GB2470410A - Tractor rear axle suspension - Google Patents
Tractor rear axle suspension Download PDFInfo
- Publication number
- GB2470410A GB2470410A GB0908852A GB0908852A GB2470410A GB 2470410 A GB2470410 A GB 2470410A GB 0908852 A GB0908852 A GB 0908852A GB 0908852 A GB0908852 A GB 0908852A GB 2470410 A GB2470410 A GB 2470410A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chassis
- axle
- rear axle
- tractor
- axis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000725 suspension Substances 0.000 title description 21
- 238000013016 damping Methods 0.000 claims abstract description 17
- 239000012530 fluid Substances 0.000 description 7
- 238000012544 monitoring process Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G9/00—Resilient suspensions of a rigid axle or axle housing for two or more wheels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
- B60G17/005—Suspension locking arrangements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G9/00—Resilient suspensions of a rigid axle or axle housing for two or more wheels
- B60G9/02—Resilient suspensions of a rigid axle or axle housing for two or more wheels the axle or housing being pivotally mounted on the vehicle, e.g. the pivotal axis being parallel to the longitudinal axis of the vehicle
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2200/00—Indexing codes relating to suspension types
- B60G2200/40—Indexing codes relating to the wheels in the suspensions
- B60G2200/44—Indexing codes relating to the wheels in the suspensions steerable
-
- 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
- B60G2204/40—Auxiliary suspension parts; Adjustment of suspensions
- B60G2204/46—Means for locking the suspension
- B60G2204/4605—Means for locking the suspension hydraulically, e.g. interrupting communication between the chambers of a hydraulic cylinder
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60G—VEHICLE SUSPENSION ARRANGEMENTS
- B60G2300/00—Indexing codes relating to the type of vehicle
- B60G2300/08—Agricultural vehicles
- B60G2300/082—Tractors
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Vehicle Body Suspensions (AREA)
Abstract
A tractor having a chassis 10, rear axle mounting means for mounting a rigid rear axle 11 on the chassis for pivoting about a first axis generally parallel to the longitudinal axis of the chassis to allow vertical movement of rear wheels carried by the rear axle, and first spring/damping means 17 acting between the rear axle and the chassis. A lock-out means may be provided to prevent pivoting of the rear axle about the first axis when desired and the rear wheels may be provided with steering means for steering the rear wheels relative to the rear axle to provide a four wheel steering capability when desired.
Description
Tractor Suspension This invention relates to tractor suspension and in particular to arrangements for proving rear axle suspension on a tractor.
It is well known to provide a suspension of front axle of a tractor and typically such a front axle suspension is provided by mounting a rigid front axle on the chassis of the tractor for pivoting about a first axis generally parallel to the longitudinal axis of the chassis to allow vertical movement of front wheels carried on the ends of the front axle. The rear axle of the tractor is normally rigidly attached to the chassis and ride quality for the driver is improved by vibrationally isolating the driver's cab from the chassis.
Whilst this arrangement may cope with small ground irregularities it does not cope well with larger bumps and obstacles nor with sideway movements of the cabin and driver.
There is therefore a requirement to provide a simply robust and relative cheap form of suspension for the rear axle of a tractor to further improve ride quality.
Thus according to the present invention there is provided a tractor having a chassis, rear axle mounting means for mounting a rigid rear axle on the chassis for pivoting about a first axis generally parallel to the longitudinal axis of the chassis to allow vertical movement of rear wheels carried by the rear axle, and first spring/damping means acting between the rear axle and the chassis.
A lock-out means may be provided to prevent pivoting of the rear axle about the first axis when desired. Such an arrangement may be particularly desirable when ploughing and may be achieved by locking-up the spring damping means or a mechanical lock between the axle and chassis.
The rear wheels may be provided with steering means for steering the rear wheels relative to the rear axle to provide a four wheel steering capability when desired.
The tractor may also be provided with a front axle suspension of any type or similar to the above rear axle suspension. This front axle suspension may comprise a front axle mounting
I
means for mounting a rigid front axle on the chassis for pivoting about a second axis also generally parallel to the longitudinal axis of the chassis to allow vertical movement of the front wheels carried by the front axle, second spring damping means act between the front axle and the chassis, and second steering means act to steer the front wheels relative to the front axle.
In some vehicles it may be possible for the front and rear axles to be identical or very similar in constmction thus achieving further economies of production.
The front or rear axle mounting means may also allow vertical movement of the front or rear axle relative to the chassis.
The first or second damping means referred to above may be passive, semi-active or frilly active depending on the operational requirements of the vehicle.
One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:-Figure 1 shows diagrammatically a perspective view of a tractor rear suspension in accordance with the present invention; Figure 2 shows the rear axle used in the suspension of Figure 1; Figures 3 and 4 shows perspective and end views respectively of an actual tractor rear suspension of the form shown in Figure provided with a wheel steering fhnction; Figure 5 shows diagrammatically a hydraulic passive suspension circuit for use in the damping of the movement of the axles of Figures ito 4; Figure 6 shows diagrammatically a hydraulic semi-active suspension circuit for semi-active damping of the movement of the axles of Figures ito 4; Figure 7 shows diagrammatically a hydraulic active suspension circuit for the fully active damping of the movement of the axles of Figures ito 4, and Figure 8 shows diagrammatically a tractor chassis provided with similar suspended rear and front axles.
Referring to the drawings a tractor chassis iO has a rigid rear axle casing ii which is mounted on the chassis i 0 for pivoting about a longitudinally extending axis X-X.
Drive into axle ii is via an input shaft 9 into a differential 13 and hence through drive shafts 12 to final drive assemblies 14 and hence to the rear wheels mounted on bolts i5.
The chassis includes a transversely extending cut-out 16 which allows the pivoting of axle I I about axis X-X. Pivotting of axle ii is controlled by one or more springs/dampers i 7 which act between the axle I I and the chassis iO. These springs/dampers may be hydraulic or pneumatic piston type actuators or could be steel spring with hydraulic or pneumatic damping.
In the arrangement shown diagrammatically in Figures i and 2, the wheels are not steerable relative to the axle ii but in the arrangement shown in Figures 3 and 4 the rear wheels are steerable about axes Y by a control hydraulic steering cylinder 18 and steering rod i 8a to provide a tractor with a four wheel steering capability.
When desired, the pivoting of axle 11 relative to chassis 10 can be locked-out using springs/dampers i7 or a mechanical lock between the axle II and the chassis iO.
Typically the pivoting of the axle about axis X-X is in the range +/-5degrees as shown by the angle 0 in Figure 4.
When hydraulic suspension is used the springs/dampers i 7 can be arranged to act either passively, semi-actively or fully actively using the hydraulic connections shown diagrammatically in Figures 5,6 and 7 respectively.
In the arrangement shown in Figure 5 each actuator 17 is connected with a source of fluid pressure (which could be hydraulic or pneumatic) from a pump 25 via fluid a flow control valve 26. Normally control valve 26 remains closed so that any movement between the axle 11 and the chassis 10 results in movement of a piston 20 of the actuator 17 and consequently the movement of fluid from one side to the other of the piston 20 and hence via fixed orifices 21 into associated accumulators 22. Thus a fixed damping and spring support characteristic is provided which does not vary with the operating conditions of the tractor. Solenoid locking valves 27 and 28 are provided which when closed isolate the actuator 17 from the accumulators 22 and hence lock the axle 11 relative to the chassis 10 when required.
Using this basic rear axle suspension arrangement it is possible to attenuate the roll of the chassis and, in combination with the customary cab and seat suspension used on tractors, control the vibrations experienced by the tractor driver.
The control valve 26 is provided so that fluid can be admitted either above or below the piston to provide automatic level control of the axle 11 using a position sensor 23. Valve 26 can also be used to tilt the axle relative to the chassis when e.g. plough or operating across a sloping field. In this case an additional inclinometer (not shown) is needed to determine the inclination of the tractor.
The circuitry shown in Figure 6 is basically the same as that of Figure 5 with the exception that the fixed orifices 21 are replaced by variable orifices in the form of proportional fluid control valves 24 which receive control signals from an associated electronic control unit into which the tractor driver can enter his requirement for harder or softer axle suspension damping and which can also be controlled automatically by an electronic monitoring system in response to the speed and movement of the axle relative to the chassis. In this arrangement in addition to the position sensor 23 an axle inclinometer and/or or a gyroscope (or two accelerometers) are provided to generate the input signals for automatically controlling the size of the orifices provided by the valves 24 which, as explained above, will vary in accordance with the speed and degree of movement of the axle relative to the chassis. Again inclination of the axle when operating on a slope or when ploughing can be controlled by valve 26 by adjusting to adjust the amount of fluid above or below the piston 20 and automatic level control of the axle 11 is again provided.
Figure 7 shows a frilly active spring and damping system in which the pressure above and below the piston 20 and the movement of piston 20 is controlled by a proportional flow valve to provide the necessary force in response to the roll movements of the axle relative to the chassis. In this active control system the valve 25 will again receive operating signals from an associated electronic control unit into which the tractor driver can enter his requirement for harder or softer axle damping and which can also be controlled automatically by an electronic monitoring system in response to the speed and movement of the axle relative to the chassis.
In this arrangement in addition to the position sensor 23 an axle inclinometer and/or or a gyroscope (or two accelerometers) are provided to generate the input signals for automatically controlling the size of the orifices provided by the valves 30 which, as explained above, will vary in accordance with the speed and degtee of movement of the axle relative to the chassis.
Again the inclination of the axle when operating on a slope or when ploughing can also be controlled by the valve 30 by adjusting the amount of fluid above or below the piston 20 and automatic level control of axle 11 is again provided.
With passive, semi-active and fhlly active arrangements of Figures 5 to 7 the axle suspension can also be arranged to stiffen during cornering.
Conveniently the tractor chassis may be provided with a similar (or even identical) suspended front axle 30 having front wheels 31 steered by rods 32 and spring/damper 33 similar to spring/damper 17. Such an arrangement is shown in Figure 8.
Also, although in the arrangement described above all the spring/dampers are hydraulic or pneumatic, the damping of the movements of the rear and front axles can be controlled by mechanical springs.
Also, the rear and front axles may be designed to allow vertical movement of the axle pivot.
Claims (6)
- Claims 1. A tractor having a chassis, rear axle mounting means for mounting a rigid rear axle on the chassis for pivoting about a first axis generally parallel to the longitudinal axis of the chassis to allow vertical movement of rear wheels carried by the rear axle, and first spring/damping means acting between the rear axle and the chassis.
- 2. A tractor according to claim 1 provided with a lock-out means to prevent pivoting of the rear axle about the first axis when desired.
- 3. A tractor according to claim 1 or 2 in which the rear wheels provided with steering means for steering the rear wheels relative to the rear axle to provide a four wheel steering capability when desired.
- 4. A tractor according to any one of claims ito 3 having a front axle mounted on the chassis by a front axle mounting means for pivoting about a second axis also generally parallel to the longitudinal axis of the chassis to allow vertical movement of the front wheels carried by the front axle, second spring/damping means act between the front axle and the chassis, and second steering means act to steer the front wheels relative to the front axle.
- 5. A tractor according to any on of claims ito 4 in which the first andlor second spring/damping means may be passive, semi-active or frilly active depending on the operational requirements of the vehicle.
- 6. A tractor having a rear axle mounting means constructed and arranged substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0908852A GB2470410A (en) | 2009-05-22 | 2009-05-22 | Tractor rear axle suspension |
PCT/IB2010/001197 WO2010133955A1 (en) | 2009-05-22 | 2010-05-20 | Tractor suspension |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0908852A GB2470410A (en) | 2009-05-22 | 2009-05-22 | Tractor rear axle suspension |
Publications (2)
Publication Number | Publication Date |
---|---|
GB0908852D0 GB0908852D0 (en) | 2009-07-01 |
GB2470410A true GB2470410A (en) | 2010-11-24 |
Family
ID=40862841
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB0908852A Withdrawn GB2470410A (en) | 2009-05-22 | 2009-05-22 | Tractor rear axle suspension |
Country Status (2)
Country | Link |
---|---|
GB (1) | GB2470410A (en) |
WO (1) | WO2010133955A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11259463B1 (en) * | 2018-10-04 | 2022-03-01 | Harper Industries, Inc. | Slope mower with automatic leveling suspension and system for maintaining vertical orientation of mower body |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3171556A (en) * | 1962-09-17 | 1965-03-02 | Koehring Co | Front end and overshot loader |
GB1486255A (en) * | 1973-12-07 | 1977-09-21 | Hammarstrand S | Vehicle chassis having pivoting axle systems |
US4580797A (en) * | 1983-08-05 | 1986-04-08 | Umea Mekaniska Ab | Device at cross-country vehicles or machines |
US4669566A (en) * | 1983-10-07 | 1987-06-02 | Valmet Oy | Means for improving the stability of a tractor or working machine |
DE3632416A1 (en) * | 1986-09-24 | 1988-04-07 | Schaeff Karl Gmbh & Co | Centre pivot-steered work vehicle with height adjustable wheels |
EP1972471A2 (en) * | 2007-03-22 | 2008-09-24 | CNH Italia S.p.A. | Active axle suspension system |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4018296A (en) * | 1974-04-19 | 1977-04-19 | Jerome Leslie Knudson | Four wheel tractor |
US5813697A (en) * | 1994-12-05 | 1998-09-29 | Trak International, Inc. | Forklift stabilizing apparatus |
IT1287898B1 (en) * | 1996-05-14 | 1998-08-26 | Carraro Spa | SPRING AND VARIABILITY SYSTEM OF A DIFFERENTIAL BRIDGE |
US5944130A (en) * | 1997-11-04 | 1999-08-31 | Caterpillar Inc. | Trunnion mounted drive train arrangement |
GB0002154D0 (en) * | 2000-02-01 | 2000-03-22 | Bamford Excavators Ltd | Working apparatus |
AT410303B (en) * | 2000-04-04 | 2003-03-25 | Moertl Engelbert | MULTI-PURPOSE VEHICLE WITH SWITCHABLE AIR SUSPENSION |
IT1319455B1 (en) * | 2000-06-29 | 2003-10-10 | Dana Italia Spa | DEVICE FOR THE DYNAMIC STABILITY CONTROL OF AN INDUSTRIAL VEHICLE. |
DK1226985T3 (en) * | 2001-01-26 | 2004-08-02 | Dana Italia Spa | Suspended axle of the articulated joint type for industrial vehicles |
GB2451244B (en) * | 2007-07-21 | 2011-09-28 | Bamford Excavators Ltd | Working machine |
-
2009
- 2009-05-22 GB GB0908852A patent/GB2470410A/en not_active Withdrawn
-
2010
- 2010-05-20 WO PCT/IB2010/001197 patent/WO2010133955A1/en active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3171556A (en) * | 1962-09-17 | 1965-03-02 | Koehring Co | Front end and overshot loader |
GB1486255A (en) * | 1973-12-07 | 1977-09-21 | Hammarstrand S | Vehicle chassis having pivoting axle systems |
US4580797A (en) * | 1983-08-05 | 1986-04-08 | Umea Mekaniska Ab | Device at cross-country vehicles or machines |
US4669566A (en) * | 1983-10-07 | 1987-06-02 | Valmet Oy | Means for improving the stability of a tractor or working machine |
DE3632416A1 (en) * | 1986-09-24 | 1988-04-07 | Schaeff Karl Gmbh & Co | Centre pivot-steered work vehicle with height adjustable wheels |
EP1972471A2 (en) * | 2007-03-22 | 2008-09-24 | CNH Italia S.p.A. | Active axle suspension system |
Also Published As
Publication number | Publication date |
---|---|
WO2010133955A1 (en) | 2010-11-25 |
GB0908852D0 (en) | 2009-07-01 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |