Assembly having a splined shaft and splined hubs

Abstract

The invention relates to an assembly having a mechanical shaft (2) comprising two splined ends (4) and two splined hubs (6), each hub (6) being formed of at least two half-shells, the two splined ends (4) comprising at least eight splines, the splined ends (4) having a cross-section that is shaped in such a way as to allow the shaft (2) to be disengaged from a half-shell in a direction perpendicular to a longitudinal axis (X) of the shaft (2).

Description

[0001] Description Title of the invention: Assembly of a splined shaft and splined hubs

[0002] The invention relates to an assembly formed by a shaft and hubs, and more precisely to an assembly of a shaft and splined hubs.

[0003] It is recalled that a shaft (transmission or return) is a mechanical component transmitting power in the form of torque and rotational movement. It is generally made from forged blanks then machined by turning. Extrusion is also a common method for obtaining this type of part. The manufacturing processes for shafts and the materials forming them are chosen in order to obtain parts with the best possible mechanical resistance, taking into account the forces undergone by the shafts during power transmission.

[0004] The ends of the shafts can be mounted in hubs to enable the power transmission described above. The shafts can, for example, be used in assemblies comprising several shafts connected to each other by hubs. The hubs are clamped against the ends of the shafts to enable power transmission through the shaft.

[0005] It is known to lock a rotating shaft in a hub by using keys inserted into two grooves made at the hub (for example formed by two half-shells) and the shaft, the grooves being placed opposite each other to lock the shaft relative to the hub by means of a key. Power transmission is then carried out by the keys. However, and because of the mounting clearance of the keys placed at the interface between the shaft and the hub, a phenomenon of matting is observed. This leads to fatigue of the materials. We therefore observe the appearance of clearances, misalignments and breakages.

[0006] The use of keys does not allow, due to the presence of assembly clearances, a perfect alignment of the shaft and hubs by simple assembly, a fortiori when multiplying the shafts and therefore the keys. This would increase the risk of breakage and it is therefore necessary to adjust this alignment manually by tightening the hub screws located on either side of the key. Tightening a screw allows the shaft to turn in one direction or another depending on the position of the screw in relation to the key (left or right). This alignment adjustment process, which is quite artisanal, is not optimal and involves assembly constraints.

[0007] In order to increase the torque transmitted by a shaft, it is known to make splines at the ends of a shaft, these splines collaborating with complementary splines made on the internal face of the hubs collaborating with the splines of the shaft.

[0008] This configuration avoids the assembly clearances described above regarding a key lock. The use of splines also allows for angular alignment of the shaft relative to the hub. Indeed, it is possible to place the shaft splines inside the hub splines in order to be able to orient them at a certain angle (this angle depends on the number of splines: 12 splines allow angular alignment every 30°). It should be noted that angular alignment is possible with a key locking system by providing several grooves on the shaft.

[0009] Splined shafts do, however, have a maintenance drawback. It may be necessary to replace a shaft for replacement or maintenance purposes. However, splined shafts are difficult to disassemble due to the need for strong interaction with the hubs in order to transmit power with high torque.

[0010] The invention aims in particular to provide a set of a shaft and hubs allowing satisfactory resistance to forces, while allowing varied angular adjustment and easy maintenance.

[0011] To this end, the invention relates to an assembly of a mechanical shaft comprising two splined ends and two splined hubs, each hub being formed by at least two half-shells, the two splined ends comprising at least eight splines, the splined ends having a cross-section of a shape configured to allow clearance of the shaft from a half-shell in a direction perpendicular to a longitudinal axis of the shaft.

[0012] Thus, an assembly is obtained comprising a splined shaft, which is advantageous for the transmission of powers having a high torque while having a reduced risk of breakage. The presence of at least eight splines per end of the shaft allows for varied and precise angular setting. Above all, the shape of the section of the splined ends allowing radial clearance of a shaft from the half-shells is very advantageous for maintenance reasons. Indeed, and if it is necessary to replace a shaft for one reason or another, it is sufficient to remove a half-shell from each hub to be able to radially extract the shaft whereas, for splined shafts according to the prior art, the superposition between the splines of the ends of a shaft and those of the hubs prevents such clearance as soon as the number of splines becomes too large.

[0013] Depending on other optional features of the set taken alone or in combination:

[0014] The splined ends of the shaft each include twelve splines. This allows the shaft to be angularly adjusted every 30°;

[0015] The cross-section of the splined ends is in the shape of a convex polygon. This allows, through the relationship between the splines of the shaft and those of the hubs, to guarantee the precision of the angle between the shaft and the hub;

[0016] The cross-section of the splined ends is lobed. This is an alternative way of making the shape of the shaft splines;

[0017] The cross section of the fluted ends comprises flat portions connected to each other by lobed portions;

[0018] The hub splines have the same shape as the splines on the splined ends. This allows for contact of the entire surface of the hub splines with the shaft and therefore optimal transmission of forces; and

[0019] - At least one hub includes multiple bores configured to accommodate a splined end.

[0020] The invention also relates to a waste sorting device comprising a waste receiving surface and a plurality of devices for stirring the waste receiving surface, each stirring device comprising a plurality of shaft and hub assemblies according to the invention. According to other optional features of the waste sorting device taken alone or in combination:

[0021] At least one hub comprises two bores, a splined end of a shaft being received in each bore. This allows the formation of cranks by bending a stirring device at least once;

[0022] At least two hubs comprise two bores, a splined end of a shaft being housed in each bore, the distance between the two bores varying from one hub to the other. This allows the amplitude of the cranks formed by the shafts and the hubs to be varied in order to vary the amplitude of the agitation of the waste receiving surface;

[0023] The hubs extend in at least two different directions. This allows for customization of the agitation kinematics of the waste receiving surface; and

[0024] At least one tree is covered with an enclosure extending around the tree. This allows for the attachment of various elements forming the waste receiving surface.

[0025] Brief description of the figures

[0026] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings in which:

[0027] [Fig. 1] is a side view of a shaft comprising splined ends according to the invention,

[0028] [Fig. 2] is a side view of an assembly formed by a shaft and two hubs according to the invention,

[0029] [Fig. 3] is a sectional view of the assembly of Figure 2 along the section plane AA, the grooved end having a cross-section of a shape according to a first embodiment of the invention,

[0030] [Fig. 4] is a sectional view of the assembly of Figure 2 along the section plane BB, the grooved end having a cross-section of a shape according to a first embodiment of the invention,

[0031] [Fig. 5] is a sectional view of a hub in which a splined end of a shaft is housed, the splined end having a cross-section of a shape according to a second embodiment of the invention, [Fig. 6] is a sectional view of a hub in which a splined end of a shaft is housed, the splined end having a cross-section of a shape according to a third embodiment of the invention,

[0032] [Fig. 7] is a view of a stirring device of a waste sorting device according to the invention,

[0033] [Fig. 8] is a view along section plane AA of the stirring device of Figure 7,

[0034] [Fig. 9] is a first perspective view of a first face of a waste sorting device according to the invention, and

[0035] [Fig. 10] is a second perspective view of a second face of a waste sorting device according to the invention.

[0036] Detailed description

[0037] We now refer to figure 1 illustrating a shaft 2. This shaft 2 can conventionally be made of steel (for example SAE 1040 or 4140 carbon steels) or any other material allowing the design of sufficiently strong shafts.

[0038] The shaft 2 comprises two splined ends 4 extending on either side of a main body 3. The number of splines is greater than or equal to eight. Multiplying the number of splines allows for better distribution of forces between the shaft 2 and the hubs 6, illustrated in figures 2 to 6 (which can also be made of steel), which are also splined (this can be seen by observing the splined bores 8 formed in a hub 6). This multiplication also allows for varied angular setting of the shaft 2 relative to the hubs 6. In the examples illustrated in the figures, the shaft 2 and the bores 8 of the hub 6 all have 12 splines, which allows for angular setting every 30°.

[0039] The hubs 6 are formed of at least two half-shells. This contributes to the radial clearance of the shaft 2. In the example illustrated in Figures 3 to 6, the hubs 6 comprise two bores 8 (this configuration will be explained later) and are formed by three parts: a central part 10 forming a first half of the two bores 8 and two eccentric parts 12 each forming a second half of a bore 8 and placed on either side of the central part 10. The hubs 6, or at least one of the hubs 6, could be formed only by two half-shells, comprising one or more bores 8, each half of which is carried by a half-shell.

[0040] The grooved ends 4 have a cross-section of a shape configured to allow a release of the shaft 2 from a half-shell in a direction perpendicular to a longitudinal axis X of the shaft 2. In other words, the shaft 2 can be disengaged from the hubs 6 in a radial direction. As explained above, this greatly facilitates the maintenance of a device comprising the assembly of a shaft 2 and two hubs 6 according to the invention because it is sufficient to dismantle a half-shell to locally extract the shaft 2 without the need to slide it inside the bore 8. Figure 4 illustrates a dismantling of a shaft 2: for this purpose, an eccentric part 12 forming a half-shell is removed from a bore 8, which allows the shaft 2 to be disengaged in a radial direction, upwards in the example illustrated in Figure 4.The operation is the same if the hub 6 is formed by two half-shells and for all the shapes of splines of the different embodiments illustrated.

[0041] As will be described later, the cross-section of the grooved ends 4 can take different shapes. In any case, this shape must allow radial disengagement. It can therefore be specified that the portions / faces forming the grooved ends 4 are:

[0042] Perpendicular to a plane comprising the longitudinal axis X of the shaft 2 and capable of extending at the interface between two half-shells when the shaft 2 is placed in the hubs 6 (which corresponds for example to twelve planes for a configuration with twelve splines), or

[0043] Convex with respect to a plane comprising the longitudinal axis X of the shaft 2. Convex is understood to mean that the portions / faces of the splined ends 4 form an acute angle with a plane comprising the longitudinal axis X of the shaft 2, an angle turned towards the inside of the shaft 2 (i.e. the portions / faces are curved or rounded towards the inside). There is therefore a convergence of these portions / faces which tend to return towards the inside and none extending by forming an acute angle with a plane comprising the longitudinal axis X of the shaft 2, an angle turned towards the outside of the shaft 2. Such a configuration, favored in the prior art in order to promote the transmission of forces between the shaft 2 and the hubs 6, leads to an interlocking of the splines of the splined ends and the hubs preventing disassembly of the shaft from the hubs in a radial direction.

[0044] In the examples illustrated in Figures 1 and 3 to 6, the splined ends 4 comprise twelve splines. This allows angular adjustment every 30°. It can be seen in these same figures that the hubs 6 also comprise bores 8 with twelve splines. In the example illustrated, the hubs 6 comprise a number of splines identical to the number of splines of the two splined ends, the splines of the two splined ends 4 all being in contact with the splines of the hubs 6. In general, the splines of the hubs 6 have the same shape as the splines of the splined ends 4. This allows contact of the entire surface of the hub splines 6 with the shaft 2 and therefore optimal transmission of forces. Alternatively, it would be possible to design hubs 6 comprising only certain splined portions and other smooth portions, the splined portions serving for angular adjustment and transmission of forces.It would also be possible that the splines of the hubs 6 have a greater amplitude than that of the splined ends 4, in which case a part of their surfaces would not be in contact with the splined ends 4 of the shaft 2.

[0045] In the exemplary embodiments of Figures 3 and 4 illustrating a first embodiment of the invention, the cross section of the grooved ends 4 comprises flat portions 13 connected to each other by lobed portions 13'. The length of the flat portions 13 as well as the curvature of the lobed portions 13' can vary, in particular depending on the number of grooves, while respecting the aforementioned radial clearance conditions.

[0046] Figure 5 illustrates a second embodiment of the invention. In the latter, the grooves are lobed in shape. Lobes 14 therefore form the grooves of the grooved ends 4. The amplitude of the lobes forming the grooves can vary while respecting the aforementioned radial clearance conditions.

[0047] According to a third embodiment of the invention illustrated in Figure 6, alternative or combinable with the first embodiment, the cross section of the grooved ends can be in the form of a convex polygon. It is recalled for this purpose that a convex polygon is a polygon of which all the interior angles are less than 180°. It can be seen in Figure 6 that the grooves of the grooved end 4 form “V” grooves 15, here twelve in number (at the hub 6 there is a structure comprising a plurality of “V”s complementary to those of the grooved end).

[0048] In addition to the radial disassembly capacity and the angular setting, the convex polygon-shaped cross-section makes it possible to position the shaft 2 with optimal precision. Indeed, it is no longer necessary in this case to adjust the tightening of the hub screws in order to adjust the positioning of a shaft in a hub in a fairly manual manner. With a structure such as illustrated in Figure 6, it is possible to position a plurality of shafts 2 with high angular precision. For example, and for a stirring device 16 (see Figures 7 to 10) comprising 22 interfaces between shafts 2 and hubs 6, the total offset measured is only about 0.1°, i.e. an offset per interface of the order of about 0.005°.Other shapes, simple or combined, of splines other than those illustrated in the figures are conceivable, provided that the cross-section of the splined ends 4 is of a shape allowing radial clearance of the shaft 2 relative to the hubs 6.

[0049] The assembly described above can be used in the context of a waste sorting device 20. Such a device can therefore be composed of a waste receiving surface 22. The latter is composed of a plurality of slats 24 (eight in Figures 9 and 10, which can for example measure six meters and weigh three hundred kilos each), for example made of steel, receiving the waste to be sorted. The different slats 24 are driven by a circular translational movement in an asynchronous manner. For example, it is possible to have two blocks of four slats 24 synchronized with each other, the two blocks being asynchronous. Such a movement allows separation of the waste according to its weight. The slats 24 can also include orifices 26 of variable size allowing the passage of smaller waste.

[0050] The slats 24 are attached to several stirring devices 16 each comprising a plurality of sets of shafts 2 and hubs 6 according to the invention described above. The operating principle of the waste sorting device is as follows. Different waste of varying sizes and weights are positioned on the waste receiving surface. The stirring device 16 of the waste receiving surface allows separation of the different wastes thanks to this stirring. More precisely, each slat 24 is attached to several stirring devices 16 parallel to each other and perpendicular to the direction of extension of the slats 24.These stirring devices 16, similar to modular and removable crankshafts, are all adjusted in the same way in order to obtain the circular translation of each slat 24 as well as an asynchronous circular translation between at least two blocks of slats 24 from the rotational movement of each stirring device 16.

[0051] According to an embodiment illustrated in Figures 7 to 10, at least one hub 6 comprises two bores 8 (this is also visible in Figures 3 to 6) in which the grooved ends 4 of two shafts 2 are housed. This allows the formation of cranks by bending the stirring device 16 at least once. In fact, the shafts 2 will extend in directions parallel to each other and perpendicular to that of the hub 6. This configuration is advantageous for ensuring stirring of the waste receiving surface.

[0052] The cranks of different stirring devices 16 aligned with each other according to the direction of extension of the slats 24 are oriented in the same way and the different stirring devices 16 are synchronized in order to obtain the circular translation described above. Alternatively or in combination with this embodiment, it would be possible to provide hubs 6 comprising a single bore 8 receiving two grooved ends 4. The shafts 2 are therefore aligned and can comprise at least one protuberance present on the shaft 2. These protuberances make it possible to obtain agitation of the waste receiving surface.

[0053] It is also possible to provide that two hubs 6 comprise two bores 8 in which the grooved ends 4 of two shafts 2 are housed, the distance between the two bores varying from one hub to the other. This makes it possible to vary the amplitude of the cranks formed by the shafts 2 and the hubs 6 in order to vary the amplitude of the agitation of the waste receiving surface by modulating the amplitude of movement of the slats 24. This can also make it possible to compensate for variations in the height of the agitation device 16.

[0054] It is also possible to provide an extension of the hubs 6 in different directions, for example in addition to the height variations described above. This makes it possible to customize the agitation kinematics of the waste receiving surface. For example, it can be provided that, when one or more first shafts 2 are in a vertical position, one or more second shafts 2 are located opposite those of the first, and one or more third shafts 2 extend in an intermediate direction between the first and second shafts 2. Obviously, the arrangement of the shafts 2 can vary depending on the desired agitation kinematics.

[0055] The shafts 2 may be covered with enclosures. The latter are rotatable around the shafts 2 and are fixed to slat supports 28, which makes it possible to connect the slats 24 to the stirring devices 16, the enclosures and the slat supports 28 forming connecting rods between the stirring devices 16 and the slats 24 forming the waste receiving surface 22. A translation of the slats 24 is therefore obtained from the rotation of the stirring devices 16. List of references

[0056] 2: tree

[0057] 3: main body

[0058] 4: fluted ends

[0059] 6: hubs

[0060] 8: bores

[0061] 10: central part

[0062] 12: eccentric parts

[0063] 13: flat portions

[0064] 13': lobbed portions

[0065] 14: lobes

[0066] 15: V-shaped grooves

[0067] 16: stirring device

[0068] 20: waste sorting device

[0069] 22: waste reception area

[0070] 24: slats

[0071] 26: orifices

[0072] 28: slat supports

[0073] X: longitudinal axis

Claims

Demands

1. Assembly of a mechanical shaft (2) comprising two splined ends (4) and two splined hubs (6), each hub (6) being formed by at least two half-shells, the two splined ends (4) comprising at least eight splines, characterized in that the splined ends (4) have a straight section of a shape configured to permit clearance of the shaft (2) from one half-shell in a direction perpendicular to a longitudinal axis (X) of the shaft (2).

2. Assembly according to claim 1, wherein the grooved ends (4) of the shaft (2) each comprise twelve grooves (13, 13', 14, 15).

3. Assembly according to any one of the preceding claims, wherein the cross-section of the grooved ends (4) is in the form of a convex polygon.

4. Assembly according to any one of the preceding claims, wherein the straight section of the grooved ends (4) is lobed in shape.

5. Assembly according to any one of the preceding claims, wherein the straight section of the grooved ends (4) comprises flat portions (13) connected to each other by lobed portions (13').

6. Assembly according to any one of the preceding claims, wherein the splines (13, 13', 14, 15) of the hubs (6) have the same shape as the splines of the grooved ends (4).

7. Assembly according to any one of the preceding claims, wherein at least one hub (6) comprises several bores (8) configured to accommodate a splined end (4).

8. Waste sorting device (20) comprising a waste receiving surface (22) and several surface agitation devices (16) waste reception, each stirring device comprising a plurality of shaft assemblies (2) and hubs (6) according to any one of the preceding claims.

9. Waste sorting device according to claim 8, wherein at least one hub (6) comprises two bores (8), a splined end (4) of a shaft (2) being housed in each bore (8).

10. Waste sorting device according to any one of claims 8 or 9, wherein at least two hubs (6) comprise two bores (8), a splined end (4) of a shaft (2) being housed in each bore (8), the distance between the two bores (8) varying from one hub (6) to the other.

11. Waste sorting device according to any one of claims 8 to 10, wherein the hubs (6) extend in at least two different directions.

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