Description:FIELD OF INVENTION

The present invention relates to testing of tyres for automobiles. In particular, the present invention relates to a tyre testing rig for testing the rolling resistance coefficient (RRC) of automotive tyres. More particularly, the present invention relates to a versatile tyre measurement/testing rig for testing the rolling resistance coefficient (RRC) of automotive tyres.

BACKGROUND OF THE INVENTION

The rolling resistance, also called rolling friction or rolling drag, is the force resisting the motion of a body (such as a tyre or wheel) rolling on a surface and is primarily the result of non-elastic effects, because all energy required for deformation (or movement) of the wheel or roadbed is not recoverable on removing the pressure therefrom. For example, hysteresis losses and permanent (plastic) deformation of the wheel or the road surface. It is to be noted that the slippage between the wheel and the road surface also results in the dissipation of energy. There are different opinions amongst researchers whether to include this energy dissipation term in the rolling resistance or not, because it is caused due to the torque applied to the wheel and a slip results between the wheel and ground, i.e. a slip loss or slip resistance.

Any coasting wheeled vehicle gradually slows down due to rolling resistance including that of the bearings. The factors contributing to the rolling resistance are the deformation of wheels and road surface, and movement thereunder. In addition, wheel diameter, load on wheel, surface adhesion, sliding, and relative micro-sliding between the surfaces of contact also contribute therein. The hysteresis losses are also based on the material properties of the wheel/tyre and the road surface. For example, a rubber tyre has higher rolling resistance on a paved road than a steel railroad wheel on a steel rail. Similarly, sand present on the ground imparts more rolling resistance than concrete. The rolling resistance coefficient (RRC) of tyres depends on the properties of the tyre material, road surface, and the tyre dimensions (R=radius) as well as the velocity.

Due to ever increasing fuel price and also because of stricter regulatory norms imposed for reducing greenhouse gas emissions, there is a consistent demand to improve the fuel efficiency of vehicles. The driving style, vehicle weight, engine, tyre, aerodynamics and weather conditions also affect the vehicle’s fuel efficiency to a great extent.

However, the impact of tyre construction, tyre wear, inflation pressure and driver behaviour greatly affect the Rolling Resistance Coefficient (RRC) of a tyre and thereby RRC has a significant effect on the vehicle’s fuel efficiency.

An engine-dyno directly measures power from the engine, whereas a chassis-dyno measures the engine or drivetrain output at the drive wheels of the vehicle. The chassis-dyno includes a platform with drum or roller pairs, brake or power absorption system, and software to calculate the power output.

PRIOR ART

JPH0452544A (Figures 1a-1b) discloses an apparatus for measuring the resistance to tyre rotation to accurately detect the traction due to resistance when tyre is rotated by pressing a load sensor by a swaying arm added with the traction, for obtaining correct input to load sensor with a small traction. When the rotating resistance of tyre is to be measured, with the traction vehicle running with a constant speed of the measuring cart, the traction load of cart is added to a ball joint. An arm is ready to sway around a shaft toward the rear side of the vehicle and a load corresponding to the traction of the cart is added through a projecting part colliding against this arm to press a load sensor. When the ratio between the swaying radius around the joint coupling the arm with cart and the swaying radius of the pressing point is suitably set, a desired level of the load change corresponding to traction can be obtained and load/rotating resistance of tyre is detected with high accuracy even with a small traction.

JP5874374B2 (Figure 2) discloses a tyre traction performance measuring device to accurately evaluate the traction performance of the tyre to be tested by preventing the reduction in precision of measurement due to vibration. Accordingly, this device measures traction performance of tyre to be tested by pulling a vehicle by a pulling vehicle mounted with the tyre to be tested. The pulling vehicle and pulled vehicle are connected by a wire rope provided with a traction force measuring device to measure the traction force of the pulling vehicle, and an attenuating mechanism, which improves the measurement precision of the traction force measuring device by attenuating the vibrations of wire rope. However, the invention uses a wire to hitch the vehicle (Figure 2).

KR101300002B1 (Figure 3) discloses a system and method for the measurement of tyre rolling resistance. The method is capable of calculating a rotational resistance value by using a test cart, u-shaped road surface, a sensor for sensing the number of tyre rotations, the number of cart reciprocations, and a maximum height where the cart is stopped in a curved portion, and a rotational resistance calculating algorithm. The system comprises a test cart, u-shaped road surface, a sensor, and a rotational resistance calculation unit. The test cart connects a plurality of tyres to a shaft and has an object to load the loads on the shaft. The U-shaped road surface has a planar portion, a first and second curved portion each. The first curved portion is connected to one side of planar portion and formed as a quartile circle circumference. The second curved portion is connected to the other side of planar portion and formed as the other quartile circle circumference facing the quartile circle. The sensor senses the number of tyre rotations, number of cart reciprocations, and the maximum height where the cart is stopped in a curved portion. The rotational resistance calculation unit calculates a rotational resistance value by using a rotational resistance calculating algorithm based on the number of tyre rotations, the number of cart reciprocations, and the maximum cart height. However, this method of measurement involves calculation by allowing a free movement of cart on the U-shaped surface without applying any external force and calculating the tyre resistance based on the physics based algorithm. There is no direct force measurement, restricted to a particular road surface (Figure 3).

Therefore, there is an existing need for an improved tyre rolling resistance coefficient (RRC) measurement rig which enables versatile use thereof, i.e. both for on-road and dyno application. The desired test rig should also be capable of isolating the cart from wind and aerodynamic forces and measuring the individual tyre traction forces.

DESCRIPTION OF THE INVENTION

In accordance with the present invention, there is provided a versatile tyre rolling resistance coefficient (RRC) measurement rig for on-road and dyno applications, which comprises a sliding linkage mechanism for isolating the cart from wind and aerodynamic forces and for measuring the traction force in individual tyre by adding an aero-shield to the frame of the connecting arm thereof.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig for automotive tyres.

Another object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig which can be used for both on-road and dyno applications in the automotive vehicle.

Still another object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig which can isolate and measure the traction forces on individual tyres of the automotive vehicle.

Yet another object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig which can isolate the test-rig cart from wind and aerodynamic forces faced during tyre testing.

A further object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig with a cart anchored to chassis-dyno to measure the tyre rolling resistance coefficient (RRC).

A still another object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig which ensures a parallelism with the road surface.

A still further object of the present invention is to provide a versatile tyre rolling resistance coefficient (RRC) measurement/testing rig which is used accurately on wide range of tyres at high-speeds by axle supporting greater weights.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.
SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a versatile, portable testing rig to measure tyre Rolling Resistance Coefficient (RRC) at different vehicle weight/loads, the testing rig comprises:

(a) at least one suspension spring;

(b) at least one axle for mounting of wheels fitted with tyres on either side thereof;

(c) a container for holding/carrying dead weight/s therein;

(d) a respective support column on either side of the axle;

(e) the towing frame for moving or anchoring the testing cart with the container thereon;

(f) a pair of connecting linkages fitted on the axle;

(g) a respective anchoring arm fitted on sides of the towing frame;

(h) a respective pulling leg fitted on the towing frame; and

(i) a towing eye fitted on the front-end of the towing frame for the attachment thereof to a pulling vehicle;

wherein a sliding joint and the connecting linkage are fitted on the towing frame and a load cell is fitted thereon by a bracket for measuring the pulling force acting at the connecting linkage; and the load cell measures the forces applied due to the rolling resistance of the tyre/s and acting in a horizontal direction thereon.

Typically, the height of the towing eye is adjustable based on the rolling radius of the tyre for ensuring a horizontal alignment of the towing frame during the towing of the testing cart.
Typically, the connecting rod is connected between the sliding joint and the load cell for measuring the force/s transmitted therethrough to the towing frame and required for pulling the testing cart.

Typically, the connecting rod couples the towing frame to the testing cart for supporting the towing frame thereon and facilitates an independent horizontal movement and transmission of forces therebetween.

Typically, the spring mounted between the support column and the dead-weight container forms a respective suspension system for isolating the container from the vibrations generated during the movement of the testing cart on road during the testing of the rolling resistance coefficient (RRC).

Typically, an independent front cart is configured as the towing frame mounted with an aerodynamic shield thereon for pulling the testing cart loaded with the dead weights.

Typically, the testing cart is configured to be capable of mounting tyres of varying rim diameter and dimensions ranging from R14 to R20, thereon,and the testing cart is operated at speeds up to 180 kmph and supports up to 2000 kg of dead-weight/s on the axle.

Typically, the testing rig is configured for measuring the force within 5-100 Newton per tyre with an accuracy of ±0.5 N and least count of 0.1 N.

Typically, the testing rig comprises:

(i) the testing cart with an axle fitted with a wheel on either side thereof and mounted with a respective tyre under testing;

(ii) the testing cart includes at least one axle with wheels mounted on either side thereof with at least one tyre for testing the Rolling Resistance Coefficient (RRC) thereof at different vehicle weight/loads;
(iii) a respective suspension spring supported on a support column on either side of the axle;

(iv) a respective support column fitted on either side of the container to carry at least one dead weight therein, the support column resting on a respective journal bearing encompassing the axle;

(v) a respective sliding joint mounted on a block; the sliding joint fitted between the axle supporting a container thereon to carry dead weights therein, and the towing frame;

(vi) the load cell measures only the forces applied due to the rolling resistance of the tyre/s and acting in a horizontal direction thereon.

Typically, the load cell is configured for measuring the pulling force acting at the connecting rod; and the load cell measures only the forces applied due to the rolling resistance of the tyre/s and acting in a horizontal direction thereon, after accounting for the drag of wheel and bearings.

DESCRIPTION OF THE INVENTION

The versatile tyre rolling resistance coefficient (RRC) measurement rig 20 configured in accordance with the present invention (Figures 5a-5b, 6) and to be used for on-road and dynamometer (dyno) applications at different vehicle weights/ loads. This rig consists of two sections, namely a testing cart 20 and a towing frame 8. The cart has a container 4 to hold the dead weights supported on an axle 5 consisting of two low-friction bearings 9 and having provision for mounting of tyres 7 of different sizes, (e.g. R14 to R20 tyres) by means of adapters or universal hubs 11 (not shown). A suspension system consisting of springs 2 is also provided between support columns 6 and the load or dead-weight container 4 for isolating them from the vibrations generated during the movement of testing cart 20 on road. The support columns 6 rest on a respective journal bearing 13 encompassing the axle (not shown). The towing frame 8 is required to anchor the entire setup to the chassis dynamometer (dyno) or to connect it to a towing vehicle V while taking measurements by moving the testing cart 20 on road. The towing frame 8 is connected to the testing cart 20 by means of intermediate or connecting linkages 14. A respective low-friction sliding joint 10 is provided between the axle (5) and the linkage 14 to allow for a transverse motion therebetween. A respective connecting rod 12 is provided between the block mounting the sliding joint 10 and the load cell 22, through which the force is transmitted and measured. A towing eye 18 is provided at the end of the towing frame 8 to hitch the testing cart 20 to the towing vehicle V (Fig. 4). The height of the towing eye 18 is adjustable based on the rolling radius of tyres 7 for ensuring that the towing frame 8 is horizontal during the towing of the testing cart 20.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described in the following with reference to the accompanying drawings.

Figure 1a shows a first embodiment of the apparatus for measuring the resistance to tyre rotation to accurately detect the traction as disclosed in the prior art document JPH0452544A.

Figure 1b shows a second embodiment of apparatus for measuring the resistance to tyre rotation to accurately detect the traction as taught in prior art document JPH0452544A.

Figure 2 shows an embodiment of a tyre traction performance measuring apparatus 100 as disclosed in the prior art document JP5874374B2.

Figure 3a shows a schematic diagram of the cross-sectional view of the tyre rotation resistance measuring system disclosed in the prior art document KR101300002B1.

Figure 3b shows a schematic diagram of the test cart of the tyre rotation resistance measuring system disclosed in above prior art document.

Figure 4 shows a versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention for on-road and dyno applications in the automotive vehicle.

Figure 5a shows a side view of the versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention for on-road and dyno applications at different loads in the automotive vehicle.

Figure 5b shows a top view of the versatile tyre rolling resistance coefficient (RRC) measurement rig shown in Figure 5a.

Figure 6 shows an enlarged detailed side perspective view of the versatile tyre rolling resistance coefficient (RRC) measurement rig shown in Figure 5a.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, a versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention for on-road and dyno applications in the automotive vehicle, will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention.

Figure 1a shows first embodiment of the apparatus for measuring the resistance to tyre rotation to accurately detect the traction as disclosed in the prior art document JPH0452544A, which includes a measuring truck 10 with a load detection unit 20 for detecting the tractive force for towing thereof and towing car 30. The measuring carriage 10 includes a frame-shaped truck-body 11 with a pair of left and right leaf springs 12 attached to a lower portion thereof, tyres 13 attached to the left and right sides of the truck-body 11 for measuring the rolling resistance thereof, and a beam axle (not shown) supported by leaf springs 12 and supporting tyres 13. The towing car 30 has a front and rear detachable weights 14, 15 attached to truck-body 11 for changing the wheel-load, and a traction member 16 mounted on the front end part of truck-body 11 for transmitting the traction force from the towing car or traction vehicle 30 to the truck-body 11. The towing car 30 has a rear-wheel 41, and a rear-end member 42 fixed with a sensor housing 21, and a shackle 43 displaceably connecting a rear-end of truck-body 11 and a rear-end of the leaf spring 12.

Figure 1b shows a second embodiment of apparatus for measuring the resistance to tyre rotation to accurately detect the traction as disclosed in the prior art document JPH0452544A, in which the load detection unit 20 includes a sensor housing 21 fixed to the rear-end of towing car 30, and an arm 22 swingably attached to sensor housing 21 for swinging a swinging part 22a on the upper end in the longitudinal direction. A ball joint 23 connects the upper end of arm 22 and traction member 16 in a freely swingable manner and a load sensor 24 is stored in sensor housing 21 for abutting on the intermediate part of arm 22. The load sensor 24 includes a sensor body 25, a protrusion 26, and a strain gauge housing 27. The protrusion 26 is pressed by arm 22 with a load corresponding to a force for pulling the measuring truck 10, and a strain of the sensor body 25 receiving this load is input by a strain gauge (not shown) of strain gauge housing 27. The ball joint 23 is made of a stud portion 28 fastened to arm 22 and a socket portion 29 fixed to traction member 16 and rotatably engaged with stud portion 28, which allows a relative movement between the measuring truck 10 and the towing car 30. The sensor housing 21 has a stopper bolt 31 and an elastic stopper 32 to limit a front-rear swing stroke of arm 22. The stopper bolt 31 is spring-coupled to a bracket 33 formed on sensor housing 21 and fixed by a nut 34. The elastic stopper 32 is made of rubber, for absorbing the impact to prevent the measuring truck 10 from receiving the impact due to inertia when the towing car 30 is braked.

However, the above-described mechanisms (Figures 1a-1b) for transmitting traction force to the load detection unit 20 cannot isolate the traction force of individual tyres because the sensor housing 21 is located at the point of hitching the measuring truck 10 to the towing car or traction vehicle 30.

Figure 2 shows an embodiment of a tyre traction performance measuring apparatus 100 as disclosed in the prior art document JP5874374B2. The measuring apparatus 100 is used for evaluating the traction performance of a tyre 123 under testing and mounted on a towing vehicle 121. The measuring apparatus 100 comprises a wire rope 101, a traction force measuring device 102, a damping mechanism 103, and an in-vehicle unit 104. In the towing vehicle 121, the tyre 123 is mounted on the left and right rear-wheels, and the driving force from the towing vehicle 121 is almost evenly applied thereto. For this reason, it is desirable that the towing vehicle 121 is not provided with a differential gear. The towing vehicle 121 is connected to a towed vehicle 122 by the wire rope 101. A connecting rod or the like can also be used in addition to the wire rope 101, as a connecting member to connect the towing vehicle 121 and the towed vehicle 122. The towed vehicle 122 is not a self-propelled vehicle and is connected to generate a load during towing thereof. The wire rope 101 has a traction force measuring device 102 on the towing vehicle 121 side and a damping mechanism 103. For example, the tractive force measuring device 102 is a load cell for measuring the tractive force from towing vehicle 121 during traveling thereof. For example, the values obtained by the device 102 is output to in-vehicle unit 104 by an output line in the wire rope 101. The damping mechanism 103 damps the vibration of the wire rope 101. However, the above-described traction force measuring device 102 cannot isolate the traction force of individual tyres. Moreover, a wire rope 101 is provided with a measuring device 102 to measure the traction force of the towing vehicle 121 and a damping mechanism 103 is also provided to minimize error due to vibrations.

Figure 3a shows a schematic diagram of the cross-sectional view of the tyre rotation resistance measuring system 100 disclosed in the prior art document KR101300002B1, which is rolling on a U-shaped road 200 equipped with curved portions 240, 260 connected on either side of the planar section 220 to a respective sensor 300 which in turn is connected to a rotary resistance output unit 400. In a preferred embodiment, the test cart 100 is positioned at the end of the first curved portion 240 and released from the stationary condition thereof to roll down the curved portion 240 and passes the planar section 220, and then climbs the second curved portion 260 and reaches and stops at the maximum height thereof. Thereafter, the test cart 100 comes down via/through second curved portion 260 and passes the planar section 220 to reclimb the first curved portion 240 to reach and stop at the maximum height thereof.

Figure 3b shows a schematic diagram of the test cart 100 of the tyre rotation resistance measuring system disclosed in above prior art document. The tyre rotation resistance measuring system 100 comprises a tyre 10, test cart 100 equipped with shaft 30 connecting the tyre 10 and object 50. The measuring system calculates the rotational resistance value by using test cart 100 rolling on U-shaped road surface 200 and the sensor 300 sensing the number of tyre rotations, the number of reciprocation of the test cart 100, and the maximum height at which the test cart 100 stops in the curved portions 240, 260, by using the rotational resistance calculating algorithm. However, the method of measurement disclosed in the prior art document KR101300002B1 uses calculations by allowing free movement of the test cart 100 on the U-shaped road surface 200 without applying any external force and calculating the tyre resistance based on a physics-based algorithm rather than using a direct force measurement and is restricted to a particular road surface.
Figure 4 shows a versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention for on-road and dyno applications at different loads in the automotive vehicle. An automotive vehicle V is shown pulling a test cart TC carrying weights and attached with the tyres T to be tested.

Figure 5a shows a side view of the versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention for on-road and dyno applications at different loads in the automotive vehicle. This RRC measurement rig is configured as a testing cart 20 fitted with tyres 7 to be tested fixed on either side of the cart axle 3. The testing cart 20 also includes a suspension 2 supported on support columns 6 and accommodated within a dead weight container 4 mounted on a towing frame 8 fitted with towing eye 18 at the front-end of the testing cart 20. A sliding joint 10, connecting rods 12, connecting linkage 14 and a pair of anchoring arms 16 are provided under the towing frame 8.

Figure 5b shows a top view of the versatile tyre rolling resistance coefficient (RRC) measurement rig shown in Figure 5a. The tyres 7 to be tested are fixed on either side of the axle 3 of testing cart 20. It shows sliding joint 10, connecting rods 12, connecting linkage 14, and anchoring arm 16 on towing frame 8 fitted with a towing eye 18 to be attached to a pulling vehicle V in Figure 4.

Figure 6 shows an enlarged detailed side perspective view of the versatile tyre rolling resistance coefficient (RRC) measurement rig 20 shown in Figure 5a. Here, the suspension spring 2 is supported on support column 6 mounting a dead weight container 4 thereon. The support column 6 rests on axle 3 which is connected through a connecting linkage 14 to the towing frame 8. The sliding joint 10 and connecting rod 12 are fitted on the connecting linkage 14 and a load cell 22 is fitted thereon by a suitable bracket arrangement. The testing cart 20 consists of axle 3, a platform for placing dead weights in the container 4 placed thereon, low-friction bearings 9 and hubs 11 for mounting the wheels 5 fitted with tyres 7 (Figures 5a-5b) to be tested. The force required by the towing vehicle V for pulling the testing rig is measured, which is equivalent to the rolling resistance of these tyres 7. A connecting linkage 14 couples the testing cart 20 to towing vehicle V and also mounts an aerodynamic shield (not shown). The connecting rod 12 couples the connecting linkage 14 to the testing cart 20 so that connecting linkage 14 is supported on testing cart 20 while an independent horizontal movement is also facilitated therebetween. As an alternative thereto, an independent front cart can be used to mount the aerodynamic shield for pulling the loaded testing cart 20. The load cell 22 measures the pulling force acting at the connecting rod 12 for measuring only the forces applied due to the rolling resistance of tyres 7 under testing and which act in a horizontal direction thereon. The testing cart 20 is configured to mount R14 to R20 tyres to be tested and the force to be measured is in a range of 5-100 Newton per tyre with an accuracy of ±0.5 N and having a least count of 0.1 N. The testing cart 20 is operated at speeds up to 180 kmph and its axle 3 is capable of supporting up to 2000 kg dead-weight. The testing cart 20 is also equipped with a data acquisition system for recording its speed and for measuring the values of forces applied thereon.

WORKING MODES OF THE INVENTION

The versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention is used for on-road and dyno applications at different loads in the automotive vehicle. It measures the rolling resistance forces on a set of tyres 7 or even the resistance force on individual tyres 7 moving at different rotational speeds and carrying different dead weights by means of evaluating the loads acting thereon. When this testing rig is used on road hitched to a towing vehicle V by means of towing eye 18, it is pulled on a straight track and the force required for pulling the testing cart 20 is transmitted to the towing frame 8 via the connecting rod 12 provided between the sliding joints 10. This force is measured by the load cell 22 and the tyre rolling resistance is calculated from this measured force after accounting for the wheel 5 and bearing 9 drags. In addition, an aerodynamic shield can be mounted on the towing frame 8 to eliminate the air impingement on this testing cart 20 while it is towed by the towing vehicle V. Therefore, the aerodynamic drag operating on the testing cart/rig is excluded from the measured force required to pull the testing cart 20. Therefore, these measured forces accurately represent this tyre rolling resistance.

In contrast, when this testing rig 20 is used on a chassis dynamometer (dyno), rig 20 is positioned on the roller of dyno and anchored to support columns 6 on sides of the roller by a swinging/ anchoring arm 16 and also by providing a vertical support at the front of towing frame 8. Then, the roller rotates the tyres 7 at a targeted velocity and the reaction force is transmitted to the towing frame 8 of testing rig 20 by means of connecting rod 12, as explained above and this reaction force is then measured by the load cells 22.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The versatile tyre rolling resistance coefficient (RRC) measurement rig configured in accordance with the present invention offers the following advantages:

• Precisely measures the tyre rolling resistance force alone by eliminating air impingement to exclude the aerodynamic forces by mounting an aerodynamic shield on the towing frame.

• Usable for the measurement both on road and on chassis dynamometer,

• Usable for measuring the rolling resistance of tyres with a wide range of rolling radius, while ensuring that the towing frame is horizontal by adjusting the height of the towing eye.

• Provides an innovative sliding linkage mechanism for isolating and measuring the individual tyre traction forces.

• Uses two load cells for measuring the individual tyre traction forces by sliding linkages to connect the towing arm to the testing cart.

• Provides a higher measurement accuracy because of a smaller magnitude of forces transmitted to the load cell for accurately determining the RRC of the individual tyre.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

Although, the embodiments presented in this disclosure have been described in terms of its preferred embodiments, the skilled person in the art would readily recognize that these embodiments can be applied with modifications possible within the spirit and scope of the present invention as described in this specification by making innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to imply including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps. The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

The description of the exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are to be considered part of the entire written description. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well as derivatives thereof (e.g. “horizontally”, “inwardly”, “outwardly”; “downwardly”, “upwardly” etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion.

These relative terms are for convenience of description and do not require that the corresponding apparatus or device be constructed or operated in a particular orientation. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected”, refer to a relationship, wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.

LIST OF REFERENCE NUMERALS

2 Suspension spring
3 Axle
4 Container
5 Wheel
6 support column
7 Tyre
8 Towing frame
9 Bearing
10 Sliding joint
11 Hub
12 Connecting rod
13 Journal bearing
14 Connecting linkage
16 Pulling leg
18 Towing eye
20 Testing cart
22 Load cell
24 Bracket arrangement , Claims:We claim:

1. A versatile, portable testing rig to measure the tyre Rolling Resistance Coefficient at different vehicle loads, said testing rig comprising:

(a) at least one suspension spring (2);

(b) at least one axle (3) for mounting of wheels (5) fitted with tyres (7) on either side thereof;

(c) a container (4) for holding/carrying dead weight/s therein;

(d) a respective support column (6) on either side of said axle (3);

(e) a towing frame (8) for moving or anchoring a testing cart (20) with said container (4) thereon;

(f) a pair of connecting rods (12) fitted on said axle (3);

(g) a respective connecting linkage (14) fitted on sides of towing frame (8);

(h) a respective pulling leg (16) fitted on said towing frame (8); and

(i) a towing eye (18) fitted on the front-end of said towing frame (8) for the attachment thereof to a pulling vehicle (V);

wherein a sliding joint (10) and said connecting rod (12) are fitted on said towing frame (8) and a load cell (22) is fitted thereon by a bracket (24) for measuring the pulling force acting at said connecting rod (12); and said load cell (22) measures the forces applied due to the rolling resistance of said tyre/s (7) and acting in a horizontal direction thereon.

2. The testing rig as claimed in claim 1, wherein the height of said towing eye (18) is adjustable based on the rolling radius of said tyre (7) for ensuring a horizontal alignment of said towing frame (8) during the towing of said testing cart (20).
3. The testing rig as claimed in claim 1, wherein said connecting rod (12) is connected between said sliding joint (10) and said load cell (22) for measuring the force/s transmitted therethrough to the towing frame and required for pulling said testing cart (20).

4. The testing rig as claimed in claim 1, wherein said connecting rod (12) couples said towing frame (8) to said testing cart (20) for supporting said towing frame (8) thereon and facilitates an independent horizontal movement and transmission of forces therebetween.

5. The testing rig as claimed in claim 1, wherein said spring (2) mounted between said support column (6) and said dead-weight container (4) forms a respective suspension system for isolating said container (4) from the vibrations generated during the movement of said testing cart (20) on road during the testing of the rolling resistance coefficient (RRC).

6. The testing rig as claimed in claim 1, wherein an independent front cart is configured as said towing frame (8) mounted with an aerodynamic shield thereon for pulling said testing cart (20) loaded with the dead weights.

7. The testing rig as claimed in claim 2, wherein said testing cart (20) is configured to be capable of mounting tyres (7) of varying rim diameter and dimensions ranging from R14 to R20 thereon, and said testing cart (20) is operated at speeds up to 180 kmph and supports up to 2000 kg of dead-weight/s on said axle (3).

8. The testing rig as claimed in claim 1, wherein said testing rig is configured for measuring the force within 5-100 Newton per tyre (7) with an accuracy of ±0.5 N and least count of 0.1 N.

9. The testing rig as claimed in claim 1, wherein said testing rig comprises:

(I) said testing cart (20) with an axle (3) fitted with a wheel (5) on either side thereof and mounted with a respective tyre (7) under testing;

(II) said testing cart (20) includes at least one axle (3) with wheels mounted on either side thereof with at least one tyre (7) for testing the Rolling Resistance Coefficient (RRC) thereof at different vehicle weight/loads;

(III) a respective suspension spring (2) supported on a support column (6) on either side of said axle (3);

(IV) a respective support column (6) fitted on either side of said container (4) to carry at least one dead weight therein, said support column (6) resting on a respective journal bearing (13) encompassing said axle (3);

(V) a respective sliding joint (10) mounted on a block; said sliding joint (10) fitted between said axle (3) supporting a container thereon to carry dead weights therein, and said towing frame (8);

(VI) said load cell (22) measures only the forces applied due to the rolling resistance of said tyre/s (7) and acting in a horizontal direction thereon.

10. The testing rig as claimed in claim 9, wherein said load cell (22) is configured for measuring the pulling force acting at said connecting rod (12); and said load cell (22) measures only the forces applied due to the rolling resistance of said tyre/s (7) and acting in a horizontal direction thereon, after accounting for the drag of wheel (5) and bearings (9).

Dated this 15th day of November 2023.

Digitally / e-Signed by:

SANJAY KESHARWANI
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA-2043.