WORK VEHICLE

Description

TECHNICAL FIELD

[0001] The present invention concerns a work vehicle.BACKGROUND OF THE INVENTION

[0002] Work vehicles are known comprising a main body, a locomotion system including wheels or tracks for moving the main body with respect to the ground, a propulsion system including a thermal engine and / or an electric motor, and a driveline, which operatively connects the locomotion system to the propulsion system.

[0003] In general, the drivelines comprise a plurality of mechanical components (e.g., gears and bearings), which are lubricated to reduce friction and wear between their contact surfaces. By way of example, the drivelines are lubricated by oil splashing, i.e., by splashing caused by the movement of the mechanical components.

[0004] For this purpose, the work vehicle comprises an oil sump, which contains oil in which the mechanical components are partially immersed, and which is adapted to collect the oil that falls due to gravity after lubricating the mechanical components.

[0005] However, the capacity of oil of the drivelines is limited by the fact that as the amount of oil increases, the power losses increase, as a consequence of the fact that the oil level in the oil sump rises and the portion of the mechanical components immersed in the oil increases.

[0006] The work vehicles are known to further comprise at least one hydraulically operated implement and a relative hydraulic circuit for the actuation of the implement.

[0007] In detail, the circuit comprises the oil sump, the hydraulically operated implement, a pump and a remote valve, as shown for example in DE102015223566A1. The oil pump is adapted to suck oil from the oil sump and to deliver it to the remote valve. The oil flowing through the remote valve is used to actuate the implement and is then discharged into the oil sump. In other words, the oil contained in the oil sump is adapted both to lubricate the mechanical components of the driveline and to actuate the implement(s).

[0008] However, the flow of oil arriving in the oil sump from the remote valve is characterized by high velocity and tends to cause turbulence of the oil contained therein, consequently affecting lubrication quality.

[0009] The quality of lubrication is further reduced by aeration of the oil caused by splashing and high velocity of the flow coming from the remove valve.

[0010] Therefore, there is a need within the industry for a driveline assembly for a work vehicle allowing the quality of lubrication of the mechanical components of the driveline to be improved.SUMMARY OF THE INVENTION

[0011] The aforementioned aim is reached by a work vehicle, as claimed in the appended independent claim.

[0012] Preferred embodiments of the invention are realized according to the claims dependent or related to the above independent claim.BRIEF DESCRIPTION OF DRAWINGS

[0013] For a better understanding of the present invention, one preferred embodiment is described in the following, by way of a non-limiting example, with reference to the attached drawing wherein: Figure 1 is a schematic representation of a work vehicle comprising a driveline assembly according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] With reference to figure 1, numeral 10 indicates a work vehicle, in particular an agricultural vehicle such as a tractor.

[0015] Work vehicle 10 comprises a main body 11, a plurality of wheels 12, which are rotatable relative to main body 11 about respective rotational axes and motor means 13 (e.g., a thermal engine and / or an electric motor) adapted to rotate wheels 12 about their respective rotational axes.

[0016] Work vehicle 10 further comprises a driveline assembly 1. Driveline assembly 1 comprises, in turn, a driveline 2 adapted to operatively connect motor means 13 to wheels 12 and an oil sump 3 for collecting by gravity an oil adapted to lubricate driveline 2.

[0017] Driveline 2 comprises a plurality of mechanical components - which are known per se and not shown - adapted to transmit motion from motor means 13 to wheels 12. By way of example, driveline 2 comprises a plurality of wheels and bearings. In further detail, at least some of the mechanical components are at least partially immersed in the oil contained in oil sump 3.

[0018] Driveline assembly 1 also comprises a container 5 enclosing at least in part driveline 2. In addition, container 5 comprises oil sump 3 or is defined at least in part by oil sump 3. Preferably but not necessarily, oil sump 3 constitutes the lowermost portion of container 5 according to a direction vertical to the ground on which wheels 12 rest, i.e., the portion of container 5 closest to the ground.

[0019] Advantageously, driveline assembly 1 comprises an oil reservoir 4 adapted to contain oil, fluidly connected to oil sump 3 and arranged at least in part below oil sump 3 according to the direction of the gravitational acceleration vector g. In particular, oil reservoir 4 is adapted to contain the same oil contained in oil sump 3.

[0020] Specifically, the acceleration vector g to be considered is the one acting on driveline assembly 1 or work vehicle 10. For example, the acceleration vector g is applied in the center of mass of work vehicle 10.

[0021] In other words, oil reservoir 4 is closer to the ground on which wheels 12 rest than oil sump 3.

[0022] Preferably, oil reservoir 4 is arranged underneath oil sump 3 according to the direction of the gravitational acceleration vector g.

[0023] Oil reservoir 4 is arranged externally to container 5. Therefore, the mechanical components of driveline 2 are not immersed in the oil volume contained in oil reservoir 4.

[0024] In detail, driveline assembly 1 comprises a duct 6 fluidly connecting oil sump 3 to oil reservoir 4. Accordingly, the oil contained in oil sump 3 flows to oil reservoir 4 through duct 6 due to gravity.

[0025] Work vehicle 1 further comprises at least one implement 50, which is hydraulically operated and an actuation circuit 51 for the actuation of implement 50. By way of example, implement 50 is a front end loader.

[0026] The actuation circuit 51 comprises, in turn, a pump 52 adapted to suck oil from oil sump 3, a remote valve 20 fluidly connected to pump 52, the implement 50 fluidly connected to remote valve 20 and a duct 7 fluidly connecting remote valve 20 to driveline assembly 1 (Figure 1).

[0027] Pump 52 is adapted to deliver the oil sucked from oil sump 3 to remote valve 20.

[0028] As schematized in Figure 1, actuation circuit 51 comprises in succession a stretch 24a fluidly connecting pump 52 to remote valve 20, a stretch 24b fluidly connecting remote valve 20 to implement 50 and a stretch 24c fluidly connecting implement 50 to remote valve 20.

[0029] Duct 7 comprises a stretch 21 extending from remote valve 20, a stretch 22 fluidly connecting stretch 21 to oil sump 3 and a stretch 23 fluidly connecting stretch 21 to oil reservoir 4. In detail, stretches 21, 22 and 23 are jointed with one another by a T-connection or a three-way fitting.

[0030] According to the invention, driveline assembly 1 comprises valve means adapted to control the flow of oil between stretch 21 and oil sump 3 and / or between stretch 21 and oil reservoir 4. In particular, the valve means are arranged at duct 7 and comprise a hydraulically actuated valve or an electro-hydraulically actuated valve.

[0031] In detail, the valve means are adapted to control the flow of oil such that the flow rate of oil flowing between stretch 21 and oil reservoir 4 is greater than the flow rate of oil flowing between stretch 21 and oil sump 3. In further detail, the valve means may be adapted to completely deny the fluidic communication between stretch 21 and oil sump 3 and allow the fluidic communication between stretch 21 and oil reservoir 4.

[0032] Furthermore, the extension of the cross section of duct 6 is greater than the extension of the cross section of duct 7. In detail, cross section shall mean the section of the duct 6, 7 perpendicular to the longitudinal direction of the same duct 6, 7.

[0033] Preferably, actuation circuit 51 comprises deaeration means 53 adapted to remove oxygen and other dissolved gases from the oil flowing through it. In detail, actuation circuit 51 comprises a deaerator 54 at stretch 22 and / or a deaerator 55 at stretch 23.

[0034] Preferably but not necessarily, drivelines assembly 1 also comprises a pumping system 8, which is adapted to suck oil from oil sump 3 and to direct it to the mechanical components of driveline 2 to be lubricated.

[0035] The operation of driveline assembly 1 and work vehicle 10 according to the present invention is described in the following.

[0036] In use, the oil of driveline assembly 1 is contained in part in oil sump 3 and in part in oil reservoir 4.

[0037] During operation, driveline 2 transmits motion from motor means 13 to wheels 12 and the mechanical components of driveline 2 are lubricated by oil splashing and pumping system 8. In particular, at least some of the mechanical components of driveline 2 are partially immersed in the oil contained in oil sump 3 and lubricate the contact surfaces thereof by virtue of their movements. At the same time, pumping system 8 sucks oil from oil sump 3 and sprays it towards the mechanical components of driveline 2.

[0038] After lubricating the surfaces of mechanical components, the oil falls by gravity and is collected by oil sump 3. In addition, the oil flows from oil sump 3 to oil reservoir 4 through duct 6 due to gravity.

[0039] At the same time, pump 52 sucks oil from oil sump 3 and delivers it to remote valve 20. Remote valve 20, in turn, delivers the sucked oil towards implement 50. In detail, oil flows from pump 52 to remote valve 20 through stretch 24a and from remote valve 20 to implement 50 through stretch 24b.

[0040] After actuating implement 50, the oil flows back to remote valve 20 through stretch 24c and then towards oil sump 3 through stretch 22 and oil reservoir 4 through stretch 23.

[0041] In the not-shown embodiment comprising the valve means, valve means control the flow of oil flowing between stretch 21 and oil sump 3 and / or between stretch 21 and oil reservoir 4.

[0042] In view of the foregoing, the advantages of driveline assembly 1 and work vehicle 10 according to the invention are apparent.

[0043] In particular, since driveline assembly 1 comprises oil reservoir 4, which is connected to oil sump 3 and arranged below oil sump 3, the oil capacity of driveline assembly 1 is increased without causing an increase in power losses.

[0044] Since driveline assembly 1 comprises duct 7, which fluidly connects remote valve 20 to oil sump 3 and oil reservoir 4, the oil flow from remote valve 20 is split between oil sump 3 and oil reservoir 4. This allows the velocity of the flow coming from remote valve 20 and directed to oil sump 3 to be reduced. As a result, turbulence and aeration of the oil is limited. In particular, oil reservoir 4 allows the oil to stagnate and to be deaerated. This effect can be enhanced by causing the oil flow rate directed to the oil reservoir to be much greater than the oil flow rate directed to the oil sump.

[0045] For the same reason as above, the suction capability of pumping system 8 is increased.

[0046] In addition, since the extension of the cross section of duct 6 is greater than the extension of the cross section of duct 7, the velocity of the oil flowing from oil reservoir 4 to oil sump 3 through duct 6 is significantly reduced. This allows turbulence and aeration of the oil to be further limited. Deaeration may be enhanced also by means of deaerator means 53.

[0047] It is clear that modifications can be made to driveline assembly 1 and work vehicle 10 which do not extend beyond the scope of protection defined by the claims.

[0048] In particular, work vehicle 10 might comprise tracks instead of wheels 12.

[0049] Work vehicle 10 might comprise more than one implement 50 and more than one actuation circuits 51.

Claims

1. Work vehicle (10) comprising: - a main body (11); - locomotion means (12) adapted to move said main body (11) with respect to a reference system; - motor means (13) adapted to drive said locomotion means (12); - a driveline assembly (1) comprising: - a driveline (2) adapted to operatively connect the motor means (13) of said work vehicle (10) to the locomotion means (12; of said work vehicle (10); - an oil sump (3) adapted to collect an oil lubricating, in use, said driveline (2); - an oil reservoir (4) adapted to contain said oil; wherein said oil reservoir (4) is fluidly connected to said oil sump (3) and arranged at least in part below said oil sump (3) according to the direction of the gravitational acceleration vector (g); said work vehicle further comprising: - at least one implement (50), which is hydraulically operated, in use; - an actuation circuit (51) for the actuation of said implement (50); characterized in that said actuation circuit (51) comprising: - a pump (52) adapted to suck said oil from said oil sump (3); - a remote valve (20) fluidly connected to said pump (52) and said implement (50); - a second duct (7) fluidly connecting said remote valve (20) to said driveline assembly (1); said pump (52) being adapted to deliver, in use, said oil sucked from said oil sump (3) to said remote valve (20), wherein said second duct (7) comprises: - a first stretch (21) extending from said remote valve (20) ; - a second stretch (22) fluidly connecting said first stretch (21) to said oil sump (3); and - a third stretch (23) fluidly connecting said first stretch (21) to said oil reservoir (4), said work vehicle comprises valve means adapted to control the flow of oil between said first stretch (21) and said oil sump (3) and / or between said first stretch (21) and said oil reservoir (4).

2. Work vehicle according to claim 1, comprising a container (5) enclosing at least in part said driveline (2); said container (5) enclosing said oil sump (3) or defined at least in part by said oil sump (3); wherein said oil reservoir (4) is arranged externally to said container (5).

3. Work vehicle according to claim 1 or 2, comprising a first duct (6) fluidly connecting said oil sump (3) to said oil reservoir (4).

4. Work vehicle according to any one of the foregoing claims, comprising a pumping system (8) adapted to suck said oil from said oil sump (3) and to direct it, in use, to said driveline (2) to lubricate it.

5. Work vehicle according to any of the foregoing claims, wherein said valve means are adapted to control the flow of oil such that the flow rate of said oil flowing, in use, between said first stretch (21) and said oil reservoir (4) is greater than the flow rate of said oil flowing, in use, between said first stretch (21) and said oil sump (3).

6. Work vehicle according to any of the foregoing claims, wherein said valve means comprise a hydraulically actuated valve or an electro-hydraulically actuated valve.

7. Work vehicle according to any of the foregoing claims, wherein the extension of the cross section of said first duct (6) is greater than the extension of the cross section of said second duct (7).

8. Work vehicle according to any of the foregoing claims, wherein said actuation circuit (51) comprises deaeration means (53).

9. Work vehicle according to any of the foregoing claims, wherein deaeration means (53) comprise a deaerator (54, 55) at said second stretch (22) and / or at said third stretch (23).