Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G5/00—Resilient suspensions for a set of tandem wheels or axles having interrelated movements
  • B60G5/01—Resilient suspensions for a set of tandem wheels or axles having interrelated movements the set being characterised by having more than two successive axles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G5/00—Resilient suspensions for a set of tandem wheels or axles having interrelated movements
  • B60G5/04—Resilient suspensions for a set of tandem wheels or axles having interrelated movements with two or more pivoted arms, the movements of which are resiliently interrelated, e.g. the arms being rigid
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D55/00—Endless track vehicles
  • B62D55/08—Endless track units; Parts thereof
  • B62D55/084—Endless-track units or carriages mounted separably, adjustably or extensibly on vehicles, e.g. portable track units
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D55/00—Endless track vehicles
  • B62D55/08—Endless track units; Parts thereof
  • B62D55/104—Suspension devices for wheels, rollers, bogies or frames
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D55/00—Endless track vehicles
  • B62D55/08—Endless track units; Parts thereof
  • B62D55/14—Arrangement, location, or adaptation of rollers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
  • B60G2204/80—Interactive suspensions; arrangement affecting more than one suspension unit
  • B60G2204/81—Interactive suspensions; arrangement affecting more than one suspension unit front and rear unit
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2204/00—Indexing codes related to suspensions per se or to auxiliary parts
  • B60G2204/80—Interactive suspensions; arrangement affecting more than one suspension unit
  • B60G2204/83—Type of interconnection
  • B60G2204/8302—Mechanical
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2300/00—Indexing codes relating to the type of vehicle
  • B60G2300/32—Track vehicles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D55/00—Endless track vehicles
  • B62D55/08—Endless track units; Parts thereof
  • B62D55/104—Suspension devices for wheels, rollers, bogies or frames
  • B62D55/108—Suspension devices for wheels, rollers, bogies or frames with mechanical springs, e.g. torsion bars
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D55/00—Endless track vehicles
  • B62D55/08—Endless track units; Parts thereof
  • B62D55/104—Suspension devices for wheels, rollers, bogies or frames
  • B62D55/112—Suspension devices for wheels, rollers, bogies or frames with fluid springs, e.g. hydraulic pneumatic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D55/00—Endless track vehicles
  • B62D55/08—Endless track units; Parts thereof
  • B62D55/30—Track-tensioning means
  • B62D55/305—Track-tensioning means acting on pivotably mounted idlers

Definitions

• the present invention relates to a suspension system, in particular to a suspension system for a track band transmission for agricultural vehicles, such as a tractor.
• Agricultural vehicles for sake of example tractors, may use track band transmissions instead of ordinary wheels for the motion of the vehicle on the ground.
• a typical track band transmission for agricultural vehicles comprises a drive wheel configured to supply a torque to a track band, which is wrapped around a boogie assembly typically coupled to the vehicle itself; such boogie assembly comprises an undercarriage essentially provided with two or more idler wheels and a suspension system.
• the suspension system is necessary to maintain the track band in contact with the ground and to dampen the vibration transmitted to the vehicle.
• Quadtrac or “Rowrtrac” system, by CNH Industrial, comprises a suspension system comprising three rollers arranged between two idler wheels, which are all connected together by a rod; such rod is suspended with respect to an undercarriage fixed to the vehicle and to which the idler wheels are singularly hinged.
• Another known suspension system by Zuidberg, comprises an undercarriage pivotally connected in the rotation center of the driving wheel and comprising one single suspension element for each roller coupled to the undercarriage.
• Versatile Delta Track or John Deere HSD systems disclose suspension systems comprising a boogey journaled to the undercarriage with the journal point coplanar with the pivot axis of the undercarriage.
• the system further comprises two rollers hinged to the boogey.
• Such systems have an high ground pressure and an uneven load distribution on the rollers.
• the suspension is not configured to support vertical loads and therefore such vertical loads are transferred directly to the vehicle.
• GB396888 discloses an elastic suspension system for the rollers of endless track band vehicles.
• this configuration discloses a suspension system comprising first and second rocking arms pivotally coupled to an undercarriage and linked with one another by a leaf spring.
• the first rocking arm have a substantially triangular shape having three distinct end portions, pivotally coupled respectively with one roller, the undercarriage and one first end of the leaf spring.
• the second rocking arm presents, in turn, three distinct end portions, two of which are pivotally coupled respectively to the undercarriage and to a boogie assembly, which pivotally carries two rollers.
• the other end portion is rigidly coupled to a second end of the leaf spring.
• Such system is capable of reducing the torsional stress to which the rollers are subjected, especially during steering operations. Furthermore, the weight of the vehicle is distributed uniformly over the rollers, in normal conditions .
• An aim of the present invention is to satisfy at least one of the above mentioned needs.
• Figure 1 is a perspective view of a track band transmission comprising a suspension system according to the present invention
• Figure 2 is a partial sectioned view of the track band transmission of figure 1;
• Figure 3 is a perspective view of the suspension system according to the present invention.
• Figure 4 is a schematic representation of the suspension system of figure 3;
• Figure 5 is a partial sectioned view of a track band transmission comprising a first alternative embodiment of the suspension system of the present invention
• Figure 6 is a perspective view of the suspension system of the track band transmission of figure 5;
• Figure 7 is a partial sectioned view of a track band transmission comprising a second alternative embodiment of the suspension system of the present invention.
• Figure 8 is a perspective view of the suspension system of the track band transmission of figure 7; • Figure 9 is a schematic representation of the suspension system of figure 8;
• Figure 10 is a partial sectioned view of a track band transmission comprising a third alternative embodiment of the suspension system of the present invention.
• Figure 11 is a perspective view of the suspension system of the track band transmission of figure 10.
• Figure 12 is a partial sectioned view of an alternative embodiment of the track band transmission comprising a suspension system according to the present invention .
• FIG. 1 it is disclosed a track band transmission 1 for an agricultural vehicle (not shown) , such as a tractor, according to a preferred embodiment of the present invention.
• Track band transmission 1 essentially comprises a driving wheel 2 and two couples of wheels 3,4, more specifically a couple of front idler wheel 3 and a couple rear idler wheel 4 and an endless track band 5 which is wrapped around the driving wheel 2 and the front and rear idler wheels 3,4.
• the track band transmission 1 further comprises an undercarriage 10 coupled to the agricultural vehicle and comprising a main portion 11 having substantially a rectangular shape and a secondary portion 12, defining substantially a vertical abutment extending from the middle of the main portion 11 towards driving wheel 2.
• the secondary portion 12 comprises an hinge 13 by which the undercarriage 10 is coupled pivotally, around an axis A of rotation, to the agricultural vehicle.
• the main portion 11 comprises instead respective front and rear extremities 11a, lib to which the couple of idler wheels 3, 4 are hinged in a common way
• the track band transmission 1 may further comprise preloading means 16 coupled to undercarriage 10 and configured to ensure a predetermined level of tension of endless track band 5 around wheels 2, 3 and 4.
• Preloading means 16 may be housed inside an inner volume 17 of the undercarriage 10 and essentially comprise an hydraulic cylinder 20 whose housing is fixed to the rear extremity lib of the main portion 11 of the undercarriage 10, dampening means 22 fixed to the coupling of front wheel 3 to the undercarriage 10 and a movable sleeve 21 fixed to its rear extremity to a road of the hydraulic cylinder 20 and to its front extremity to the dampening means 22.
• Dampening means 22 may comprise a spring 22a and a damper 22b coaxial to spring 22a itself.
• the hydraulic cylinder 20, modifying the length of its road allows front wheel 3 to get closer or farther with respect to rear wheel 4 thereby increasing or lowering the tension, i.e. the preload, of track band 5.
• Dampening means 22 allow preset fluctuations of the tension of the track band 5 during its use.
• the track band transmission 1 further comprises a suspension system 30 coupled to the undercarriage 10 in a lower central part of the main portion 11 and configured to cooperate with track band 5 as below described.
• the suspension system 30 essentially comprises first and second roller groups 31, 32 each hinged to the undercarriage 10 through respective first and second rocker arms 33, 34 which are further coupled together through a third rocker arm 35.
• first and second rocker arms 33, 34 are hinged to the undercarriage 10 thanks to respective hinges 42, 43 positioned between the extremities of the first and second rocker arms 33, 34 themselves.
• hinges 42, 43 each are positioned substantially in the middle with respect to the length of the respective first and second rocker arms 33, 34.
• lower extremities 33a, 34a of first and second rocker arms 33, 34 are further hinged to first and second roller groups 31, 32 via hinges 44, 45 and upper extremities 33b, 34b of first and second rocker arms 33, 34 are hinged to the third rocker arm 35 via hinges 46, 47.
• the first roller group 31 may comprise two couples of rollers 31a, 31b connected together thanks to a boogie 37 and configured to cooperate with the track band 5.
• each roller 31a, 31b may be hinged to the boogie 37 thanks respective hinges 48a, 48b and the boogie 37 is hinged the rocker arm 33 via hinge 44.
• the couple of rollers 31a, 31b are hinged to boogie 37 symmetrically with respect to hinge 44.
• the second roller group 32 may comprise a single couple of rollers 32a connected to the rocker arm 34 via hinge 45 and configured to cooperate with the track band 5.
• the rocker arm 35 allows that the movement of the rocker arm 34 is transmitted to the rocker arm 33, i.e. the movement of roller group 31 will cause a movement on roller group 32.
• the third rocker arm 35 may be realized as a rigid element so that the movement of the roller group 31 directly cause a movement on the roller group 32 without any substantial damping.
• the rocker arm 35 being coupled pivotally via hinges 46 and 47 respectively to rocker arms 33 and 34 works mainly in a compression/traction state, therefore it can bear very high loads.
• the suspension system 30 of the aforementioned embodiment may be schematized as follows. For sake of clarity, all the distances are referred to the hinge 13 which defines the pivot around axis A of the undercarriage 10.
• the hinges 46 and 47 of the third rocker arm 35 define two axis B, C of rotation for respectively the first and second rocker arms 33, 34 with respect to the third rocker arm 35.
• the hinges 42, 43 of the first and second rocker arms 33, 34 on the undercarriage 10 define two further axis of rotation D, E of these latter with respect to the undercarriage 10.
• the hinge 44 of first rocker arm 33 with the boogie 37 defines a further axis F of rotation of the boogie 37 around the rocker arm 33.
• the hinges 48a, 48b define axis I, II of rotation of the rollers 31a, 31b with boogie 37 and finally hinge 45 defines axis III of rotation of roller 32 with the extremity of the rocker arm 34. All the aforementioned axis are parallel to each other.
• axis A is collinear with axis II.
• the horizontal distance between axis A and D is XI while the horizontal distance between axis A and axis E is two times XI.
• the horizontal distance between axis F axis A is equal to X2 while the distance between axis III and axis A is equal to two times X2.
• the axis I, II, III are collinear to each other and similarly axis F and E are collinear between them.
• the axis B and D are respectively positioned vertically closer to axis A with respect to axis C and E.
• a force e.g. 3F
• hinge 13 If a force, e.g. 3F, acts on hinge 13, thanks to the above described geometrical configuration, it can be split in equal parts, i.e. on three forces equal to F, on each of the pairs of rollers 31a, 31b and 32a.
• roller groups 31 or 32 If one of the roller groups 31 or 32 is moved from its position by ground irregularities, e.g. a stone on the ground which give an impulse to roller group 31, thanks to the third rocker arm 35 the impulse given to the roller group 31 is transmitted to roller group 32 and therefore, thanks to the aforementioned described configuration, equally divided between the pairs of rollers 31a, 31b and 32a.
• ground irregularities e.g. a stone on the ground which give an impulse to roller group 31
• the impulse given to the roller group 31 is transmitted to roller group 32 and therefore, thanks to the aforementioned described configuration, equally divided between the pairs of rollers 31a, 31b and 32a.
• undercarriage 10 and the suspension system 30 are internally balanced.
• the undercarriage 10 rotates about pivot A independently from the dynamic of the elements of the suspension system 30. In this way, the movement of suspension system 30 is not transmitted to the vehicle as well as the vibrations due to ground contour.
• Dampening means 60 may comprise a spring 61 and/or a damper 62.
• the spring 61 may be realized as a coil spring and the damper 62 may be realized as an hydraulic cylinder.
• the spring 61 and the damper 62 are positioned coaxially in parallel between hinges 46 and 47.
• dampening means 60 allows to vary the position of roller groups 31 and 32 with respect to the ground by increasing or decreasing the length of the damping means 60 themselves. This allows to achieve a sort of "levelling function" which improve the capability of the rollers to follow the ground contour.
• the suspension system 30 comprises two roller groups 31, 32, each comprising two rollers 31a, 31b; 32a, 32b connected together by respective boogies 37; in particular, each roller 31a, 31b; 32a, 32b may be hinged to the boogies 37 through respective hinges 48a, 48b; 49a, 49b.
• the boogies 37 are hinged the respective rocker arms 33 via hinges 44, 45.
• suspension system 30 of the aforementioned embodiment may be schematized as follows. For sake of clarity, all the distances are referred to the hinge 13 which defines the pivot around axis A of the undercarriage 10.
• the hinges 46 and 47 of the third rocker arm 35 define two axis B, C of rotation for respectively the first and second rocker arms 33, 34 with respect to the third rocker arm 35.
• the hinges 42, 43 of the first and second rocker arms 33, 34 on the undercarriage 10 define two further axis of rotation D, E of these latter with respect to the undercarriage 10.
• the hinges 44, 45 of first and second rocker arm 33, 34 with boogies 37 define further axis F, G of rotation of the boogies 37 around the respective arms.
• the hinges 48a, 48b; 49a, 49b of the two couples of rollers 31a, 31b; 32a, 32b define axis I, II, III and IV of rotation of the two couple of rollers 31a, 31b; 32a, 32b themselves with respective boogies 37.
• axis A is positioned in the middle of the horizontal distance between axis II and III.
• axis I, II, III and IV are collinear to each other, similarly axis F and G, axis D and E and axis B and C are respectively collinear to each other .
• a force e.g. 4F
• hinge 13 If a force, e.g. 4F, acts on hinge 13, thanks to the above described geometrical configuration, it can be split in equal parts, i.e. on four forces equal to F, on each of the two pairs of rollers 31a, 31b; 32a, 32b.
• roller groups 31 or 32 If one of the roller groups 31 or 32 is moved from its position by ground irregularities, e.g. a stone on the ground which gives an impulse to roller group 31, thanks to the third rocker arm 35 the impulse given to the roller group 31 is transmitted to roller group 32 and therefore, thanks to the aforementioned described configuration, divided between the two pairs of rollers 31a, 31b; 32a, 32b.
• ground irregularities e.g. a stone on the ground which gives an impulse to roller group 31
• the impulse given to the roller group 31 is transmitted to roller group 32 and therefore, thanks to the aforementioned described configuration, divided between the two pairs of rollers 31a, 31b; 32a, 32b.
• the hinges 48a, 48b of the first roller group 31 and the hinge 45 of the second roller group 32 may allow a rotation of rollers 31a, 31b and 32 around an axis Y perpendicular to their axis of rotation I, II and III.
• First and second roller groups 31, 32 further comprise stop means 70 configured to limit the amplitude of rotation of the pair of rollers 31a, 31b and 32 around axis Y.
• stop means 70 may comprise a couple of stops 71 fixed respectively to the boogie 37 and to the rocker arm 34 and configured to cooperate with a respective couple of projections 72 fixed respectively to the hinges 48a, 48b of the first roller group 31 and the hinge 45 of the second roller group 32.
• rollers 31a, 31b and 32 The rotation of rollers 31a, 31b and 32 around axis Y is limited in function of the relative angular position of stops 71 with respect to projections 72 thereby defining an angular clearance.
• Figure 12 discloses an alternative embodiment for track band transmission 1 comprising a suspension system 30 as previously described.
• the main portion 11 of the undercarriage 10 comprises two portions, an upper portion 90 and a lower portion 91.
• the upper portion 90 defines the inner volume 17 into which the preloading means 16 are housed, the lower portion 91 instead defines the support for hinges 42 and 43 of the suspension system 30.
• the lower portion 91 is coupled to upper portion 90 by a couple of lateral hinges 93 defined in the extremities 11a, lib of the main portion 11.
• Lateral hinges 93 may be realized as elastic joints defining a damping between the lower portion 91 and the upper portion 90.
• the undercarriage 10 may further comprise stop means 94 comprising bumpers 95 carried, e.g., to the upper portion 90 and configured to limit excessive vertical movements of the lower portion 91 with respect to the upper portion 90 by cooperating with correspondent stops 96 carried by the lower portion 91.
• the lower portion 91 may be uncoupled from the upper portion 90, it may be possible to couple and uncouple different typologies of lower portion 91 to the same upper portion.
• the suspension system 30 guarantees an equal repartition of the loads acting on each roller 31a, 31b, 32 even in case of impulse forces acting on one of them.
• the dynamic independency of the undercarriage 10 and the suspension system 30 allows a substantial reduction of the vibration transmitted from the ground to the vehicle.
• the suspension system 30 is made only of mechanical elements and therefore is simply to manufacture and cheap. Moreover the maintenance of such mechanical elements is simpler and there is no need of hydraulic circuits or complex electronic controls.
• the useful life of the track band 5 is improved since the load of the rollers 31a, 31b, 32 is equal even if the ground contour is irregular. In fact, as said, force impulses are equally divided between rollers 31a, 31b, 32 and there are not overloads on the track band 5.
• each roller 31a, 31b, 32 is substantially free of moving in vertical and horizontal direction, obviously dynamically coupled to the other rollers 31a, 31b, 32 themselves, allows a better capacity of the rollers 31a, 31b, 32 to follow the ground contour and therefore enhance the capability of the system to cross obstacles.
• rollers 31a, 31b, 32 moreover decreases their resistance and therefore the fuel consumption of the vehicle and the wear of the machine.
• dampening means 60 increase the capability of the suspension system 30 to dampen the vibrations; further it increases the possibility of rollers 31a, 31b, 32 to follow ground contours.
• rollers 31a, 31b; 32a, 32b allows the use of the suspension system 30 also in vehicle which have heavy loads acting on track band 5.
• the additional revolute joints 48a, 48b; 49a, 49b in longitudinal direction improve the lateral compliance of the rollers 31a, 31b, 32 on the ground.
• the main portion 11 of the undercarriage 11 comprise a lower portion 91 which may be uncoupled from an upper portion 90 and substituted by a different one, increase the flexibility of the track band transmission 1.
• its manufacture may be simplified since all the upper parts will be equal for different typologies of lower parts of the undercarriage 10, thereby reducing again costs.
• rocker arms 33, 34, 35 or of other elements of suspension system 30 may be varied if the relative distances between the hinges are maintained.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Vehicle Body Suspensions (AREA)
• Communication Control (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=62089985

Family Applications (1)

Country Status (2)

Cited By (1)

Citations (6)

• 2018
  • 2018-02-22 IT IT102018000002954A patent/IT201800002954A1/it unknown
• 2019
  • 2019-02-19 WO PCT/EP2019/054038 patent/WO2019162247A1/en active Application Filing

Patent Citations (6)

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