Suspension element and construction vehicle

Abstract

The disclosure concerns a suspension element (12) for a suspension between a cabin (6) and a chassis (4) of a vehicle (2). The suspension element (12) comprises: a hydraulic cylinder (14), an end member (20) arranged at an end portion (26) of the cylinder (14) and displaceable in relation to a first fastening member (16) by the cylinder (14), a first sleeve connected to the end member (20), a second sleeve (30) arranged around a portion of the first sleeve (28) and being connected to a second fastening member (22), and a resilient member (32) arranged between the first and second sleeves (28, 30). An axial load is transferable between the first and second sleeves (28, 30) via the resilient member (32).

Description

[0001] Suspension Element and Construction Vehicle

[0002] TECHNICAL FIELD

[0003] The invention relates to a suspension element and to a construction vehicle.

[0004] BACKGROUND

[0005] A cabin of a vehicle that is used on, and / or travels on, rough and uneven surfaces is subjected to bumps, shocks, and other sudden directional changes. Construction vehicles are typically such vehicles.

[0006] Accordingly, a driver sitting in the cabin of a construction vehicle is subjected to these sudden directional changes. At the least such sudden directional changes may be uncomfortable to the driver.

[0007] Therefore, on a modern construction vehicle, a suspension system is provided between the cabin and the chassis of the construction vehicle. The suspension system dampens shocks to eliminate some of the effects that the sudden directional changes have on the cabin and to at least alleviate the impact of some of the larger sudden directional changes on the cabin.

[0008] The suspension system may comprise a number of individual suspension elements to be arranged between the cabin and the chassis.

[0009] Such suspension elements may comprise one or more elastic members. For instance, EP 3798029 discloses a suspension arrangement for suspending a cab with respect to a body of a work vehicle. The suspension arrangement comprises a primary elastic block, a second elastic block and an intermediate mass interposed in series between first and second elastic blocks. The primary elastic block cooperates at contact with a portion of the body of the work vehicle from one side and with the intermediate mass from the opposite side. The second elastic block cooperates at contact with a portion of the cab from one side and with the intermediate mass from the opposite side. The first and second elastic blocks and the intermediate mass are maintained in contact with the cab and the portion of the body in a preset preload by means of a compacting means in the form of a screw.

[0010] In other suspension systems, the individual suspension elements may comprise hydraulic elements. For instance, EP 2223845 discloses an agricultural vehicle having a hydraulic system, a cab for the vehicle operator and a self-levelling cab suspension system. The suspension system comprises a plurality of suspension units each having a spring, a damper and an accumulator. The accumulator comprises a hydraulic working chamber which is separated by a movable wall from a gas filled chamber serving as a spring. The working chamber is also connected to a working chamber of the damper in a closed hydraulic circuit. There is no need for a dedicated oil pump since a hydraulic actuator powered by the vehicle hydraulic system is provided for causing hydraulic fluid to flow in the closed hydraulic circuit between the working chamber of the accumulator and the damper, so as to vary the height of the cab without any fluid from the vehicle hydraulic system entering or leaving the closed hydraulic circuit of the damper and the accumulator.

[0011] As a construction vehicle is used on, and / or travels over, uneven ground, different parts of the vehicle and accordingly, different parts of the cabin are subjected to different directional changes, which lead to the individual suspension elements of a suspension system between the cabin and the chassis being subjected to different sudden directional changes. This leads to the cabin taking various tilted positions in relation to the chassis. Moreover, in a suspension system of the hydraulic kind e.g., as discussed in EP 2223845, the cabin may be actively tilted in relation to the chassis in order to at least partially compensate for the vehicle standing on, or traveling along, an inclined surface.

[0012] Also, EP 3059104 discloses a hydraulic cylinder device to be used at a suspension arrangement for shock, noise and vibration damping suspension of an operator cab on a frame of a working machine. An outer end of a piston rod of the hydraulic cylinder is provided with a fastening ring in which a resilient rubber bushing is mounted which has an eccentric positioned metal sleeve having a through hole, through which a rod formed attachment on the lower side of the operator cab is adapted to be inserted for articulated connection between the hydraulic cylinder and the operator cab.

[0013] SUMMARY

[0014] It would be advantageous to achieve a suspension element for a suspension system of a cabin that enables a tilting of the cabin in relation to the chassis. In particular, it would be desirable to reduce effects of stress on a hydraulic suspension element when the cabin of the vehicle tilts in relation to the chassis. To better address one or more of these concerns, one or more of a suspension element and a construction vehicle having the features defined in one or more of the independent claims is provided.

[0015] According to an aspect of the invention, there is provided a suspension element for a suspension between a cabin and a chassis of a vehicle. The suspension element comprises a hydraulic cylinder having a longitudinal centre axis, a first fastening member arranged at a first end portion of the hydraulic cylinder, the first fastening member being configured for fastening to the chassis of the vehicle, an end member arranged at a second end portion of the hydraulic cylinder and displaceable along the longitudinal centre axis in relation to the first fastening member by the hydraulic cylinder, a first sleeve arranged around a portion of the hydraulic cylinder and being connected to the end member, a second fastening member arranged radially outside the hydraulic cylinder between the first fastening member and the end member and displaceable along the longitudinal centre axis, the second fastening member being configured for fastening to the cabin of the vehicle, a second sleeve arranged around a portion of the first sleeve and being connected to the second fastening member, and a resilient member arranged between the first and second sleeves. A first portion of the resilient member is fixedly arranged in relation to the first sleeve and a second portion of the resilient member is fixedly arranged in relation to the second sleeve, such that an axial load is transferable between the first and second sleeves via the resilient member.

[0016] Since the first portion of the resilient member is fixedly arranged in relation to the first sleeve and the second portion of the resilient member is fixedly arranged in relation to the second sleeve, such that an axial load is transferable between the first and second sleeves via the resilient member - the cabin, which is connected to the second fastening member, is supported on the chassis via the resilient member, which in turn is connected to the chassis via the hydraulic cylinder and the first fastening member. Moreover, since the resilient member is arranged between the first and second sleeves - the first and second sleeves and accordingly, the thereto connected first and second fastening members are permitted to tilt in relation to each other as parts of the resilient member are compressed and / or displaced between the first and second sleeves. This provides for the first and second fastening members to be tilted in relation to each other while a negative effect of a resulting bending load on the hydraulic cylinder is eliminated or at least reduced. Thus, when installed in a construction vehicle, stress on the hydraulic cylinder of the suspension element due to tilting of the cabin in relation to the chassis is eliminated or at least reduced.

[0017] Moreover, in comparison with the use of a fastening ring at the end of a piston rod of a hydraulic cylinder as disclosed in EP 3059104, the present suspension element provides a construction that allows for a lower total height thus, being more compact. Specifically, a distance between the first fastening member being configured for fastening to the chassis of the vehicle and the second fastening member being configured for fastening to the cabin of the vehicle can be made smaller than the distance between the connection elements / points to the cabin and the chassis of the EP3059104 hydraulic cylinder. According to a further aspect of the invention, there is provided a construction vehicle comprising a chassis, a cabin, and at least one suspension element according to any one of aspects and / or embodiments discussed herein arranged between the chassis and the cabin.

[0018] In a manner as discussed above, in the construction vehicle, the at least one suspension element provides for a tilting of the cabin in relation to the chassis while a negative effect of a resulting bending load on the hydraulic cylinder is eliminated or at least reduced. Thus, in the construction vehicle, stress on the hydraulic cylinder of the suspension element due to tilting of the cabin in relation to the chassis is eliminated or at least reduced.

[0019] The construction vehicle may be any vehicle that is used on, and / or travels on, rough and uneven surfaces and as such is subjected to bumps, shocks, and other sudden directional changes. The construction vehicle may be used e.g., at construction sites, for road clearing, in forestry, and / or in agriculture. For instance, the construction vehicles may be a wheel loader, a tractor, an excavator, a road grader, a dumper truck, or a tracked vehicle.

[0020] The cabin of the construction vehicle is arranged on the chassis of the construction vehicle. The suspension element is arranged between the cabin and the chassis. For instance, the suspension element is arranged between the cabin and the chassis such that the suspension element is subject to a vertical load by a portion of the weight of the cabin when the construction vehicle is standing on a horizontal surface.

[0021] In the construction vehicle, when standing on a horizontal surface, the suspension element may be arranged on the chassis with the first fastening member connected to the chassis and with the longitudinal center axis of the hydraulic cylinder extending substantially vertically. The cabin is connected to the second fastening member.

[0022] The suspension element may form part of a set of suspension elements wherein each of the individual suspension elements supports part of the weight of the cabin. Accordingly, the set of suspension elements supports the entire weight of the cabin. For instance, one suspension element may be arranged at outer portions, such as corner portions, of the cabin. One set of suspension elements may comprise 2, 3, 4, or more individual suspension elements. The suspension elements of the set of suspension elements may be of the same kind or of different kinds. Suspension elements of the same kind may be of the same or of different dimensions. For instance, they may be of different dimensions because some of the suspension elements carry a greater portion of the total load of the cabin than other of the suspension elements.

[0023] The set of suspension elements forms part of a suspension system and a hydraulic system. The suspension and hydraulic systems may include hydraulic components for supplying hydraulic fluid to the hydraulic cylinders of the suspension elements, and / or components for controlling flow, pressure, etc. of the hydraulic fluid. The suspension system may comprise components for controlling the suspension elements e.g., one or more sensors, control electronics, an input device, etc.

[0024] Herein, axial and radial references are made in relation to the longitudinal center axis of the hydraulic cylinder.

[0025] The hydraulic cylinder may comprise a tubular member, a piston, and a rod connected to the piston. An inside of the tubular member is divided into two chambers by the piston. A channel between the two chambers may extend through the piston. Thus, the two chambers are arranged in fluid communication with each other, and the pressure of a hydraulic fluid will be the same in the two chambers when the hydraulic cylinder is in a state of equilibrium.

[0026] Since the piston area of the piston is smaller on its side where the piston is connected to it than on its opposite side, a resulting force of the hydraulic fluid in the hydraulic cylinder will bias the piston and the rod in a direction away from the chamber at the larger piston area. Accordingly, a cabin that is supported on a chassis by the suspension element may be raised when the hydraulic pressure in the hydraulic cylinder causes a resulting force on the piston to be larger than the weight supported by the suspension element. The piston assumes a rest position when the resulting force on the piston equals the gravitational force of the weight supported by the suspension element.

[0027] For instance, the hydraulic cylinder may comprise one or more features of the hydraulic cylinder described in EP 3059104.

[0028] In operation of the construction vehicle, the rest position may be chosen when the piston is at a position about midway of its stroke within the tubular member. From this position the hydraulic cylinder can now dampen sudden directional changes of the construction vehicle as the directional changes cause the piston to move along the longitudinal center axis of the hydraulic cylinder, such as upwardly and downwardly along the longitudinal center axis. In doing so the amount of hydraulic fluid within each of the two chambers will change. The construction vehicle comprises a hydraulic system including components for providing the pressurized hydraulic fluid to the two chambers, for receiving hydraulic fluid from the two chambers, and for providing a resilience of the hydraulic cylinders.

[0029] The first fastening member comprises suitable means for connecting it to the chassis of the vehicle. Such means may comprise a flange or other protrusions that are provided with through holes for use with screws and nuts, or threaded holes for use with screws, to attach the first fastening member to the chassis. Further alternatives may be to weld or rivet the flange or other protrusions to the chassis.

[0030] The first fastening member may form an axial limiting surface of one of the chambers of the hydraulic cylinder.

[0031] As mentioned above, the end member is displaceable along the longitudinal center axis by the hydraulic cylinder. For instance, the end member may be connected to the rod of the hydraulic cylinder and thus, be displaced as hydraulic pressure within the two chambers changes.

[0032] The second fastening member comprises suitable means for connecting it to the cabin of the vehicle. Such means may comprise a flange or other protrusions that are provided with through holes for use with screws and nuts, or threaded holes for use with screws, to attach the second fastening member to the cabin. Further alternatives may be to weld or rivet the flange or other protrusions to the cabin.

[0033] The first and second sleeves together with the resilient member enable the tilting between the first and second fastening members. Or seen from point of view of the cabin and the chassis, as the cabin is tilted in relation to the chassis from a level position of the cabin and the chassis, the second fastening member will be tilted in relation to the first fastening member. Since the first fastening member is connected via the hydraulic cylinder and the end member to the first sleeve and the second fastening member is connected to the second sleeve, the tilting causes the second sleeve to be angled in relation to the first sleeve.

[0034] This angled position between the first and second sleeves is possible firstly, because the first and second sleeves are arranged with a radial space between them. Namely, within this radial space the resilient member is arranged. As mentioned above, the first portion of the resilient member is fixedly arranged in relation to the first sleeve and the second portion of the resilient member is fixedly arranged in relation to the second sleeve for the axial load caused by part of the cabin to be transferred to the chassis via the resilient member. Thus, secondly, since the resilient member is resilient it permits the angled position between the first and second sleeves by being compressed and expanded at different portions thereof.

[0035] Moreover, due to the arrangement of the second fastening member radially outside the hydraulic cylinder between the first fastening member and the end member, the first and second sleeves, and the resilient member - the rod of the hydraulic cylinder is relieved of the bending force caused by tilting of the cabin in relation to the chassis. Thus, the stress caused by the bending force is less harmful to the hydraulic cylinder. Overall, this provides for a durable suspension element.

[0036] Accordingly, the resilient member may be configured to permit the first sleeve to be angled in relation to the second sleeves. In this manner, as discussed above the tilting of the second fastening member in relation to the first fastening member may be provided for.

[0037] According to embodiments, the resilient member may comprise an elastic ring-shaped member. In this manner, the resilient properties may be provided by a member that is readily positionable between the first and second sleeves.

[0038] According to alternative embodiments, the resilient member may comprise e.g., a helical compression spring.

[0039] According to embodiments, there may be at least one circumferential gap between the first sleeve and the elastic rings-shaped member and / or between the elastic ring-shaped member and the second sleeve. In this manner, at least portions of the circumferential gap may provide room for the elastic ring-shaped member to expand into when the second sleeve is angled in relation to the first sleeve.

[0040] According to embodiments, the first sleeve may comprise a first protrusion extending radially outwardly from the first sleeve and the second sleeve may comprise a second protrusion extending radially inwardly from the second sleeve. The first protrusion may be arranged closer to the first fastening member than the second protrusion. At least a portion of the resilient member may be arranged axially between the first and second protrusions. In this manner, the resilient member may find support against the first and second protrusions, respectively. Thus, an axial load may be transferred between the first and second sleeves via the resilient member. Each of the first and second protrusions may comprise e.g. a flange.

[0041] According to embodiments, the first portion of the resilient member may be arranged at the first protrusion and the second portion of the resilient member may be arranged at the second protrusion. In this manner, the first portion of the resilient member may be fixedly arranged in relation to the first sleeve at the first protrusion and the second portion of the resilient member may be fixedly arranged in relation to the second sleeve at the second protrusion. Thus, an axial load is transferable between the first and second sleeves via the resilient member.

[0042] Further features of, and advantages with, the invention will become apparent when studying the appended claims and the following detailed description.

[0043] BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Various aspects and / or embodiments of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

[0045] Fig. 1 schematically illustrates a construction vehicle according to embodiments, Figs. 2a - 2c illustrate a suspension element according to embodiments, Figs. 3a and 3b illustrate cross sections through a suspension element,

[0046] Figs. 4a and 4b illustrate a suspension element mounted between a chassis and a cabin of a vehicle, and

[0047] Fig. 5 schematically illustrates a hydraulic system of a vehicle.

[0048] DETAILED DESCRIPTION

[0049] Aspects and / or embodiments of the invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and / or clarity.

[0050] Fig. 1 schematically illustrates a construction vehicle 2 according to embodiments.

[0051] The construction vehicle 2 comprises a chassis 4 and a cabin 6. The chassis 6 is provided with wheels 8 and is configured for being driven over rough terrain by a non-shown powertrain of the construction vehicle 2. The construction vehicle 2 may be provided with a working implement 10, such as a bucket, a blade, agricultural equipment, cutting equipment, etc.

[0052] At least one suspension element 12 according to any one of aspects and / or embodiments discussed herein is arranged between the chassis 4 and the cabin 6.

[0053] Figs. 2a - 2c illustrate a suspension element 12 according to embodiments. Fig. 2a shows a perspective view and Figs. 2a and 2b show side views of the suspension element 12.

[0054] The suspension element 12 is a suspension element for a suspension between a cabin and a chassis of a vehicle. The suspension element 12 may be a suspension element for a suspension between a cabin and a chassis of a construction vehicle, such as the schematically illustrated construction vehicle 2 in Fig. 1.

[0055] The suspension element 12 comprises a hydraulic cylinder 14, a first fastening member 16 arranged at a first end portion 18 of the hydraulic cylinder 14, an end member 20 arranged at a second end portion (not visible) of the hydraulic cylinder 14, and a second fastening member 22 arranged radially outside the hydraulic cylinder 14 between the first fastening member 16 and the end member 20.

[0056] The first fastening member 16 is configured for fastening to the chassis of the vehicle. The end member 20 is displaceable in relation to the first fastening member 16 by the hydraulic cylinder 14 along a longitudinal centre axis 24 of the hydraulic cylinder 14 as indicated by the two side views of Figs. 2a and 2b. The second fastening member 22 is displaceable together with the end member 20 along the longitudinal centre axis 24.

[0057] The second fastening member 22 is configured for fastening to the cabin of the vehicle. Thus, the cabin may be suspended on the chassis by the suspension element 12.

[0058] In Figs. 2a and 2b the suspension element 12 is shown in a non-extended or compressed state. In Fig. 2c the suspension element 12 is shown in a partially extended or operational state.

[0059] In use of the suspension element 12 in a vehicle, in the operational state, the cabin is raised in relation to the chassis in comparison with when the suspension element 12 is in the nonextended or compressed state. When in the operational state, the suspension element 12 can be compressed or extended in order to dampen and / or eliminate sudden directional changes of the cabin in relation to the chassis. Typically, such sudden directional changes are caused by the vehicle traveling over uneven ground.

[0060] Moreover, in the operational state, the cabin and the second fastening member 22 together with the end member 20 can be set at different positions along the longitudinal centre axis 24 in relation to the first fastening member 16 and the chassis. Thus, the cabin may be repositioned in a vertical direction within at least part of the stroke provided by the hydraulic cylinder 14. For instance, such repositioning may be utilized for at least partially compensating a height difference between different parts of the cabin caused by the vehicle traveling or standing on an inclination.

[0061] The suspension element 12 is discussed in further detail below with reference to Figs. 3a - 4b. General use of the suspension element 12 is discussed in further detail inter alia with reference to Fig. 5.

[0062] Figs. 3a and 3b illustrate cross sections along the longitudinal centre axis 24 of the suspension element 12 of Figs. 2a - 2c. In Fig. 3a the suspension element 12 is shown in its non-extended or compressed state and in Fig. 3b the suspension element 12 is shown in its partially extended or operational state.

[0063] In the cross section of Figs. 3a and 3b, the entire hydraulic cylinder 14 is shown. Accordingly, in addition to showing the first fastening member 16 being arranged at the first end portion 18 of the hydraulic cylinder14 also, the second end portion 26 of the hydraulic cylinder 14 is shown with the end member 20 being arranged at the second end portion 26.

[0064] The suspension element 12 further comprises a first sleeve 28 arranged around a portion of the hydraulic cylinder 14, a second sleeve 30 arranged around a portion of the first sleeve 28, and a resilient member 32 arranged between the first and second sleeves 28.

[0065] The first sleeve 28 is arranged around a portion of the hydraulic cylinder 14 and is connected to the end member 20. The second sleeve 30 is arranged around a portion of the first sleeve 28 and is connected to the second fastening member 22.

[0066] A first portion 34 of the resilient member 32 is fixedly arranged in relation to the first sleeve 28. A second portion 36 of the resilient member 32 is fixedly arranged in relation to the second sleeve 30. Accordingly, an axial load is transferable between the first and second sleeves 28, 30 via the resilient member 32. In use of the suspension element 12, the axial load includes inter alia a portion of the weight of the cabin.

[0067] The above discussed arrangement of the end member 20, the first sleeve 28 being connected thereto, the second sleeve 30 being connected to the second fastening member 22, and portions 34, 36 of the resilient member 32 being connected to the first and second sleeves 28, 30 provide for the second fastening member 22 being displaceable along the longitudinal centre axis 24 by the hydraulic cylinder 14. Moreover, this also provides for the suspension element 12 carrying at least part of the weight of the cabin that is supported by the suspension element 12, as the second fastening element 22 is connected to the cabin and the first fastening element 16 is connected to the chassis during use of the suspension element 12. Accordingly, the hydraulic cylinder 14 may also dampened effects of sudden directional changes between the cabin and the chassis, as discussed herein.

[0068] For the purpose of connecting the first fastening element 16 to the chassis, in the illustrated embodiments, the first fastening element 16 is provided with a threaded hole 38 for fastening a screw therein. For the purpose of connecting the second fastening element 22 to the cabin, in the illustrated embodiments, see Fig. 2a, the second fastening element 22 is provided with a through holes 40 for fastening screws therethrough. Alternative ways of fastening the first and second fastening members to the chassis and the cabin, respectively, may be utilised.

[0069] The resilient member 32 is configured to permit the second sleeve 30 to be angled in relation to the first sleeve 28, as is also discussed below with reference to Figs. 4a and 4b.

[0070] More specifically, between the first and second sleeves 28, 30 there is a radial space 42. Within the radial space 42 the resilient member 32 is arranged. The resilient member 32 enables the second sleeve 30 to be angled in relation to the first sleeve 28 when the second fastening member 22 is subjected to a bending force. Namely, due to its resilience the resilient member 32 will be compressed at certain portions thereof and / or be expanded at other portions thereof.

[0071] The bending force will be transferred from the second sleeve 30 via the resilient member 32 to the first sleeve 28.

[0072] As mentioned above, the first sleeve 28 is arranged around a portion of the hydraulic cylinder 14. More specifically, the first sleeve 28 is arranged around the hydraulic cylinder 14 in close radial proximity, or in sliding contact with, a tubular member 52 of the hydraulic cylinder 14. In this manner, a bending force applied to the second fastening member 22 and being transferred to the first sleeve 28 via the second sleeve 30 and the resilient member 32 will be transferred to the tubular member 52.

[0073] Thus, although the first sleeve 28 is connected to the end member 20, if at all, the bending force will applied only to a limited extend to the end member 20 and the end of the hydraulic cylinder 14 where it connects to the end member 20. As mentioned above, the bending force is mainly transferred to the tubular member 52 of the hydraulic cylinder 14, which tolerates bending force to a higher degree than the end of the hydraulic cylinder 14 where it connects to the end member 20. Also, the bending force will be applied closer to the first fastening member 16 than at the end member 20, which also is beneficial.

[0074] As a consequence, in the vehicle, the cabin can be tilted in relation to the chassis without putting high stress in the hydraulic cylinder 14.

[0075] According to some embodiments, such as the illustrated embodiments, the resilient member 32 may extend circumferentially around the first sleeve 28. In this manner, the resilient member 32 may be easily positioned between the first and second sleeves 28, 30.

[0076] In the illustrated embodiments, the resilient member 32 comprises an elastic ring-shaped member 33. In this manner, the resilient properties may be provided by a member that is readily positionable between the first and second sleeves 28, 30.

[0077] According to embodiments, such as the illustrated embodiments, the elastic ring-shaped member 33 may be made from polyurethane. Polyurethan may provide desirable properties for the transfer of axial load between the first and second sleeves 28, 30 and permitting the second sleeve 30 to be angled in relation to the first sleeve 28. Such properties are durability and tolerance of compressible forces.

[0078] The ring-shaped member 33 may be made from other materials having similar properties e.g., natural rubber, synthetic rubber, silicone, thermoplastic material etc.

[0079] There is at least one circumferential gap 44’, 44” between the first sleeve 28 and the elastic rings-shaped member 33 and / or between the elastic ring-shaped member 33 and the second sleeve 30. The at least one circumferential gap 44’, 44” provide room within the radial space 42 between the first and second sleeves 28, 30 for the elastic ring-shaped member 33 to expand into when the second sleeve 30 is angled in relation to the first sleeve 28.

[0080] The first sleeve 28 comprises a first protrusion 46 extending radially outwardly from the first sleeve 28 and the second sleeve 30 comprises a second protrusion 48 extending radially inwardly from the second sleeve 30. The first protrusion 46 is arranged closer to the first fastening member 16 than the second protrusion 48. At least a portion of the resilient member 32 is arranged axially between the first and second protrusions 46, 48.

[0081] Thus, the resilient member 32 is positioned to extend in an axial direction between the first and second sleeves 28, 30. Also, in this manner the axial load from the cabin is transferable between the second sleeve 30 and its second protrusion 48 via the resilient member 32 to the first protrusion 46 and the first sleeve 28.

[0082] According to embodiments, the resilient member 32 may extend axially beyond the first protrusion 46 and / or axially beyond the second protrusion 48.

[0083] Each of the first and second protrusions 46, 48 may comprise e.g. a circumferentially extending flange.

[0084] The first portion 34 of the resilient member 32 is arranged at the first protrusion 46 and the second portion 36 of the resilient member 32 is arranged at the second protrusion 48. This provides a way for the first portion 34 of the resilient member 32 to be fixedly arranged in relation to the first sleeve 28 and for the second portion 36 of the resilient member 32 to be fixedly arranged in relation to the second sleeve 30.

[0085] In more detail, the first portion 34 of the resilient member 32 abuts against the first protrusion 46 of the first sleeve 28. Thus, at the first protrusion 46 the resilient member 32 cannot move past the first protrusion 46 in a direction towards the first fastening member 16. Similarly, the second portion 36 of the resilient member 32 abuts against the second protrusion 48 of the second sleeve 30. Thus, at the second protrusion 48 the resilient member 32 cannot move past the second protrusion 48 in a direction towards the end member 20. Moreover, in use of the suspension element 12, gravitational forces acting on the second fastening member 22 and the second sleeve 30 may securely position the first and second end portions 34, 36 of the resilient member 32 against the first and second protrusions 46, 48, respectively. Optionally, each of the first and second end portions 34, 36 of the resilient member 32 may be glued against respective of the first and second protrusions 46, 48.

[0086] According to embodiments, such as the illustrated embodiments, the suspension element 14 may comprise a further resilient member 50 arranged between the first and second sleeves 28, 30. The further resilient member 50 may be arranged closer to the end member 20 than the resilient member 32. In this manner, a bending force causing the second sleeve 30 to be arranged at an angel to the first sleeve 28 may be distributed also over the further resilient member 50 and accordingly, over a longer axial distance along the first sleeve 28 and the hydraulic cylinder 14 than if only the resilient member 32 were arranged between the first and second sleeves 28, 30.

[0087] According to some embodiments, such as the illustrated embodiments, the further resilient member 50 may be arranged between the second protrusion 48 and the end member 20.

[0088] According to alternative embodiments, as mentioned above, the resilient member 32 may extend axially beyond the second protrusion 48. In such embodiments, the resilient member 32 may form a resilient member having a total axial extension corresponding to the that of the resilient member 32 and the further resilient member 48, as shown e.g. in Figs. 3a and 3b.

[0089] According to embodiments, such as the illustrated embodiments, the hydraulic cylinder 14 may comprise a tubular member 52 extending concentrically with the longitudinal centre axis 24 and connected to the first fastening member 16, an end cap 54 connected to the tubular member 52 at an end thereof opposite to the first fastening member 16, a piston 56 arranged within the tubular member 52 and being displaceable along the longitudinal centre axis 24, and a rod 58 extending through the end cap 54 and being connected to the piston 56 and the end member 20. In this manner, the hydraulic cylinder 14 of the suspension arrangement 12 may be provided.

[0090] According to embodiments, such as the illustrated embodiments, a first chamber 60 may be formed within the tubular member 52 at a first side of the piston 56 and a second chamber 62 may be formed within the tubular member 52 at a second side of the piston 56. An inlet channel 64 may extend into the first chamber 60, an intermediate channel 66 may extend through the piston 56 from the first chamber 60 to the second chamber 62, and an outlet channel 68 may extend from the second chamber 62. A bypass channel 70 may extend through the piston 56 and a check-valve 72 may be arranged at the bypass channel 70 for permitting a flow of hydraulic fluid through the bypass channel 70 in a direction from the first chamber 60 to the second chamber 62. In this manner, hydraulic fluid may be supplied to, and led from, the hydraulic cylinder 14 via the inlet and outlet channels 64, 68. Moreover, in this manner, hydraulic fluid may be led from the first chamber 60 to the second chamber 62 via the intermediate channel 66 and the bypass channel 70.

[0091] More specifically, the first and second chambers 60, 62 are arranged in fluid communication with each other via the intermediate channel 66. Thus, during use of the suspension element 12, hydraulic fluid will flow into the first chamber 60 via the inlet channel 64 and through the intermediate channel 66 from the first chamber 60 into the second chamber 62. The hydraulic fluid leaves the second chamber 62 via the outlet channel 68.

[0092] According to some embodiments, such as the illustrated embodiments, the inlet channel 64 may be formed at least partially through the first fastening member 16 and the outlet channel 68 may be formed at least partially through a body of the tubular member 52.

[0093] During use of the suspension element 12, when the suspension element is not subject to any change in load, the hydraulic cylinder 14 is in a state of equilibrium and the pressure of the hydraulic fluid in the first and second chambers 60, 62 will be the same. Depending on how the suspension element 12 is operated, a limited flow of hydraulic fluid may flow continuously, or intermittently, through the hydraulic cylinder 12 i.e. , in sequence through the inlet channel 64, the first chamber 60, the intermediate channel 66, the second chamber 62, and the outlet channel 68.

[0094] Such a limited flow may provide for an exchange of the hydraulic fluid in the hydraulic cylinder 14 e.g., for cooling purposes, or for warming purposes at cold ambient temperatures, and / or for providing freshly filtered hydraulic fluid. The limited flow may be controlled e.g., by dimensions of the intermediate and / or outlet channel 66, 68 and / or by flow restrictions arranged in one or more of the intermediate and outlet channels 66, 68.

[0095] Due to the area difference of the piston 56 on the side facing the first chamber 60 and the side facing the second chamber 62, although the pressure is the same within the first and second chambers 60, 62, a resulting hydraulic force on the piston 56 will bias the piston in a direction away from the first fastening member 16. Namely, since the rod 58 is connected to the piston 56 at the second chamber 62, the piston 56 has a smaller area facing the second chamber 62 than its area facing the first chamber 60. A hydraulic biasing force acting on the piston 56 will cause the piston 56, the rod 58, and the end member 20 to be displaced in a direction away from the first fastening member 16 until an opposing force equals the biasing force.

[0096] When used in a vehicle, the opposing force is formed by gravity acting on the cabin of the vehicle. Since the cabin is connected to the second fastening member 22 and since the second fastening member 22 is connected to the end member 20 via the first and second sleeves 28, 30 and the resilient member 32, the opposing force will be directed against the hydraulic biasing force.

[0097] As the piston 56 is displaced by the hydraulic biasing force, the end member 20 is moved along the longitudinal centre axis 24 and the second fastening member 22 and the cabin with it. When the hydraulic biasing force and the opposing force are equal, the cabin is stationary in a vertical direction.

[0098] As the vehicle travels over uneven ground, bumps cause acceleration forces by acceleration of the cabin along the vertical direction, which acceleration forces will act on the second fastening member 22 and disturb the equilibrium of the forces acting on the piston 56. The acceleration forces cause the piston 56 to move downwardly i.e. , towards the first fastening member 16 or upwardly i.e. away from the first fastening member 16. The downward movement is made possible inter alia by the bypass channel 70 and the check valve 72, which allow hydraulic fluid from the first chamber 60 to flow into the second chamber 62 quicker than through the intermediate channel 66 only. The upward movement is made possible by hydraulic fluid in the second chamber 62 flowing through the intermediate channel 66 into the first chamber 60 and / or escaping through the outlet channel 68.

[0099] Moreover, external hydraulic components connected to the inlet and outlet channels 64, 68 may receive hydraulic fluid from the first and second chambers 60, 62 when acceleration forces act on the second fastening member 22 and the hydraulic cylinder 14. Moreover, such external hydraulic components may also affect damping characteristics of the hydraulic cylinder 14 as it is subjected to acceleration forces.

[0100] The first fastening member 16 may form an axial limiting surface of the first chamber 60. The end cap 54 may form an axial limiting surface of the second chamber 62. The tubular member 52 may form radial limiting surfaces of the first and second chambers 60, 62. According to some embodiments, such as the illustrated embodiments, the hydraulic cylinder 14 may comprise a compression spring 74 arranged within the second chamber 62 and abutting against the piston 56. In this manner, the position of the piston 56 within cylinder 14 during use of the suspension arrangement 12 may be defined.

[0101] Namely, a stiffness of the compression spring 74 may be chosen to match the area difference between the two sides of the piston 56, an operating pressure of the hydraulic fluid, and the weight of the cabin in order to position the piston 56 at a desired position along its full stroke within the hydraulic cylinder 14.

[0102] According to embodiments, the first sleeve 28 may be arranged around the hydraulic cylinder 14 in close radial proximity, or in sliding contact with, the tubular member 52 of the hydraulic cylinder 14. In this manner, the first sleeve 28 may be supported in a radial direction by the tubular member 52. Thus, the end member 20 and the rod 58 may be largely relieved of radial forces and bending force, which overall improves the stress tolerance of the hydraulic cylinder 14 and the suspension element 12.

[0103] Figs. 4a and 4b illustrate the herein discussed suspension element 12 mounted between a chassis 4 and a cabin 6 of a vehicle, such as the vehicle 2 discussed above with reference to Fig. 1. Fig. 4a shows a side view of the suspension element 12 and Fig. 4b shows a cross section view of the suspension element 12.

[0104] The first fastening member 16 is shown connected to a portion of the chassis 4 and the second fastening member 22 is shown connected to a portion of the cabin 6. Moreover, In Figs. 4a and 4b the cabin 6 is tilted in relation to the chassis 4.

[0105] As previously discussed, the first fastening member 16 is connected via the hydraulic cylinder 14 and the end member 20 to the first sleeve 28 and the second fastening member 22 is connected to the second sleeve 30. Due to the resilient member 32 being arranged between the first and second sleeves 28, 30, tilting of the second fasting member 22 in relation to the first fastening member 16 and accordingly also, tilting of the cabin 6 in relation to the chassis 4 is enabled.

[0106] As discussed, the further resilient member 50, or an axial extension of the resilient member 32 beyond the second protrusion 48, may be provided to further improve robustness of the suspension element 12 when the cabin 6 is tilted in relation to the chassis 4. The tilting of the cabin 6 in relation to the chassis 4 is enabled since the second sleeve 30 can be angled in relation to the first sleeve 28. This means that a centre axis 76 of the second sleeve 30 can be angled in relation to the longitudinal centre axis 24. As mentioned above, the longitudinal centre axis 24 is a centre axis of the hydraulic cylinder 14. However, the longitudinal centre axis 24 is also a centre axis of the first sleeve 28 which is arranged around a portion of the hydraulic cylinder 14. Thus, the angle between the second sleeve 30 and the first sleeve 28 can be indicted by an angle a between the centre axis 76 of the second sleeve 30 and the longitudinal centre axis 24.

[0107] Fig. 5 schematically illustrates a hydraulic system 78 of a vehicle, such as the construction vehicle 2 shown in Fig. 1.

[0108] In the illustrated embodiments, the hydraulic system 78 comprises a set of four suspension elements 12 according to any one of aspects and / or embodiments discussed herein. The hydraulic system 78 may form at least part of a suspension system.

[0109] Again, the suspension elements 12 are arranged between a cabin and a chassis of the vehicle.

[0110] The hydraulic system 78 further comprises a hydraulic pump 80 for supplying pressurised hydraulic fluid to the hydraulic cylinders 14 of the suspension elements 12, a tank 82 for receiving hydraulic fluid from the hydraulic cylinders 14, one accumulator 84 for each hydraulic cylinder 14, and a manifold 86 for directing hydraulic fluid within the hydraulic system 78.

[0111] There are various different ways of providing suitable functionality of the hydraulic system 78 and the suspension elements 12. Accordingly, the layout and components of the manifold 86 may differ between different hydraulic systems 78 e.g., between systems devised for different vehicles.

[0112] The general functionality of the suspension elements 12 has been discussed above e.g., with reference to Figs. 4a and 4b. In Fig. 5 the flow directions through conduits of the hydraulic system 78 during operation of the system 78 are indicated with arrows.

[0113] Initially, we assume that Fig. 5 shows the hydraulic system 78 in operation in a construction vehicle and the suspension elements 12 unaffected by any vertical position changes of the cabin in relation to the chassis. The respective pistons 56 of the hydraulic cylinders 14 are at an about midway position of their strokes. Hydraulic fluid is circulated through the system 78 by the pump 80 from the tank 82, via the manifold 86 through the first and second chambers 60, 62 and the piston 56 of each hydraulic cylinder 14 as discussed above, and back to the tank 82 via the manifold 86.

[0114] When the vehicle travels over a bump, the cabin may be subjected to a downward movement and one or more of the suspension elements 12 may be subjected to a downwardly directed force. As discussed above, this causes the piston 56 to press downwardly onto the hydraulic fluid in the first chamber 60 of the hydraulic cylinder 14, which in turn forces hydraulic fluid through the piston 56 into the second chamber 62. However, the pressure thus built up in the first chamber 60 also, may cause hydraulic fluid to be pressed against an ordinary flow direction through the inlet channel of the cylinder back to the manifold 86. In the manifold 86, the first chamber 60 and the inlet channel of each hydraulic cylinder 14 are connected to one of the accumulators 84, which takes up the pressure increase and excess hydraulic fluid.

[0115] Alternatively, or subsequently, from the travel over the bump, one or more of the suspension elements 12 may be subjected to an upwardly directed force. This causes the piston 56 to press upwardly onto the hydraulic fluid in the second chamber 62 of the hydraulic cylinder 14, which in turn forces hydraulic fluid out of the second chamber 62 back into the first chamber 60 and sometimes also back to the tank 82 via the manifold 86.

[0116] It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the invention, as defined by the appended claims.

Claims

CLAIMS1. A suspension element (12) for a suspension between a cabin (6) and a chassis (4) of a vehicle (2), the suspension element (12) comprising a hydraulic cylinder (14) having a longitudinal centre axis (24), a first fastening member (16) arranged at a first end portion (18) of the hydraulic cylinder (14), the first fastening member (16) being configured for fastening to the chassis (4) of the vehicle (2), an end member (20) arranged at a second end portion (26) of the hydraulic cylinder (14) and displaceable along the longitudinal centre axis (24) in relation to the first fastening member (16) by the hydraulic cylinder (14), a first sleeve (28) arranged around a portion of the hydraulic cylinder (14) and being connected to the end member (20), a second fastening member (22) arranged radially outside the hydraulic cylinder (14) between the first fastening member (16) and the end member (20) and displaceable along the longitudinal centre axis (24), the second fastening member (22) being configured for fastening to the cabin (6) of the vehicle (2), a second sleeve (30) arranged around a portion of the first sleeve (28) and being connected to the second fastening member (22), and a resilient member (32) arranged between the first and second sleeves (28, 30), wherein a first portion (34) of the resilient member (32) is fixedly arranged in relation to the first sleeve (28) and a second portion (36) of the resilient member (32) is fixedly arranged in relation to the second sleeve (30), such that an axial load is transferable between the first and second sleeves (28, 30) via the resilient member (32).

2. The suspension element (12) according to claim 1, wherein the resilient member (32) is configured to permit the second sleeve (30) to be angled in relation to the first sleeve (28).

3. The suspension element (12) according to claim 1 or 2, wherein the resilient member (32) extends circumferentially around the first sleeve (28).

4. The suspension element (12) according to any one of the preceding claims, wherein the resilient member (32) comprises an elastic ring-shaped member (33).

5. The suspension element (12) according to claim 4, wherein there is at least one circumferential gap (44’, 44”) between the first sleeve (28) and the elastic rings-shaped member and / or between the elastic ring-shaped member (33) and the second sleeve (30).

6. The suspension element (12) according to claim 4 or 5, wherein the elastic ring-shaped member (33) is made from polyurethane.

7. The suspension element (12) according to any one of the preceding claims, wherein the first sleeve (28) comprises a first protrusion (46) extending radially outwardly from the first sleeve (28) and the second sleeve (30) comprises a second protrusion (48) extending radially inwardly from the second sleeve (30), wherein the first protrusion (46) is arranged closer to the first fastening member (16) than the second protrusion (48), and wherein at least a portion of the resilient member (32) is arranged axially between the first and second protrusions (46, 48).

8. The suspension element (12) according to claim 7, wherein the first portion (34) of the resilient member (32) is arranged at the first protrusion (46) and the second portion (36) of the resilient member (32) is arranged at the second protrusion (48).

9. The suspension element (12) according to any one of the preceding claims, comprising a further resilient member (50) arranged between the first and second sleeves (28, 30), wherein the further resilient member (50) is arranged closer to the end member (20) than the resilient member (32).

10. The suspension element (12) according to claims 8 and 9, wherein the further resilient member (50) is arranged between the second protrusion and the end member (20).

11. The suspension element (12) according to any one of the preceding claims, wherein the hydraulic cylinder (14) comprises a tubular member (52) extending concentrically with the longitudinal centre axis (24) and being connected to the first fastening member (16), an end cap (54) connected to the tubular member (52) at an end thereof opposite to the first fastening member (16), a piston (56) arranged within the tubular member (52) and being displaceable along the longitudinal centre axis (24), and a rod (58) extending through the end cap (54) and being connected to the piston (56) and the end member (20).

12. The suspension element (12) according to claim 11 , wherein a first chamber (60) is formed within the tubular member (52) at a first side of the piston (56) and a second chamber (62) is formed within the tubular member (52) at a second side of the piston (56), wherein an inlet channel (64) extends into the first chamber (60), an intermediate channel (66) extends through the piston (56) from the first chamber (60) to the second chamber (62), and an outlet channel (68) extends from the second chamber (62), and wherein a bypass channel (70) extends through the piston (56) and a check-valve (72) is arranged at the bypass channel (70) for permitting a flow of hydraulic fluid through the bypass channel (70) in a direction from the first chamber (60) to the second chamber (62).

13. The suspension element (12) according to claim 11 or 12, wherein the hydraulic cylinder (14) comprises a compression spring (74) arranged within the second chamber (62) and abutting against the piston (56).

14. The suspension element (12) according to any one of claims 11 - 13, wherein the first sleeve (28) is arranged around the hydraulic cylinder (14) in close radial proximity, or in sliding contact with, the tubular member (52) of the hydraulic cylinder (14).

15. A construction vehicle (2) comprising a chassis (4), a cabin (6), and at least one suspension element (12) according to any one of the preceding claims arranged between the chassis (4) and the cabin (6).

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