A Project Report on reverse gear Mechanism

Under the Guidance of

Mr. N.K Yadav

(Deputy Manager)

Engine assembly

InScooters India Limited, Lucknow

Submitted by

Prinsu Kumar

Amity University Lucknow

CONTENTS

Certificate

Acknowledgement

Vision Mission

Quality Policy

About Scooter India Ltd.

Products

Departments

About Machine Shop

About Line No. 7

Machine Used in Line No. 7

Manufactured Component of Line No. 7

Main Project

 

DECLARATION

I certify that Mr. Prinsu Kumar, a student of amity university lucknow, Mechanical & Automation Engineering 3rd year has completed a project on "reverse gear mechanism" under my guidance. I certify the originality of the project report. I wish a bright future for him.Date:

Mr. N.K yadav(Deputy Manager) engine assembly S.I.L. Lucknow

 

VISION OF THE   ORGANISATION

 To grow into global company constantly striving meet the changing needs of customer through constantly improving existing product adding new products and opting new technology and expanding the customer base.

CORPORATE MISSION

 To fulfill customer needs for economical and staff made of road transport and quality engineering product through contemporary technology.

QUALITY POLICY OF S.I.L.

We are committed to meet the customer requirements andcontinuously improve our quality management system. The company sales and services quality objective within the frame work of this policy.

ABOUT SCOOTERS INDIA

Incorporated in 1972, Scooters India Limited is an ISO 9001:2000and ISO 14001 Company, situated at 16 Km mile stone, South-west of Lucknow, the capital of Uttar Pradesh on NH No 25 and is well-connected by road, rail and air. It is a totally integrated automobile plant, engaged in designing, developing, manufacturing and marketing  a broad spectrum of conventional and non-conventional fuel driven 3-wheelers.Company’s

plant owes its origin to M/s. Innocenti of Italy from which it bought over the plant and machinery, design, documentation, copyright etc. The company also possesses the world right of the trade name LAMBRETTA / LAMBRO. In 1975, company started its commercial production of Scooters under the brand name of Vijai Super for domestic market & Lambretta for overseas market. It added one more wheel to its product.range and introduced three wheelers under the brand name  of  VIKRAM/LAMBRO. However, in 1997, strategically, the company discontinued its two-wheeler production and concentrated only on manufacturing and marketing of 3 wheelers. These three wheelers have become more relevant in the present socio-economic environment as it transports goods and passengers at least cost. The company has its own marketing network of Regional Sales Offices all over India, catering to customer’s requirements in the areas of sales and services.

DESIGN AND DEVELOPMENT DEPARTMENT

Design & Development has become the prime mover for theorganisation. The business today is customer driven. The department remains in constant touch with the customers to transplant their needs and thinking on the drawing board - nay on the computer screen. The department serves the internal customers through design, development, standardization, value engineering, defect removal etc. Equipped with computer aided design lab ( CAD lab ), AdvancedInstrumentation, testing rigs prototype manufacturing facilities andinternet, the company's D & D is recognized by the Ministry of Science and Technology, Govt. of India. It has the distinction of the developing first zero pollution electric three wheelers in the world. Company besides its own in-house R&D; also works in association with leading

ResearchAssociations & Educational Institution like I.I.T 's. Kanpur; I.I.T., Dehradun; A.R.A.I. Pune; T.C.I.R.D. Patiala etc

Computer Aided Design Laboratory

 The CAD laboratory provides a wide range of facilities. The versatility of brains combines with the flavor of new creation to evolve quality product. All the designing & drafting process moulds into a shape in this well equipped environmentof CAD laboratory. Which includes FE analysis, Working model simulation & designing through Auto-Cad 14.

 

ASSEMBLY DEPARTMENT

 The components manufactured in plant as well as those bought have to be finally assembled to make the product three wheelers. In the.process many sub assemblies, too, are involved. However, two mainassemblies worth mentioning are engine assembly and vehicle assembly. Both are conveyorised. Every 5 minutes a three wheeler rolls down the conveyor. The vehicle conveyor has 23 stations. Speed can be adjusted to meet increasing demand. 

DIE CASTING SHOP

 The biggest die casting shop in this part of the country handles both Aluminum and Zinc alloys. Equipped with pressure die casting machines of 160, 250, 400 and 1,000 tons locking pressure, the metal is fed to machines from individual holding furnaces of 75 /150 kg., which in turn are fed by mother melting furnace of 500 kg. aluminum.capacity. The shop based on projected area, is capable of producing aluminum die casting up to 5 kg. in weight. The shop is backed by chemical and metallurgical labs as also with a die maintenance section. The well-equipped machineries are used in this department in single shift, except two machines that are used in two shifts; that produce all the accessories required by this organization. The die casting of various type of components like Gear box housing, Crank case, Front wheeldrum, Rear wheel drum, Bell housing, Magneto flange, Cylinder head, lower and upper Handle bar, Levers, Differential housing cover, Brake shoe etc are undertaken. Die casting some components for fulfilling customers' requirement are also taken up. Some of our customers are BHEL, Bhopal; Greaves India Limited, Aurangabad to whom supplying theGear boxes and 422 cc aluminum Engine are supplied.

 

FABRICATION DEPARTMENT 

 The fabrication operations are carried out in Two departments viz. Press Shop and Welding Shop. The Press Shop is equipped with 20 presses ranging from 10tons to 550 tons. Presses are fed by sheets cut to size on shearing machines of 3000x6 & 2500x3 mm. size. Components ranging from washer to cabin roof and door (1000x1200 mm.) are being processed in this shop. The Welding Shop is equipped with battery of Spot welding, MIG welding, Seam welding as well as Arc welding machines. CO2 welding is extensively used for getting close tolerance on welded structures. The department has its own auxiliary shop for maintenance of tools and dies.

FOUNDRY LAB

 The foundry, most modern in this part of the country, canproduce all grades of grey cast iron as well as S. G. iron. In fact, it had been innovative to find new processes of modulisation, for which it was granted 2 patents. Equipped with an Induction Melting furnace, Shell Molding Machines & Core Shooters, Green Sand Molding facilities,.Isothermal Heat Treatment Furnace, one sand muller machine, twoshot blasting machine, two set jolting machines for green sa

ndmoulding, fettling and shot blasting equipments, its normal range of production weighs upto 8 Kgs. on a pattern plate of 450x600 mm.However, foundry men are trained to make casting even of 1 ton weight if emergent requirement arises. The foundry is not fully loaded with its captive requirement.Spare capacity is utilised for producing sophisticated castings of prestigious customers like BHEL, Indian Railways, Aerospace, Brakes India Limited, Crompton Greaves limited. The induction furnace has a capacity of 1.3 tons. The two types of molding is been done here. 1. Shell molding 2. Green sand molding. The foundry can manufacture a wide range of products namely Differential housing, Differential cages, Power transmission wheel, Crankcase flange, Magneto motor, Engineoutput flange, Adapter plate for electric vehicle, Cylinder for bothVikram 410 petrol version and Vikram 750 diesel version. 

ABOUT MACHINE SHOPMachine shop has a wide variety of machines like General purpose machine, Special purpose machine, Multispindle automatic machine, Single spindle automatic machine etc; which are mainly working onsingle shift through eight different lines. Line no 2 is basicallymachining the aluminium components. Crank shaft and cylindermachining is usually done on line no 3. Line no. 4 is the Grinding line where the grinding process is done. Heat treatment is performed in line no. 5, while different turning of shafts and gear shaping and shaving are carried on line no 6.Line no. 7 includes the functioning of gearmanufacture process mainly broaching, hobbing, finish turning, gears having etc. Machining of different levers, centre less grinding of tubes and shafts, serration / thread rolling operations is achieved in line no. 8& lastly different components are fed in two other lines by line no. 9.Blank Turing of gear and machining of parts is done on

multi spindle and single spindle automatic machine. Engine components and some vehicle component are the prime production.

 

PAINT SHOP

Paint shop includes three sections namely Paints section, sprayphosphating section, pickling.Paint section includes two conventionpainting spray booth & one electrostatic painting plant. The first one is called conventional primer where mainly frame paintings are done. The equipments used for conventional painting are Bellow’s 230 spray gun and pressure fit tanks (we prepare paints). The various types of frames like Diesel 750, Mini petrol, Mini diesel, Diesel floor mounting, DieselNepal, Diesel scrubber, Electric vehicle are painted here. The otherconventional booth is known as conventional finish booth. Here the frame accessories like cabin front, roof top, front fork, axle housing are painted. In electrostatic plant the accessories of the frame, the component of lighter weight and minimum size like silencer, pillar and various brackets are painted here. In spray phosphate the main work is to clean the components before painting or to make surface according to paint requirement. After phosphate the products goes to passivation for converting ferrous to ferric for paintings need. The products come from welding shop, press shop and machine shop to phosphate, and after the process is being done the products go to vehicle assembly. The pickling department is mainly for maintaining the surface of heavily corroded materials.

 

TOOL ROOM

 The tool room is a cell where brain combines with versatility to evoke the new era of invention. The designs of tool coming from maintool planning departments are implemented here. The tool room isfurnished with well equipped machineries namely, CNC machine(Taiwan), Jig Boring machine (Czech Republic), Jig Grinding machine(Switzerland), Profile Grinding machine (Germany), Die shieldingmachine (Czech Republic), EDM (USA), Schaublin machine(Switzerland). Tool room evoke a high performance output, consisting almost99.9% of company's requirement : one die casting die per year, 1-10press tools per month, 8-10 jigs per month, 10-12 gauges per month and 400 C.T. tools per month These machines are efficiently used to manufacture different tools and dies like Jigs & fixture,Gauges,Cuttingtools, Forging dies, Die casting dies, Development items etc. The different activities like turning, milling different shapes, grinding, heat treatment, jig boring, jig grinding, checking in the standard room, heat treatment according to the job requirement, final inspection are undertaken in the tool room.

 

DEPARTMENTS

The.organisation has various departments to perform differentactivities competently. SIL has an organized system to control differentactivities. Personnel & administration department looks after theemployees welfare, medical benefits, conveyance facilities, maintainstheir personal records and controls their regularity. It also take care.of the security for the organization. Marketing & services  department. Looks after the marketing of the products, provide services to the customer and regulates the activities in its various regional offices. Materials controls the purchasing of the raw

material, keep aneye on the cost of the material in the market, store the different materials and products and establishes a company-vendor relationship. Workshop manufactures different products in steps in different lines. Design & development is the prime creative unit for the organization. It brings out some brilliant design with.modern.technologies.Finance.&.accounts section keeps track on the  financial growth and the maintenance of various types of accounts. 

PRODUCTS OF S.I.L.

Scooters India Limited makes various & versatile types of three wheelers: Vikram 450D, Vikram 410G, Vikram 600G, Vikram

750D,Vikram 750D (WC), Vikram EV. The products have a high payload capacity and efficiency. These are specially designed and

developed for local transportation. However, the generation of Vikram runs successfully in different countries also. Our product is

very demanding in various countries all over the world .Germany

, Italy, Sudan, Nigeria, Nepal, Bangladesh are few of thecountries. For product details click on the product options.

 

MACHINES USED IN LINE NO. 7

Broaching Machines

1. Internal Splines Broaching 49762. Oil groove broaching machine 35053. Bore Broaching 20214. Bore Broaching 3271

5. Bore Broaching  2997

 

Hobbing Machines

1. Semi Automatic Hobbing Machine – 104882. Semi Automatic Hobbing Machine – 105763. Semi Automatic Hobbing Machine – 101204. Tag Teeth Hobbing – 20145. Semi Automatic Hobbing Machine – 102906. Eight Head Shaft Hobbing Machine – 25867. Eight Head Shaft Hobbing Machine – 2585

Hydraulic Press & Turning Facing, Chamfering Machines

1 . Fresh turning, facing & bore chamfering Machine – 21482. Hydraulic Press – 3923. Fresh Turning, Facing & Bore Chamfering – 104894. Hydraulic Press – 7285. Turning – 32496. Hydraulic Press – 27737. Turning – 2968. Turning – 104989. Hydraulic Press – 38310. Turning Machine – 1049011. Turning Machine – 10387

Shaving Machines1. Teeth Shaving – 48172. Teeth Shaving – 4102

3. Speed Gear Teeth Shaving –   4395

Milling Machines

1. Milling Machine – 104662. Horizontal Milling Machine – 27323. Horizontal Milling Machine – 106214. Cam Milling – 103885. Cam Milling – 916. Cam Milling – 5137. Cam Milling – 511

Lathe Machine

  1. Central Lathe Machine 441

Drilling Machines

1. Portable Drilling Machine – 24192. Portable Drilling Machine – 5035

Teeth Chamfering Machine

1. Teeth Chamfering Machine – 21682. Teeth Chamfering Machine – 29923. Teeth Chamfering Machine – 10623

Bench Grinding Machine for Deburring COMPONENTS MADE IN LINE NO. 7

1. Ring Nut2. Speed Gears (I, II, III & IV)3. Primary Transmission Wheel

4. Engine output Gear5. Reverse Gears6. Spline Sleeve7. Transmission Shafts8. Big Sprockets9. Couplings10. Sliding Dog11.Reverse Gear Sprockets12. Central Lug  

ABOUT LINE NO. 7

Broaching:-

Broaches tools for cutting metal, comprising a plain pilot portion, a tapered toothed portion and a plain shank engaging with the pulling head on a broaching machine. The teeth have normally single cuttingedges and on a circular broaches run in series round the taperedportion, gradually increasing in cross section as they near the shank. They are either pushed or pulled mechanically through a previously cored or drilled round, square, rectangular or hexagonal hole to produce the current form. They will also finish flat surfaces, irregularity – formed holes and open grooves such as key ways in hubs. Another application is to the forming of teeth in internal gears and rackets, splines in shafts etc. They are usually made of a tough, hard, sound, non distorting steel alloy, high carbon and case hardening types, the precise steeldepending on the service life required, the material to be cut, and the length and form of the broached areas. Relatively few are made of.casecarburizing steel and hardened high speed steel is now the mostpopular material for the cutting teeth of solid and some other broaches. The tools have to be heat treated and ground and the heat

treatment is extremely important. Broaches for finishing internal holes differ from those for finishing the external surface of a component. Those to be pushed through the work are shorter than those to be pulled through. For internal work the.tools are usually solid, unless their diameter is so great as to render distortion in heat treatment probable and serious. The teeth are of size and form for the operation and if the broach is more than 3½inches.How it is often made as a composite consisting of a tough centralportion of carbon steel, conically ground, on to which cutting segments of nickel or high speed steel are mounted in the form of toothed rings set one over the other until the cutting portion is adequate for the job. This makes its possible tomorrow a segment or ring when pulled or worm and insert a replacement each ring then move up one this costs for less than replacing the entire broach.

Hobbing:-In this process, the gear bank is rolled with a rotating cutter called hob. A majority of involutes gears are produced by this method. . A gear hob looks like a worm, but carries a number of straight flutes (gashes), cut all around, parallel to its axis. This results in theproduction of separate cutting teeth and cutting edges, as shown. In operation, the hob is rotated at a suitable speed and fed into the gear blank. The blank also rotates simultaneously. The speeds of the two are so synchronized that the bank rotates through one pitch distance for each complete revolution of the hob. There is no intermittent motion of any of the two and the generating motion continues steadily. The hob teeth are just like screw threads, i.e. having a definite helix angle. The hob is, therefore titled to its own helix angle while cutting the gear so that its teeth are square with the blank and produces a true involutes shape. Spur, helical and herringbone gears and many other shapes like spindles and gear

sprockets etc. can be cut by hobbing process. Each cutting tooth of the hob is provided relief at its back to enable clearance. In portion, the hob can be conceived as a cylindrical body, around which the teeth of a long rack are wrapped along a helical path and provided with straight flutes at regular intervals, parallel to the axis of the cylinder. Cross section of every tooth across the helix resembles that of the rack teeth.

Types of Hobbing:- This hobbing process is classified into different types according to the directions of feeding the hob for gear cutting. This classification is as follows: 1.Hobbing with axial feed.2.Hobbing with radical feed3.Hobbing with tangential feed.

Shaving:It is a process of finishing gear teeth by running the gear at high speed in mesh with a. Gear shaving tool which is in the form of a rack or pinion. The teeth of the shaving tool are hardened, accurately ground and their faces are provided with serration.

 These serrations form the cutting edges which actually provide a sort of scraping operation on the mating faces of the gear teeth to be finished. The gear is pressed into contact with the shaving tool and the latter rotated at high speed. The.gear also rotates in mesh with the tool and is also reciprocated simultaneously. The shaving tool carries a little inclined teeth so that their axes can be crossed as the two come in contact. This prevents the jamming of the two. The above relative motion of the gear and the shaving tool results in a highly finished surface on the gear teeth.

When a rack type tool is used, the gear is mounted on a reciprocating arbor and is brought in mesh with a horizontal rack situated under it. The rack is reciprocated longitudinally at high speed and the gear across it. The lengthwise movement of the rack type tool also rotates the gear.

Shaving with rack.type tool, however, suits only small gears. Theshaving tools, although costly, have a fairly long life. 

Drilling:Drilling is an operation through which holes are produced in a solid metal by means of a revolving tool called drill.Since it is not possible to produce a perfectly true hole by drilling, it is considered as. a roughing operation. Obviously, therefore, where a very close dimensional accuracy is to be maintained, this forms only the basic operation. For such holes, drilling is followed by another operationcalled reaming, in which the required dimensional accuracy and fine surface finish is obtained by means of a multi-tooth resolving tool called reamer

BoringIt is the operation employed for enlarging an existing hole. The hole may be previously drilled, cast, punched or produced through any other suitable operation. In line no. 7 there are portable drilling machine are used. It is very small, compact and self-contained unit carrying a small electric-motor inside it. It is very commonly used for drilling holes in such components that cannot be transported to the shop due to their size or weight or where lack of space  does not permit their transportation to the bigger type of drilling machine. In such cases, the operation is performed on the site by means of the portable electric drill. Portable drills are fairly light in weight so that they can

be easily handled by one or two men only. They are manufactured in different sizes and capacities, thus being suitable for a wide range of whole sizes. Also, on account of the high speeds available, a considerable saving in time is affected by their use. Another advantage is that the holes can be drilled by means of them at any desired inclination. Usually they are made to hold drills up to a maximum diameter of 12 mm. However, portable drills of up to 18 mm. dia. capacity are available.

 

Milling:‘Milling’ is the same given to the machining process in which there movable of metal takes place due to the cutting action of a revolving cutter when the work is fed past it. The revolving cutter is held on a spindle or arbor and the work, clamped on the machine table, fed part the same. In doing so, the teeth of the cutter remove the metal, in the form of chips, for the surface of the work to produce the desired.shape.Milling machine has acquired an indispensible position in allmodern production workshops. Its specific significance lies in itscapability to perform a large number of operations which no other single machine tool can perform. At the same time, it gives production at afairly high rate and within very close machine tools like shapers, planers, slotters etc., but for small and medium size jobs only; as it willprove to be too slow for machining very long jobs. For small andmedium jobs, the milling machine gives probably the fastest production with very high accuracy. For this reason, it has gained a very wide application in mass production work. Obviously, therefore, it is very versatile machine tool. In line no. 7 there are horizontal milling machine are used. In housing for electrical, the main drive, spindle bearings, etc. The knee acts as a support for thesaddle, worktable and other accessories like indexing head etc.

Over arm provides support for the yoke which in turn, supports the free end of the arbor. The arbor carrying the cutter rotates about a horizontal.axis. The table can be given straight motions in three directions: Longitudinal, cross and vertical up and down but cannot be swiveled. For giving vertical movement to the table the knee itself, together with the whole unit above it, slides up and down along the ways provided in front of the column. For giving cross movement to the table, the saddle is moved towards or away from the column along with the whole unit above it. A brace is employed to provide additional support and rigidly to the arbor when a long arbor is used. Both hand and power feeds can be employed for the work.

Cam Milling: The constant rise and fall cams can easily be cut on a universal milling machine, equipped with a universal dividing head and as witching type vertical milling attachment. The dividing head is geared to the table feed scare in the same way as for spiral milling.end milling cutters are usually employed in this operation. If the table is moved towards right, the blank approaches nearer to the cutter.Also,becauseof the gearing at the back, the dividing head spindle revolvessimultaneously. The combination of these two movements. I.e. the table movement and the spindle rotation, enables milling of cam on the blank fitted on the dividing head spindle. Both, the cutter as well as the dividing head spindle, should be inclined at the same angle. Steeper the angle of inclination quicker will be the approach of the blank to the cutter. Alternatively, we can have the cam axis above and the cutter axis below. In that case, we will be required to move the table towards the left for feeding the blank against the cutter. 

Plain Step   And   Fresh Turning   Between Centers:

When the work is held between centers for any sort of turning operation, one end (left hand end) is firmly gripped in a table dog and then the same end is supported on the tip of the live centre. Tail of the dog engages with the driving plate and the other end (right hand end) of the job is supported on the dead centre fitted in the tail stock. Work revolves during the operation and the tool is fed against the job. Enough care should be taken while starting the operating, particularly.by.abeginner. Speed of spindle and its direction of rotation should bechecked and suitably adjusted. Rough cuts in the beginning.should.befollowed by finishing cuts for which the spindle speed should beincreased and depth of cut reduced. Check the controls and practice hand feeds which, in due course, can be followed by power feeds. For taking any sort of measurement always stop the machine. In this first the tail stock is moved and brought near the head stock to ensure a true alignment of dead and live centers by sighting along the axes of the two. Work is then held between centers and revolved. A chalk is held in hand gently against the revolving work and marks made near both the ends. Continuity of these marks indicates the trueness of the marked. Centers, otherwise the chalk marks will be found only on  elevated portions of the periphery of the work. Once the larger part of the excess material has been removed through rough turning, it is followed by

Finish turning:-Operation in order to bring the job to correct size and provide a fine surface finish on it. The amount of excess material to be removed through this operation is very less and, therefore, lighter feed and

smaller depth of cut are used and the heavier tool is replaced by a finish turning too.

Facing:-It is an operation which enables the production of a flat surface through machining at the end of a job. In this operation the tool is fed at right angles to the axis of the job. Since no longitudinal feed is needed, the carriage is usually clamped to the bed so that it remains stationary during the operation. Feed to the tool is provided by moving the cross-slide by hand. Depending upon the diameter of the work piece the power feed can also be used. Two methods of holding the tools are usually employed. One is to set the tool slightly inclined to the exact right angle position so that only the tip of the cutting edge remains in contact with the job face and the remainder of the tool is free of the job. Another method is to set the tool parallel to the axis of the job. This is done when the job is held in a chuck or a face plate. In both the cases the tool can either be fed outwards, i.e., away from the centre. Normally the selection of any one to these methods is according to convenience; still the latter method is more commonly employed. The facing operation is usually performed in two steps. In the first step a rough facing operation is done by using a heavy cross of the order of 0.5 to 0.7 mm and a deeper cut up to 5 mm (maximum). It is followed by a finer cross feed of 0.1 to 0.3 mm and a smaller depth of cut of about 0.5 mm. In the first step the idea is to remove major part of excess material while in the second step a fine finish is provided to the surface. 

MAIN PROJECT

Reverse gear mechanismThe implementation of the reverse gear is usually different, implemented in the following way to reduce the cost of the transmission. Reverse is also a pair of gears: one gear on the countershaft and one on the output shaft. However, whereas all the forward gears are always meshed together, there is a gap between the reverse gears. Moreover, they are both attached to their shafts: neither one rotates freely about the shaft. When reverse is selected a small gear, called a, reverse idler is slid between them. The idler has teeth which mesh with both gears, and thus it couples these gears.

In other words, when reverse gear is selected, it is in fact actual gear teeth that are being meshed, with no aid from a synchronization mechanism. For this reason, the output shaft must not be rotating when reverse is selected: the car must be stopped. In order that reverse can be selected without grinding even if the input shaft is spinning initially, there may be a mechanism to stop the input shaft from spinning. The driver brings the vehicle to a stop, and selects reverse. As that selection is made, some mechanism in the transmission stops the input shaft. Both gears are stopped and the idler can be inserted between them. There is a clear description of such a mechanism in the scooters India limited Service Manual, which refers to it as a "reverse gear mechanism":

Whenever the clutch paddle is depressed to shift into reverse, the main shaft continues to rotate because of its inertia. The resulting speed difference between main shaft and reverse idler gear produces gear noise. The reverse gear noise reduction system employs a cam

plate which was added to the reverse shift holder. When shifting into reverse, the 5th/reverse shift piece, connected to the shift lever, rotates the cam plate. This causes the 5th synchro set to stop the rotating main shaft.

A reverse gear implemented this way makes a loud whining sound, which is not normally heard in the forward gears. The teeth on the forward gears of scooters India limited are spur gear cut. When the spur gears rotate, there is constant contact between gears, which results in quiet operation. In spite of all forward gears being always meshed, they do not make a sound that can be easily heard above the engine noise. By contrast, most reverse gears are spur gears, meaning that they have straight teeth, in order to allow for the sliding engagement of the idler, which is difficult with helical gears. The teeth of spur gears clatter together when the gears spin, generating a characteristic whine.

It is clear that the spur gear design of reverse gear represents some compromises (less robust, unsynchronized engagement and loud noise) which are acceptable due to the relatively small amount of driving that takes place in reverse. The gearbox of 450D/750D is a notable example of a gearbox with a spur reverse gear engaged in the same synchronized manner as the described above.

GEAR ASSEMBLY

The assembly of gear has been done in different stages at assembly line:-

Station no.1

Gearbox hosing loading assembly.

Inner lever. G.C Shaft.

Station no.2

Lay shaft.

Lay shaft spacer.

Dowel pin.

Station no.3

Gear set. G.B. flange. Seam clearance (0.07 to 0.3 mm).

Station no.4

P.T. wheel. Clutch bell. Umbrella flange.

Station no.5

Clutch assembly. Bell housing.

Station no.6

Reverse gear. Push rod, selector, T.O.P shaft & reverse gear complete assembly. Torque – Lay shaft tighten 8.50 to 9.00 kgmtr.

Station no.7

Top cover gas kit. Top cover.

O-ring. Nut, washer & bolt assembly.

Station no.8

Companion flange & nut assembly. O-ring, spring, R.G lever assembly.

Station no.9

Mounting pad, nut tighten.

On loading gear box.