FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
BRAKE DISC ROTOR ASSEMBLY
APPLICANT: MAHINDRA & MAHINDRA LIMITED
an Indian Company of R&D Centre, Automotive Division, 89, M.I.D.C, Satpur, Nashik -422007,
Maharashtra, India.
INVENTORS: (a) VALLABHA RAO JAMMALAMADAKA, (b) GOEL NISHIT;
and (c)N. VISWANATHAN
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention relates to braking systems of a vehicle.
Particularly, the present invention relates to disc brakes or brake discs.
BACKGROUND OF THE INVENTION
A disc brake or a brake disc is a device adapted to slow or stop the rotation of a wheel of a vehicle while it is in motion. The disc brake is connected to a wheel and/or an axle. Generally, the disc brake includes a rotor, a brake pad and a brake caliper. The brake pad is mounted on the brake caliper. To stop the wheel, friction material in the form of the brake pad is forced mechanically, hydraulically or electromagnetically against both sides of the rotor. The friction between the brake pad and the both sides of the rotor causes the rotor and attached wheel to slow or stop. Disc brakes convert the kinetic energy of the vehicle into heat energy. However, excessive heating causes the disc brakes to be less effective.
Further, for preventing skidding and allowing the wheel to continue interacting tractively with the road surface as directed by driver steering inputs, an anti-lock braking system (ABS) is required. For proper functioning of the anti-lock braking system (ABS), the data related to the wheel speed needs to be inputted to the anti-lock braking system (ABS).

Some of the prior art braking systems are as follows:
For example, US5332065 patent having priority date of April 5, 1991 discloses an integral hub and exciter ring for a motor vehicle equipped with an anti-lock braking system. The exciter ring is integrally formed with the hub by machining grooves into the hub forming spaced teeth about the circumference of the hub. It is stated to improve the magnetic permeability of the teeth as compared to the cast iron of the hub; a steel band is insert cast into the hub resulting in a steel band having improved magnetic permeability and also being molecularly bonded to the cast iron to ensure retention of the band in the hub. However, the integral hub and exciter ring of the US5332065 patent is comparatively ineffective in heat dissipation.
US6568512 patent having priority date of May 16, 2002 discloses a rotational element for a wheel comprises a cast iron segment and an anti-lock brake system exciter ring adhering to the cast iron segment as a cast-in insert. The anti-lock brake system exciter ring is made of a material stated to have greater corrosion resistance and a higher melting point than the cast iron. The exciter ring includes at least a first tang penetrating the cast iron segment. The exciter ring is preferably made from ferritic stainless steel. For disk brake systems the rotational element serves as a disk brake rotor. In vehicles using drum brakes the rotational element serves as a wheel hub. However, the exciter ring of the US6568512 patent includes at least one tang penetrating the cast iron rotor.
US20040140166 publication having priority date of January 21, 2003 discloses a ferromagnetic brake rotor having an integral tone ring. A sensor

is positioned adjacent to the rotor for sensing magnetic property variations in the ferromagnetic brake rotor. Magnetic property variations in a ferromagnetic brake rotor disc are sensed. Rotational properties for a wheel attached to the ferromagnetic brake rotor disc are determined based on the magnetic property variations. A brake system is then modulated based on the rotational properties the wheel. However, the ferromagnetic brake rotor of the US20040140166 publication is comparatively ineffective in heat dissipation.
US7116096 patent having priority date of August 13, 2003 discloses a tone ring preferably for use in a braking system of a vehicle. The tone ring has a first pattern of excitation indicative of speed of rotation of the tone ring, and a second pattern of excitation including frequency variations that is indicative of direction of rotation of the tone ring. The tone ring is rotated past a sensor, preferably a 2-wire passive sensor. A series of events are sensed during rotation of the tone ring past the sensor. The timing of occurrence of the events is detected and, on the basis of the timing detection, the direction of rotation of the tone ring is determined. However, the tone ring of US7116096 patent discloses the arrangement of teeth wherein a first plurality of the teeth being shorter than a second plurality of the teeth.
US7219778 patent having priority date of October 29, 2004 discloses exciter rings, wheel assemblies and methods of assembling. In some aspects, a wheel assembly includes a brake rotor including a barrel section having an interior surface defining a barrel cavity, and a projection extending from the interior surface of the barrel section into the barrel cavity. The wheel assembly also includes an exciter ring formed separately from the brake

rotor and engagable with the projection within the barrel cavity to removably connect the exciter ring to the brake rotor. In other aspects, an exciter ring is formed separately from and removably connectable to a brake rotor and includes a body portion having an outer surface, the body portion including a detent protruding outwardly from the outer surface and extending around the outer surface of the body portion. The exciter ring also includes a flange extending radially outwardly from the body portion and having a plurality of apertures. However, the exciter ring of US7219778 patent includes a body portion and a ring flange extending radially outward from the body portion.
US7306293 patent having priority date of December 10, 2004 discloses a tone ring of a vehicle anti-lock braking system of the type that is integrated into a disc brake rotor. The protective layer is applied by thermally spraying a selected one of a plurality of materials, such as a nickel-based alloy, a high-chrome stainless steel, or non-ferrous materials such as aluminum, copper-based alloys or a ceramic, on teeth of the tone ring, and without causing the protective layer to be deposited on the rotor braking surfaces. It is stated that the protective layer generally prevents the formation of oxidation and corrosion byproduct layers on the teeth, to thereby maintain sensitivity for detection of teeth movement by the anti-lock braking system sensor during operation of the system. However, the tone ring of a vehicle anti-lock braking system of US7306293 patent is comparatively ineffective in heat dissipation.
US20060272906 publication having priority date of June 3, 2005 discloses a wheel assembly. The wheel assembly includes a wheel hub and brake rotor that rotates about an axis. The brake rotor includes an outer circumferential

surface area that cooperates with brake pads to provide braking for the wheel assembly. The brake rotor includes an inner circumferential surface area that has two different sets of mounting bosses. A first set of mounting bosses is spaced circumferentially about the axis and provides a mounting interface for a tone ring as used in an anti-lock brake system. A second set of mounting bosses is also spaced circumferentially about the axis but does not overlap the first set of mounting bosses. The second set of mounting bosses provides a mounting interface for securing a brake rotor and tone ring assembly to the wheel hub. However, the wheel assembly of the US20060272906 publication includes a tone ring mounted to the brake rotor wherein the first set of mounting bosses provides a first mount interface between the tone ring and the brake rotor and the second set of mounting bosses provides a second mount interface between the brake rotor and the wheel hub.
US7487862 patent having priority date of September 7, 2005 discloses an exciter ring/disc brake rotor assembly. The exciter ring/disc brake rotor assembly allows snap in fitting of the exciter ring onto the disc brake rotor. However, the exciter ring/disc brake rotor assembly of the US7487862 patent includes a plurality of tangs arranged radially with respect to one another and extending from one major surface for snap fit engagement with the plurality of engagement points on the cylindrically shaped interior surface of the cast iron rotor.
US20090218183 publication having priority date of October 2, 2006 discloses a brake assembly for use on vehicles. The brake assembly includes a rotor having connection tabs and a hub having bobbins, integrally formed

or separate, with the rotor connection tabs being positioned between the hub bobbins and clamped together with a top plate. An ABS tone ring is fastened to the hub and is circumscribed by the rotor. Alternatively, an ABS tone ring can be formed as part of the top plate. A spring clip can be used with the top plate to accommodate thermal expansion of the rotor and eliminate rotor rattling. Torque is transferred from the brake rotor to the hub in a common plane to prevent twisting in the fastener connection. However, the brake assembly of the US20090218183 publication includes a plurality of exciter formations mounted for rotation with the hub and a clamping mechanism.
US2008099288 publication having priority date of October 26, 2006 discloses a disc brake assembly. The disk brake includes a rotor with an ABS tone ring insert assembly that functions as a rotation indicator in an anti-lock braking system. The insert is positioned in the hat of a rotor disc in a spaced relationship and is mounted to the mounting flange of the rotor disc. Forming the ring insert separately from the rotor disc also allows different coating materials to be used on the tone ring that may be more heat resistant. The ring insert assembly can be made of powder metal or made as a cast iron cylinder with a toothed cap made of powder metal having a corrosion resistant coating. However, the disc brake assembly of the US2008099288 publication discloses positioning of tone ring on the outer circumference of the rotor disc.
US20090188762 publication having priority date of January 30, 2008 discloses a disc brake assembly. The disc brake assembly includes a rotor defining a rotational axis. Further, the disc brake assembly includes a barrel portion and a disc portion extending generally radially outward from the

barrel portion. The barrel portion defines an inner surface. The inner surface defines a groove, a biasing element received in the groove, and a tone ring having an outer surface and including a step formed on the outer surface. The tone ring being positioned in the barrel portion such that the step is aligned for engagement with the biasing element. However, the disc brake assembly of the US20090188762 publication includes a biasing element received in the groove.
US20100032251 publication having priority date of August 8, 2008 discloses an ABS tone ring made of a thermo-set plastic material transparent to electro-magnetic radiation. A plurality of discrete, spaced magnets or ferro-magnetic buttons is arrayed in a circle, embedded in the tone ring. The thermo-set plastic is heat tolerant and resistant to road salt and oxidation and protects the magnets or buttons from oxidation and corrosion. However, the ABS tone ring of the US20100032251 publication includes a plurality of discrete, spaced magnetically active buttons arrayed as a repeating pattern in a circle embedded in the nonmagnetic matrix.
Accordingly, there is a need for a brake disc rotor assembly that is comparatively more effective in heat dissipation. Also, there is a need for a brake disc rotor assembly that is adapted to provide faster cooling. Further, there is a need for a brake disc rotor assembly that is adapted to provide better thermal characteristics. Furthermore, there is a need for a brake disc rotor assembly that is adapted to provide information related to wheel speed to anti-lock braking system (ABS). Additionally, there is a need for a brake disc rotor assembly that is adapted to provide better dimensional accuracy.

OBJECTS OF THE INVENTION
An object of the present invention is to provide a brake disc rotor assembly that is comparatively more effective in heat dissipation.
Another object of the present invention is to provide a brake disc rotor assembly that is adapted to provide faster cooling.
Yet another object of the present invention is to provide a brake disc rotor assembly that is adapted to provide better thermal characteristics.
Still another object of the present invention is to provide a brake disc rotor assembly that is adapted to provide information related to wheel speed to anti-lock braking system (ABS).
One more object of the present invention is to provide a brake disc rotor assembly that is adapted to provide better dimensional accuracy.
An additional object of the present invention is to provide a brake disc rotor assembly that is comparatively cheaper.
Also, an object of the present invention is to provide a brake disc rotor assembly that is adapted to provide comparatively longer life.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention there is provided a brake disc rotor assembly. The brake disc rotor assembly includes a rotor and a toner ring. The rotor has a plurality angular vanes and a mounting flange. The plurality of angular vanes is disposed between a first portion and

a second portion of the rotor. The mounting flange is disposed on an inner circumference of the first portion and in plane of an outer surface of the first portion. The toner ring is disposed on an inner circumference of the second portion. The toner ring includes a plurality of teeth configured on an inner circumference thereof.
Preferably, the rotor is a one-piece structure.
Typically, the rotor and the toner ring are of different materials.
Typically, a hairline gap is provided between the rotor and the toner ring.
Preferably, a plurality of grub screws is adapted to dispose the toner ring on the inner circumference of the second portion of the rotor.
Furthermore, the toner ring is disposed on the inner circumference of the second portion of the rotor by means of interference fit and a plurality of grub screws.
Typically, a sensor is functionally coupled to the toner ring for sensing wheel speed.
In one embodiment of the present invention, the sensor is a Hall Effect chip.
Preferably, an anti-lock braking system is functionally coupled to the toner ring.

Typically, the toner ring is manufactured by powder metallurgy.
Further, the mounting flange has a plurality of apertures.
Furthermore, in another aspect of the present invention, there is provided a brake disc assembly. The brake disc assembly includes a rotor, a toner ring, a brake caliper, and a brake pad mounted on the brake caliper.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention will now be described in relation to the accompanying drawings in which,
Figure 1 illustrates a side perspective view of a brake disc rotor assembly, in accordance with one embodiment of the present invention;
Figure 2 illustrates a front view of the brake disc rotor assembly as shown in Figure 1;
Figure 3 illustrates a perspective view of a toner ring of the brake disc rotor assembly as shown in Figure 1;
Figure 4 illustrates a cut-away view of a rotor of the brake disc rotor assembly as shown in Figure 1; and
Figure 5 illustrates another cut-away view of the rotor of the brake disc rotor assembly as shown in Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Preferred embodiments will now be described in detail with reference to the accompanying drawings. The preferred embodiments do not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
The present invention provides a brake disc rotor assembly for facilitating better heat dissipation and better anti-lock braking characteristics. Due to better heat dissipation and faster cooling, the brake disc rotor assembly of the present invention has comparatively longer life. Accordingly, the brake disc rotor assembly of the present invention may be used in a front brake disc, a rear brake disc, a parking brake mechanism, and various other braking applications.
Referring to Figures 1 to 5, a brake disc rotor assembly 100 is described. The brake disc rotor assembly 100 includes a rotor 102, and a toner ring 104.
The rotor 102 has a plurality of angular vanes, such as a vane 106a, a vane 106b, and a vane 106c (hereinafter collectively referred to as "plurality of angular vanes 106") and a mounting flange 108. The plurality of angular vanes 106 is disposed between a first portion 110 and a second portion 112 of the rotor 102. The plurality of angular vanes 106 is adapted to facilitate better heat dissipation and faster cooling. More specifically, the hollow portion between two consequent vanes is adapted to facilitate better heat dissipation and faster cooling. In one embodiment of the present invention, the number of the plurality of angular vanes 106 is 31. However, the present

invention is not limited to any particular number of the plurality of angular vanes 106.
The mounting flange 108 is disposed on an inner circumference 114 (shown in Figure 4 and Figure 5) of the first portion 110 and in plane of an outer surface of the first portion 110. In one embodiment of the present invention, the mounting flange 108 has a plurality of apertures, such as an aperture 116a, 116b, 116c, 116d, 116e (shown in Figure 2) (hereinafter collectively referred to as "plurality of apertures 116"). The plurality of apertures 116 is adapted to facilitate connection of the mounting flange 108 of the brake disc rotor assembly 100 to a wheel hub (not shown) of a vehicle. In one embodiment of the present invention, the mounting flange 108 is adapted to be connected to the wheel hub (not shown) of the vehicle by means of five numbers of 10.2 Grade Bolts of M 10 X 1.5. However, the present invention is not limited to any particular number, any particular type of bolt used for connecting the mounting flange 108 to the wheel hub. Accordingly, in other embodiments of the present invention, various other fasteners, such as nuts and bolts, screws and the like may be used for connecting the mounting flange 108 to the wheel hub of the vehicle.
In one embodiment of the present invention, the rotor 102 is a one-piece structure. However, the present invention is not limited to the one-piece structure of the rotor 102. Accordingly, in other embodiments of the present invention, the rotor 102 may be an assembly of two or more components. In one embodiment of the present invention, the rotor 102 has an outer diameter of 302mm, an inner diameter of 95.27mm, a thickness of 26 mm, surface finish of braking surface Ra 1.2 to 3.6, and the rotor offset of 31.66

mm. However, the present invention is not limited to any particular dimension, any particular surface finish and any particular offset disclosed. Additionally, in one embodiment of the present invention, the rotor 102 is of grey cast iron with grade of FG 260A. However, the present invention is not limited to any particular material used for manufacturing the rotor 102. Alternatively, in other embodiments of the present invention, the rotor 102 is of various other materials known in the art.
Further, in one embodiment of the present invention, the rotor 102 and the toner ring 104 are of different materials. Alternatively, in another embodiment of the present invention, the rotor 102 and the toner ring 104 are of same material. Accordingly, the present invention is not limited to any particular material used for manufacturing the rotor 102 and the toner ring 104. Also, in one embodiment of the present invention, a hairline gap 118 (shown in Figure 2) is provided between the rotor 102 and the toner ring 104. The hairline gap 118 is adapted to provide space for thermal expansion of the rotor 102 or the toner ring 104, in case the rotor 102 or the toner ring 104 is overheated.
A plurality of grub screws, such a grub screw 120a, 120b, 120c (shown in Figure 2) (hereinafter collectively referred to as "plurality of grub screws 120") is adapted to dispose the toner ring 104 on an inner circumference 122 (shown in Figure 4 and Figure 5) of the second portion 112 of the rotor 102. In another embodiment of the present invention, the toner ring 104 is disposed on the inner circumference 122 of the second portion 112 of the rotor 102 by means of interference fit and the plurality of grub screws 120. The toner ring 104 disposed on the inner circumference 122 of the second

portion 112 of the rotor 102 by means of interference fit and the plurality of grub screws 120 is adapted to provide better coupling between the toner ring 104 and the inner circumference 122 of the second portion 112 of the rotor 102 during high temperature applications. However, the present invention is not limited to any particular securing apparatus or securing method used for disposing the toner ring 104 on the inner circumference 122 of the second portion 112 of the rotor 102. Accordingly, in other embodiments of the present invention, other fasteners known in the art may be used for disposing the toner ring 104 on the inner circumference 122 of the second portion 112 of the rotor 102.
The toner ring 104 includes a plurality of teeth, such as a teeth 124a, a teeth 124b, a teeth 124c and the like, (shown in Figure 3) (hereinafter collectively referred to as "plurality of teeth 124") configured on the inner circumference 122 thereof. The toner ring 104 is adapted to facilitate measurement of wheel speed. The toner ring 104 is adapted to cut the magnetic flux with its tooth and valley arrangement.
A sensor (not shown) may be functionally coupled to the toner ring 104 for sensing wheel speed. In one embodiment of the present invention, the sensor is a Hall Effect chip. More specifically, in another embodiment of the present invention, the sensor is a face wheel speed sensor with Hall Effect chip. However, the present invention is not limited to any particular type of sensor used. Accordingly, in other embodiments of the present invention, the sensor may be any of the sensors capable of sensing wheel speed that are known in the art. The sensor is adapted to generate magnetic flux when the sensor is rotating. The sensor is located on the knuckle centrally aligned

with the help of bolting. Accordingly, the sensor facilitates the toner ring 104 to cut the magnetic flux with its tooth and valley arrangement for measurement of the wheel speed.
Further, in one embodiment of the present invention, the brake disc rotor assembly 100 includes an anti-lock braking system (not shown) functionally coupled to the toner ring 104. The anti-lock braking system is adapted to prevent skid and allows the wheels of the vehicle to continue interacting tractively with the road surface as directed by driver steering inputs.
In one embodiment of the present invention, the toner ring 104 may be manufactured by powder metallurgy. The toner ring manufactured by powder metallurgy is adapted to provide better dimensional accuracy and cost. However, the present invention is not limited to any particular manufacturing method used for manufacturing the toner ring 104. Further, in one embodiment of the present invention, the toner ring 104 has an outer diameter of 156.4mm; an inner diameter of 141.4mm; a thickness of 12mm and number of teeth 60. However, the present invention is not limited to any particular dimension of the outer diameter, the inner diameter, the thickness, and any particular number of teeth of the toner ring 104.
Additionally, in one embodiment of the present invention, the toner ring 104 is manufactured by sintering process. However, the present invention is not limited to any particular manufacturing process used for manufacturing the toner ring 104. Accordingly, in other embodiments of the present invention,

the toner ring 104 may be manufactured by various other manufacturing methods and processes used in the art.
In another aspect of the present invention, a brake disc assembly (not shown) including the rotor 102 and the toner ring 104 of the present invention is disclosed. Additionally, the brake disc assembly includes a brake caliper (not shown), and a brake pad (not shown) mounted on the brake caliper.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The brake disc rotor assembly of the present invention is comparatively more effective in heat dissipation. Further, the brake disc rotor assembly is adapted to provide comparatively faster cooling. Moreover, the brake disc rotor assembly is adapted to provide better thermal characteristics. Also, the brake disc rotor assembly is adapted to provide information related to wheel speed to anti-lock braking system (ABS). Additionally, the brake disc rotor assembly that is adapted to provide better dimensional accuracy. In addition, the brake disc rotor assembly is comparatively cheaper. Also, the brake disc rotor assembly has comparatively longer life.
The numeral values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.

While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim:
1. A brake disc rotor assembly comprising:
• a rotor having,
o a plurality of angular vanes disposed between a first portion and a second portion of said rotor; and
o a mounting flange disposed on an inner circumference of said first portion and in plane of an outer surface of said first portion; and
• a toner ring disposed on an inner circumference of said
second portion, said toner ring comprising a plurality of
teeth configured on an inner circumference thereof.
2. The brake disc rotor assembly as claimed in claim 1, wherein said rotor is a one-piece structure.
3. The brake disc rotor assembly as claimed in claim 1, wherein said rotor and said toner ring are of different materials.
4. The brake disc rotor assembly as claimed in claim 1, wherein a hairline gap is provided between said rotor and said toner ring.
5. The brake disc rotor assembly as claimed in claim 1, further comprising a plurality of grub screws adapted to dispose said toner ring on said inner circumference of said second portion of said rotor.

6. The brake disc rotor assembly as claimed in claim 1, wherein said toner ring is disposed on said inner circumference of said second portion of said rotor by means of interference fit and a plurality of grub screws.
7. The brake disc rotor assembly as claimed in claim 1, wherein a sensor is functionally coupled to said toner ring for sensing wheel speed.
8. The brake disc rotor assembly as claimed in claim 7, wherein said sensor is a Hall Effect chip.
9. The brake disc rotor assembly as claimed in claim 15 which includes an anti-lock braking system functionally coupled to said toner ring.
10.The brake disc rotor assembly as claimed in claim 1, wherein said toner ring is manufactured by powder metallurgy.
11.The brake disc rotor assembly as claimed in claim 1, wherein said mounting flange has a plurality of apertures.
12. A brake disc assembly comprising said rotor and said toner ring as claimed in claim 1, further comprising:
• a brake caliper; and
• a brake pad mounted on said brake caliper.