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FIELD OF INVENTION
This invention relates to MacPherson strut type suspension system of vehicle.
The invention is classified as independent suspension system.
BACKGROUND/PRIOR ART OF THE INVENTION
Suspension system of vehicle is classified as Dependent and Independent
suspension system. Independent suspension system includes MacPherson
strut type suspension system. The invention focuses on said MacPherson strut
type suspension system.
Currently MacPherson strut type suspension system is known to have been
provided, for which reference may be made to fig. 1. The Macpherson strut (S)
is connected to Knuckle (K) of wheel (W), which is provided in connection with
suspension arm/lower arm (A) of vehicle constituting the suspension system.
The suspension system comprising a damper (1), piston rod (2) of which is
mounted with jounce bumper (3) co-axially. A dust cover is also mounted coaxially
so as to cover the exposed area of the piston rod. A coil spring (4) is
provided co-axially with the damper to withstand the load. Said spring is
placed between upper and lower spring pad (5, Not shown). The spring pad sits
inside the respective spring seat (6, 7). The above suspension system is topped
with support comp. (C).
The jounce bumper acts as an active part only in bump stroke not in rebound
stroke.
The above said suspension system works on the principle that, in the initial
stroke, the coil spring plays major roll as it bears the entire load till jounce
bumper (bump stopper) comes into contact. Therefore, the coil spring has the
linear load deflection (L/D) characteristics as shown in fig. 2 and jounce
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bumper has the parabolic load deflection characteristics as indicated in fig. 3
according to the requirement of getting into contact at later stage of the stroke.
The purpose of the coil spring is to store energy due to resilience and
subsequently release it in order to absorb shock or to maintain a force between
contacting surfaces.
The drawbacks associated with the prior art can be listed herein below:-
- Involves more number of parts including coil spring.
- Heavy weight and high cost due to more parts.
- High rebound damping force
Now, reference may be made to the following known arts:-
US 20040178552;- It relates to an upper strut assembly comprising a strut
rod, a jounce bumper, a jounce bumper cup, and an upper strut mount
attached to the strut rod by a fastener. The jounce bumper axially
encompasses the strut rod. The jounce bumper cup includes an upper surface
that is fixed about a top portion of the jounce bumper.
Another prior art relates to an energy absorption device for providing a softer
stop arrangement between a pair of components. A bumper is provided with a
cylindrical insert mounted therein. Upon application of force between the
components, the compressible bumper collapses around the insert and
outward. The insert prevents the bumper from expansion inward of the bumper
to limit the amount the bumper compresses and further is made of a flexible
material to absorb energy. The combination of the bumper and the insert
provides a definite stop to the bumper assembly. The device is usable between
any two components to prevent collisions between the components up to a
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certain force between them and is also usable between a strut assembly and a
vehicle suspension to prevent the strut assembly from bottoming out.
Still another prior art is known, which discloses a mount structure for a vehicle
damper, configured in such a manner that an end of the piston rod of the
damper is supported by a vehicle-side member. A nut engaged with the male
thread section formed on a reduced diameter section of the piston rod
collectively fastens upper and lower gripping members, a collar member, and
upper and lower elastic sections to the reduced diameter section. An input
from the damper body side is transmitted to the vehicle body-side member
through a transmission member.
None, of the above cited arts fulfill requirements of the present invention.
Hence, the present invention introduces "No coil spring - MacPherson strut"
type suspension system of vehicle so as to address the aforesaid drawbacks.
OBJECTS OF THE INVENTION
Primary objective of the present invention is to provide MacPherson strut type
suspension system of vehicle which overcomes disadvantages associated with
the prior art.
Another objective of the present invention is to provide MacPherson strut type
suspension system of vehicle which involves less number of parts, thereby
reducing weight.
Further object of the present invention is to provide MacPherson strut type
suspension system of vehicle which is simple in construction and cost effective.
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Still another object of the present invention is to provide MacPherson strut type
suspension system of vehicle which is efficient and reliable.
SUMMARY OF THE INVENTION
According to this invention, there is provided MacPherson strut type
suspension system of vehicle comprising a damper, piston rod of which is
mounted with a longer jounce bumper.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objectives and advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanying
drawings and wherein:
Fig. 1 shows: exploded view of conventional MacPherson strut,type suspension
system of vehicle.
Fig. 2 shows: load deflection curve of coil spring according to prior art.
Fig. 3 shows: load deflection curve of jounce bumper (bump stopper) according
to prior art.
Fig. 4 shows: exploded view of "No coil spring - MacPherson strut" type
suspension system of vehicle in accordance with present invention.
Fig. 4A shows: mounting of longer jounce bumper.
Fig. 5 shows: load deflection curve of present invention.
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DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE
ACCOMPANYING DRAWINGS
The invention discloses MacPherson strut type suspension system of vehicle.
Now, reference may be made to fig. 4, wherein novel "No coil spring -
MacPherson strut" (S') is connected to one side of vehicle's knuckle (K),
otherside of which is connected to suspension arm/lower arm (L) as in the
prior art.
The "No coil spring - MacPherson strut" constitutes inventiveness of the
present invention. As shown in fig. 4, the suspension system comprises a
damper (1), piston rod (2) of which is mounted with jounce bumper (3) coaxially.
The jounce bumper (bump stopper) is longer in size, which collectively
provides function .of coil spring as well as the bump stopper of conventional
suspension system.
The upper end of the jounce bumper is accommodated inside upper seat
(4)which is smaller in size. The upper seat (4) is positioned between the bumper
(3) and support comp. (5) as shown. The jounce bumper is provided in contact
with the damper at other end. Thus, the jounce bumper (3) is positioned
between said damper (1) and upper seat (4) as shows in fig. 4A.
The provision of the longer bumper results in the following:-
- Elimination of lower spring pad and lower spring seat.
- Smaller size (less diameter) of upper spring seat.
- Elimination of upper spring pad and dust cover of the jounce bumper.
The jounce bumper acts as active part of the suspension system throughout
the stroke. It constitutes an active part both in bump and rebound stroke.
Thus, the system functions efficiently during both bump and rebound stroke.
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The entire load of the vehicle is independently borne by the longer jounce
bumper. Hence, it is always an active part of the suspension system. The load
deflection (L/D) curve of the new jounce bumper is such that, it meets the
collective load deflection (L/D) properties of the coil spring 86 the bump stopper
of the existing suspension system as shown in fig. 5. The invention also
sustains the overall vehicle dynamic behavior while improving the ride.
It can be concluded that, the suspension system of invention acts collectively
for both coil and bumper £ind works more efficiently as compared to prior art.
Advantageous Features
- Less number of parts.
- Lighter in weight.
- Cost effective.
- Reduction in rebound damping force.
- Helps in maintaining overall vehicle dynamic behavior.
- Meets the collective load deflection properties of the coil spring and bump
stopper of the available suspension system.
- Acts more efficiently in both bump and rebound stroke.
- Lower end of the longer jounce bumper is provided constantly (in all
conditions) in contact with the damper thereby covering the piston rod,
which eliminates requirement of dust cover.
It is to be noted that the present invention is susceptible to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and features of this invention are intended to be within
the scope of the present invention, which is further set forth under the
following claims:-

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WE CLAIM
1. MacPherson strut type suspension system of vehicle comprising a
damper, piston rod of which is mounted with a longer jounce bumper.
2. MacPherson strut type suspension system as claimed in claim 1, wherein
the jounce bumper, upper end of which rests against upper seat which is
smaller in size.
3. MacPherson strut type suspension system as claimed in claim 1 or 2,
wherein the jounce bumper, lower end of which is provided in contact
with the damper.
4. MacPherson strut type suspension system of vehicle as claimed in any of
the preceding claims, wherein the jounce bumper acts as an active part
both in bump and rebound stroke.
5. MacPherson strut type suspension system of vehicle as claimed in any of
the preceding claims, is associated with the advantageous features such
as herein described.
6. MacPherson sisrut type suspension system of vehicle substantially as
herein described with reference to the accompanyi^^g drawings.