Light weight swing arm assembly for motorcycle

Abstract

Present invention discloses light weight swing arm with enhanced strength and load bearing capacity, weight of which is reduced by some technical modifications. The swing arm(100) consists right and left main tubes(101)&(102), cross tube(103) with splined surface, corrugated right and left bush(104)&(105), corrugated shocker bolts(106), chain cover MTG bracket & support front (107)&(108), Right and left reinforcements(109) and brackets (110)&(111), chain cover MTG bracket LH lower rear upper and rear upper (112)&(113) connected to bracket(110) on the right side only and removed from left side in order for weight reductions. Further, it include rear brake holder(114), L-shaped bracket(HS), washers(116), U-shaped middle chain cover support(117), Spring holder arm brake(118) and M6 Hex Nut (119). These technical modifications reduced the weight of swing arm assembly upto21%. The profile / corrugation / splining is created by machine comprising die having die case with profile used for making parts of said swing arm assembly during cold forging process.

Description

[0001] LIGHT WEIGHT SWING ARM ASSEMBLY FOR MOTORCYCLE

[0002] FIELD OF INVENTION

[0003] The invention generally relates to the field of Automobile Engineering. More specifically it pertains to a light weight swing arm assembly for motorcycle.

[0004] BACKGROUND OF THE INVENTION

[0005] The following background includes information which is important for the better understanding of the present invention.

[0006] Corrugation of metal sheet:

[0007] Today the corrugation process is carried out using the process of roll forming. This modern process is highly automated to achieve high productivity and low costs associated with labor. In the corrugation process sheet metal is pulled off huge rolls and through rolling dies that form the corrugation. After the sheet metal passes through the rollers it is automatically sheared off at a desired length. The traditional shape of corrugated material is the round wavy style, but different dies form a variety of shapes and sizes. Industrial buildings are often built with and covered by trapezoidal sheet metal.

[0008] Many materials today undergo the corrugation process. The most common materials for corrugated iron are ferrous alloys (e.g. stainless steels), aluminum and copper. Regular ferrous alloys are the most common due to price and availability. Common sizes of corrugated material can range from a very thin 30 gauge (0.012 inches, 0.3 mm) to a relatively thick 6 gauge (0.1943 inches, 5 mm). Thicker or thinner gauges may also be produced. Other materials such as thermoplastic and fiberglass-reinforced plastic sheets are also produced with corrugations. Clear or translucent products can allow light to penetrate below.

[0009] Corrugated metal starts with carbon steel sheet which is then pressed into three-dimensional patterns, called corrugations, using a series of rollers in a cold roll forming process. Different roller die arrangements produce different types of corrugation, including waves, squares and angles. Cold rolling allows a thicker and stronger product that also presents a better appearance than hot-formed steel. Finished sheet is then sheared off to the desired length.

[0010] The corrugations are described in terms of pitch (the distance between two crests) and depth (the height from the top of a crest to the bottom of a trough). It is important for the pitch and depth to be quite uniform, in order for the sheets to be easily stackable for transport, and to overlap neatly when joining two sheets. Pitches have ranged from 25 mm (1 inch) to 125 mm (5 inches).

[0011] Swing arm assembly in motorcycle:

[0012] Swing arm also known as swing fork or pivoted fork is a hardware and mechanical component and main part of the rear suspension on a motorcycle, which attach the rear wheel of the motorcycle to its body. It is one of the main component of the bike allowing the fitment of the rear axle of the bike as well as allowing the vertical movement of the rear tire which helps in managing the undulations or bumps present on the road. (https: / / en.wikipedia.org / wiki / Swingarm). Swing arm is characterize the behavior of motorcycle as it regulates interaction of rear wheel with road through system of springs and dampers by connecting rear wheel to the main chassis of the vehicle. The swing arms comes in two basic designs i.e., single sided swing arm and double sided swing arm.

[0013] Traditional swing arm assembly comprises a symmetric structure with a two parallel beams / pipes connecting the rear axle at one end and pivoting at the other end and traditional swing arm is generally manufactured using steel, magnesium and aluminum alloys as raw material through the standard process of welding multiple pieces together to create complete swing arm assembly.

[0014] Problems in Swing arm assembly:

[0015] The swing arm must be strong enough to handle the loads and hurdles experienced on the field and roads and stiff enough in order to increase the response, stability as well as performance of the motorcycle. However, while maintaining the stiffness and strength of swing arm, the weight of the swing arm automatically increases, which in turns increase the overall weight of the motorcycle which in turns emit higher pollution, higher gross carbon foot print and consume higher amount of fuel and thus decreases the performance as well as the efficiency of the motor cycle. (Researchgate)

[0016] Thus, the weight of the swing arm should be reduced in order to improve motorcycle performance and to increase the road holding of the rear wheel. Lesser the weight of the swing arm, lesser will be the weight of the motorcycle and higher will the performance and efficiency of the bike. Further, a lightweight swing arm not only reduces the total weight of the bike, but more importantly reduces the un-sprung mass at the rear, which hugely improves the overall handling of the motorcycle. (https: / / www.ijitee.org / wp- content / uploads / papers / v8i8 / H7048068819.pdf)

[0017] There are various existing light weight swing arms available in prior art which offer light weight swing arm assemblies, however the strength, rigidity, load bearing capacity, durability and stiffness of the existing light weight swing arm assemblies are still under question. Hence, there was an immense need to manufacture light weight swing arm assembly with enhanced strength, durability, rigidity and stiffness, in order to enhance the performance, handling and overall efficiency of the motorcycle.

[0018] Innovative approach by Present invention

[0019] In order to address the problems associated with heavy weight swing arms assemblies and existing light weight swing arms assemblies, the inventors of present invention came up with an approach of disclosure of a light weight swing arm assembly for motorcycle with enhanced strength and durability. The inventors of present invention have innovatively altered the swing arm assembly for motorcycle by way of some technical modifications including curved profiling, corrugation, thickness and length reduction etc, which not only reduces the weight of the swing arm but also enhances the durability of the same without compromising the strength, thus to enhance the performance of the motorcycle accordingly.

[0020] Present invention is confined to light weight swing arm assemblies with enhanced strength and stiffness, improving overall performance and efficiency of bikes. Present invention is not anticipated by prior art patents and non-patents literature, however related prior art is as below:

[0021] Prior art patents

[0022] Indian Patent Application No: 202241069140 discloses "A modular swing arm assembly for a motorcycle and a method thereof"

[0023] The above cited patent discloses a modular swing arm with detachable left and right side swing arms enabling easy service and maintenance. The same is lighter in weight, high in strength and durability due to its optimized design. Further it comprises combination of ribbed swing arm members with vaulted (arc / curved) mid-section, combined with split mounting at primary motorcycle frame, enables disclosure of lightweight complex shape swing arms with high strength and structural rigidity.

[0024] The object of above patent is to provide detachable left and right side swing arms which in also results in lightweight complex shape swing arms. Providing a corrugated and curved profile is not the manner in which light weight is achieved.

[0025] Indian Patent Application No. 201944036859 discloses "Motorcycle swing arm"

[0026] The above cited patent discloses a motorcycle swing arm consisting of a pivot portion at a distal end portion which swingably support a body frame, a driving wheel supporting portion at a rear end portion, supporting a driving wheel and pair of left and right arm portions which is formed inside member and outside member made of press material or a sheet of press material. Further, the reinforcing members are also disposed between the inside and outside member.

[0027] The corrugation and profiling of different parts of swing arm as disclosed in present invention is not mentioned in above cited patent, making present invention differs from above cited patent.

[0028] Indian Patent Application No. 23 / DEL / 2014 discloses "Swing arm for motorcycle"

[0029] The above cited patent discloses a swing arm for motorcycle consisting a pivot shaft support part for swinging, a left-and-right pair of pipe members extending toward a rear side from the pivot shaft support part supporting a wheel; and a joint member welded at each of intermediate parts of the left-and-right pipe members. The left and right pipe members includes a bent part bending in vehicle body inner side direction at an intermediate position in longitudinal direction and flat surface parts at upper and lower surfaces, further, there is a joint surface, bracket for mounting rear cushion unit etc.

[0030] The corrugated bush based assembly with curved profiling and modified brackets as disclosed in present invention is not disclosed anywhere in above cited patent.

[0031] Indian Patent Application No. 201811049097 discloses "Swing arm of vehicle"

[0032] The above cited patent discloses a sheet metal swing arm having pivot section including right end portion and left end portion, the pivot section swingably supporting the swing arm to the body frame. The sheet metal swing arm has a right arm extending rearwardly from the right end portion of the pivot section. The sheet metal swing arm has a left arm extending rearwardly from the left end portion of the pivot section. The sheet metal swing arm further has a bridge member extending in vehicle width direction between the right arm and the left arm and attached to the right arm and the left arm. The swing arm further has at least one reinforcement member joined to the right arm and at least one reinforcement member joined to the left arm. The swing arm assembly further comprises a bridge member attached to both left and right arm.

[0033] The bushes in above cited swing arm are plain, whereas in present invention, the bushes are corrugated to reduce the weight of the swing arm.

[0034] Patent application no. JP3125259B2 discloses "Motorcycle taper swing arm"

[0035] Above cited patent discloses a swing arm consisting hollow tapered front and rear portion. Further is comprises a cross member connecting the arms with tapered portions. By making the taper swing, substantially equal stress is generated in each portion, so that the weight can be reduced. In the cross member, a pair of cross plates are formed with a U-shaped deep cut and a shallow cut from the front and rear, and U-shaped curved end plates are welded so as to cover the cuts.

[0036] Tapering is disclosed in above cited patent to reduce the weight of the spring arm, however, corrugated bush based assembly is not disclosed. Patent Application No. JPH03164390A discloses "Swing arm for motorcycle"

[0037] The above cited patent discloses a light and low-cost swing arm for motorcycle. In cited patent, a pipe material is cut into a predetermined length to set as an outer die to form right and left forks with thick forward parts and thin rear parts and rectangular portions. Further, the forward parts of left and right fork are welded and connected with each other by a bridge equipped with suspension bosses.

[0038] The above cited patent discloses a completely different swing arm. Hence, not relevant to present invention.

[0039] Patent Application no. US7815005 discloses "Motorcycle swing arm Assembly"

[0040] The above cited patent discloses a light weight swing arm assembly with higher strength and rigidity. The left and right arms of the Swing arm assembly are made of a magnesium alloy instead of aluminum in order to reduce the weight of the same. Further, it consists of pivot bushings connected to respective front ends of the left and right arms, end pieces connected to respective rear ends of the left and right arms for supporting an axle and a connecting member by which the left and right arms are connected together. It further, comprises a pair of mounting brackets positioned below the upright walls and extending downwardly therefrom supporting a lower end of a suspension unit which has an upper end supported by the motor cycle frame structure.

[0041] The bushes are not corrugated in above cited patent, further, the design of brackets as modified in present invention is not disclosed in above cited patent.

[0042] Patent application no. US 2018 / 0215440 Al discloses "Swing arm"

[0043] The above cited patent discloses a swing arm which is rigid and lighter in weight. The swing arm consist of a hollow body with a pivot hole in which a pivot shaft is disposed, a suspension fixing portion in the body connected to one end portion of a suspension unit , and a pair of arms extending from the body and supporting respective ends of a wheel axle. Each pairs of arms further consists of outer and inner members with cross section. The disclosed swing arm is equipped with a reinforcing wall crossing the internal space of the body, which aids in weight reduction. Weight of the swing arm in present invention is reduced by providing break downs between reinforcement pins, by corrugating and creating profiles in bushes / pivots and eliminating brackets from right end, however, such specifications are not disclosed in cited patent.

[0044] Non Patents Literature

[0045] Swathikrishnan S, et.al; Design and Analysis of Swingarm for Performance Electric Motorcycle; International Journal of Innovative Technology and Exploring Engineering; 2278-3075, Volume-8 Issue-8, June, 2019

[0046] The above cited research article discloses modified swing arm. Major modification includes the change in cross section of the lower arm from circular hollow to square hollow, thickness. Few other modifications include reinforcements to make the swingarm stiffer and help distribute stresses evenly. The current weight of the disclosed swing arm was 4.168 kg.

[0047] The corrugated bushes based designing and profiling as disclosed in present invention is not discussed in above cited article.

[0048] Trupti Rankhambe and Gajendra Kumar Nhaichaniya; Topology Optimization of Motorcycle Swing Arm; IJSART - Volume 3 Issue 5 - May 2017

[0049] The above cited article discloses topology optimization method, which removes inefficient material from structure according to stress level of elements. The resulting design provides a clear definition of Topology. Element removal can be done by simply assigning material property number of rejected elements to zero and ignoring those elements when the global stiffness matrix is assembled in subsequent finite element analysis. Weight of design space is about 11.2 Kg, it reduces by Topology Optimization up to 5.8 Kg. which is notable.

[0050] Corrugated bush based assembly is not disclosed in above cited research article, thus cited article is not relevant to the present invention.

[0051] Syed Hassaan Abdullah, et.al; Design of Racing Motorcycle Swingarm with Shape Optimization; International Journal for Scientific Research & Development ! Vol. 6, Issue 06, 2018 | ISSN (online): 2321-0613 The above cited article discloses initial design and shape optimization of the aluminum swingarm. In cited article, shape optimization of the generic swingarm design was performed by multiaxial structural analysis method. About 4.2 kg of weight was reduced in the original design while maintaining the factor of safety.

[0052] The above cited article just discloses that shape iteration can reduce the weight, but which shapes are altered is not mentioned in cited article, thus same is not relevant to present invention.

[0053] OBJECT OF THE PRESENT INVENTION

[0054] The primary object of the present invention is to disclose a light weight and high strength swing arm for motorcycle with curved / corrugated profile.

[0055] One more object of the present invention is disclose a light weight swing arm, weight of which is reduced by at least 21% than the weight of the commercially available swing arm.

[0056] Yet another object of the present invention is to disclose a light weight swing arm, which possesses high strength, durability and enhanced load bearing capacity despite being low weight.

[0057] SUMMARY OF THE INVENTION

[0058] The present invention discloses a light weight swing arm assembly with enhanced strength, durability, stiffness and load bearing capacity. The disclosed swing arm assembly (100) consists of right and left main tube assemblies (101) & (102), splined cross tube (103), corrugated right and left bush (104) & (105), shocker bolt Right and Left (106), chain cover MTG bracket front comp with -2 nuts (107), chain cover support frame (108), Right and left reinforcement (109), left end bracket (110), right end bracket (111), chain cover MTG bracket LH side lower rear comp -01 nut (112) and chain cover mounting bracket left hand side rear upper comp -01 Nut (113), bolt bracket arm rear brake holder (114), L-shaped bracket (115), washer left and right (116), U- shaped middle chain cover support (117), spring holder arm rear brake bracket RH side lower (118) and M6 hex nut (119). The swing arm assembly for motorcycle is altered in present invention by way of technical modifications, including splining / corrugation of cross tube (103) at both inner and outer surfaces, corrugation / creating curved profiles over the right and left bushes (104) & (105), shocker bold left and right (106) and left and right reinforcement (109) at both inner and outer surfaces, chain cover support frame (108), which results in weight reduction from 43g to 22g, modifying the shape of left and right end brackets (110) & (111) earlier the same was supporting the main arms from top side only but in new design, the support main tubes (101) &

[0059] (102) are covered from both top and bottom side, which enhances the durability & load bearing capacity of the same without compromising the strength to enhance the performance of the motorcycle accordingly. The said technical modifications reduced the weight of overall swing arm assembly upto 21%.

[0060] The profile / corrugation / splining is created by the existing machine used for making parts of said swing arm assembly during cold forging process as the machine comprises a die having die case with the profile, which needs to be crafted over the specific parts of the swing arm assembly, further, the profiled parts are welded together to form the complete swing arm assembly.

[0061] DESCRIPTION OF FIGURES-

[0062] Figure 1 to 7- Prior art figures

[0063] Fig 8- Front view of swing arm

[0064] Fig 9 (a) and (b) - Perspective view of swing arm

[0065] Numbering details-

[0066] (100) Swing arm assembly

[0067] (101) Right main tube

[0068] (102) Left main tube

[0069] (103) cross tube

[0070] (104) Right Bush

[0071] (105) Left bush

[0072] (106) shocker bolt right and left (107) chain cover MTG bracket front comp with -2 nuts

[0073] (108) Chain cover support frame

[0074] (109) Reinforcement LH & RH

[0075] (110) END Bracket RH

[0076] (111) END Bracket LH

[0077] (112) Chain cover MTG bracket LH side lower rear comp -01 nut

[0078] (113) Chain cover mounting bracket LH rear Upper comp -01 Nut

[0079] (114) Bolt bracket arm rear brake holder

[0080] (115) L shaped bracket

[0081] (116) Washer Left and Right

[0082] (117) U shape middle chain cover support

[0083] (118) Spring holder arm rear brake bracket RH side lower

[0084] (119) M6 Hex Nut

[0085] Figure 10- Dimensions of swing arm assembly

[0086] Figure 11(a) and (b) - Drawing of corrugated profile over right and left main tube (101 & 102)

[0087] Figure 12- Drawing of corrugated profile over cross tube (103)

[0088] Figure 13- Drawing of corrugated profile of bush (104) & (105)

[0089] Figure 14- Drawing of corrugated profile over shocker bolt right and left (106)

[0090] Figure 15- Drawing of Chain cover MTG bracket front (107)

[0091] Figure 16- Drawing of Chain cover support front (108)

[0092] Figure 17(a) & (b)- Drawing of LH & RH reinforcement (109) Figure 18(a) and (b)- End bracket RH & LH (110&111)

[0093] Figure 19- Drawing of chain cover MTG bracket LH side lower rear comp (112)

[0094] Figure 20- Drawing of chain cover mounting bracket left hand rear upper (113)

[0095] Figure 21- Drawing of Bolt bracket arm rear brake holder (114)

[0096] Figure 22- Drawing of L shaped bracket (115)

[0097] Figure 23- Drawing of washer (L) and (R)

[0098] Figure 24- Drawing of U shape middle chain cover support (117)

[0099] Figure 25- Drawing of spring holder arm rear brake bracket RH side lower (118)

[0100] Figure 26- Graphical representation of bending strength (failure load) for plain and profiled main tube (101 & 102)

[0101] Figure 27- Graphical representation of bending strength (failure load) for plain and profiled cross tube (103)

[0102] Figure 28- Graphical representation of tensile strength (failure load) for plain and profiled cross tube (103)

[0103] Figure 29- Graphical representation of bending strength (failure load) for plain and profiled main tube (101 & 102)

[0104] The light weight swing arm assembly for motorcycle is now disclosed in detail with reference to the accompanying drawings.

[0105] DETAILED DESCRIPTION OF THE INVENTION

[0106] The present invention discloses a light weight swing arm assembly (100) with enhanced durability and load bearing capacity without comprising the strength and stiffness of the same. The swing arm is particularly altered in the present invention by creating curved profile and corrugation over the outer and inner surfaces of various parts including bushes, pins / bolts etc used for creating swing arm assembly, which not only reduce the weight of the said swing arm assembly, but also enhances the durability and load bearing capacity of the same without compromising the required strength. By such modifications, the weight of the said swing arm assembly is reduced upto 14% in comparison to the conventionally existing swing arms.

[0107] Bushings are akin to thin tubes most commonly used for machinery with rotating or sliding shafts to improve efficiency and reduce vibration and noise. So modification in profile of the bush with particular pitch and depth is a major modification in the present invention.

[0108] Constructional Features of the present invention:

[0109] The swing arm assembly is present invention is prepared using conventional raw material i.e., cold rolled sheets of different grades of steel.

[0110] The swing arm assembly (100) as disclosed in present invention consists of right and left main tube assemblies (101) & (102), splined cross tube (103), corrugated right and left bush (104) & (105), shocker bolt Right and left (106), Chain cover MTG bracket front comp with -2 nuts (107), chain cover support frame (108), Reinforcement LH & RH (109), end bracket RH and LH (110) & (111) with modified shape, chain cover MTG bracket LH side lower rear comp -01 nuts (112) and chain cover mounting bracket LH rear upper comp-01 nut (113).

[0111] The overall swing arm assembly has the following dimensions:

[0112] Overall height: 629mm

[0113] Overall width: 204.6±1.0mm

[0114] Distance between two bushes (104 & 105): 127±1.0mm

[0115] Distance between right and left main tube assemblies (101 & 102): 208.6mm

[0116] Distance between bush (104) and reinforcement (109): 126±0.5mm

[0117] Distance from bush (104) to cross tube (103): 73.05mm

[0118] Length of main tubes (101 & 102) from bush (103) to end bkt (110): 473.9±0.5mm (Figure 10)

[0119] The raw material used for manufacturing of different parts is provided in table 1 below:

[0120] Table 1- Raw material used for manufacturing different parts along with their dimensions.

[0121] Technical Modifications

[0122] Some technical modifications are done in the overall swing arm design, in order to reduce the weight of the same without compromising the strength, stiffness and durability. The technical modification by way of corresponding figures are described below for better understanding of the present invention.

[0123] Referring to Figure 1 and Figure 2

[0124] Figure 1 discloses front view and figure 2 discloses perspective view of light weight swing arm assembly (100) consisting of:

[0125] Corrugated Right and left main tube (101) & (102) connected by welding with a cross tube (103), whereby the thickness of the main tubes is reduced from 2mm to 1.6mm, which results in reduction of weight of these arms from 1.185 kg to 0.776 Kg. The length of the main tube is 404±0.5mm with outer diameter (OD) is 28.6mm and wall thickness 1.6mm, which is reduced due to corrugation over the surface. The said corrugation formed crest and trough like structure with outward protruding portions (crest) at 6 places of radius 2mm and width of 5.33mm and inward portions (trough) at 6 places of radius 0.5mm and 5.27mm width. Further both the main tubes are bent. The left tube is bent at tube bending point of 109.3mm and right tube is bent at tube bend point of 99.3mm, and the bend angle for both the tubes is 9o and radius of bend is 500mm with drain hole of 4mm diameter (Figure 11 a & b) The right and left main tubes possess yield strength of 160, tensile strength of 310, 20% elongation and the weight of right main tube is 0.390Kg and weight of left main tube is 0.159Kg after corrugation;

[0126] Cross tube (103) splined at the outer diameter i.e., characterized by deep grooves or splines at outer and inner surfaces, in order to enhance the strength of the swing arm. The outer diameter of the cross tube is similar to that of main pipe (101 & 102) i.e., 28.6mm, however, the length is different i.e., 179.8mm, due to which both the tubes has different tensile strength and bending loads. The corrugation over the surface of the tube formed crest and trough like structure with outward protruding portions (crest) at 6 places of radius 2mm and width of 5.33mm and inward portions (trough) at 6 places of radius 0.5mm and 5.27mm width and said corrugation reduces the wall thickness of the cross tube (103) to 1.6mm. The chamfer length of the cross tube is 5mm with 45o Chamfer angle. (Figure 12)

[0127] Corrugated right and left bush assembly (104) & (105), in which curved profiling / corrugation is created over the bushes in order to reduce the weight from 118g to 104g of the disclosed swing arm assembly. The yield strength of same is 235 MPa, Tensile strength 340 MPa and elongation 25%. Due to corrugation, the bush has outward protrusions with radius of 1mm at 16 places and inner curve of Radius 2mm at 8 places and this distance is from the center of the part to the minimum point in the groove. The outer diameter of the bush is 28.6mm and inner diameter is 22.6mm and the chamfer at one end is at angle lx45o and other end 0.5x45o. (Figure 13)

[0128] Shocker bolt Right and Left (106) with corrugated / splined surface and a profile is created over them in order to increase the strength and to reduce the weight from 72g to 68g. The length of the overall shocker bolt is 46+0.1mm and the length of corrugated part is 32mm with diameter 12mm and thread end M10xl.25. The corrugation / splining over the surface forms outer grooves (crest) with radius 1mm at 12 places and inner grooves (trough) of radius 2mm at 6 places and distance between two outer grooves is 5.1mm at 6 places. (Figure 14)

[0129] Chain cover MTG bracket front (107) of total length 76.5±0.2mm with diameter of 21.5±0.2mm and thickness 2.5mm. Further, it has bending height of 13.4±0.2mm and the top and bottom has a hole of diameter 6.5 mm for screw / nut placement. (Figure 15)

[0130] Chain cover support frame (108): The length of the same is 52.6±0.2mm, whereby the length of the same is reduced in order to remove the excess length to reduce the weight of the same from 43g to 22g. The width of the chain cover support frame is 32±0.2mm and height is 11.4±0.2mm with wall thickness of 1.6mm. Further, the angle of side bend is 5o with central curved width of 48.7mm. The bend radius is 14.3mm, radius of intermediate fillet curve is 2mm and radius of Final return curve near side bends is 3.5mm. (Figure 16)

[0131] Left and right reinforcements (109) below the cross tube (103) is also corrugated and splined with an objective to reduce the weight by 44g. The length of the reinforcement is 114.5±0.2mm, height 47.5mm, width of wide end 33.3mm, width of narrow end 16.8mm and the same is bent from the wide end with bend angle 54. Oo and material thickness 2mm. (Figure 17 a & b)

[0132] End bracket right and left (110) & (111) with modified shape (instead of two parts assembly, a single assembly is prepared in order to enhance the properties and particularly reduce the weight). Earlier, in existing system, the end brackets (110) & (111) were supporting the main tubes from top side only, however, in present invention, Instead of two parts assembly welded together, a single assembly is prepared by modifying the shape in such a way, that the support main tubes (102) & (102) gets covered from both top and bottom side to enhance the properties and particularly increase the weight by 195g. The length of the end bracket is 150.7mm, height 68.2±0.2mm, wall thickness 6mm, width of central long slot is 12±02mm, and width of rear open end 28.6±0.5mm, width of front open end 33.0±0.2mm, front slot of width 8±0.1mm and width of front part is 41.6±0.2mm. (Figure 18 a & b) Chain cover MTG bracket LH side lower rear comp -01 nut (112) of length 20.2±0.2mm, width 23mm, wall thickness 3mm and it has hole for nut placement of 8mm radius and 6.5±0.15mm diameter and has angle of 19o. It is connected to end brackets (110) and (111) (Figure (19)

[0133] Chain cover mounting bracket left hand rear upper (113) connected to end bracket (110) on the right side only and from left side such part is remove in order to reduce the weight by removing unwanted material. It has length of 20.9mm, width 28.5mm, wall thickness 3mm, nut hole radius 8mm and diameter 6.5±0.2mm. (Figure 20)

[0134] Bolt bracket arm rear brake holder (114) of length 39±0.2mm. It has a corrugated top of 18mm diameter with outer grooves of radius 1mm at 16 places and inner grooves at 8 places of radius 2mm and distance between 2 inner grooves is 8.1mm at 8 places, corrugated body of diameter 12mm with outer grooves at 8 places of radius 2mm, inner grooves of radii 1mm at 16 places and distance between two outer grooves is 5.5mm at 8 places. Further the non-corrugated part has a slot of 2mm diameter and M8X1.25. (Figure 21)

[0135] L-shaped bracket (115) of length 39.4mm, width 39.3mm, nut hole of diameter 12mm and thickness 4mm with L-shaped curve of radii 4mm and length of the part after curve is 26mm. (Figure 22)

[0136] Washer Left and Right (116) of inner diameter 12.5±0.2mm, outer diameter 24±0.2mm and wall thickness 2mm (Figure 23)

[0137] U shape middle chain cover support (117) of length 85±0.2mm, wall thickness 1.6mm, outer width 52±0.1mm and inner width 35±0.1mm (Figure 24)

[0138] Spring holder arm rear brake bracket RH side lower (118) of length 25.9mm, width 23.7mm and slot of Length 6mm and diameter 8mm and has wall thickness of 2mm. (Figure 25)

[0139] To summarize, the key changes in various parts of swing arm assembly wrt existing are as below: Table 2- Summarization of key changes in swing arm assembly

[0140] The aforementioned technical modifications by way of curved profiling, splining, corrugation, shape modification etc reduced the weight of the swing arm assembly by 14% with 22% reduction in net weight. Reduction of 714g of the weight of raw material is achieved.

[0141] Manufacturing process and details

[0142] The manufacturing process for obtaining such light weight swing arm assembly comprises the following steps:

[0143] Cold forging: Cold forging is a process, where the work piece is placed between dies of specific radius and profiling, so that the metal work piece attains a desired shape. Cold forging process starts by selecting uncoiled large wire rods / wire of raw material particularly steel, which is further cut into the length of the required size as per the requirement. Further, using special tooling, the wire is cold forged into the right shape. At this step, the steel is molded at room temperature, by forcing the raw material through a series of dies at high pressure.

[0144] Further, the required strength for the various parts of swing arm and a profile is crafted through steel wire followed by applying said profile in the die case and placing the die case in the machine;

[0145] Furthermore, a profile is created on various parts of the swing arm assembly such as bushes (104 & 105), shocker bolt right and left (106), Chain cover MTG bracket front (107) during the cold forging process by the machine comprising the die case. The said profile is created by passing annealed wire through the die case having the profile.

[0146] The profiled parts of the swing arm are further welded together to form or create the overall swing arm assembly.

[0147] Simulation results

[0148] The simulation analysis of plain and profiled main tube (101) & (102) as well as plain and profiled cross tube (103) were analyzed for determination of tensile strength, bending strength and how much pressure such tubes can withstand. Further the results obtained for profiled tubes are also compared with plain tubes, to determine the superiority or profiled structures over the plain structures.

[0149] The plain and profiled main tube (101 & 102) & plain and profiled cross tube (103) made using CDS_2 i.e., cold drawn steel material of density 7.85e-06 Kg / mm3 and yield strength of 154 MPa undergoes bending test and flattening tests, to determine their strength and other properties. Both the tests analyze the load / pressure applied, von mises stress and maximum displacement.

[0150] Failure Load refers to the intentional external force or pressure exerted on the tube till the tube undergoes deformation or failure to evaluate its structural strength.

[0151] Von Mises Stress is the calculated value representing the overall internal stress distribution within the material. It should ideally be close to the material's yield strength, as significant deviations may indicate a risk of permanent deformation or failure.

[0152] Maximum Displacement is the extent to which the tube moves or deforms from its original position as a result of the applied load.

[0153] Simulation analysis of Main Tube: The results for main tube simulation analysis are as follows:

[0154] Bending test: Bending test evaluates the tube's ability to withstand bending loads and deformations without cracking or fracturing.

[0155] For plain and profiled main pipe: The bending test results for Plain and profiled main tube are as follows:

[0156] Table 3: Bending test results for plain and profiled main tube

[0157] From table 3 above, it is concluded that the profiled main tube has 12 % higher bending strength as compared to the plain main tube, as the profiled pipe withstood higher load of 450N before reaching its limit compared to 400N for the plain pipe, this indicates that the profiled main tube (101 & 102) has superior performance under bending loads compared to plain main pipe. The profiled pipe exhibited lower von mises stress of 160MPa, indicating better stress distribution and resistance to localized failure. This implies that the profiled geometry contributes to improved structural integrity, allowing the tube to absorb more load and deform without cracking or fracturing, thereby enhancing its overall bending performance. Figure 26 discloses the comparative bending strength of plain and profiled tube, showing failure load for profiled tube is higher than plain tube.

[0158] For plain and profiled cross pipe: The bending test results for Plain and profiled cross tube are as follows:

[0159] The bending test results for the plain and profiled cross pipes reveal that both configurations undergoes and can bear an identical load of 600N and experienced the same Von Mises stress of 160 MPa, indicating similar internal stress behavior under loading. Figure 27 discloses the comparative bending strength of plain and profiled cross tube (103).

[0160] Flattening test: Flattening test assesses tube's ductility and ability to withstand deformation without failure under compressive force.

[0161] Flattening test results for profiled main pipe and profiled cross tube

[0162] Both the profiled main pipe and profiled cross pipes are capable of withstanding an internal pressure of ISOMPa. Tensile strength test for profiled cross tube:

[0163] Tensile strength determines material's resistance to breaking under tension and determines material's ability to resist breaking or failure when subjected to stretching (tensile) force. It reflects maximum amount of tensile stress / load a material can withstand before it deforms or undergoes fractures. The tensile strength results for plain and profiled main tube are as follows:

[0164] From table 6, it was concluded that the profiled cross pipe demonstrates better performance that plain cross pipe. The profiled pipe withstands a load of 15,000N prior to deformation, while the plain counterpart failed at 11000N, highlighting 1.36 times and 36% better tensile strength. Figure 28 discloses the comparative tensile strength of plain and profiled cross tube, showing failure load for profiled cross tube is higher than plain cross tube.

[0165] Tensile strength test for profiled main tube:

[0166] Failure load for plain main pipe is 6500N, whereas failure load for profiled main pipe is 10000N, indicating that plain tube deforms when 6500N load is applied, whereas profiled main tube deforms after application of 10000N load. Thus, profiled tube has 54% load bearing capacity in comparison to plain main tube. Figure 29 discloses the comparative tensile strength of plain and profiled tube, showing failure load for profiled tube is higher than plain tube.

[0167] These results confirm that the profiled design enhances the tensile performance, making it more suitable for applications requiring higher strength and flexibility under tensile loading.

[0168] Technical modifications in swing arm assembly including splining, curved profiling, corrugations, shortening the length of the bracket, modifying the shape of parts, not only results in reduction of weight but also enhances the durability and load bearing capacity of the same without compromising the strength in order to enhance the performance of the swing arm assembly and motorcycle accordingly.

[0169] Novelty of the present invention is duly clear as per the non-disclosure of above features in the prior art patent and other non-patent literature.

[0170] Inventive step by way of technical advancement of knowledge lies in providing curved profile and corrugation over the surface of various parts including bushes, pins / bolts, reducing thickness of main arms, shortening the length of brackets etc which not only reduce the weight of the said swing arm assembly, but also enhances the durability and load bearing capacity of the same without compromising the required strength.

[0171] Industrial Application is duly clear as the present invention will boost the automobile industry, by providing low weight and low cost swing arm assembly, which is capable of enhancing the performance of the motorcycle.

[0172] As used herein, the word "a" or "an" should be understood as not excluding plural elements or operations, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0173] The present disclosure is not to be limited in scope by the specific embodiments described herein. Other embodiments and modifications apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings are intended to fall within the scope of the present disclosure. Furthermore, although the present disclosure has been described herein in the context of above, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any pump for similar purpose.

Claims

1. im1. A light weight swing arm assembly characterized in that for a length of 473.9 mm and width of 204.6 tl.Omm, it has the following constructional features:Right and left main tube assemblies (101 & 102) of 404±0.5mm length, 28.6mm outer diameter and 1.6mm wall thickness having curved profiles drawn on outer and inner surfaces forming outer grooves of 2mm radius and 5.33mm width at 6 places and inner curves of radius 0.5mm and width 5.27mm at 6 places;Cross tube (103) of length 179.8mm, outer diameter 28.6mm and wall thickness 1.6mm having corrugated profile drawn over surface forming outer grooves of radius 2mm and width 5.33mm at 6 places and inner curve of radius 0.5mm and width 5.27mm at 6 places; Right and left bushes (104) and (105) having outer diameter of 28.6mm, inner diameter of 22.6mm, chamfer at end at angle 1x45° and other end 0.5x45° having curved profiles drawn over surface forming outer grooves of radii 1mm at 16 places and inner curve of radii 2mm at 8 places with distance of 13.3mm between opposite inner curves;Shocker bolt Right and Left (106) of length 46±0.1mm and 12mm diameter have curved profiling over 32mm length forming outer grooves of radii 1mm at 12 places and inner curves of radii 2mm at 6 places with distance of 5.1mm between outer groves at 6 places; a chain cover MTG bracket front (107) of length 76.5±0.2mm, diameter 21.5±0.2mm and wall thickness of 2.5mm with 8mm hole for screw placement; a chain cover support frame (108) of 52.6±0.2mm length, 32±0.2mm width and 11.4±0.2mm height with wall thickness of 1.6mm. reinforcement members left and right (109) of length 114.5±0.2mm, height 47.5m, thickness 2mm and bend angle 54.0° having curved profiles drawn on the outer and inner surface; end bracket right (110) and end bracket left (111) of length 150.7mm, height 68.2±0.2mm, and wall thickness 6mm, have modified shape enclosing the main tubes from top and bottom sides;a chain cover MTG bracket LH side lower rear (112) of length 20.2±0.2mm, width 23mm, wall thickness 3mm and hole of 8mm radii and 6.5±0.15mm diameter with 19° bend angle; a chain cover mounting bracket LH side rear upper (113) of length 20.9mm, width 28.5mm, wall thickness 3mm, nut hole of 8mm radius and 6.5±0.2mm diameter; bolt bracket arm rear brake holder (114) of length 39±0.2mm with corrugated top of 18mm diameter forming outer grooves of radius 1mm at 16 places and inner curves of 2mm radius at 8 places with distance of 8.1mm between 2 inner grooves and corrugated body of diameter 12mm forming outer grooves at 8 places of radius 2mm, inner grooves of radii 1mm at 16 places with distance between two outer grooves is 5.5mm at 8 places; L shaped bracket (115) of length 39.4mm, width 39.3mm, nut hole of diameter 12mm and thickness 4mm;Washer (LH) and (RH) (116) of inner diameter 12.5±0.2mm, outer diameter 24±0.2mm and wall thickness 2mm;U-shaped middle chain cover support (117) of length 85±0.2mm, wall thickness 1.6mm, outer width 52±0.1mm and inner width 35±0.1mm;Spring holder arm rear brake bracket RH side lower (118) of length 25.9mm, width 23.7mm and slot of Length 6mm and diameter 8mm and has wall thickness of 2mm;- M6 Hex Nut (119). wherein curved profiling reduces the material between the curved radius and flat diameter by 597g such that the weight of the spring arm is reduced by 21% with capability to withstand the internal pressure of 150MPa.

2. The light weight swing arm assembly as claimed in claim 1 wherein the chain cover support frame (108) has side bend at angle 5° with central curved width of 48.7mm, bend radii of 14.33mm, 2mm inner fillet curve and 3.5mm final return curve.

3. The light weight swing arm assembly as claimed in claim 1 wherein left and right reinforcement (109) has 33.3mm wide end and 16.8mm narrow end.

4. The light weight swing arm assembly as claimed in claim 1 wherein the end bracket (110 & 111) has central long slot of 12±0.2mm width, rear open end of 28.6±0.5mm width, front open end of 33.0±0.2mm width and front slot of 8±0.1mm width.

5. The light weight swing arm assembly as claimed in claim 1 wherein the L-shaped bracket (115) has L-shaped curve of radii 4mm and length 26mm.

6. The lightweight swing arm assembly as claimed in claim 1 wherein, the main tubes (101 & 102), cross tube (103) & bushes (104 & 105) are manufactured from cold drawn steel (CDS-2), shocker bolts left and right are manufactured from low-carbon boron steel (10B21 / 15B25), chain cover MTG bracket front (107), Reinforcements (109), chain cover MTG bracket LH side lower rear (112) & Chain cover mounting bracket LH rear Upper (113) are manufactured from cold rolled coil and brackets & end brackets are manufactured from HRC (Hot rolled coil) sheet grade B.

7. The lightweight swing arm assembly as claimed in claim 1 wherein end brackets (RH) and LH (110 & 111) are formed as single integrating parts covering main tubes (101 & 102) from both top and bottom sides, enhancing durability and reducing need for separate welded assemblies.

8. The lightweight swing arm assembly as claimed in claim 1 wherein the chain cover mounting bracket LH rear upper (113) is connected only on the left-hand side and material on the right hand side for weight reduction.

9. The lightweight swing arm assembly as claimed in claim 1 wherein profiled main tubes (101 & 102) has 12% better bending strength as compared to plain tube.

10. The lightweight swing arm assembly as claimed in claim 1 wherein profiled cross tube (103) is capable of withstanding 600N load before bending and possess 36% higher tensile strength as compared to plain tube.

11. The method for obtaining profiling on the parts of lightweight swing assembly as claimed in claim 1 wherein the profiling is achieved by passing annealed steel rod through a die case having a specific radius and profiling, the die case being mounted in a forging machine such that, upon drawing the rod through the die case, the resulting part automatically acquires the desired profile along its circumference.

2. The method for obtaining profiling on the lightweight swing assembly as claimed in claim 1 wherein the profiling is achieved by cold forging steel rod using a die with a specific radius and profiling, the die being installed in the final station of the forging machine so that the respective part, upon forging at the final station, automatically attains the desired profile along its radius.

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