|
by Bonaprene
Products Ltd
Revolutionise
Your Ride
We offer a range of urethanes with different
hardnesses and properties. They provide the development
engineer the following benefits over rubber and give
superior mechanical charasteristics over cold cured
and injection moulded urethanes:
 |
A longer working life, three to
four times that of rubber |
|
Impervious to petrol and vehicle oil |
|
High resilience, the ability and speed of returning
back to its original shape |
|
Low compression set and so an excellent resistance
to permanent deformation |
Visit
Polybush and buy products online
Why use Polyurethane
for your suspension requirements?
Polyurethane is an ideal
material for making into suspension bushes. Its combination
of high tensile strength and elasticity translates
into immense durability in the toughest conditions.
It has excellent relilience, springing back in to
shape effortlessly to absorb shock and prevent dirt
ingress and wear. Lastly, it doesn't age or perish
- rubber both perishes and is attacked by oils and
fuels.
|
Anti
Roll Bar Bushes
You need the relilience of polyurethane to
ensure a tight fit to the bar. This avoids knock
and squeaks from loose bushes and minimises
wear. The "Touring" grade is best
for this, but the "Performance" grade
is best if you want to reduce body roll and
sharpen up steering. |
Control
Arm Bushes
Polyurethane's elasticity allows control arms
to move as intended whilst its tensile strength
soaks up punishment from cornering, braking,
accelerating and poor road surfaces. Go for
a "Touring" grade bush to preserve
ride quality for longer, or choose the harder
"Performance" grade to improve body
control and steering. |
|
|
Spring
Bushes
Spring bushes are subject
to the same forces as a control arm bush, as
well as supporting the weight of the vehicle.
Polybushes, with their combination of strength
and elasticity, improve bush life and ride quality
in on. |
Shock
Bushes
Shock bushes can crush
down leaving the shock to rattle on its mountings.
Polyurethane's relilience counters this without
needing as hard a bush, so you can specify the
"Touring" grade for all but the most
arduous applications. |
|
|
Mounting
Bushes
All the vehicle's moving
components cause noise and vibration so Polybush
make a range of mounting bushes for steering,
suspension, engines and transmissions. The polyurethane
isolates these unwanted buzzes and rattles,
but holds the components firmly in place improving
ride smoothness and body control. |
We Solve Your Problems!
If you are a design and development
engineer for vehicle suspension parts, we can solve
your problems with a material that overcomes the following
drawbacks of rubber suspension parts:
|
A too high wear rate |
|
|
The high cost of tooling and prototypes |
|
The long lead time for prototypes |
|
The wearing away of mating metal parts |
|
The deterioration due to the effects of petrol
and oil |
|
Poor relilience especially at high hardness |
|
Poor load bearing and low tensile strength |
|
High copmression set causing permanent deformation |
|
High temperatures generating by the working
bush leading to failure. |
Mercedes Buses
The Mercedes 309-814 and Vario range
of buses are the workhorse of the First Bus, Stagecoach
and Arriva bus fleets.
The constant stop-start regime,
poor roads and speed bumps cause havoc to their van
derived suspensions. High bush wear leads directly
to the bus not being out earning money.
For over 10 years we have been supplying
the after sales market with Polybush link, spring
eye, anti-roll bar clamp and shock absorber bushes
for this range of buses. Our specially designed link
bush is shown below:
These link bushes trialed
at Travel West Midlands and First Bus PMT exceeded
50,000 miles of 12 months and still did not need replacing.
This compared exceptionally well with the 6 - 8 weeks
and 6,000 miles that they used to get with rubber
bushes.
Click
here for a comparison of common elastomers and more
information on polyurethane
Proves Long Working
Life
|
A European bus manufacturer was
looking for a link bush that would offer the
ultimate performance and longevity.
Using the Millbrook Proving Ground in Bedfordshire,
they compared standard rubber bushes with:
The tests were repetitive +/-
80mm anti-roll bar movement cycles on a fixed
test bed plus ride comparisons on a road vehicle.
The results were:
- The rubber bushes failed after 5,000 to
15,000 cycles
- Our Polybushes lasted 55,000 cycles
- Our Polybushes were measured at 10 - 15
degrees celcius cooler than the rubber bush
while operating on the test bed
- Our polybushes did not change the ride of
the vehicle
Bonaprene Products are now a supplier of a
range of Polybush parts to European bus manufacturers. |
 |
 |
Compression
Deflection Tests
A customer asked us to compare
samples taken from a problem suspension bush
with two possible Polybush alternatives. The
customer's bush was permanently compressing
under load and then splitting radially.
The samles were compressed
at 30mm per minute to 50% of their original
thickness and relaxed at the same rate. This
cycle was repeated without interruption over
20 cycles.
The actual force and reduction
in force between the first and last cycle were:
| |
Max
force
1st cycle |
Max
force
last cycle |
Force
loss |
| Polybush
65 °A |
1644
N |
1614
N |
1.8% |
| Polybush
75 °A |
2756
N |
2656
N |
3.6% |
| Original
rubber bush65 °A |
1912
N |
1700
N |
11.1% |
The table shows how quickly
the rubber permanently compresses compared to
the equivalent hardness of Polybush. Once in
this state, the rubber's resilience and ability
to flex is geatly reduced causing splitting
and failure. |
Visit
Polybush and buy products online |
