AXLE system for a trailer
The axle system with idler axles and retarder assemblies addresses positioning and efficiency issues by directly connecting to wheel groups, ensuring effective braking and adaptability for different trailers.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CAMAGNI FAUSTO
- Filing Date
- 2025-10-29
- Publication Date
- 2026-05-15
AI Technical Summary
Existing auxiliary braking systems for trailers are ineffective due to positioning challenges on the frame, which leads to continuous variations in distance from the idler axle shafts, reduced efficiency, and difficulty in adapting to different trailer types.
An axle system with idler axles and retarder assemblies that directly connect to the wheel groups, allowing for independent braking action through hydraulic retarders and a crown-pinion gear mechanism, enabling adaptable positioning and efficient braking force transmission.
The axle system provides effective braking assistance, reduces jackknifing, and adapts to various trailer configurations, enhancing braking efficiency and stability.
Smart Images
Figure IB2025061017_15052026_PF_FP_ABST
Abstract
Description
" AXLE SYSTEM FOR A TRAILER"DESCRIPTION
[0001] The present invention relates to an axle system for a trailer controllable by a tractor. Furthermore, the present invention relates to a trailer comprising said axle system.
[0002] In particular, the present invention falls within the field of auxiliary braking systems for trailers.
[0003] In the state of the art, solutions of auxiliary braking systems for a trailer towed by a tractor are known, mounted on the frame of the trailer.
[0004] In particular, in the state of the art, solutions are known in which the trailer comprises a frame including a lower surface identifying a support plane for the load to be transported. Preferably, the auxiliary braking systems are mounted precisely on said lower surface facing the ground so as to be then connected to the axle and / or to the wheel groups.
[0005] A typical issue with these systems is their difficult positioning. In fact, being positioned on the frame, the known auxiliary braking systems are affected during travel by the continuous variation of the distancebetween the frame and the idler axle shafts due to the irregularities of the road surface. Therefore, the braking assistance proves to be ineffective because said systems are subject to continuous variations. In addition, in order to make the braking assistance effective, the systems of the known art require compensation systems suitable for compensating for the movements due to the suspensions between the frame and the axle.
[0006] A further issue associated with the systems of the known art is the limitation related to their positioning. In fact, the auxiliary braking systems of the known art are limited to the aforementioned single positioning on the frame. Consequently, it is difficult to adapt the present systems to different types of trailers because the positioning on the frame may be cumbersome for trailers in which, for example, the distance between the axle and the frame proves to be insufficient for the proper functioning of the auxiliary braking system.
[0007] Furthermore, the auxiliary braking systems of the known art present problems related to reduced efficiency since, being connected to the frame and not tothe axle shafts, the transmission of the braking force does not act directly on the wheel group.
[0008] The object of the present invention is to meet the needs of the sector and to overcome the drawbacks of the known art mentioned above.
[0009] Said object is achieved by means of an axle system as claimed in claim 1. Said object is also achieved by means of a trailer according to claim 15. The dependent claims seek protection for further features and involve further technical advantages.
[0010] In addition, further features and advantages of the invention will appear from the description below of its preferred embodiments, given by way of non-limiting example, with reference to the accompanying figures, in which:- Figure la shows a schematic cross-sectional view of an axle system according to the present invention in accordance with a first embodiment;- Figure lb shows a schematic top view of an axle system according to the present invention in accordance with the embodiment of figure la;- Figure 2 shows a schematic cross-sectional view of an axle system according to the present invention in accordance with a second embodiment;- Figure 3 shows a schematic cross-sectional view of an axle system according to the present invention in accordance with a third embodiment;- Figure 4 shows a schematic cross-sectional view of an axle system according to the present invention in accordance with a fourth embodiment;- Figure 5a shows a schematic cross-sectional view of a detail of the crown-pinion gear in accordance with a first embodiment of the present invention;- Figure 5b shows a schematic cross-sectional view of a detail of the crown-pinion gear in accordance with a second embodiment of the present invention;- Figure 6a shows, in a schematic perspective view, an idler axle shaft suitable for being coupled to a central idler axle shaft in accordance with one embodiment of the present invention;- Figure 6b shows a schematic cross-sectional view of an idler axle shaft suitable for being coupled to a centralidler axle shaft in accordance with the embodiment of figure 6a;- Figure 7 shows a schematic cross-sectional view of the auxiliary braking means in accordance with one embodiment of the present invention.
[0011] With reference to the accompanying figures, number 1 denotes an axle system for a trailer controllable by a tractor.
[0012] The term "trailer" means a vehicle without an engine intended to be towed by motor vehicles equipped with appropriate towing systems and, where necessary, with an appropriate braking system, said motor vehicles being generically referred to as "tractors".
[0013] For greater clarity, in the following description, the term "trailer" also includes a subcategory of trailers, known as semi-trailers, i. e. vehicles without an engine suitable for being towed by a tractor, being suitable for unloading part of their weight on their own axles and part on the fifth wheel of said tractor.
[0014] The axle system 1 comprises two-wheel groups 2, 2'
[0015] In accordance with one embodiment, each wheel assembly of the two-wheel groups 2, 2' consists of a single tyre.
[0016] According to one embodiment, each wheel group of the two-wheel groups 2, 2' consists of a pair of twin tyres.
[0017] Furthermore, the axle system 1 comprises an idler axle 3 suitable to connect in an idler manner the two-wheel groups 2, 2'.
[0018] " Idler axle" means an axle having only a load-bearing function.
[0019] In accordance with one embodiment, the idler axle 3 is steerable.
[0020] In accordance with one embodiment, the idler axle 3 is fixed.
[0021] The idler axle 3 comprises two idler axle shafts 31, 31' aligned along an axle direction A.
[0022] In accordance with a preferred embodiment, the axle direction A is contained in a first axle plane Pa substantially parallel to the ground. Said first axleplane Pa identifies a lower axle portion 501 facing the ground and an upper axle portion 502.
[0023] In other words, the upper axle portion is the portion delimited by the first axle plane Pa and by the lower surface of the trailer.
[0024] In accordance with a preferred embodiment, the axle direction A is contained in a second axle plane Pa'' substantially perpendicular to the first axle plane Pa. Said second axle plane Pa'' identifies a front axle portion 503 and a rear axle portion 504. In other words, the second axle plane Pa'' identifies a front axle portion facing the tractor towing the trailer and a rear axle portion facing the rear of the trailer.
[0025] Each idler axle shaft 31; 31' extends between a first axle shaft end 311; 311' and a second axle shaft end 312; 312'.
[0026] In accordance with one embodiment, the first axle shaft end 311; 311' is operatively connected to a wheel group 2; 2', respectively. In other words, the wheel group 2; 2 ' is operatively connected to an idler axle shaft 31; 31' at the first axle shaft end 311; 311'.
[0027] Furthermore, the idler axle 3 comprises two crowns 32, 32'.
[0028] Each crown 32; 32' is engaged with the second axle shaft end 312; 312' of each idler axle shaft 31; 31'.
[0029] Therefore, each idler axle shaft 31; 31' is operatively connected to a wheel group 2; 2' at the first axle shaft end 311; 311 ' and engages a crown 32; 32' at the second axle shaft end 312; 312'.
[0030] In accordance with a preferred embodiment, each crown 32; 32' extends in a crown plane Pc; Pc' substantially perpendicular to the first axle plane Pa.
[0031] The axle system 1 comprises a retarder assembly 4.
[0032] The retarder assembly 4 comprises at least two retarder groups 41, 41'.
[0033] Each retarder group 41; 41' comprises a stator 411; 411' and a rotor 412; 412' operatively coupled to the stator 411; 411'.
[0034] Each retarder group 41; 41' comprises a retarder chamber 410; 410' suitable for housing at least the rotor 412; 412
[0035] In accordance with one embodiment, the retarder chamber 410; 410' houses the rotor 412; 412'.
[0036] In accordance with a further embodiment, the retarder chamber 410; 410' houses the rotor 412; 412' and the stator 411; 411'.
[0037] Each retarder group 41; 41' also comprises a pinion 413; 413' meshed with a crown 32; 32' of the two crowns 32, 32'.
[0038] Furthermore, each retarder group 41; 41' comprises a connection shaft 414; 414' that operatively connects the pinion 413; 413' to the rotor 412; 412'.
[0039] In accordance with the present invention, the axle system is configurable in a free configuration and in a braking configuration.
[0040] The free configuration corresponds to the configuration in which the rotor is free to rotate with respect to the stator, i. e. the rotation of the rotor with respect to the stator is not affected by external braking means.
[0041] The braking configuration corresponds to the configuration in which the rotation of the rotor with respect to the stator is affected by the action ofexternal braking means that increase the friction force present between the rotor and the stator.
[0042] In the free configuration, during travel, the two-wheel groups 2; 2' are free to rotate. Since the two-wheel groups 2; 2' are connected to the two idler axle shafts 31; 31', the rotation of the two-wheel groups 2; 2' sets the two idler axle shafts 31; 31' in rotation. Said rotational movement of each idler axle shaft 31; 31' is transmitted to the rotor 412; 412' by means of the crown-pinion gear and the connection shaft 414; 414'. Therefore, in the free configuration, the rotational movement of the idler axle shaft 31; 31' is transmitted to the rotor 412; 412'.
[0043] On the contrary, in the braking configuration, the external braking means 51 intervene by increasing the friction force present between the rotor 412; 412' and the stator 411; 411' and, consequently, determining a reduction in the rotation of the rotor with respect to the stator. This reduction in the rotation of the rotor 412; 412' is transmitted to the idler axle shaft 31; 31' and to the wheel group 2; 2' by means of the connection shaft 414; 414' that connects the rotor to the pinion and the crown-pinion gear. Therefore, the connection shaft 414; 414' transmits the reduction in the rotation of therotor 412; 412' caused by the external braking means 51 to the crown-pinion gear, to the idler axle shaft, and finally to the wheel group, implementing the braking action of the trailer.
[0044] In accordance with one embodiment, the crownpinion gear pair has a conical shape.
[0045] In accordance with a first embodiment shown by way of example in figure 5a, the connection shaft 414; 414' of each retarder group 41; 41'; 42; 42' extends along a connection shaft axis C substantially parallel to the axle direction A.
[0046] In accordance with a second embodiment shown by way of example in figure 5b, the connection shaft 414; 414' of each retarder group 41; 41'; 42; 42' extends along a connection shaft axis C substantially perpendicular to the axle direction A.
[0047] In accordance with one embodiment, the retarder assembly 4 comprises two retarder groups 41, 41 '.
[0048] In accordance with one embodiment, the retarder assembly 4 comprises four retarder groups 41, 41', 42, 42
[0049] Furthermore, the axle system 1 comprises at least one braking assembly 5.
[0050] In accordance with one embodiment, the braking assembly 5 comprises a braking mean 51. Said braking mean 51 is suitable for being activated by the tractor and for interacting with the rotor 412; 412' of each retarder group 41; 41'. In other words, the braking action of the tractor determines the activation of the braking mean 51.
[0051] In accordance with the present invention, in the braking configuration, the braking mean 51 actuated by a braking action of the tractor inhibits the rotation of the rotor 412; 412' of each retarder group 41; 41' and of each axle shaft 31; 31' implementing a braking action of the trailer.
[0052] In accordance with one embodiment, the at least two retarder groups 41, 41' are hydraulic-type retarders.
[0053] In accordance with a preferred embodiment, the retarder assembly consists of two hydraulic-type retarder groups 41, 41'.
[0054] In accordance with a further preferred embodiment shown by way of example in figure 4, theretarder assembly consists of four hydraulic-type retarder groups 41, 41', 42, 42'.
[0055] In accordance with the embodiment in which each retarder group is of the hydraulic type, shown by way of example in figure 1, the braking mean 51 is a braking fluid.
[0056] In accordance with one embodiment, the braking assembly 5 is actuated by the braking action of the tractor so that the braking fluid enters the retarder chamber 410 exerting a resistance force between the rotor 412; 412' and the stator 411; 411' of each retarder group 41; 41' so as to brake the trailer.
[0057] In accordance with said embodiment, the braking assembly 5 comprises a reservoir group 52 containing the braking fluid. Said reservoir group 52 is fluidically connected to the retarder chamber 410; 410' of each retarder group 41; 41'.
[0058] In accordance with one embodiment, the crown plane Pc of a first crown 32 connected to a first idler axle shaft 31 is substantially parallel to the crown plane Pc' of a second crown 32' connected to a second idler axle shaft 31
[0059] In accordance with one embodiment shown in figure 3, the crown plane Pc of the first crown 32 is substantially parallel to the crown plane Pc' of the second crown 32' in a central position with respect to the two-wheel groups 2, 2'. In other words, in the embodiment shown in figure 3, the idler axle 3 is composed of two idler axle shafts 31, 31', in which the first crown 32 and the second crown 32' are arranged parallel to each other and close together in a central position with respect to the first axle shaft end 311 of the first idler axle shaft 31 and the first axle shaft end 311' of the second idler axle shaft 31
[0060] In accordance with said embodiment, the two retarder groups 41, 41' are positioned in the upper axle portion 502. Said retarder groups 41, 41' are also referred to as upper retarder assemblies.
[0061] In accordance with the embodiment of figure 3, the reservoir group 52 comprises two reservoirs 52a, 52b separated from each other. Each reservoir 52a, 52b is fluidically connected to the retarder chamber 410; 410' of each of the two upper retarder groups 41, 41 '.
[0062] In accordance with one embodiment shown by way of example in figure la, the axle assembly 3 comprises acentral idler axle shaft 33. Said central idler axle shaft 33 extends between a first central axle shaft end 331 and a second central axle shaft end 332.
[0063] In accordance with said embodiment, the central idler axle shaft 33 is operatively connected in an idler manner to a first idler axle shaft 31 at the first central axle shaft end 331 and to a second idler axle shaft 31' at the second central axle shaft end 332.
[0064] In other words, the idler axle 3 is composed of two idler axle shafts and one central idler axle shaft mutually connected in an idler manner.
[0065] In accordance with one embodiment shown in figure 6a, each idler axle shaft 31; 31' has a circular cross-section having an axle shaft diameter d.
[0066] In accordance with a preferred embodiment shown in figure 6a, the second axle shaft end 312; 312' has a second end diameter D greater than the axle shaft diameter d of the idler axle shaft.
[0067] In accordance with one embodiment shown in figure 6a, the central idler axle shaft 33 has a circular cross-section having a central axle shaft diameter dc substantially equal to the axle shaft diameter d.
[0068] In accordance with one embodiment shown in figure 6a, the first central axle shaft end 331 has a circular cross-section having a central axle shaft end diameter De greater than the central axle shaft diameter de. Preferably, the central axle shaft end diameter De is much greater than the central axle shaft diameter de.
[0069] In accordance with the embodiment in which the idler axle comprises a central idler axle shaft, the connection of each idler axle shaft to the central idler axle shaft is reinforced by a dual male-female coupling.
[0070] In accordance with a preferred embodiment, each idler axle shaft 31; 31' comprises a female coupling portion 320; 320 ' which extends along the circumference of the cross-section of the second idler axle shaft end 312; 312'. In accordance with said embodiment, the central idler axle shaft 33 comprises a male coupling portion 330; 330 ' which extends along the circumference of the cross-section of the first central axle shaft end 331 and of the second central axle shaft end 332 so as to be coupled with the female coupling portion 320; 320' of each idler axle shaft. Therefore, the coupling of the female coupling portion 320; 320' with the male coupling portion 330; 330' implements a male-female shape coupling.
[0071] In other words, the connection of each idler axle shaft 31; 31' to the central idler axle shaft 33 is achieved by means of a male-female shape coupling of the male coupling portion 330; 330' with the female coupling portion 320; 320'.
[0072] In accordance with one embodiment, the first central axle shaft end 331 and the second central axle shaft end 332 comprise a plurality of male connection means 350. In accordance with said embodiment, the second axle shaft end 312; 312' of each idler axle shaft 31; 31' comprises a plurality of female connection means 340; 340' suitable for being coupled by means of a male-female shape coupling with the plurality of male connection means 350 of the central idler axle shaft.
[0073] In other words, the connection between the central idler axle shaft and the two idler axle shafts is reinforced by a second male-female coupling achieved by coupling the plurality of male connection means 350 with the plurality of female connection means 340; 340'.
[0074] In accordance with said embodiment shown in figure 6a, at the first central axle shaft end 331 and at the second central axle shaft end 332, the central idler axle shaft 33 comprises an opening 3310 suitable forhousing the crown 32; 32' connected respectively to the first idler axle shaft 31 and to the second idler axle shaft 31 '.
[0075] Preferably, the male connection means 350 are bolts.
[0076] Preferably, the female connection means 340; 340' are openings suitable for housing the bolts 350.
[0077] In accordance with the embodiment shown in figure 1, the reservoir group 52 consists of a single reservoir fluidically connected to the two upper retarder groups 41, 41' positioned in a central position of the central idler axle shaft 33. In other words, the axle system shown in figure 1 comprises an axle assembly composed of two idler axle shafts and one central idler axle shaft mutually connected in an idler manner and a retarder assembly composed of two retarder assemblies fluidically connected to a single reservoir containing the braking fluid.
[0078] In accordance with the embodiment shown in figure 2, the axle assembly is composed of a first retarder group 41 positioned in the upper axle portion 502 and operatively connected to the first idler axle shaft 31 and a second retarder group 41' positioned inthe lower axle portion 501 and operatively connected to the second idler axle shaft 31'. In this case, the reservoir group 52 comprises two separate reservoirs 52a, 52b respectively positioned in the upper axle portion 502 and in the lower axle portion 501.
[0079] In accordance with one embodiment, the axle assembly is composed of a first retarder grup 41 positioned in the front axle portion 503 and operatively connected to the first idler axle shaft 31 and a second retarder group 41' positioned in the rear axle portion 504 and operatively connected to the second idler axle shaft 31'. In this case, the reservoir group 52 comprises two separate reservoirs 52a, 52b respectively positioned in the front axle portion 503 and in the rear axle portion 504.
[0080] In accordance with one embodiment, the axle system 1 comprises connection means suitable for operatively connecting the axle system 1 to the tractor.
[0081] In accordance with one embodiment, the connection means connect the braking assembly 5 to a lever present in the tractor. In accordance with said embodiment, the user, by actuating the lever, activates each retarder group present in the axle system of the trailer, causing the introduction of the braking fluid,for example viscous oil, between the blades of the rotor and the stator so that the braking fluid exerts a resistance due to the viscosity of the oil.
[0082] In accordance with a preferred embodiment, the axle system 1 comprises a control unit configured to communicate with the tractor so as to activate the braking assembly 5 and transmit the braking action of the tractor to the axle system 1. Preferably, the control unit, after receiving an activation signal from the tractor, activates the braking assembly so that the braking fluid enters the retarder chamber to exert a resistance force to the rotation of the rotor with respect to the stator, implementing an auxiliary braking action of the trailer.
[0083] In accordance with one embodiment, the braking assembly 5 comprises a pumping system suitable for pumping the braking fluid from the reservoir group to the retarder chamber.
[0084] In accordance with one embodiment, the two idler axle shafts 31; 31' and the central idler axle shaft 33 are divided with respect to a longitudinal plane into an upper axle shaft structure and a lower axle shaft structure facing the ground.
[0085] In accordance with one embodiment, each retarder group is mounted externally to the idler axle 3.
[0086] In accordance with a preferred embodiment, each retarder group is mounted directly in the idler axle 3.
[0087] In accordance with a preferred embodiment, the at least two retarder groups 41; 41' are independent from one another. In other words, the at least two retarder groups 41; 41' are not connected to one another, i. e., they operate independently.
[0088] As previously described, the two preferred embodiments of the present invention comprise an axle system with two or four retarder assemblies.
[0089] The retarder assembly comprising two retarder groups independent from one another is also referred to as "biretarder". Therefore, the minimum retarder assembly is the biretarder. Consequently, the retarder assembly with four retarder grousp is also referred to as "double biretarder", i. e., it comprises two biretarders positioned respectively in the lower axle portion and in the upper axle portion.
[0090] Having an axle assembly with two or four retarder groups allows for the correct balancing of theweight of the retarder assemblies themselves when mounted on the idler axle.
[0091] In accordance with one embodiment shown by way of example in figure 7, each retarder group 41; 41' comprises auxiliary braking means 451; 451' meshed with the pinion 413; 413' and / or the crown 32; 32' so as to increase the rotation of the rotor in the braking configuration.
[0092] In accordance with a first embodiment described above, the pinion of each retarder group is meshed with the crown of an idler axle shaft. Said crown-pinion gear is referred to as a direct gear.
[0093] In accordance with a second embodiment, the pinion of each retarder group is meshed with auxiliary braking means, which in turn are meshed with the crown of the idler axle shaft. Said crown-pinion gear via auxiliary braking means is referred to as an indirect gear.
[0094] In accordance with one embodiment, in the free configuration, each idler axle shaft 31; 31' is disconnected from the respective crown 32; 32'.
[0095] In accordance with a preferred embodiment, the axle system comprises a connection assembly configured to connect, in the braking configuration, each idler axle shaft 31; 31' to the respective crown 32; 32' and to disconnect, in the free configuration, each idler axle shaft 31; 31' from the respective crown 32; 32'. In other words, in accordance with said embodiment, each retarder group is connectable and disconnectable from the respective idler axle shaft.
[0096] In accordance with the embodiment in which each retarder is of the hydraulic type, the braking fluid 51 has an inlet temperature Tin at the inlet of the retarder chamber 410; 410 ' and an outlet temperature Toutat the outlet of the retarder chamber 410; 410'.
[0097] Once the braking fluid interacts with the rotor 412; 412' to reduce its rotational speed, due to the friction force with the rotor itself, the braking fluid heats up reaching a working temperature Tworkhigher than the inlet temperature Tin.
[0098] In accordance with one embodiment, the control unit is configured to set a threshold temperature Tthresholdof the braking fluid.
[0099] In accordance with said embodiment, the retarder system 1 comprises a plurality of temperature sensors suitable for communicating with the control unit and for measuring the working temperature Tworkof the braking fluid.[000100] Furthermore, the control unit is configured to monitor the working temperature Tworkof the braking fluid. Indeed, if the working temperature Twork is lower than the threshold temperature Threshold, the control unit continues to monitor the working temperature. On the contrary, if the working temperature Tworkis higher than the threshold temperature Tthreshold, the control unit stops the operation of the retarder system because a working temperature higher than the threshold temperature would cause damage to the operation of the retarder system 1.[000101] In accordance with the embodiment in which each retarder is of the hydraulic type, the retarder system 1 comprises a cooling system suitable to cool the braking fluid 51 exiting from each retarder chamber 410; 410'. In other words, the cooling system is suitable for lowering the outlet temperature Tout.[000102] The object of the present invention also relates to a trailer towable by a tractor.[000103] In accordance with the present invention, the trailer comprises at least one axle system 1.[000104] Innovatively, the retarder system and the tractor-towable trailer comprising it fully achieve the intended purpose by overcoming the typical issues of the known art.[000105] Advantageously, the axle system comprising the retarder assembly according to the present invention reduces the space and time necessary to decelerate tractors towing a trailer.[000106] Advantageously, the axle system comprising the retarder assembly according to the present invention reduces the probability of the jackknifing phenomenon occurring, that is, when the articulated vehicle or trailer truck folds in on itself, especially in cornering situations with poor road grip of the articulated vehicle or trailer truck.[000107] Advantageously, the axle system comprising the retarder assembly according to the present invention provides assistance to the braking action of the tractor because it slows down the trailer, preventing the trailer from pushing the tractor.[000108] Advantageously, the conical shape of the crownpinion gear pair reduces the spatial bulk of the gears themselves. Advantageously, the conical shape allows the connection shaft to be arranged both in a direction parallel and in a direction perpendicular to the axle direction A.[000109] Advantageously, the division along the longitudinal plane of the two idler axle shafts and the central idler axle shaft gives the axle assembly a solid structure capable of withstanding high loads.[000110] Advantageously, the crown-pinion gear amplifies the deceleration force of the retarder assembly.[000111] Advantageously, the arrangement of a retarder assembly in the upper axle portion and a retarder assembly in the lower axle portion reduces the bulk of the retarder assembly mounted on the idler axle.[000112] Advantageously, the retarder groups comprised in the axle system according to the present invention may be positioned indifferently in the front axle portion, in the lower axle portion, in the rear axle portion, or in the upper axle portion. Advantageously, the axle system according to the present invention adapts to the different requirements of a trailer. Advantageously, theaxle system according to the present invention is versatile.[000113] Advantageously, the dual male-female coupling obtained through the shape coupling of the male coupling portion with the female coupling portion and the shape coupling between the male coupling means and the female coupling means reinforces the connection between the two idler axle shafts and the central axle shaft. Advantageously, the dual male-female coupling strengthens the axle system when the two retarder assemblies are positioned one in the upper axle portion and one in the lower axle portion.[000114] Advantageously, mounting each retarder assembly externally to the axle facilitates maintenance or possible replacement since, if necessary, each retarder group may be disassembled and detached from the central axle shaft and / or from the idler axle shaft while still allowing the trailer to be moved.[000115] Advantageously, mounting the retarder directly in the axle overcomes the difficulties due to changes in the distance between the frame and the idler axle shafts. Advantageously, mounting each retarder assembly directly in the axle provides the possibility of mounting it inany position of the axle assembly, i. e., on the idler axle shafts or on the central idler axle shaft, simply by rotating the axle itself, making it adaptable to the different space requirements of different trailers.[000116] Advantageously, the two or four independent retarder groups maintain separate the two-wheel groups to which they are operatively connected. Indeed, the two-wheel groups must be independent of each other because, when cornering, the two-wheel groups perform a different number of revolutions per second. In a turn, the wheel group on the outside of the turn travels more distance than the wheel group on the inside. Therefore, when the trailer takes a curve, the retarder group connected to the outer wheel group tends to decelerate more than the retarder group connected to the inner wheel group. In other words, during a turn, the two retarder groups decelerate in proportion to the number of revolutions per second that each of the two-wheel groups individually performs.[000117] Advantageously, the axle system with independent retarder groups avoids the use of a differential like the one commonly mounted in the tractor.[000118] Advantageously, the indirect gear increases the number of revolutions per second of the rotor. Advantageously, the indirect gear through auxiliary braking means results in greater deceleration of the trailer, which cannot take advantage of the resistance of the tractor' s engine.[000119] Advantageously, the axle system in which, in the free configuration, each axle shaft is disconnected from the respective crown reduces the friction phenomena due to the rotational movements of the crown, pinion, and rotor.[000120] Advantageously, the plurality of temperature sensors constantly monitors the working temperature of the braking fluid to ensure the correct functioning of each retarder group. Advantageously, monitoring the proper operation of each retarder group ensures homogeneous braking of the trailer, avoiding decelerating the trailer more on one side than on the other, which could cause the trailer itself to skid.[000121] It is clear that a person skilled in the art, in order to meet contingent needs, could make changes to the invention described above, all of which are withinthe scope of protection as defined by the following claims.
Claims
Claims1. An axle system ( 1 ) for a trailer controllable by a tractor comprising:( i ) two-wheel groups ( 2, 2 ' );( ii ) an idler axle ( 3 ) suitable for connecting the two-wheel groups ( 2, 2 ' ) in an idler manner, wherein the idler axle ( 3 ) comprises:- two idler axle shafts ( 31, 31 ' ) aligned along an axle direction (A), wherein each idler axle shaft ( 31; 31 ' ) extends between a first axle shaft end ( 311; 311 ' ) and a second axle shaft end ( 312; 312 ' ), wherein the first axle shaft end ( 311; 311 ' ) is operatively connected to a wheel group ( 2; 2 ' ), respectively;- two crowns ( 32, 32' ), wherein each crown ( 32; 32 ' ) is engaged with the second axle shaft end ( 312; 312 ' ) of each idler axle shaft ( 31; 31 ' );( iii ) a retarder assembly ( 4 ) comprising at least two retarder groups ( 41, 41 ' ), wherein each retarder group ( 41; 41 ' ) comprises:- a stator ( 411; 411 ' );- a rotor ( 412; 412 ' ) operatively coupled to the stator ( 411; 411 ' );a retarder chamber (410; 410' ) suitable for housing at least the rotor (412; 412' );- a pinion (413; 413' ) meshed with one crown (32; 32' ) of the two crowns (32, 32' );- a connection shaft (414; 414' ), wherein the connection shaft (414; 414' ) operatively connects the pinion (413; 413' ) to the rotor (412; 412' );(iv) at least one braking assembly (5) comprising a braking mean (51), wherein the braking mean (51) is suitable for being actuated by the tractor and interacting with the rotor (412; 412' ) of each retarder group (41; 41' );wherein the axle system (1) is configurable in a braking configuration, wherein the braking mean (51) actuated by a braking action of the tractor inhibits the rotation of the rotor (412; 412' ) of each retarder group (41; 41' ) and, thus, of each axle shaft (31;31' ), implementing a braking action of the trailer.
2. Axle system (1) according to claim 1, wherein the at least two retarder groups (41, 41' ) are retarders of the hydraulic type, wherein the braking mean (51) is a braking fluid, wherein the braking assembly (5) comprises a reservoir group (52) containing the brakingfluid (51), wherein the reservoir groud (52) is fluidically connected to the retarder chamber (410; 410' ) of each of the at least two retarder groups (41; 41' ).
3. Axle system (1) according to claim 2, in the braking configuration, the braking assembly (5) is actuated by the braking action of the tractor so that the braking fluid enters the retarder chamber (410) by applying a resistance force between the rotor (412; 412' ) and the stator (411; 411' ) of each retarder group (41; 41' ) so as to brake the trailer.
4. Axle system (1) according to any one of the preceding claims, wherein each retarder group (41; 41' ) comprises auxiliary braking means (451; 451' ) meshed with the pinion (413; 413' ) and / or the crown (32; 32' ) so as to increase the rotation of the rotor, in the braking configuration.
5. Axle system (1) according to any one of the preceding claims, wherein the axle direction (A) is contained in a first axle plane (Pa) substantially parallel to the ground, wherein said first axle plane (Pa) identifies a lower axle portion (501) facing the ground and an upper axle portion (502).
6. Axle system (1) according to claim 5, wherein each crown (32; 32' ) extends in a crown plane (Pc; Pc' ) substantially perpendicular to the first axle plane (Pa), wherein the crown plane (Pc) of a first crown (32) connected to a first idler axle shaft (31) is substantially parallel to the crown plane (Pc' ) of a second crown (32' ) connected to a second idler axle shaft (31' ) in a central position with respect to the two-wheel groups (2, 2' ).
7. Axle system (1) according to any one of claims 1-5, comprising a central idler axle shaft (33), wherein the central idler axle shaft (33) extends between a first central axle shaft end (331) and a second central axle shaft end (332), wherein the central idler axle shaft (33) is operatively connected in an idler manner to a first idler axle shaft (31) at the first central axle shaft end (331) and to a second idler axle shaft (31' ) at the second central axle shaft end (332).
8. Axle system (1) according to claim 6 or according to claim 7 when dependent on claim 5, wherein two upper retarder groups (41, 41' ) are positioned in the upper axle portion (502).
9. Axle system (1) according to claim 8, wherein two lower retarder groups (42, 42' ) are positioned in the lower axle portion (501).
10. Axle system (1) according to any one of the preceding claims, wherein the connection shaft (414; 414' ) of each retarder group (41; 41'; 42; 42' ) extends along a connection shaft axis (C) substantially parallel to the axle direction (A).
11. Axle system (1) according to any one of claims 1-9, wherein the connection shaft (414; 414' ) of each retarder group (41; 41'; 42; 42' ) extends along a connection shaft axis (C) substantially perpendicular to the axle direction (A).
12. Axle system (1) according to any one of the preceding claims, wherein the at least two retarder groups (41; 41' ) are independent of each other.
13. Axle system (1) according to any one of the preceding claims, wherein each retarder group (41; 41' ) is directly mounted in the idler axle (3).
14. Axle system (1) according to any one of the preceding claims, comprising a control unit configured to communicate with the tractor so as to actuate thebraking assembly (5) and transmit the braking action of the tractor to the axle system (1).
15. A tractor-towable trailer comprising at least one axle system (1) according to any one of claims 1-14.