DESC:TECHNICAL FIELD
[0001] The present subject matter relates generally to saddle-ride type 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) to a front wheel. 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 saddle-ride type vehicle, frame structure is such that an internal combustion (IC) engine is positioned in the forward direction of the vehicle. The IC engine is positioned in a manner such that the cylinder head is either vertical or inclined forwardly. Typically, in the saddle-ride type vehicle, a fuel tank assembly is mounted to the frame assembly above the IC engine and an air intake system is disposed below a seat assembly, where 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 the steering assembly connected to the front wheel. The steering assembly may comprise 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 a cross sectional view of a portion of the steering assembly taken along the axis AA`.
[0008] Fig.4a illustrates a perspective view of a dust seal member according to an embodiment of the present invention.
[0009] Fig. 4b illustrates a sectional view of a dust seal member taken along xy plane in Fig. 4a.
[00010] Fig. 5 illustrates a detailed view of a portion of the sectional view of the dust seal member according to an embodiment.
DETAILED DESCRIPTION
[00011] Generally, a frame assembly of the vehicle acts as a skeleton. The internal combustion engine or the like, which acts as the primary drive source of the vehicle, is mounted to the frame assembly. The IC engine is cranked by using a kick-start mechanism or an electric start mechanism. Air fuel mixture is combusted in a combustion chamber of the IC engine. Generally, a fuel tank supplies 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 for maneuvering of the vehicle. The steering assembly comprises a handle bar assembly, a steering shaft, a lower bracket, and an upper bracket. 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 suspension. The front fork assembly and the steering shaft are mounted to the lower bracket. Typically, in a saddle-ride type vehicle, the steering assembly comprises of a lower bracket, an upper bracket, steering races, balls, an upper dust seal member, a lower dust seal member, a steering arrestor, and a locking member. The complete steering assembly is integrated in the two-wheeled vehicle frame assembly by a locking member. The upper bracket is positioned between the bottom arrestor, the top arrestor, and a locking member.
[00014] The steering races and the balls used in the steering assembly sustain the load received from the road and provide a smooth rotation of the steering assembly. One or more dust seal members are used in the steering assembly to prevent dust entry, water entry and entry of any other foreign particles into the steering assembly, which are detrimental to the durability and to the smooth rotation of the steering shaft.
[00015] The dust seal member comprises of a number of annularly formed ridges on an inner surface of the dust seal member. The annular ridges extend in at least one of an axial direction or in a radial direction of the dust seal member. The annular ridges prevent the entry of water and dust into the steering assembly.
[00016] Further, the annular ridges are configured to obtain different assembly conditions with the mating parts in assembled condition. The various assembly conditions include clearance fit, interference fit, and transition fit.
[00017] The dust seal member configured to obtain clearance fit with the steering shaft leads to dust and water entry into the steering assembly, which is detrimental to the durability of the steering races and balls resulting in the various problems related to vehicle handling overtime. Hence, the clearance fit is not preferred.
[00018] Further, the dust seal member configured to achieve interference fit with the mating parts prevents the water and dust entry in to the steering assembly. However, there is a negative impact on handling the vehicle due to higher friction involved between the mating parts including dust seal member and a frame head tube. Hence, the interference fit is not desirable.
[00019] Furthermore, the dust seal member configured to achieve transition fit has trade-off benefits and drawbacks between the clearance fit and the interference fit. Hence, a desired fit for the dust seal member is obtained based on requirement of dust prevention, durability and various vehicle-handling requirements.
[00020] Further, typically, the dust seal member is entirely made of a polymer material or the like and the dust seal member made up of polymer is best suitable for clearance fit. In clearance fit, the prevention of dust entry is not achieved. Furthermore, there exists a dust seal member made up of a rubber end molded with a metal part. Typically, dust seal member made of a poly carbon is designed for transition fit, where prevention of dust entry is critical. The aforementioned design of the dust seal member is not preferred due to their disadvantages including failure in providing full protection to the steering races and the balls inside the steering assembly.
[00021] Hence, an objective of the present invention is to provide a steering assembly with a dust seal member capable of effectively preventing the dust and water entry into the steering assembly in assembled condition and the proposed dust seal member is able to overcome the above-mentioned drawbacks.
[00022] According to an embodiment of the present invention, an integrated dust seal member configured to include both annular ridges axial and annular ridges radial is able to effectively prevent the entry of dust, water and other foreign particles inside the steering assembly. Further, the durability of the steering assembly is not affected as the steering races and balls are protected from the entry of water, dust and other foreign particles.
[00023] Further, the friction occurring between the dust seal member and the corresponding mating part, for example, the head tube in assembled condition is reduced in the proposed invention.
[00024] The previously mentioned and other advantages of the present subject matter would be described in detail in conjunction with the figures in the following description.
[00025] Fig. 1 illustrates a right side view of a saddle-ride type vehicle, in accordance with an embodiment of present subject matter. The figure depicts a front portion F of the vehicle and the rear portion R along the longitudinal direction of the vehicle 100 from right to left. The vehicle 100 has a frame assembly 105, which acts as the skeleton for the motorcycle 100. The frame assembly 105 includes a head tube 105A, a main tube (not shown) and may have a down tube (not shown). A swing arm 110 is swingably connected to a pivotal point of the frame assembly 105. The swing arm 110 rotatably supports a rear wheel 115. 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 an anterior portion of the seat assembly 125. An engine assembly 135 is mounted in the anterior portion of the frame assembly 105. The engine assembly 135 includes an internal combustion, 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.
[00026] Fig. 2 illustrates a right side view of the steering assembly 200. The steering assembly 200 comprises a steering shaft 220 (not shown) 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 303 of the steering shaft 220. A lower bracket 215 is affixed to a bottom portion of the steering shaft 220. A handle bar assembly 205 is mounted to the upper bracket 210. A first front fork 145A and a second front fork 145B are connected to the lower bracket 215 and the upper bracket 210. The front wheel 150 is rotatably connected to the first fork and the second fork therebetween. A steering shaft 220 rotates within an angle with respect to an axis of the steering shaft 220.
[00027] Fig. 3 depicts a cross sectional view of a portion of the steering assembly 200 taken along the axis AB. A steering shaft 220 is rotatably mounted through the head tube 105A. A lower bearing assembly 235A is positioned at a lower end of the head tube 105A. The lower bearing assembly 235A comprises a lower ball(s) and a lower race(s). The lower bracket 215 is positioned below the lower bearing assembly 235A. The lower bracket 215 is affixed to the steering shaft 220. An upper bearing assembly 235B is positioned at a top end of the head tube 105A. The upper bearing assembly 235B comprises an upper ball(s) and an upper race(s). An upper end of the steering shaft 220 is provided with threads. A bottom steering arrestor 230B is positioned above the upper bearing assembly 235B member and the bottom steering arrestor 230B is fastened to the steering shaft 220 through the threads. A top steering arrestor 230A is placed above the bottom steering arrestor 230B. The upper bracket 210 is positioned above the top steering arrestor 230A through the threads. An inner diameter of the upper bracket 210 is greater than that the outer diameter of the steering shaft 220 enabling easy assembly of the upper bracket 210. A locking member is positioned above the upper bracket 210 and is fastened to the steering shaft 220 through the threads. A dust seal member 245 is disposed above the upper bearing assembly 235B to avoid entry of dust and water. A lower dust seal member 250 is disposed below the lower bearing assembly 235A to prevent the entry of dust, water and other foreign particles inside the steering assembly 200.
[00028] Fig.4a illustrates a perspective view of a dust seal member according to an embodiment of the present invention. The dust seal member 245 is disposed above the upper bearing assembly 235B. The dust seal member 245 according to an embodiment lies in between the bottom steering arrestor 230B and the upper bearing assembly 235B. The dust seal member 245 functions as a barrier to prevent entry of water, dust and other foreign material into the steering assembly 200, which is detrimental to the functionality of the steering assembly 200. Further, a smooth steering of the steering assembly 200 is provided by the present invention due to integration of various assembly conditions of the dust seal member 245 with the steering shaft 220.
[00029] In accordance with another embodiment, the dust seal member 245 is capable of being employed in a two-wheeled vehicle with a single steering arrestor in the steering assembly.
[00030] Fig. 4b illustrates a sectional view of a dust seal member taken along xy plane in Fig. 4a In accordance with an embodiment of the present invention, the dust seal member 245 according to an embodiment is an integrated dust seal member comprising of both at least one annular ridge(s) disposed axially and at least one annular ridge(s) disposed radially on an inner surface 315 of the dust seal member 245. The inner surface 315 is closer to the head tube 105A. According to an embodiment, at least one annular ridge axial 300 is disposed at a substantially upper portion of the surface 315 of the dust seal member 245. The at least one annular ridge radial 305 is disposed at a substantially lower portion of the inner surface 315 of the dust seal member 245. The dust seal member 245 comprises of an outer body 310 exposed to the atmosphere. The outer body 310 has an ‘L’ shaped profile, the outer body 310 includes a radial surface 310a along a radial direction with respect to the steering shaft axis AA`, and an axial surface 310b along an axial direction of the steering shaft axis AA`.
[00031] The at least one annular ridge axial 300 provides clearance fit between the dust seal member 245 and the steering shaft 220. The clearance fit effectively prevents or diverts the entry of dust and other foreign material away from the steering assembly 200. Further, the at least one annular ridge radial 305 provides interference fit between the dust seal member 245 and the steering shaft 220. The interference fit effectively prevents entry of water particles into the steering assembly 200. Hence, according to the proposed dust seal member 245, a combined effect of the at least one annular ridge axial 300 and the at least one annular ridge radial 305 efficiently prevents entry of water, dust and other foreign particles into the steering assembly 200.
[00032] Further, the dust seal member 245 includes an upper most portion 320 surrounding the head tube in assembled condition. The upper most portion 320 prevents any dust and other foreign particles that may enter the steering assembly (not shown) from the upper bracket (not shown).
[00033] However, according to yet another embodiment, the dust seal member 245 can be configured to include various fits including clearance fit, transition fit, and interference fit in the at least one annular ridge radial and at least one annular ridge axial.
[00034] Fig. 5 illustrates a detailed view of a portion of the sectional view of the dust seal member according to an embodiment. The dust seal member 245 comprises of the at least one annular ridge radial 305 disposed in the radial direction and the at least one annular ridge axial 300 disposed along the axis of the steering shaft. The at least one annular ridge radial 305 comprises a first wall 305a including a first face 305aa extending away from the head tube 105A and a second face 305ab substantially parallel to the head tube 105A. The second face 305ab is at a first angle O from an imaginary line pq. The imaginary line pq passes through the first face 305aa. The first face 305aa and the second face 305ab form a curved structure. The curved structure ensures less material deposition around the area of contact of the at least one annular ridge radial 305 with the head tube 105A. Less material deposition ensures less stiffness of the at least one annular ridge radial 305, and hence, friction of the dust seal member 245 with the head tube 105A is reduced. The first angle O is approximately between 15° and 75°.
[00035] Further, the at least one annular ridge radial 305 includes a second wall 305b disposed at a second angle a from the head tube 105A. The second angle a is approximately 10°.
[00036] The first angle O and the second angle a facilitate to maintain less material deposition at the inner layer of the dust seal member 245 which is at proximity to the head tube 105A. The thin layer at the inner surface 315 ensures reduced friction of the at least one annular lip radial 305 with the head tube 105A. In addition, the first angle O and the second angle a result in a required profile of the at least one annular lip radial 305, which is enough for a contact with the head tube 105A to achieve minimum friction and also to let out any water droplets that may flow from the upper bracket (not shown). Therefore, the water droplets do not enter into the steering system, instead gets collected in the angular portions in the first angle O, and the second angle a. The collected water droplets are further easily let outside in a downward motion.
[00037] Furthermore, the at least one annular ridge radial 305 includes a transition portion 305c through which a transition line cd passes through. The transition line cd indicates the variation in material deposition from the first angle O to the third angle ß. The third angle ß is approximately 10°. The transition portion 305 indicates that the first angle O is greater than the third angle ß, the transition portion ensures that the at least one annular ridge radial 305 has minimum frictional contact area with the head tube 105A. Therefore, wear and tear of the dust seal member 305 is reduced and a more reliable dust seal member 245 is achieved.
[00038] Furthermore, the dust seal member 245 includes the at least one annular ridge axial 300 to prevent the entry of dust and other foreign particles from entering into the steering system.
[00039] According to an embodiment of the present invention, the dust seal member 245 is made of a known material including elasticity like rubber.
[00040] 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. Rather, the features are disclosed as embodiments of the two-wheeled vehicle 100.
,CLAIMS:I/We claim:
1. A steering assembly (200) for a two-wheeled motorcycle (100) comprising:
a head tube (105A);
a steering shaft (220) disposed rotatably and co-axially within the head tube (105A) along a steering shaft axis (AA`);
an upper bracket (210) disposed at a top portion (303) of the steering shaft (220);
at least one steering arrestor (230A, 230B) disposed below the upper bracket (210);
an upper bearing assembly (235B) disposed in between the steering shaft (220) and the head tube (105A), said upper bearing assembly (235B) is disposed at the top portion(303) of the steering shaft (220) and below the upper bracket (210); and
a dust seal member (245) disposed in between the at least one steering arrestor (230A, 230B) and the upper bearing assembly (235B),
wherein,
the dust seal member (245) includes at least one annular ridge (305, 300) disposed in at least one of a radial direction and an axial direction with respect to the steering shaft axis (AA`) and wherein said at least one annular ridge (305, 300) is disposed on an inner surface (315) of the dust seal member (245).
2. A dust seal member (245) for preventing entry of dust particles into a steering shaft (220) of a two-wheeled motorcycle (100), said dust seal member (245) comprising
an outer body (310) including a radial surface (310a)and an axial surface (310b);
an inner surface (315)of said outer body (310),
wherein,
the dust seal member (245) includes at least one annular ridge (305, 300) disposed on said inner surface (315) and said at least one annular ridge (305, 300) is disposed in at least one of a radial direction and an axial direction with respect to a steering shaft axis (AB) of the steering shaft (220).
3. The steering assembly (200) as claimed in claim 1, wherein said at least one annular ridge (305, 300) includes at least one annular ridge radial (305) and at least one annular ridge axial (300).
4. The steering assembly (200) as claimed in claim 3, wherein said at least one annular ridge radial (305) comprises a first wall (305a) including a first face (305aa) extending away from the head tube (105A) and a second face (305ab) parallel to the head tube (105A), a second wall (305b) disposed at a second angle (a) to the head tube (105A) and, a transition portion (305c).
5. The steering assembly (200) as claimed in claim 4, wherein said second face (305ab) is disposed at a first angle (O) with an imaginary line (pq) passing through the first face (305aa), wherein the first angle (O) is in the range of 15° and 75°.
6. The steering assembly (200) as claimed in claim 4, wherein said second wall (305b) is at an second angle (a) with the head tube (105A), wherein the second angle (a) is in the range of 8° and 10°.
7. The steering assembly (200) as claimed in claim 2, wherein said dust seal member (245) is made of thermoplastic elastomer.
8. The steering assembly (200) as claimed in claim 4, wherein said transition portion (305c)is at a third angle (ß) with the head tube (105A), a transition line (cd) passes through the transition portion (305c).
9. The steering assembly (200) as claimed in claim 1, wherein the at least one steering arrestor (230A, 230B) includes at least one of a top steering arrestor (230A) and a bottom steering arrestor (230B).
10. A two-wheeled motorcycle (100) comprising a steering assembly (200) as claimed in any one of the preceding claims.