FORM 2
THE PATENTS ACT, 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
TITLE: “A SYSTEM FOR VARYING STIFFNESS OF AN ANTI-ROLL BAR”
Name and Address of the Applicant:
TATA MOTORS LIMITED of Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai - 400 001 Maharashtra, India.
Nationality: Indian
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
[001] Present disclosure relates to the field of automobiles. Particularly, but not exclusively, the present disclosure relates to an anti-roll bar in a suspension system of a vehicle. Further, embodiments of the present disclosure discloses a system for varying stiffness of the anti-roll bar.
BACKGROUND OF THE DISCLOSURE
[002] Generally, vehicles are equipped with a suspension system to act as a shock-absorbing means. The purpose of the suspension system is to isolate passengers from feeling undulations of the road and impending shocks and vibrations arising from going over the undulations, making the ride more comfortable. The suspension system includes an anti-roll bar coupled to a damper of the suspension system of the vehicle. The anti-roll bar is predefined with a stiffness to force wheels of the vehicle towards the ground, to prevent body roll of the vehicle during cornering/turning/banking and pitching movements of the vehicle arising from going over the undulations, due to centrifugal force acting on the vehicle.
[003] The stiffness is generally predetermined considering standard load conditions, i.e., the maximum load carrying capacity specified/authorized for the vehicle, and corresponding turning velocity, pitching movements of the vehicle, and deflection of the anti-roll bar in such standard load conditions. However, when the vehicle is moving at a velocity higher than the maximum turning velocity during cornering/turning/banking and high pitching movements in an overload condition of the vehicle, there is a high tendency of toppling of the vehicle.
[004] Therefore, there is a need to vary the stiffness of the anti-roll bar dynamically based on the load condition of the vehicle and deflection in the anti-roll bar during the events of cornering/turning/banking and high pitching movements of the vehicle. The present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the aspect of the stiffness of the anti-roll bar in the suspension system of the vehicle.
[005] The drawbacks/difficulties/disadvantages/limitations of the conventional techniques explained in the background section are just for exemplary purpose and the disclosure would never limit its scope only such limitations. A person skilled in the art would understand that this disclosure and below mentioned description may also solve other problems or overcome the other drawbacks/disadvantages of the conventional arts which are not explicitly captured above.

SUMMARY OF THE DISCLOSURE
[006] One or more shortcomings of the conventional anti-roll bar are overcome by a system for varying stiffness of an anti-roll bar in a suspension system of a vehicle, as described. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
[007] In a non-limiting embodiment of the disclosure, a system for varying stiffness of an anti-roll bar in a suspension system of a vehicle is disclosed. The anti-roll bar is defined with a hollow tube. The system includes a sleeve disposed on at least a portion of the hollow tube wherein the sleeve receives a magnetorheological fluid. The system further includes an encoder disposed on the hollow tube and located proximal to the sleeve. Furthermore, the system includes a control unit communicatively connected to the encoder. The control unit is configured to receive a signal based on the deflection of the anti-roll bar from the encoder and energize the magnetorheological fluid by supplying current to alter viscosity of magnetorheological fluid for varying the stiffness of the anti-roll bar.
[008] In an embodiment, the portion of the hollow tube is at least one bend portion of the anti-roll bar.
[009] In an embodiment, the system comprises at least one set of conducting wire disposed in an inner surface of the sleeve to energize the magnetorheological fluid.
[0010] In an embodiment, the system comprises a protective foam adapted to cover the at least one set of conducting wire.
[0011] In an embodiment, the system comprises a voltage regulator communicatively connected to the control unit and the magnetorheological fluid.
[0012] In an embodiment, the system comprises a power source connected to the voltage regulator.
[0013] In an embodiment, the control unit is configured to measure a viscosity of the magnetorheological fluid and determine the required voltage to be supplied to the anti-roll bar based on the signal received from the encoder and the required stiffness.
[0014] In an embodiment, the control unit is configured to actuate the voltage regulator to supply required voltage across the anti-roll bar to provide electromagnetic field to the

magnetorheological fluid to change the viscosity of the magnetorheological fluid within the sleeve for varying the stiffness of the anti-roll bar.
[0015] In an embodiment, the system comprises two bearings disposed on either ends of the sleeve for frictionless rotation of the sleeve relative to the hollow tube.
[0016] In an embodiment, the system comprises a rubber pad adapted to cover the sleeve of the anti-roll bar.
[0017] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0018] The novel features and characteristics of the disclosure are set forth in the appended description. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
[0019] Figure 1 illustrates a front view of an anti-roll bar in a suspension system of a vehicle, according to an embodiment of the present disclosure.
[0020] Figure 2 illustrates a bottom view of the anti-roll bar of Figure 1, according to an embodiment of the present disclosure.
[0021] Figures 3 illustrates a perspective exploded view of the anti-roll bar of the Figure 1, according to an embodiment of the present disclosure.
[0022] Figures 4 illustrates a block diagram of a system for varying stiffness of the anti-roll bar, according to an embodiment of the present disclosure.
[0023] The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the anti-roll bar and the system for varying stiffness of the anti-roll bar

illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0024] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by the way of example in the figures and will be described below. It should be understood, however that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
[0025] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of the anti-roll bar or the system for varying stiffness of the anti-roll bar, without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein. Also, the system for varying stiffness of the anti-roll bar in the suspension system of the present disclosure may be employed in any kind of vehicles including commercial vehicles, passenger vehicles, electric vehicles (EV), hybrid vehicles, off/road/highway vehicles, mining machinery, earth moving machinery, and among others. However, neither the vehicle nor complete suspension system of the vehicle is illustrated in the drawings of the disclosure for the purpose of simplicity.
[0026] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover non-exclusive inclusions, such that a device, assembly, mechanism, system, and method that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system, or assembly, or device. In other words, one or more elements in a system/assembly proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the assembly or system.
[0027] In the present disclosure, the term “exemplary” is used herein to mean “serving as an example, instance, or illustration”. Any embodiment or implementation of the present subject matter described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0028] Unless the context of the disclosure describes or indicates a different interpretation, any reference to an object in the specification that is preceded by a definite or indefinite article, such as 'the', 'a', or 'an', should be understood to encompass both the singular and the plural forms of the object. Accordingly, “a” means “at least one/one or more”. The phrase “a/an X” may be construed as “at least one/one or more X”.
[0029] Embodiments of the present disclosure discloses a system for varying stiffness of an anti-roll bar in a suspension system of a vehicle. The anti-roll bar is defined with a hollow tube. The system includes a sleeve disposed on at least a portion of the hollow tube wherein the sleeve receives a magnetorheological fluid. The system further includes an encoder disposed on the hollow tube and located proximal to the sleeve. Furthermore, the system includes a control unit communicatively connected to the encoder. The control unit is configured to receive a signal based on the deflection of the anti-roll bar from the encoder and energizes the magnetorheological fluid by supplying current to alter viscosity of magnetorheological fluid for varying the stiffness of the anti-roll bar. Such systems are capable of varying the stiffness of the anti-roll bar dynamically based on the deflection in the anti-roll bar during the events of cornering/turning/banking and high pitching movements of the vehicle. Such dynamic varying stiffness of the anti-roll bar prevents body roll or toppling of the vehicle, when the vehicle is moving at a velocity higher than the maximum turning velocity during cornering/turning/ banking and high pitching movements in an overload condition of the vehicle.
[0030] The following paragraphs describe the present disclosure with reference to Figures. 1 to 4. In the figures, the same element or elements which have similar functions are indicated by the same reference signs. With general reference to the drawings, the system for varying stiffness of the anti-roll bar is illustrated and generally identified with reference numeral (100). Further, the anti-roll bar operatively associated with a suspension system of a vehicle [not shown] is identified with reference numeral (10). It will be understood that the teachings of the present disclosure are not limited to any particular vehicle and may be employed in a myriad of category of vehicles including, but not limited to, commercial vehicles, passenger vehicles, electric vehicles (EV), hybrid vehicles, and among others.
[0031] Figures 1-3 illustrate the anti-roll bar (10) in the suspension system of the vehicle and Figure 4 illustrates the system (100) for varying stiffness of the anti-roll bar (10). The anti-roll bar (10) is defined with a hollow tube (1). The system (100) includes a sleeve (2) disposed on at least a portion of the hollow tube (1). The system (100) further includes an encoder (6) disposed on the hollow tube (1) and located proximal to the sleeve (2). Furthermore, the system

(100) includes two bearings (7) disposed on either ends of the sleeve (2) for frictionless rotation of the sleeve (2) relative to the hollow tube (1). Each end of the anti-roll bar (10) may be coupled to the damper of the suspension system by means of a second linkage (9) and at least one fastener (12). Also, the anti-roll bar (10) may be coupled to a frame [not shown] of the vehicle by at least one first linkage (8) and at least one fastener [not shown]. The at least one first linkage (8) comprises a bush (14) adapted to house the anti-roll bar (10). Such configuration of the at least one first linkage (8) and the second linkage (9) improves stability of the anti-roll bar (10) and reduces vibration in the anti-roll bar (10) during the operation of the vehicle, i.e., when ignition of the vehicle is ON and/or when the vehicle is moving.
[0032] As depicted in Figure 3, the sleeve (2) receives a magnetorheological fluid (4). Further, the system (100) includes at least one set of conducting wire (5) disposed in an inner surface of the sleeve (2). The at least one set of conducting wire (5) is configured to energize the magnetorheological fluid (4). In an exemplary embodiment, the at least one set of conducting wire (5) may be a number of coils made of copper. Furthermore, the system (100) includes a protective foam (3) to cover the at least one set of conducting wire (5). The protective foam (3) may be made of a poly-urethane material. Configuration of the sleeve (2) disposed on the at least a portion of the hollow tube (1) to receive a magnetorheological fluid (4) reduces weight of the anti-roll bar (10), thus reducing overall weight of the vehicle, and thereby improving fuel efficiency of the vehicle.
[0033] The portion of the hollow tube (1) may be at least one location on the anti-roll bar (10) which encounters maximum stress, particularly, maximum twisting stress, during the deflection of the anti-roll bar (10) during the events of cornering/turning/banking and high pitching movements of the vehicle. In an exemplary embodiment as depicted in Figures 1-3, the portion of the hollow tube (1) is at least one bend portion (20) of the anti-roll bar (10).
[0034] As illustrated in Figure 4, the system (100) includes a control unit (200) communicatively connected to the encoder (6). The control unit (200) is configured to receive a signal based on the deflection of the anti-roll bar (10) from the encoder (6) and energize the magnetorheological fluid (4) by supplying current to alter viscosity of magnetorheological fluid (4) for varying the stiffness of the anti-roll bar (10). The system (100) further includes a voltage regulator (300) communicatively connected to the control unit (200) and the magnetorheological fluid (4). Furthermore, the system (100) includes a power source (400) connected to the voltage regulator (300). Further, the control unit (200) is configured to measure a viscosity of the magnetorheological fluid (4) and determine the required voltage to

be supplied to the anti-roll bar (10) based on the signal received from the encoder (6) and the required stiffness.
[0035] The control unit (200) is further configured to actuate the voltage regulator (300) to supply required voltage across the anti-roll bar (10). The at least one set of conducting wire (5) is configured to produce electromagnetic field when the required voltage is applied across the anti-roll bar (10). The electromagnetic field changes the viscosity of the magnetorheological fluid (4) within the sleeve (2) for varying the stiffness of the anti-roll bar (10). Such system (100) is capable of varying the stiffness of the anti-roll bar (10) dynamically based on the deflection in the anti-roll bar (10) during the events of cornering/turning/banking and high pitching movements of the vehicle.
[0036] In an embodiment of the disclosure, the control unit (200) may be a centralized control unit (such as engine control system) configured to supply the required voltage to the anti-roll bar (10) of the system (100), or a dedicated control unit for the system (100). The control unit (200) may be implemented by any computing systems that is utilized to implement the features of the present disclosure. The control unit (200) may be comprised of a processing unit. The processing unit may comprise at least one data processor for executing program components for executing user- or system-generated requests. The processing unit may be a specialized processing unit such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processing unit may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM’s application, embedded or secure processors, IBM PowerPC, Intel’s Core, Itanium, Xeon, Celeron, or other line of processors, etc. The processing unit may be implemented using a mainframe, distributed processor, multi-core, parallel, grid, or other architectures. Some embodiments may utilize embedded technologies like application-specific integrated circuits (ASICs), digital signal processors (DSPs), Field Programmable Gate Arrays (FPGAs), and the like.
[0037] The system (100) also includes a rubber pad [not shown] adapted to cover the sleeve (2) of the anti-roll bar (10). The rubber pad effectively protects the sleeve (2) from the external objects and further provides electrical safety. In an embodiment, the voltage supplied to the anti-roll bar (10) ranges between 2-12V and the current ranges between 0-1 A. Since a small voltage and current is sufficient to vary the stiffness of the anti-roll bar (10), voltage regulator (300) may be connected to a main/common battery of the vehicle as the power source (400). The main/common battery is a power source that powers a starter motor to start an engine of

the vehicle. Alternatively, a dedicated battery may be employed as the power source (400) to supply the required voltage to the anti-roll bar (10), without deviating from the scope of the present disclosure.
[0038] In an exemplary embodiment of the present disclosure as depicted in Figure 1, the suspension system may be an independent suspension system. Further, in the vehicles which are equipped with a component to measure the deflection of the anti-roll bar (10), the control unit (200) may directly receive the input, i.e., deflection of the anti-roll bar (10), from the existing component. In such vehicles, the encoder (6) may not be necessary.
[0039] In an embodiment, the system (100) of the present disclosure is capable of varying the stiffness of the anti-roll bar (10) dynamically based on the deflection in the anti-roll bar (10) during the events of cornering/turning/banking and high pitching movements of the vehicle. Such dynamic varying stiffness of the anti-roll bar (10) prevents body roll or toppling of the vehicle, when the vehicle is moving at a velocity higher than the maximum turning velocity during cornering/turning/ banking and high pitching movements in an overload condition of the vehicle. Further, configuration of the at least one first linkage (8) and the second linkage (9) improves stability of the anti-roll bar (10) and reduces vibration in the anti-roll bar (10) during the operation of the vehicle, i.e., when ignition of the vehicle is ON and/or when the vehicle is moving.
[0040] Further, the system (100) of the present disclosure in which the sleeve (2) is disposed on the at least a portion of the hollow tube (1) to receive a magnetorheological fluid (4) reduces weight of the anti-roll bar (10), thus reducing overall weight of the vehicle, and thereby improving fuel efficiency of the vehicle. Also, the rubber pad of the present disclosure effectively protects the sleeve (2) from the external objects and further provides electrical safety. In addition, since a small voltage and current is sufficient to vary the stiffness of the anti-roll bar (10), voltage regulator (300) may be connected to a main/common battery, thereby mitigating requirement of a separate power source (400).
[0041] The magnetorheological fluid (4) of the present disclosure is capable of working in a wide temperature ranging from -40℃ to 150℃. Further, the phase change of the magnetorheological fluid (4) in the present disclosure ranges between 1-3 milliseconds. Such short phase change period of the magnetorheological fluid (4) improves driving dynamics and thereby enhancing the driving comfort. Further, the magnetorheological fluid (4) is highly

durable and requires low maintenance cost. The system (100) of the present disclosure may be employed in any vehicle having the suspension system at front and/or rear side of the vehicle.
[0042] It is to be understood that a person of ordinary skill in the art may develop a system (100) of similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.
EQUIVALENTS
[0043] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0044] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
[0045] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
[0046] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at

least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system (100)) having at least one of A, B, and C” would include but not be limited to system that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system (100) having at least one of A, B, or C” would include but not be limited to pistons that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

REFERRAL NUMERICALS

Numerical Particulars
1 Hollow tube
2 Sleeve
3 Protective foam
4 Magnetorheological fluid
5 At least one set of conducting wire
6 Encoder
7 Bearing
8 At least one first linkage
9 Second linkage
10 Anti-roll bar
12 At least one Fastener
14 Bush
20 Bend portion
100 Anti-roll bar
200 Control unit
300 Voltage regulator
400 Power source

We claim:
1. A system (100) for varying stiffness of an anti-roll bar (10) in a suspension system of a
vehicle, the anti-roll bar (10) is defined with a hollow tube (1), the system (100) comprising:
a sleeve (2) disposed on at least a portion of the hollow tube (1) wherein the sleeve (2) receives a magnetorheological fluid (4);
an encoder (6) disposed on the hollow tube (1) and located proximal to the sleeve (2); and
a control unit (200) communicatively connected to the encoder (6);
wherein, the control unit (200) is configured to receive a signal based on the deflection of the anti-roll bar (10) from the encoder (6) and energize the magnetorheological fluid (4) by supplying current to alter viscosity of magnetorheological fluid (4) for varying the stiffness of the anti-roll bar (10).
2. The system (100) as claimed in claim 1, wherein the portion of the hollow tube (1) is at least one bend portion (20) of the anti-roll bar (10).
3. The system (100) as claimed in claim 1, comprises at least one set of conducting wire (5) disposed in an inner surface of the sleeve (2) to energize the magnetorheological fluid (4).
4. The system (100) as claimed in claim 1, comprises a protective foam (3) adapted to cover the at least one set of conducting wire (5).
5. The system (100) as claimed in claim 1, comprises a voltage regulator (300)
communicatively connected to the control unit (200) and the magnetorheological fluid (4).
6. The system (100) as claimed in claim 5, comprises a power source (400) connected to the voltage regulator (300).
7. The system (100) as claimed in claim 1, wherein the control unit (200) is configured to measure a viscosity of the magnetorheological fluid (4) and determine the required voltage to be supplied to the anti-roll bar (10) based on the signal received from the encoder (6) and the required stiffness.
8. The system (100) as claimed in claim 7, wherein the control unit (200) is configured to actuate the voltage regulator (300) to supply required voltage across the anti-roll bar (10) to provide electromagnetic field to the magnetorheological fluid (4) to change the viscosity of the

magnetorheological fluid (4) within the sleeve (2) for varying the stiffness of the anti-roll bar (10).
9. The system (100) as claimed in claim 1, comprises two bearings (7) disposed on either ends
of the sleeve (2) for frictionless rotation of the sleeve (2) relative to the hollow tube (1).
10. The system (100) as claimed in claim 1, comprises a rubber pad adapted to cover the sleeve
(2) of the anti-roll bar (10).