ECHNICAL FIELD
‘[0001] The present subject matterrelates generally to saddle-ride atype
vehicles and, more particularly but not exclusively, to a steering assembly for
saddle ride-type vehicles.
BACKGROUND
[0002] Generally, a frame assembly supports the vehicle: A front portion of
the frame assembly is connected to a steering assembly comprising one or more
front suspension(s) connected to a front wheel and a handle bar assembly. The
frame assembly extends rearward of the vehicle, where a rear wheel is connected
to a frame assembly through one or more rear suspension(s). Generally, in a
4
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saddle-ride type vehicle, frame structure is such that an internal combustion (IC)
engine is positioned in the front portion of the vehicle and supported by the frame.
The IC engine is positioned in a manner such that the cylinder head 'is
either
vertical or inclined forward. Typically, in the saddle-ride type vehicle, a fuel tank
assembly is mounted to the'frame assembly and is diSposed above the IC engine.
An air intake' system is disposed below a seat assembly, wherein the seat assembly
is positioned in a posterior portion of the fuel tank.
*_[0003] Typically, the poWer/torque‘generated by the internal combustion (IC)
engine is transferred to the rear wheel through a transmission system. The vehicle
is maneuvered through a handle ‘b'arlassembly of the steering assembly connected
to the front ‘wheel. The handlebar assembly comprises important vehicle related
controls like clutch, accelerator, brake, and switches.
BRIEF DESCRIPTION OF DRAWINGS
{0004} The detailed description of a steering assembly'of the present subject
matter is described with reference to the accompanying figures. Same numbers are
used throughout the drawings to reference like features and components.
[0005] Fig. 1 illustrates a right side view of a saddle-ride type vehicle, in
accordance with an embodiment of present subject matter.
[0006] Fig. 2 illustrates a right side view of steering assembly, in accordance
with'an embodiment of the present subject matter.
[0007] Fig. 3 depicts an enlarged view of a portion of the steering assembly.
[0008] Fig. 4 depicts a cross-sectional view of a portion of the steering
assembly, in accordance with the embodiment depiCted in Fig. 3.
[0009] Fig. 5 depicts a portion of a steering assembly, in accordance with
another embodiment of the present subject matter.
[00010] Fig. 6 depicts -a cross sectional view of the steering assembly, in
accordance with the embodimentdepicted in Fig. 5.
‘
DETAILED DESCRIPTION
[00011] Generally, a frame assembly of the vehicle acts as a skeleton and
load—bearing member of the vehicle. The IC engine or the like, which acts as the
primary. drive source of the vehicle, is mounted to the frame assembly. Further,
the vehicle has an electric motor. The IC engine is cranked using a kick-start
mechanism or an electric start mechanism. Air fuel mixture IS Scornbusted in a
combustion chamber of the IC'engine. Generally, the fuel taiikvsupplies fuel to a
carburetor or the like: An air induction system provides. air to the carburetor or the
like.
.
[00012] Typically, the power/torque generated by the IC engine is transferred
to the rear wheel through a transmission system. The, rear-wheel provides the
traction required-for motion of. the vehicle. The front wheel connected to the
steering assembly enables‘maneuvering of the vehicle. The steering assembly
comprises of the handle bar assembly, a steering shaft, a lower bracket, and an
upper bracket. Generally, the lower bracket is affixed to the steering shaft and theI‘rH
15-Jun-25116/20978/3053-CHE-20‘15/Description(Complete)
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upper bracket is affixed or fastened to the steering shaft. Further, the lower
bracket transfers load from the front wheel to the frame assembly.
[00013] Typically, in a saddle-ride type vehicle, the front fork assembly is
used as front su5pension. The front fork-assembly and the steering 'shaft are
mounted to the lower bracket. The steering shaft is rotatably supported by a head
tube of the frame assembly. The upper bracket connects the front fOrk assembly to
the handle bar assembly. The upper bracket is positioned and secured between a
steering arrestor and a locking nut that are fastened to the steering shaft. Clearance
is provided between the upper bracket and the steering shaft and is removably
mounted to the steering shaft.
[00014] However, tolerance variation between the upper bracket and steering
shaft, and tolerance variation between upper bracket and the one or more front
fork(s) occurs due to positional tolerance, machining tolerance and parallelism
between upper bracket and lower bracket. Therefore, clearance or interference fit
occurs between the upper bracket and the steering shaft. However, interference fit
between the upper bracket and the steering shaft makes the assemblydifficult. In
addition, shifting tolerance band to complete clearance fit results in reduction of
-
life of bearing assembly. Especially, the steering shaft is provided 'with threads to
enables fastening of the steering arrestor and the 10cking nut to the steering shaft.
Dueto the aforementioned tolerances and 'other problems, the upper bracket is
prone to damage the steering shaft due to thread digging of the steering shaft. A
steel insert may be used to avoid the threads of steering shaft to come in contact
with the upper bracket, but it increases weight and cost of the system. -In some ,
cases, a steering shaft with a split thread may be used to avoid aforesaid problem
including thread digging by the upper bracket. However, such design increases the
cost 'due to complex machining and also need for structural strength of upper
bracket restricts reduction of thickness of upper bracket.
[00015] Hence, an objective of the present subject matter is to provide a steering
assembly for a two-wheeled vehicle. The steering assembly is capable of
providing clearance fit to enable ease of assembly of upper bracket to the steering
shaft irrespective of tolerance variations between the upper bracket and steering
shaft, and upper bracket and the front fork assembly. Further, the steering
assembly provides an arrestor member provided with an annular bulge portion
that
is capable of abutting against an annular cavity provided on an upper bracket.
[[00016] In other words, an annular protrusion provided on the arrestor
member is disposed in an axial direction of the steering shaft and extending
radially outwards from an inner diameter of the arrestor member covering at least
a distance of an outer diameter of the arrestor member.
[00017] According to one aspect of the present subject matter,
a
single thread
maybe provided on the steering shaft. Yet another aspect of the present subject
matter is,- the cost of the shock absorber is reduced.
[00018] Additional aspect of thepresent subject matter is, thread digging of upper
bracket is eliminated. Another aspect being, ease of assembly is improved as
clearance between the upper bracket and steering shaft is maintained. According
to another aspect, pre-loading of ball(s) with races(s) of the bearing assembly is
achieved.
T
[00019] It is an additional aspect that the bulge portionis inward and in
proximity to the steering shaft. The cavity is away from the steering shaft.
‘
[00020] It is an essential feature that the bulge portion is integrally formed
with the arrestor member thereby reducing number of parts.
[00021] It is a feature of the present subject matter that it works with a
steering shaft with continuous threads and with split thread design. Therefore, the
arrestor member can be communized.[00022] It is another feature
iof
the present subject matter that use of steel
insert is eliminated.
[00023] It is an advantage of the present subject matter that the life of the
steering assembly is improved.
[00024] , It is also an advantage that the performance of the steering assembly
is improved, which is an essential aspect for maneuvering the vehicle.
[00025] It is a further advantage that the assembly and maintenance time is
improved, at the same time the thread digging by upper bracket is reduced.
[00026] It is a further advantage that positional tolerance, machining tolerance
and parallelism between upper bracket and lower bracket affecting the clearance
between the steering shaft and the upper bracket is reduced.
[00027] The present subject matter is applicable to a three-wheeled vehicle .
comprising the components viz. head tube, steering shaft, upper bracket, steering
arrestors,
'of the steering assembly of the present subject matter
[00028]
‘
In an embodiment, an upper bracket is positioned between a steering
arrestor and'a locking nut that‘acts as arrestor members. A steering shaft is provided
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w1th threads in a top portion. The steering arrestor and the locking nut are screwed
to the steering shaft. Thesteering arrestor is proVided with a protrusion, which is a
bulge portion, disposed in axial direction andtextending in a radial‘ direction
'
covering at least a distance of an outer diameter 'of the steering shaft from the
inner diameter. The upper bracket is provided with
a
cavity that is capable
receiving the protrusion of the. steering arrestor. Therefore, clearance is
maintained uniformly around the steering shaft.
[00029] In another embodiment, a steering arrestor is screwed to a steering
shaft thrOugh threads provided on an upper portion of the steering shaft. The
steering arrestor is provided with a protrusion towards axial direction extending in
a radial direction covering at least a distance of an outer diameter of the steering shaft. An upper bracket is positioned on the steering arrestor. The upper bracket is
provided with a first depression ina lower portion such that it is capable receiving
the protrusion of the steering arrestor. In addition, the upper bracket is provided
with a second depression in an upper portion of the upper bracket. A locking nut is
screwed to the steering shaft above the upper bracket. The locking nut is provided
with a protrusion such that the second depression of the upper bracket is capable
of receiving the protrusion of the locking nut.
[00030] The aforesaid and other advantages of the present subject matter
would be described in greater detail in conjunction with the figures in the
following description.
[00031] Fig. 1 illustrates a right side view of a saddle-ride type vehicle 100, in
accordance with an embodiment of present subject matter. The Fig. 1 depicts the .
vehicle having a longitudinal direction extending from a front portion F of the
vehicle towards the rear portion R. Also, the vehicle. extends in lateral direction of
the vehicle 100 from right to left. The vehicle 100 has a frame assembly 105,
‘which acts as the skeleton for themotorcycle 100. The frame assembly 105
. includes a head tube 105A, a main tube (not shown) and may have a down tub/e
"Tl
(not shown). A swing arm 110 is swingably connected to a pivotal point of the
frame assembly 105.VA' rear wheel 115 is rotatably supported by the swing arm.
‘
110. one or more rear suspension(s)
.120
connect the swing arm to the" frame
assembly. A seat assembly 125 is mounted to the frame assembly. A fuel tank
assembly 130 is disposed in ananterior portion of the seat assembly 125.
[00032] An engine assembly 135 is mounted in the anterior portion to the frame
assembly 105. The engine assembly 135 includes an internal combustion coupled
to a kick-start mechanism, a transmission mechanism for transferring the power to
the rear wheel 115, an air-fuel supply mechanism for the IC engine includes a
carburetor or the like, and an exhaust mechanism. A steering assembly 200 includes one or more front fork(s) 145. A front wheel 150 is rotatably connected
to the one or more front fork(s) 145. The vehicle 100 has various electrical loads
including a headlamp 150, a tail lamp 155, and a starter motor (not shown). A
front fender 160 covers at least a portion of the front wheel 150. A rear fender 165
covers at least a portion of the-rear wheel 115. The frame assembly is covered by
plurality of panels 170.
[00033] Fig. 2 illustrates a right side view of the steering assembly 200. The
steering assembly 200 comprises a steering shaft 220 that is rotatably connected to
the head tube 105A of frame assembly 105. An upper bracket 210 is mounted with
a handle bar assembly 210 to a top portion. A lower bracket 215 is affixed to a
bottom portion of the steering shaft 220. A handle bar assembly 205 is mounted to
I
the upper bracket 210. A first front fork 145A and a second front fork (not
shown)are connected to the lower bracket 215 and extend through the lower
bracket 215 connected the upper bracket 210. The front wheel 150 (as shown in
Fig. 1)is rotatably connected to the first fork 145A and the second fork
therebetween. A steering shaft 220 rotates within an angle with respect to an axis
'
of the steering shaft 220.
[00034] Fig. 3 depicts an enlarged view of a portion of the steering assembly.
Fig. 4 depicts a cross sectional view of a portion of the steering assembly 200
taken along the axis X-X’, in accordance with the embodiment depicted in Fig. 3.
A steering shaft 220 is rotatably mounted through the head tube 105A. A lower
'
‘ bearing assembly 235L is positioned at a lower end of the head tube 105A. The
25
lower bearing assembly 235L comprises a lower ball(s) and a lower race(s). The
lower bracket2154-is
positioned below the lower bearing assembly 235L. The
lower bracket 215 is affixed to the steering shaft 220. An upper-bearing assembly
235U is positioned at a top end of the head tube 105A. The upper bearing
assembly 235U comprises an upper ball(s) and an upper race(s). An upper end of contact. area, thereby providing a clearance between the inner diameter of the
upper bracket 210 and the inner diameter of the steering shaft 220.
[00037] In other words, the upper bracket 210 is provided with an annular
cavity 210A, which 1s the counter bore 210A, on one end of the mounting portion.
The first arrestor member 230 is provided with an annular bulge portion 230A,
which is the boss 230A, that is capable of abutting against said annular cavity
210A whereby a predefined-clearance is maintained between the steering shaft
220‘ and theiiiipper bracket 210.
'
[00038] Furthermore, the possibility of upper bracket 210 coming in contact with
the steering shaft 220 threads is reduced. Therefore, any damage of the upper
bracket 210 due to contact with steering shaft 220 is prevented.
[00039] In another embodiment, a bulge portion may be provided on a lower
portion of the upper bracket and a annular may be provided on an upper portion of
the steering arrestor.
[00040] In
yet another embodiment, a first. protrusion is. provided
on
the upper
“portion of the first arrestor member disposed below the upper bracket and a
second protrusion is provided on the lower portion of a second arrestor member
that is disposed above the upper bracket. A first annular is formed on the lower
portion of the upper bracket, which is capable of ‘accommodating the first
protrusion of the first arrestor member. A second annular is provided on a top
portion of the upper bearing assembly, which‘is capable of receiving the second-
protrusion of the second arrestor member. [00041] Fig. 5 depicts a portion of a steering assembly, in accordance with
another embodiment of the present subject matter. Fig. 6 depicts a cross sectional
view, which is along the longitudinal-axis of the vehicle, of the steering assembly
depicted in Fig. 5. The steering assembly comprises a steering shaft 220._ In the
present embodiment, a support steering arrestor 245 and a steering arrestor 230 are used, wherein the steering arrestor 230 acts a first arrestor member 230. The
steering shaft 220 is rotatably mounted through the head tube 105A. A lower
bearing assembly 235L is positioned at a lower end of the head tube 105A. The
lower bearing assembly 23SL comprises a lower ball bearing and a lower race
5 assembly. The lower bracket 215 is affixed to the steering shaft 220 and disposed
below the first bearing assembly 235L. An upper bearing assembly 235U is
positioned at
a
top end of the head tube 105A. An upper end of the steering shaft
~
220 is provided with threads.
[00042] A support steering arrestor 245 is screwed to the steering shaft 220
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such that it is positioned above the upper bearing assembly 235U. In the present
embodiment double steering arrestors i.e., the first steering arrestor 230, and the
support steering arrestor 245 are used. The first arrestor member 230 is screwed
such that it is positioned above the support steering arrestor 245. A locking nut240
is screwed above the upper bracket 210 and is fastened to the steering shaft 220'
15 throughthe threads. The first arrestor member 230 is provided with a thread relief
in the lower portion. Further, the first arrestor member 230 is provided with an
'
annular bulge portion 230Aon a top surface. The upper bracket 210 is provided
with a annular 210A on a lower surface of the upper bracket 210. The annular
210A of the upper bracket 210 is capable of accommodating the bulge portion
20. 230Aof the first arrestor member 230.
A
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[00043] Therefore,- the annular cavity 210A provided on the upper bracket 210
and the bulge portion 230Aprovided on the first arrestor member 230‘enable
I
uniform contact area thereby enabling uniform clearance between the inner
diameter of the upper bracket 210 and the outer diameter of the steering shaft 220.
25 Furthermore, the possibility of upper bracket 210 coming in contact with the
steering shaft 220 threads is eliminated. Therefore, any damage of the upper
~ bracket 210 'due to steering shaft is prevented. [00044] Further, the support steering arrestor 245 enables pre—loading of the
lower bearing assembly 235L and upper bearing assembly 235U.The first member
230 prevents any. loosening of the support arrestor member 245. Further, thread
relief is provided at a bottom portion of the support steering arrestor 230 to
accommodate any tolerance variations.
[00045] The first arrestor member 230 is provided the bulge portion 230Aon a
top surface. The upper bracket 210 is provided with a annular 210A in the lower
portion. The annular 210A of the upper bracket 210 enables accommodation of
the bulge portion 230Aof the first arrestor member 230. The annular 210A of the
upper bracket 210 and the bulge portion 230Aof the first arrestor member 230
enable the upper bracket 210 from coming in contact with threads of the steering
shaft 220. Further, radial contact between the upper bracket 210 and the first
arrestor member 230 controls tolerance variation between each other. Furthermore,
the contact portion of the first arrestor member 245 and the upper bracket enables
210 uniform load distributions on the lower bearing assembly, and the upper
bearing assembly, thereby split threads may be avoided.
[00046] In another embodiment, the locking nut acts a second arrestor
member. At least
one.
at least one of said arrestor member and said lock nut
member is provided with an annular bulge portion. that is capable of abutting
against said annular whereby a predefined clearance. is maintained between the
steering shaft and the upper bracket.
V
[00047] The steering assembly of the. present subject matter enables
elimination of a metal insert. The weight of the steering assembly is reduced.
Clearance between the steering shaft and the upper bracket is maintained enabling
easy assembly. Furthermore, the steering assembly enables use of the steering
shaft with continuous threads on the upper portion.
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[00048] Although the subject matter has been described in considerable detail
with reference to certain embodiments thereof, other embodiments are possible. It
is to be understood that the aspects of the embodiments are not necessarily limited
to the features described herein. Many modifications and variations of the present
subject matter are possible in the light of above disclosure. Therefore, within the
’scope of claims of the present subject matter, the present disclosure may be
practiced other than as specifically described.
FIEE E'HEE‘alNfil LSr’fis‘fixgglG L4 [00048] Although the subject matter has been described in considerable detail
with reference to certain embodiments thereof, other embodiments are possible. It
is to be understood that the aspects of the embodiments are not necessarily limited
to the features described herein. Many modifications and variations of the present
subject matter are possible in the light of above disclosure. Therefore, within the
’scope of claims of the present subject matter, the present disclosure may be
practiced other than as specifically described.