Title of Invention

A TWO RANGE TRANSMISSION DEVICE FOR A MOTOR VEHICLE

Abstract

This invention relates to a two range transmission device for a motor vehicle, more particularly, though not exclusively, for a cargo carrier carrying less than one ton capacity. This transmission will provide the driver two sets of speed ratios using the switch over mechanism. One set of ratios will be shallower compared to the other. The driver will have the option to switch over between the two sets of ratios. Deeper ratios are suggested for the onward journey while carrying heavy loads and shallower ratios are suggested for the unloaded return journey. The advantages of deeper ratios are better acceleration and gradeability; and higher load carrying capacity.

Full Text

THE PATENTS ACT 1970 COMPLETE SPECIFICATION SECTION 10 A TWO RANGE TRANSMISSION DEVICE FOR A MOTOR VEHICLE TVS MOTOR COMPANY LIMITED, JAYALAKSHMI ESTATES, 8 HADDOWS ROAD, CHENNAI600 006, INDIA AN INDIAN COMPANY THE FOLLOWING SPECIFICATION PATICULARLY DESCRIBES THE NATURE OF THIS INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFFORMED: PCS/passage This invention relates to a two range transmission device for a motor vehicle, more particularly, though not exclusively, for a cargo carrier carrying less than one ton capacity. This transmission will provide the driver two sets of speed ratios using the switch over mechanism. One set of ratios will be shallower compared to the other. The driver will have the option to switch over between the two sets of ratios. Deeper ratios are suggested for the onward journey while carrying heavy loads and shallower ratios are suggested for the unloaded return journey. The advantages of deeper ratios are better acceleration and gradeability; and higher load carrying capacity. The advantages of shallower ratios are higher vehicle speeds, hence lesser time to travel back; better fuel economy during unloaded return journey; increased engine life due to reduced engine rpm operating range. The two range transmission device for a motor vehicle, according to this invention, comprises four shafts and four synchropacks to provide two sets of gear ratios, one set providing five deeper speed ratios while the other providing five shallower speed ratios. This invention will now be described with reference to the accompanying drawings which illustrate in Fig. 1 the layout of a typical 5 speed synchromesh transmission providing a single set of gear ratios and in Fig. 2, by way of example, an embodiment of the transmission according to this invention. Referring to Fig. 1 the layout of a typical 5 speed synchromesh transmission the transmission provides a single set of 5 gear ratios. The ratios are selected so as to provide sufficient acceleration/gradeability for heavy loads. The transmission consists of an input shaft SI, lay shaft S2 and main shaft S3. The gear pair CM acts as the constant mesh gear pair to provide a constant mesh ratio. The transmission provides in all 5 forward speed ratios and one reverse speed ratio. The desired speed ratio is selected by using one of the three synchropacks. The gears on the main shaft rotate freely over the shaft. Whenever a particular shifter sleeve is made to slide horizontally using internal gear shift mechanism, it engages with the dogteeth on the gear after synchronization and hence the gear starts rotating along with the shaft. Synchropack SP1 is used to select between 4th and 3rd speed ratios SP2 between 2nd and 1st and SP3 between reverse and 5th speed ratios. Lower ratios are used for better acceleration and gradeability but with smaller vehicle speed range, whereas higher ratios are used for higher velocities of the vehicle and better fuel economy. The major drawback with the known transmission referred to above is that during the unloaded return journey, the vehicle still operates in deeper ratios that consume more fuel. The time taken for the return journey is more because of the lower speed limits of the vehicle. Moreover, the engine continues to ran at comparatively higher rpm which decreases its life. This invention proposes to overcome the above mentioned drawback of the single range ratios, by providing a two range transmission. One set of ratios will be shallower when compared to the other. Thus in effect a 5 speed transmission is converted into 10 speed transmission. The driver will have the option to choose between either of the two sets of ratios. The deeper ratios will be used while on the onward journey to carry heavy loads while the shallower ratios are suggested for unloaded return journey (Fig.2) The proposed invention is made so as to achieve the benefits of the two range transmission. It consists of two constant mesh gear pairs (CGL and CGH), one additional synchropack SP4 and one additional shaft S4. The gear pair CGL acts as the constant mesh to provide deeper ratios during onward journey. The gear pair CGH acts as constant mesh to provide shallower ratios. Thus, the proposed invention uses one additional shaft, one additional synchropack and one additional gear pair compared to the earlier system. But it provides 10 speed ratios compared to 5 speed ratios of the existing transmission system. We Claim: 1 .A two-range transmission device for a motor vehicle comprises four shafts and four synchropacks to provide two sets of gear ratios, one set providing five deeper speed ratios while the other providing five shallower speed ratios. 2. A two range transmission device for a motor vehicle substantially as herein described and illustrated with reference to the accompanying drawings. Dated this the 30^ day of Mpf~ 2005

Documents:

0662-che-2005-claims.pdf

0662-che-2005-correspondnece-others.pdf

0662-che-2005-description(complete).pdf

0662-che-2005-drawings.pdf

0662-che-2005-form 1.pdf

662-CHE-2005 AMENDED CLAIMS 26-07-2012.pdf

662-CHE-2005 AMENDED PAGES OF SPECIFICATION 26-07-2012.pdf

662-CHE-2005 CORRESPONDENCE OTHERS 15-05-2013.pdf

662-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 26-07-2012.pdf

662-che-2005-form 26.pdf