ring 66 may comprise a coating capable of limiting sliding with the associated housing 76 of the yoke, for example a coating comprising PTFE. In the illustrated embodiment, the axial retention of the ring 66 relative to the arm 30 is obtained by a crimping operation performed on the side of the outer end face of the arm 30 so as to obtain local embossings 78 of material axially locking the As a variant, the axial retention of the ring 66 on the yoke 24 could be achieved by other means, for example by welding, gluing, etc. The mounting and retention of the other rings 66 of the spider 50 are made identically to those just described. The embodiment illustrated in FIG. 7, in which the identical elements bear the same references, differs from the previously described embodiment in that the axial retention of the mounting ring 66 relative to the arm 30 of the yoke is achieved by a washer 80 fixed at the end of the housing 76 located on the side of the outer end face of the arm 30. The washer 80 is fixed in the housing 76 by any suitable means, for example by welding, gluing, etc.. The washer 80 bears against the ring 66 and is shaped so as to fit a part of said ring. The washer 80 may advantageously be made of a material having a low coefficient of friction, for example polyamide loaded or not with mineral fibers. In this embodiment, the bore 68 of the mounting ring 66 is through. The washer 80 also has the function of avoiding the intrusion of polluting particles at the bore 68 of the ring 66. The embodiment illustrated in FIG. 8, in which the identical elements bear the same references, differs of the embodiment described above in that the axial retention of the mounting ring 66 relative to the arm 30 of the yoke is formed by a threaded cap 82 which is screwed into the bore 34 on the side of the outer end face of the arm 30 In this embodiment, the bore 34 has a generally stepped shape and comprises a threaded portion 34a cooperating with a corresponding thread of the cap 82, a frustoconical portion 34b extending from the inner end face of the arm and flaring outward, and an annular groove 34c connecting said portions. The cover 82 comprises a bore 82a of generally frustoconical shape and symmetrical with respect to the frustoconical portion 34b of the bore 34 while considering a median plane of the arm 30. The bore 82a and the frustoconical portion 34b jointly delimit a concave recess at inside which the ring 66 is mounted. In view of the spherical shape of the outer surface 74 of the ring 66 and the shape of the associated housing, the support between the ring and the arm 30 of the clevis level of four points of contact. The cap 82 closes the axial end of the bore 34 located on the outer side so as to avoid the intrusion of polluting particles at the bore 68 and the rolling elements 64 of the bearing. In the embodiment illustrated in FIG. 9, in which the identical elements bear the same references, an annular bush or cover 84 is mounted in the bore 34 of the arm 30 and delimits a concave housing 86 in concordance of shape and in contact with each other. with the outer surface 74 of the mounting ring 66. The cover 84 is arranged radially between the ring 66 and the bore 34. A washer 88 for stopping and friction is fixed in a groove (not referenced) of the bore 34 located on the side of the outer end face of the arm 30. The washer 88 may advantageously be made of a material having a low coefficient of friction, for example of polyamide which may or may not be filled with mineral fibers. The washer 88 makes it possible to prevent the intrusion of polluting particles at the bore 68. Axially on the side opposite to the washer 88, the bore 34 comprises an annular bead 89 extending radially inwards and forming a stop The embodiment illustrated in FIG. 10, in which the identical elements bear the same references, differs from the embodiment previously described in that the cap 84 has a larger radial dimension and comprises, in its bore, a protective element 90 provided with axial tabs 92 connected to a cap 94 of spherical connection to prevent the outer side of the arm 30 the intrusion of polluting particles at the bore 68 of the ring 66. axial grooves 96 are formed in the bore of the cover 84 and grooves 97 are provided on the outer surface 74 of the ring 66 to allow the mounting of the tabs 92 radially between the ring and the cover 84. Each lug 92 comprises, axially opposite the cap 94, a tongue 98 folded radially outwardly and bearing against the inner end face of the arm 30 so as to obtain the restraint. axial of the protection element 90 relative to said arm. The cover 84 may advantageously be manufactured by cutting a sheet metal tube. In the embodiment illustrated in FIG. 11, in which the identical elements bear the same references, a cover 100, mounted in the cylindrical bore 34 of the arm 30, comprises a tubular portion 102 and a spherical cap 104 extending axially one end. of the tubular portion 102. Said portion and the cap 104 together delimit a concave housing 106 concordance of shape and in contact with the outer surface 74 of the mounting ring 66. The cover 100 closes the axial end of the bore 34 located on the outside so as to avoid the intrusion of polluting particles at the bore 68 of the mounting ring. Cutouts 108 having a generally U-shaped shape are formed in the tubular portion 102 axially on the side opposite to the cap 104.

The cutouts 108 delimit tongues 110 extending obliquely outwards and coming to be housed in a radial groove 112 formed in the bore 34 of the arm 30. The tongues 110 bear against a lateral edge of the groove 112 and prohibit any axial displacement towards the outside of the cover 100 relative to the arm 30 by buttressing. The tubular portion 102 also includes protuberances 114 extending radially inwardly and provided to provide axial retention of the mounting ring 66 within the cover 100. The tabs 110 and the protuberances 114 are located substantially in a manner. same radial plane.

The cover 100 may advantageously be manufactured by cutting a sheet metal tube. In the embodiment illustrated in FIG. 12, in which the identical elements bear the same references, a cover 115, mounted in the cylindrical bore 34 of the arm 30, comprises a tubular portion 116 closed axially on the side of the outer front face. of the arm 30 by a radial bottom wall 118. The cover 115 comprises, axially opposite the bottom wall 118, tabs 120 folded radially outwardly and bearing against the inner end face of the arm 30 so as to obtain the axial retention of the cover relative to said arm . The cover 115 closes the axial end of the bore 34 located on the outside so as to prevent the intrusion of polluting particles at the bore 68 of the mounting ring. The cover 115 may advantageously be manufactured by cutting a sheet metal tube. Elastic rings 122, 124 in the form of annular rings are interposed radially between the outer surface 74 of the mounting ring 66 and the bore of the tubular portion 116 of the cap coming into contact with said outer surface and said bore. The elastic rings 122, 124 may for example be made of rubber. The elastic rings 122, 124 are axially spaced relative to one another. The elastic ring 122 is mounted axially in abutment against the bottom wall 118 of the cover. The elastic ring 124 is retained axially by tabs 126 of the bonnet folded radially inwards. The tabs 126 are arranged in the same radial plane as the tongues 120. Each elastic ring 122, 124 comprises a recess 122a, 124a having a cross section in the form of an arc of a circle of radius substantially equal to that of the outer surface 74 of the mounting ring 66. The recesses 122a, 124a delimit a concave housing for receiving the ring 66. Each elastic ring 122, 124 exerts a permanent prestress or preload force on the outer surface 74 of the ring 66 comprising axial and radial components. Thanks to the invention, it has a transmission joint comprising mounting rings of generally spherical shape mounted in corresponding housings provided on the yokes so as to form a ball joint that can, when mounting, accommodate the defects of angular alignment of the axis of articulation of the yokes and the axis of rotation of the associated journals of the spider.

Claims (11)

REVENDICATIONS1. Transmission joint comprising a spider (50) provided with four pins (54), two yokes (24, 22) interconnected by said spider and each comprising two bores (34, 36, 42, 44) arranged longitudinally in the direction of two opposite journals of the spider for mounting said journals, and bearings (60) each mounted on one of the journals to allow a relative rotational movement between each screed and the two associated journals, characterized in that it further comprises rings mounting (66) each arranged radially between one of the journals and the associated yoke, said rings being provided with a bore (68) forming a race or slide for the associated bearing (60) and an outer surface (74). ) of spherical general shape mounted within a concave housing (76) of the associated screed. 2. Transmission joint according to claim 1, wherein the housings receiving the mounting rings are formed at least in part by the bores of the yokes. 3. Transmission joint according to claim 1 or 2, comprising four covers (82; 84; 100; 115) each mounted in one of the bores of the yokes and defining at least in part the housing receiving the associated mounting ring. 4. Transmission joint according to claim 3, wherein the covers comprise means for axially retaining the mounting rings relative to the yokes. 5. Transmission joint according to claim 3 or 4, wherein each cap (82) comprises a thread cooperating with a threaded portion (34a) corresponding to the associated bore of the yoke. 6. Transmission joint according to claim 3 or 4, wherein each cover comprises radially elastic rings (122, 124) bearing against the associated mounting ring and adapted to exert at least one axial force on said ring. 7. Transmission joint according to claim 6, wherein the elastic rings are mounted radially between the associated mounting ring and the cover. 8. Transmission joint according to any one of claims 3 to 7, wherein the covers (82; 100; 115) seal an axial end of the associated bore of the yoke. 9. Transmission joint according to any one of the preceding claims, wherein the outer surface of each mounting ring comprises a coating adapted to limit sliding with the associated housing of the yoke. Transmission joint according to any one of the preceding claims, wherein the bearings (60) comprise a plurality of rolling elements (64). Aircraft flight control device comprising a housing (12), a lever (14) movable relative to the housing, a transmission shaft connected to said lever and a transmission joint according to any one of the preceding claims, in which one of the yokes is fixed to the transmission shaft and the other yoke is mounted on the housing.