Title of Invention

LIFTABLE AXLE CONTROL SYSTEM FOR VEHICLE

Abstract

This invention relates to the pneumatically controlled liftable axel control system of vehicle. The control of liftable axle (2) is done with respect to the actual load coming on the front axle (I) and rear axles (3,4) To sense the load coming on rear axles a pneumatic load-sensing value (7) is fitted between the chassis (21) and sails rear axle. To sense the load coming on front axle a pneumatic height control value (11) is fitted between front axle (1) and chassis. A load sensing value fitted on chassis bottom will sense the load on rear axles by referring the height between chassis and rear axles with the help of a bridge connection. The bridge connection is having a bridge rod (8), which is fitted over live axle (3) and dead axle (4). A displacer (9) is then fitted between bridge rod and load sensing valve adjusting lever, which will vary or control the output of load sensing valve with respect to the height between bridge rod and chassis. Front axle (1) is fitted with a height control valve (11) whose output will vary with respect to the height between front axle and chassis. The output of height control valve is then given to an electronic logic control module (13). A voltage output from electronic logic control module is then given to a solenoid controlled pneumatic valve (10), having input from load sensing valve (7), is an electro-pneumatic valve whose pressure output is controlled by voltage received from electronic logic control module. The controlled pressure output from solenoid controlled pneumatic valve is then given to suspension bellow of liftable axle.

Full Text

FORM 2 THE PATENTS ACT 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See Section 10; rule 13) TITLE OF THE INVENTION LIFTABLE AXLE CONTROL SYSTEM FOR VEHICLE APPLICANTS TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India INVENTORS Babalal Sahebji Mulani, Narayan Dattatraya Jadhav, K. Gopalakrishna and Amit Gupta, all Indian nationals of TATA MOTORS LIMITED an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India PREAMBLE TO THE DESCRIPTION The following Complete specification particularly describes the invention and the manner in which it is to be performed. 1 FIELD OF INVENTION This invention relates to the Liftable axle control system and more particularly to a pneumatically assisted liftable axle control system for vehicles. BACKGROUND OF INVENTION A liftable axle is an axle fitted on the vehicle, which can be lifted and lowered depending upon the loading condition of vehicle. The pusher type liftable axle is a liftable axle fitted in between front axle and rear axles of the vehicle. The vehicle is fitted with mechanical suspension i.e. with leaf springs on front and rear axles, where as the liftable axle is having a pneumatic suspension. Vehicle manufacturer usually defines the maximum load rating on each axle in order to fulfill the Road Transport Authority Regulation. The regulation also says that, in laden condition of vehicle the liftable axle should automatically come down to take care of its share of load. Along with this, the system should be capable of maintaining the air pressure in air suspension bellows of liftable axle, which in turn controls the load carrying capacity of liftable axle, with respect to the amount of load present in the vehicle. If the vehicle is not fitted with liftable axle control system the liftable axle will have a constant maximum axle reaction in loaded condition, irrespective of actual load coming on it, which will lead to the jacking effect of vehicle chassis at a location of liftable axle. This jacking effect will subsequently result in loss of vehicle steerability and results in instability issues, as due to jacking effect at liftable axle the front axle will get very less axle reaction from ground. So the primary object of liftable axle 2 control system is to adjust the air pressure in suspension bellows of liftable axle i.e. to lower or lift the liftable axle with respect to the actual loading condition of vehicle. OBJECT OF INVENTION The main object of this invention is to provide a liftable axle control system of vehicle having maximum safety to the vehicle and the goods handled by it. Yet another object of this invention is to provide a liftable axle control system of vehicle having simple in construction and cost effective. Yet another object of this invention is to provide a liftable axle control system of vehicle having better performance. STATEMENT OF INVENTION Liftable axle control system comprising at least one load sensing valve positioned between chassis of a vehicle and its rear axles, at least one height control valve provided between the front axle and the chassis of vehicle and a pressure regulator, output of which is connected to said load sensing valve/s; a bridge connection means having a bridge rod mounted on the live rear axle and dead rear axle; a displacer, one end of which is connected to said bridge rod and other end is connected to said load sensing valve through an adjusting lever; the output of the said height control valve is connected to an electronic logic control 3 module, output from said electronic logic control module is fed to a solenoid controlled pneumatic valve, wherein a solenoid controlled pneumatic valve is also connected with a said load sensing valve, and output of said solenoid controlled pneumatic valve is connected to the suspension bellows of liftable axle. Liftable axle control system in accordance with this invention is operable by either electro-pneumatic or electric signal means. Liftable axle control system in accordance with this invention the said bridge rod is fixed on said rear axles at the axis of the vehicle. Liftable axle control system in accordance with this invention the said bridge rod is connected to rear axles through self-aligning means. Liftable axle control system in accordance with this invention the said displacer is connected at the center of bridge rod. Liftable axle control system of vehicle in accordance with this invention the said load sensing valve is mounted in such a way that the axis of said load sensing valve is perpendicular to said displacer. Liftable axle control system in accordance with this invention the said height control valve is fixed in such a way that the axis of said valve is perpendicular to the axis of vehicle. 4 Liftable axle control system in accordance with this invention the said height control valve is either pneumatic type fitted with pressure transducer or an electronic type. Liftable axle control system of vehicle in accordance with this invention wherein the vehicle is a heavy commercial vehicle. BRIEF DESCRIPTION OF INVENTION Liftable axle control system of vehicle is basically a pneumatically controlled system shown in figure 1. The control of liftable axle (2) is done with respect to the actual load coming on the front axle (1) and rear axles (3,4). To sense the load coming on rear axles a pneumatic Load sensing valve (7) is positioned between chassis (21) and said rear axles (3,4). To sense the load coming on front axle a pneumatic height control valve (11) is provided between the front axle (1) and chassis (21). Air is supplied from air tank to a pressure regulator (6) where the system pressure is regulated at which the suspension bellow (22) will have maximum load carrying capacity. The air-line coming out from pressure regulator (18) is then connected to load sensing valve (7). A load sensing valve (7) fitted on chassis bottom will sense the load on rear axles (3,4) by referring the height between chassis and rear axles with the help of a bridge connection means. The bridge connection means is having a bridge rod (8)mounted over live axle (3) and dead axle (4). A displacer (9) is then fitted between bridge rod (8) and load sensing valve-adjusting lever (23), which will vary or control the output of load sensing valve (7) with respect to the height between bridge rod 5 (8) and chassis (21). The load sensing valve (7) is calibrated for pressure output with respect to height between chassis and bridge rod. Front axle (1) is fitted with a pneumatic height control valve (11) to which the air connection (16) is given from air tank (5). Height control valve (11) is a pneumatic valve whose output will vary with respect to the height between front axle (1) and chassis (21). One end of height control valve (11) is fitted on front axle (1) and other on the chassis bottom of vehicle. Height control valve (11) is calibrated for pressure output with respect to the height between front axle (1) and chassis (21). The output of height control valve (11) is then given to a pressure transducer (12) by an air line (20) where the pressure signal will be converted into electrical signal i.e. voltage. The voltage output from pressure transducer (12), which corresponds to the pressure output of height control valve is then given to an electronic logic control module (13). An electronic logic control module (13) is having a calibration matrix uploaded in its memory, where the output voltage is calibrated with respect to input voltage. All possible loading patterns of vehicle and corresponding load coming on each axle is previously calculated and corresponding voltage output needed from electronic logic control module is thus decided and fed. A voltage output from electronic logic control module (13) is fed to a solenoid controlled pneumatic valve (10) through electrical line (14). A solenoid controlled pneumatic valve (10) is an electro-pneumatic valve whose pressure output is controlled by voltage received from electronic logic control module. The input to said valve is given by an air line (17) coming from load 6 sensing valve (7). Solenoid controlled pneumatic valve (10) is acting as a mediator between air signal coming from rear axles (3,4) and voltage signal coming from front axle (1). The controlled pressure output coming out from solenoid controlled pneumatic valve (10) is then given to suspension bellow (22) of liftable axle (2) through an air line (19). In uniformly distributed loading condition of vehicle, where all the axles are subjected to defined reaction i.e. front axle reaction is more than allowed threshold reaction value, the control portion provided from front axle (1) to solenoid controlled pneumatic valve (10) will not come into picture. This is ensured with the help of electronic logic control module (13). In such situation the pressure output given to suspension bellows (22) of liftable axle (2) will be solely controlled with the help of load sensing valve (7) fitted on rear axles (3,4) only. In non-uniformly or partially loaded conditions of vehicle, if rear side loading area of vehicle is having more load compared to front side, the load sensing valve (7) will sense the load above which the lift axle needs to lower down and will give a rated (maximum) reaction, irrespective of physical load coming on lift axle. This will result in jacking effect of chassis at liftable axle location, thus resulting in giving minimal reaction on front axle and related issues during running of vehicle. To take care of this the front axle control part will come in to picture, because of the actual load sensed by height control valve (11). Height control valve mounted on front axle then generate the voltage signal corresponding to actual load through pressure transducer (12). This voltage 7 signal is then given to an electronic logic control module, which will decide the value of voltage signal to be given to solenoid controlled pneumatic valve (10). The voltage input received at solenoid controlled pneumatic valve (10) will thus reduce the pressure of output air line (19) by an amount, which will result in avoiding the jacking effect at lift axle and providing minimal reaction at front axle thus ensuring better stability of vehicle in running condition. DETAILED DESCRIPTION OF INVENTION Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same, Figure 1 - Shows the schematic diagram of liftable axle control system of vehicle. Figure 2 - Shows the load sensing valve used in this invention. Figure 3 - Shows the schematic diagram with two control sections. Figure 4 - Shows the solenoid controlled pneumatic valve used in this invention. Now referring to figures 1 & 3, the vehicle shown is a cargo having front axle (1), Liftable axle (2), live rear axle (3), which is a drive axle of vehicle and dead axle (4). An air tank (5) provided on vehicle is used as an air reservoir for the operation of liftable axle control system. To sense the actual load coming on each axle of the vehicle, the control system is divided in two different sections as section I and section II. In section I, for sensing the load coming on rear axles of vehicle, a bridge assembly (8) with Load sensing valve (7) is incorporated. In 8 other section, a height control valve (11) with pressure transducer (12) and electronic logic control module (13) is incorporated to sense the load coming on front axle (1). In section I, air is first passed through a pressure regulator (6), in which the pressure will be reduced to a value, which is capable of generating the rated axle reaction on lift axle through suspension bellows. The air line (18) with regulated pressure is then supplied to a Load sensing valve (7). To sense the load coming on rear axles and accordingly to adjust the output of a Load sensing valve (7), a displacer (9) is fitted between adjusting lever (23) and a bridge rod (8). A bridge assembly is consisting of a bridge rod (8) fixed between live and dead axles (3,4) in order to have accuracy in sensing the load coming on both rear axles (3,4) and a displacer (9) which is fitted vertically with one end on bridge rod (8) and other on the adjusting lever (23) of Load sensing valve (7). To take care of uneven variation in distances between live rear axle (3) and dead rear axle (4), with respect to chassis (21), the bridge rod (8) is provided with the springs at their ends which are fitted vertically in mounting brackets provided on rear axles (3,4). The bridge rod (8) is mounted at the vehicle axis in order to have more accuracy in sensing the load on rear axles (3,4). In order to avoid errors in sensing the load, it is assured that the displacer (9) is mounted perpendicular to the load sensing valve axis. The distance between bridge (8) and adjusting lever (23) is variable and depends on the load coming in the rear part of vehicle. With increase in load, the distance between chassis (21) and rear axles (3,4) will reduce and consequently try to push the adjusting lever (23) in upward direction through displacer (9). This will result in deciding the air supply output from load 9 sensing valve (7) through air line (17) and a proportionate air output will be then given to a solenoid controlled pneumatic valve (10). In section II, air supply is given to a height control valve (11) from air tank (5) through air line (16). A height control valve (11) is a pneumatic valve having two-way operation, in which the output is controlled with respect to the height between chassis (21) and the front axle (1) of vehicle. The height control valve (11) is mounted perpendicular to the vehicle axis to sense the vertical reaction coming on front axle (1). One end of height-controlled valve (11) is fitted on the front axle (1) and other end is on the bottom portion of chassis (21). Due to load coming on front axle, the distance between chassis and front axle will vary, thus controlling the output of height control valve (11). The output air supply from height control valve is then given to a pressure transducer (12) through air line (20) in which a pneumatic signal is converted into electrical signal. The electrical output i.e. voltage from pressure transducer (12) is given to an electronic logic control module (13). An electronic logic control module (13) is an electronic device in which a matrix consisting of load values and corresponding voltage output is given. This means that, with front axle load sensed by height control valve (11) is then converted into electronic signal in pressure transducer (12) and supplied to electronic logic control module (13), the electronic logic will decide that with the received input voltage what should be the output voltage. The reason behind adding second section or rather Electronic Logic Control Module (13) is that there are some circumstances in which the vehicle user may load the vehicle non-uniformly in such a way that, only rear side will have excessive load which will trigger the load sensing valve 10 (7) to lower down the Unable axle (2) with maximum (rated) reaction, as it is controlled by the distance between chassis (21) and bridge assembly (8). But in actual, the total load present in the load body is less enough to take care by front and rear axles only. The maximum (rated) reaction generated by air suspension bellows (22) of liftable axle (2) will try to jack the chassis (21) which will lead to loss of steerability of front axle (1). In such situations of non-uniform loading condition and with only first section of controlling system, the reaction coming on front axle (1) is very less and will lead to loss of steering control of vehicle. To take care of this, second section will audit for a minimum (threshold) front axle reaction, for having safer steering control. To control this minimum reaction on font axle (1), the Electronic Logic Control Module (13) will sense the load on front axle (1) and accordingly decide the voltage output to be given to a solenoid controlled pneumatic valve (10). An electrical line (14) coming from electronic logic control module (13) is the control line for solenoid controlled pneumatic valve (10). When the loading pattern in the vehicle is such that the front axle (1) is getting minimum(threshold) reaction, which is defined in the electronic logic control module (13), the section II of control circuit will not take part in deciding the suspension bellow pressure input but it will be decided by the section I of control circuit only i.e. the output of load sensing valve (7) will be directly given to suspension bellows (22) through air line(19)without any correction from section II. This is because at defined minimum (threshold) front axle reaction value and above that, the stability of vehicle will be better compared to the stability of vehicle; when front axle load is below the defined minimum 11 (threshold) value. Depending upon the value of voltage decided and supplied by electronic logic control module (13), the solenoid of solenoid controlled pneumatic valve (10) will be energized or de-energized and accordingly will allow the air output which is given to suspension bellows (22) of liftable axle (2) through airline (19). To define the minimum(threshold) reaction below that the instability issue of vehicle will come, the subjective assessment of vehicle with different loading pattern is done and rating has been given as shown below. (0-3= Poor; 4-5 Subjective Rating t= Customer Complaint; 6=Border case; 7= Fair; 8-9 ~ Good; 10=Excellent) Loading Condition (Tons) Front Axle Reaction LiftAxleReaction RearAxlesReaction Gross Vehicle Weight Center of Gravity position with respect to Live axle (mm) Steering Feel Self Centering Uniform Rated 6 6 19 31 +688.22 7.5 7.5 Non uniform partial 3.67 5.01 17.21 25.95 +435 7 6.5 Non uniform rated 3.2 5.9 21.9 31.6 +250 6 5.5 Partial 2.38 5.53 21.53 29.44 +117.33 3 2 Concentrated 1.69 5.46 21.07 28.22 +15.53 1 1 From the assessment, we found the minimum (threshold) front axle load below which, the vehicle instability will be observed. With reference to above exercise, the load on front axle below which the section II should take part in controlling 12 the suspension bellow pressure is fed in the electronic logic control module. In addition to this, the delay period is provided in the control logic, so that in peak loading condition, like on road bumps, the change in control circuit pressure should not happen instantaneously. Now with respect to figure 2, a load sensing valve (7) is a pneumatic valve, which is mounted at the bottom portion of the chassis (21) and just above the midpoint of live rear axle (3) and dead rear axle (4). It is a two-way valve whose output is controlled by an adjusting lever (23). Now with respect to figure 4, a solenoid controlled pneumatic valve (10) is a two-way valve to which input is coming from load sensing valve (7) and output, which is the final controlled output, is given to suspension bellows (22) of liftable axle (2). The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof. 13 We Claim: 1. Liftable axle control system comprising at least one load sensing valve positioned between chassis of a vehicle and its rear axles, at least one height control valve provided between the front axle and the chassis of vehicle and a pressure regulator, output of which is connected to said load sensing valve/s ; a bridge connection means having a bridge rod mounted on the live rear axle and dead rear axle ; a displacer, one end of which is connected to said bridge rod and other end is connected to said load sensing valve through an adjusting lever ; the output of the said height control valve is connected to an electronic logic control module , output from said electronic logic control module is fed to a solenoid controlled pneumatic valve ,wherein a solenoid controlled pneumatic valve is also connected with a said load sensing valve, and output of said solenoid controlled pneumatic valve is connected to the suspension bellows of liftable axle . 2. Liftable axle control system as claimed in claim 1 is operable either by electro-pneumatic or pneumatic or electrical signal means. 3. Liftable axle control system as claimed in claims 1 or 2 wherein said bridge rod is fixed on said rear axles at the axis of vehicle. 4. Liftable axle control system as claimed in claims 1 to 3 wherein said bridge rod is connected to rear axles through self aligning means. 5. Liftable axle control system as claimed in claims 1 to 4 wherein the said displacer is connected at the center of bridge rod. 14 6. Liftable axle control system as claimed in claim 1 wherein said load sensing valve is mounted in such a way that the axis of said load sensing valve is perpendicular to the said displacer. 7. Liftable axle control system as claimed in claim 1 wherein said height control valve is fixed in such a way that the axis of said valve is perpendicular to the axis of vehicle. 8. Liftable axle control system as claimed in claim 1 to 7 wherein said height control valve is of either pneumatic type fitted with pressure transducer or an electronic type. 9. Liftable axle control system as claimed in any of preceding claims wherein the vehicle is a heavy commercial vehicle. lO.Liftable axle control system of vehicle substantially as herein described with reference to accompanying drawing. Dated this 15th day of March 2007 15 Abstract Liftable Axle Control System For Vehicle This invention relates to the pneumatically controlled liftable axle control system of vehicle. The control of liftable axle (2) is done with respect to the actual load coming on the front axle (1) and rear axles (3,4). To sense the load coming on rear axles a pneumatic load-sensing valve (7) is fitted between the chassis (21) and said rear axles. To sense the load coming on front axle a pneumatic height control valve (11) is fitted between front axle (1) and chassis. A load sensing valve fitted on chassis bottom will sense the load on rear axles by referring the height between chassis and ' rear axles with the help of a bridge connection. The bridge connection is having a bridge rod (8), which is fitted over live axle (3) and dead axle (4). A displacer (9) is then fitted between bridge rod and load sensing valve adjusting lever, which will vary or control the output of load sensing valve with respect to the height between bridge rod and chassis. Front axle (1) is fitted with a height control valve (11) whose output will vary with respect to the height between front axle and chassis. The output of height control valve is then given to an electronic logic control module (13). A voltage output from electronic logic control module is then given to a solenoid controlled pneumatic valve (10), having input from load sensing valve (7), is an electro-pneumatic valve whose pressure output is controlled by voltage received from electronic logic control module. The controlled pressure output from solenoid controlled pneumatic valve is then given to suspension bellow of liftable axle.

Documents:

488-MUM-2007-ABSTRACT(GRANTED)-(31-1-2012).pdf

488-mum-2007-abstract.doc

488-mum-2007-abstract.pdf

488-MUM-2007-CANCELLED PAGES(8-8-2011).pdf

488-MUM-2007-CLAIMS(AMENDED)-(29-10-2010).pdf

488-MUM-2007-CLAIMS(AMENDED)-(8-8-2011).pdf

488-MUM-2007-CLAIMS(GRANTED)-(31-1-2012).pdf

488-MUM-2007-CLAIMS(MARKED COPY)-(29-10-2010).pdf

488-MUM-2007-CLAIMS(MARKED COPY)-(8-8-2011).pdf

488-mum-2007-claims.doc

488-mum-2007-claims.pdf

488-mum-2007-correspondence(11-4-2007).pdf

488-mum-2007-correspondence(ipo)-(27-11-2009).pdf

488-MUM-2007-CORRESPONDENCE(IPO)-(31-01-2012).pdf

488-mum-2007-correspondence-received.pdf

488-mum-2007-description (complete).pdf

488-MUM-2007-DESCRIPTION(GRANTED)-(31-1-2012).pdf

488-MUM-2007-DRAWING(GRANTED)-(31-1-2012).pdf

488-mum-2007-drawings.pdf

488-mum-2007-form 18(11-4-2007).pdf

488-MUM-2007-FORM 2(GRANTED)-(31-1-2012).pdf

488-MUM-2007-FORM 2(TITLE PAGE)-(COMPLETE)-(15-3-2007).pdf

488-MUM-2007-FORM 2(TITLE PAGE)-(GRANTED)-(31-1-2012).pdf

488-MUM-2007-FORM 3(29-10-2010).pdf

488-mum-2007-form 9(11-4-2007).pdf

488-mum-2007-form-1.pdf

488-mum-2007-form-2.doc

488-mum-2007-form-2.pdf

488-mum-2007-form-26.pdf

488-mum-2007-form-3.pdf

488-MUM-2007-REPLY TO EXAMINATION REPORT(29-10-2010).pdf

488-MUM-2007-REPLY TO HEARING(8-8-2011).pdf

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