AU5742398A - Full load-share coilspring bogie suspension - Google Patents

Description

THE TITLE

Full Load-Share coil spring bogie suspension .

This invention relates to improvements in devices used in bogie type suspension systems In the past art it has been very difficult to obtain a bogie suspension which can carry the required load without displaying very harsh ride characteristics when unladen and very limited axle articulation because of the rigidity of the suspension, in turn causing vehicle instability and in the worst cases rollover of the vehicle . The present invention virtually eliminates these problems by the combination of coil

0 springs and load share beams, the spring rate is set to the maximum load and the resultant ride is extremely smooth with a large wheel articulation increase. The limited axle articulation on bogie suspension normally results in traction problems such as dry bogging, particularly in off-road all-terrain type vehicles. The present invention allows extremely large amounts of axle articulation as a result

15 of the load-share beams' oscillation around its centre fulcrum point, in coniunction with the coil-springs' tendency to compress or expand very rapidly according to the variation in wheel motion ,(as a direct result of the greatly reduced mass of the coilsprings ) The load share beam oscillation allows around double the normal axle articulation ,whιlst maintaining full load share on the axle assemblies and wheels

20 for the greater part of the axles' up and downwards travel ,with a resultant high degree of comfort to the occupants of the vehicle, because the wheels follow the ground contour all the time the vehicle displays none of the usual traction problems associated with lack of axle articulation.

25 The present invention has the advantage over the past art of maintaining the vehicle platform almost level when traversing uneven terrain due to the interaction between the loadshare beams and the coilsprings m fact the ratio of chassis deflection to wheel

28 articulation is in the order of 1/5 to 1/4 . The present invention is a bogie type suspension system,Fig 1. comprising two live axle set assemblies(l) each end of the two axle set assemblies having a coilspring (2) vertically mounted above the axle assembly and two load share beams(3), the four ends of which (4)sit atop the four coilsprings(2), a chain(5) is secured axially inside each of the four coil springs (2) to limit expansion of the coil springs (2)and stop them escaping from their mounts(4),alternately the top and bottom of each spring(2)Fig la. is secured to its mounting(4) on the loadshare beam(3) and axle(l), to cause the coilspring (2) to operate in compression and contraction, allowing greater axle(l) articulation than with the coilspring(2) limited by a chain (5)secured axially inside it The two loadshare beams(3)F|g 2. running parallel to the chassis(6) either inside or outside of the chassis' (ό)perimeter line, the two loadshare beams(3) being fulcrummed at their mid-point and mounted to the vehicle chassis(6) at this point by rubber bushes and steel pin bolts and nuts(7) onto cheekplates(29). Above the coilspring (2)at the end of each loadshare beam (3)a bump-stop(8) Fig l.is positioned,so as to limit the upwards travel of the end of the loadshare beam(3),the loadshare beam(3) being rigid, is now limited in its downwards travel on its' opposite end, the chain(5) inside this lower end coilspring (2)extends to its maximum length,or in the alternate the coil spring (2)Fig lfextends so as to go into contraction, limiting the downwards travel of the axle(l) end to which it is connected, the axle end(l) under the opposite end of the loadshare beam(3) will keep travelling upwards compressing its' spring until it contacts the axle bumpstop(9) above it, by this means a large amount of axle (l)articulation is available, with full loadshare for most of the axle(l) articulation, the coilsprings(2) compressing or extending as the vehicle traverses rugged terrain. The vehicle platform remaining almost level at all times due to the interaction of the loadshare beams and coil suspension, the chassis deflection to axle articulation ratio is in the order of 20%-25%, making the vehicle far more stable than past art. In one form of the invention using live beam type drive axle(l) assemblies, the axle (1 assemblies are each located and secured by an 'A' arm device ( 10)Fig 2.with its two legs connected to the vehicles chassis(6) by means of robust metal shell rubber bushes (ll)fitted into tubular ends, welded crossways, onto the two ends of each ' A'arm. The apex of each 'A' arm (10)is secured to the centre top of each axle (1) assembly by means of a robust ball joint(12), the ball-pin of which passes through the 'A' arm apex plate(13) and is secured by a castellated hexagonal nut and split pin, The balljoint body(12) is bolted to a plate or anglebar which is in turn welded to the top of the axle housing(l) . The ball joint assembly (12)is the roll centre of the axle(l) assembly, controlling for/aft and sideways movement of the axle(l) assembly. Each axle(l) assembly also has two lower control rods(14) Fig 1.- secured to each end of each of the axle(l) assemblies - the four lower control rods (14)being in line with and below the chassis rails (6)and running between the axle(l) assemblies, the two lower control rods(14) each side of the vehicle being secured to the vehicle chassis(6),as near as possible to the point that the four lower control rods(14) meet each other between the axle (l)assemblies,by means of robust metal shell rubber bushes(ll) fitted into tubular ends welded crossways onto the ends of each control rod (14)and steel bolts passing through brackets welded to each axle assembly and cheek plates(29) welded to the chassis (6)of the vehicle, The load share beams (3)supporting the vehicle's weight atop the four coilsprings(2), one coilspring (2) at each end of each axle(l) assembly, each load share beam(3) being connected to the chassis(6) at the each load share beam's midpoint (3)by robust rubber bushes and bolts(7).

.In another form of the invention using independent type drive axle assemblies the axle hubs (15) Fig 4.being mounted to suspension uprights (17)which are connected to upper and lower control arm wishbone assemblies(18) by ball joints(19), the wishbone assemblies(18) being connected to the vehicle's chassis (20)by robust metal

5 shell rubber bushes and bolts(21).The four lower control arm wishbone assemblies

(18) each having a coilspring(22) atop them and the two coil springs(22) on each side of the vehicle being interconnected by one loadshare beam(23) atop them on each side of the vehicle,the loadshare beam (23)having its longitudinal axis in line with the centre axis of the coilsprings(22), so as to balance the sideloads at the loadshare beam pivot(24)

10 the loadshare beam(23) being secured at it's mid-point to the chassis(20) by means of robust metal shelled rubber bushes and steel pin bolts and nuts(24). The loadshare beam(23) in the independent suspension system is straight in both planes unlike the loadshare beam (3)in the live axle(l) configuration , this is so that the coil springs (22)are not caused to roll too far away from their ideal position in

15 relation to the lower control arms (18)which they are mounted to . The loadshare beam (23)may be fabricated by cutting and welding of steel plate or by forging or casting some other metal eg. aluminium alIoy,aluminium bronze ,steel alloy, titanium etc, or laying up some type of composite such as carbon fibre. In the live axle(l)system Figs l&2.due to relative motions of the associated componentry ,

20 it is imperitive that the loadshare beam (3) mount to the chassis (6) as near as possible to the mounting points of the lower control rods (14)and A"arms (10)so as to maintain the coilsprings(2) in their correct attitude with regard to their respective axle(l) ends , to this end the loadshare beam(3) should be a bow shape with the loadshare beam (3)ends uppermost and the pivot point of the loadshare beam(3),

25 lowest and at the centre of the beam and .with a coilspring (2)under each end of the each loadshare beam(3) and supporting the vehicles weight via the chassis.. The loadshare beam (3)is required to be shaped on its underside on each end to accept the top of the coilsprings (2)and can be either tapered hollow box section tapered solid beam or tapered I-beam construction in cross section. The loadshare beam (3)must attach to the chassis(6)Fig la.mountings at the fulcrum point of the loadshare beam(3) so as to have proper 50/50 loadshare and as close as possible to the lower control rods and 'A'arm chassis mounting points to control the motions of these components in order to reduce driveline problems to a minimum. Figure 1 : Shows one example of a loadshare beam according to this invention. /»\ Figure 2 : Shows the application of a loadshare beam in a live axle bogie drive configuration. (J^

Figure^: Shows the application of a loadshare beam in an independant suspension bogie drive configuration. Referring to Fig, la - it can be seen that the loadshare beam(3) device according to this invention is best when it comprises of a very rigid beam(3) it can be made of steel plate , cut and welded in such a way as to form a box section having sides parallel to each other and top and bottom of sinusoidal wave shape being closer together at each end and further apart at the centre fulcrum point, allowing a constant tension in the beam (3) and a thicker centre section for the mounting bush and bolts (7)to fit into without weakening the beam(3) as a whole. The beam ends are fitted with spring mount pads(4) to their underside for the coilsprings(2) to mount to. In the live axle(l) configuration the loadshare beam (3)must take this bow shape in side elevation so as to allow the coilsprings (2)to stay in their proper alignment to the drive axle (l)assemblies, as they articulate up and down through their arc of movement. The loadshare beaπ s(3) plan elevation should always be with it's sides parallel to each other in order not to put any unnecessary angular torque into their mounting bushes (7)as this would cause premature deterioration of the bush. o

Referring to Fig lb-it can be seen that the loadshare beams(3) can be positioned inside the chassιs(6) penmeter so as to allow the loadshare beams (3)to sit directly above the coil spπngs(2)

Referring to Fig lc-it can be seen that the loadshare beams (3)can be positioned outside the chassιs(6) perimeter so as to allow the loadshare beams (3)to sit directly above the coil spπngs(2)

Referring to Fig 2a- being a layout for a live axle( 1 ) configuration , it can be seen that the loadshare beam(3) takes sinusoidal shape in the side elevation , with the loadshare beam (3)mounted to the chassis (6)at the loadshare beams fulcrum point (25) and fixed to the top of the coιlsprmgs(2) , by mounting the loadshare beam (3)at this point the geometry of the resulting suspension system is as close as possible to the ideal with regard to the position of the coil springs (2)as they are working through their arc of movement It can be seen that the loadshare beam(3) is able to pivot up or down at each end according to axle(l) motion until it contacts it's bump stop(8) Then the coilspring (2)on the axle(l) end moving upwards compresses until the axle(l) meets it's bumpstop (9) The axle(l) end on the opposite end of the same loadshare beam (3)hangs down and the coil spπng(2) on this end operates in contraction allowing very large axle articulation Referring to Fig 2 - It can be seen that the top 'A' arms(lθ) are fixed to the chassιs(6) Referring to Fig 4- It can be seen that the loadshare beam (23)sιts atop the coilsprings (22) ,one loadshare beam (23)on each side of the vehicle sitting atop the two coilspπngs each side of the vehicle, the said loadshare beam(23) is less offset than the loadshare beam (3)m the live axle(l ) configuration and can be straight in both the plan and side elevation views This is possible as a result of the suspension being of the independant type with upper and lower 'A' arms(l 8) both of which pivot from the outside of the chassis (20)allowmg the coιlspπngs(22) to remain in a fairly constant position at all times, regardless of the articulation of the independent axles(15)

Claims (6)

The claims defining the invention are as follows,

1. A full loadshare coilspring bogie suspension . comprising two live axle set assemblies(l) each end of the two axle set assemblies having a coilspring (2) vertically mounted above the axle assembly and two load share beams(3), the four ends of which (4)sit atop the four coilsprings(2), a chain(5) is secured axially inside each of the four coil springs (2)to limit expansion of the coil springs (2)and stop them escaping from their mounts(4),alternately the top and bottom of each spring(2)Fig la. is secured to its mounting(4) on the loadshare beam(3) and axle(l), to cause the coilspring (2) to operate in compression and contraction, allowing greater axle(l) articulation than with the coi!spring(2) limited by a chain (5)secured axially inside it, the two loadshare beams(3)Fig 2. running parallel to the chassis(6) either inside or outside of the chassis' (6)perimeter line, the two loadshare beams(3) being fulcrummed at their mid-point and mounted to the vehicle chassis(6) at this point by rubber bushes and steel pin bolts and nuts(7) onto cheekplates(29), above the coilspring (2)at the end of each loadshare beam (3)a bump-stop(8) Fig l.is positioned.so as to limit the upwards travel of the end of the loadshare beam(3),the loadshare beam(3) being rigid, is now limited in its downwards travel on its' opposite end, the chain(5) inside this lower end coilspring (2)extends to its maximum length,or in the alternate the coil spring (2)Fig 1. extends so as to go into contraction, limiting the downwards travel of the axle(l) end to which it is connected, the axle end(l) under the opposite end of the loadshare beam(3) will keep travelling upwards compressing its' spring until it contacts the axle bumpstop(9) above it, by this means a large amount of axle (l)articulation is available, with full loadshare for most of the axle(l) articulation, the coilsprings(2) compressing or extending as the vehicle traverses rugged terrain, the vehicle platform remaining almost level at all times due to the interaction of the loadshare beams and coil suspension, the chassis deflection to axle articulation ratio is in the order of 20%-25%, making the vehicle far more stable than past art, in one form of the invention using live beam type drive axle(l) assemblies, the axle ( 1 assemblies are each located and secured by an 'A' arm device ( 10)Fig 2. with its two legs connected to the vehicles chassis(6) by means of robust metal shell rubber bushes (ll)fitted into tubular ends, welded crossways, onto the two ends of each ' A'arm,the apex of each 'A' arm (10)is secured to the centre top of each axle (1) assembly by means of a robust ball joint(12), the ball-pin of which passes through the 'A' arm apex plate(13) and is secured by a castellated hexagonal nut and split pin, the balljoint body(12) is bolted to a plate or anglebar which is in turn welded to the top of the axle housing(l) , the ball joint assembly (12)is the roll centre of the axle(l) assembly, controlling for/aft and sideways movement of the axle(l) assembly, each axle(l) assembly also has two lower control rods(14) Fig 1.- secured to each end of each of the axle(l) assemblies - the four lower control rods (14)being in line with and below the chassis rails (6)and running between the axle(l) assemblies, the two lower control rods(14) each side of the vehicle being secured to the vehicle chassis(6),as near as possible to the point that the four lower control rods(14) meet each other between the axle (l)assemblies,by means of robust metal shell rubber bushes(ll) fitted into tubular ends welded crossways onto the ends of each control rod (14)and steel bolts passing through brackets welded to each axle assembly and cheek plates(29) welded to the chassis (6)of the vehicle, the load share beams (3)supporting the vehicle's weight atop the four coilsprings(2), one coilspring (2) at each end of each axle(l) assembly, each load share beam(3) being connected to the chassis(6) at the each load share beam's midpoint (3)by robust rubber bushes and bolts(7).

2.A full loadshare coilspring bogie suspension comprising of two independent type drive axle assemblies the axle hubs (15) Fig 4.being mounted to suspension uprights (17)which are connected to upper and lower control arm wishbone assemblies(18) by ball joints(19)the wishbone assemblies(18) being connected to the vehicle's chassis (20)by robust metal shell rubber bushes and bolts(21),the four lower control arm wishbone assemblies (18) each having a coilspring(22) atop them and the two coil springs(22) on each side of the vehicle being interconnected by one loadshare beam(23) atop them on each side of the vehicle,the loadshare beam (23)having its longitudinal axis in line with the centre axis of the coiisprings(22), so as to balance the sideloads at the loadshare beam pivot(24) the loadshare beam(23) being secured at it's mid-point to the chassis(20) by means of robust metal shelled rubber bushes 0 and steel pin bolts and nuts(24),the loadshare beam(23) in the independent suspension system is straight in both planes unlike the loadshare beam (3)in the live axle(l) configuration , this is so that the coil springs (22)are not caused to roll too far away from their ideal position in relation to the lower control arms (18)which they are mounted to .

3. The loadshare beam (23)may be fabricated by cutting and welding of steel plate or by forging or casting some other metal eg. aluminium alloy-aluminium bronze .steel alloy, titanium etc, or laying up some type of composite such as carbon fibre.

4. In the live axle(l)system Figs l&2.due to relative motions of the associated componentry , it is imperitive that the loadshare beam (3) mount to the chassis (6) as near as possible to the mounting points of the lower control rods (14)and A"arms (10) so as to maintain the coilsprings(2) in their correct attitude with regard to their respective axle(l) ends , to this end the loadshare beam(3) should be a bow shape with the loadshare beam (3)ends uppermost and the pivot point of the loadshare beam(3), at the centre of the beam and .with a coilspring (2)under each end of the each loadshare beam(3) the loadshare beam (3)is required to be shaped on its underside on each end to accept the top of the coilsprings (2)and can be either tapered hollow box section tapered solid beam or tapered I-beam construction in cross section, the loadshare beam (3) ust attach to the chassis(6)Fig la.mountings at the fulcrum point of the loadshare beam(3) so as to have proper 50/50 loadshare.

5. A loadshare coilspring bogie suspension having a chassis deflection to wheel articulation ratio of 1/5 to 1/4 as a result of the interaction of the loadshare beams with the coilsprings.

6.A loadshare coilspring bogie suspension having characteristics of softness of ride whilst giving extreme wheel articulation together with higher than normal levels of both load capacity and roll stiffness due to the interaction between the loadshare beams and the coilsprings.