DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
AN ELECTROMAGNETIC BRAKING APPARATUS

Applicant:
Tata Motors Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India

The following specification describes the invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present application claims priority from Indian Patent application no. (201821012245) filed on 31st March, 2018.

TECHNICAL FIELD
[002] The present disclosure in general relates an electromagnetic braking apparatus. More particularly, the present disclosure relates to the electromagnetic braking apparatus with a gradual engagement feature along with a manual release system.
BACKGROUND
[003] It is to be noted that, a vehicle may be rolling, thus in order to prevent vehicle rolling back, conventionally, a vehicle has engine resistance to prevent against roll back. However, in case of electric vehicles that uses an electric motor that does not have any engine resistance offered to wheels as in conventional vehicles that prevent vehicle roll back on a gradient. In addition, a load on hydraulic brakes is higher due to absence of an engine inertia. Hence, there is a need for an automatic braking system such as an Electromagnetic brake (EM brake) system. The existing Electromagnetic brake (EM) available may comprise gradual disengaging function of brakes, but lacks to exhibit functions like smooth braking function during sudden emergency braking, and gradual or smooth engaging of brakes.
SUMMARY
[004] It is to be understood, that this application is not limited to the particular systems, and methodologies described, as there can be multiple possible embodiments, which are not expressly illustrated, in the present disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce concepts related to an electromagnetic braking apparatus. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[005] In one implementation, an electromagnetic braking apparatus is illustrated. The electromagnetic braking apparatus comprises an end plate, a pressure plate, a friction liner, a primary electromagnetic coil, and a secondary electromagnetic coil. In one embodiment, the end plate is coupled to a housing. Further, the pressure plate is mounted within the housing and a plurality of permanent magnets are mounted along a circumference of the pressure plate. Furthermore, the friction liner is sandwiched between the end plate and the pressure plate. In addition, the primary magnetic coil is within the housing, and opposite to the friction liner. In one aspect, the secondary electromagnetic coil is mounted on a surface of the end plate, in another aspect, the secondary electromagnetic coil is located opposite to the primary electromagnetic coil, and the plurality of permanent magnets are located between the primary electromagnetic coil and the secondary electromagnetic coil.
BRIEF DESCRIPTION OF DRAWINGS
[006] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.
[007] Figure 1 illustrates a cross sectional view of an electromagnetic braking apparatus, in accordance with an embodiment of the present subject matter.
[008] Figure 2 illustrates an exploded view of the electromagnetic braking apparatus from one side, in accordance with an embodiment of the present subject matter.
[009] Figure 3 illustrates an exploded view of the electromagnetic braking apparatus from other side, in accordance with an embodiment of the present subject matter.

DETAILED DESCRIPTION
[0010] Some embodiments of the present disclosure, illustrating all its features, will now be discussed in detail. The words “comprising”, “including”, and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, an electromagnetic braking apparatus is now described. The disclosed embodiment of the electromagnetic braking apparatus is merely exemplary of the disclosure, which may be embodied in various forms.
[0011] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure an armrest with dual side opening is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0012] As described above, there are some limitations in the conventional electromagnetic braking apparatus. In conventional approach, the existing electromagnetic braking (EM) apparatus available may comprise gradual disengaging function of brakes, but lacks to exhibit functions like sudden emergency braking, and gradual engaging of brakes. Further, the existing electromagnetic magnetic braking comprises only a primary magnetic coil for the operation of brakes. Furthermore, during manual release of brakes in case of an emergency like battery failure, low voltage unit failure, battery drain up and the like, the existing electromagnetic braking apparatus comprises a release mechanism for brakes having complex design and more number of components in use. Thus there is a need overcome the limitation of the conventional electromagnetic braking apparatus.
[0013] In one implementation, an electromagnetic braking apparatus is illustrated. The electromagnetic braking apparatus comprises an end plate, a pressure plate, a friction liner, a primary electromagnetic coil, and a secondary electromagnetic coil. In one embodiment, the end plate is coupled to a housing. Further, the pressure plate is mounted within the housing and a plurality of permanent magnets are mounted along a circumference of the pressure plate. Furthermore, the friction liner is sandwiched between the end plate and the pressure plate. In addition, the primary magnetic coil is within the housing, and opposite to the friction liner. In one aspect, the secondary electromagnetic coil is mounted on a surface of the end plate, in another aspect, the secondary electromagnetic coil is located opposite to the primary electromagnetic coil, and the plurality of permanent magnets are located between the primary electromagnetic coil and the secondary electromagnetic coil.
[0014] In one embodiment there may include an advantage, the electromagnetic braking apparatus has less number of components used for manual release of the brake.
[0015] In another embodiment there may include an advantage, the electromagnetic braking apparatus has controlled gradual braking.
[0016] Now, referring to Figures 1-3, various elements of an electromagnetic braking apparatus 100 in accordance with an embodiment of the present subject matter is illustrated. In one embodiment, the electromagnetic braking apparatus 100 comprises an end plate 15, a pressure plate 5, a friction liner 7, a primary electromagnetic coil 6, and a secondary electromagnetic coil 23. In one implementation, the end plate 15 is coupled to a housing 1. The end plate 15 may act as a cover plate to the electromagnetic braking apparatus 100. The end plate 15 may be bolted to the housing 1. Further, the pressure plate 5 is mounted within the housing 1, and a plurality of permanent magnets 24 are mounted along a circumference of the pressure plate 5. The pressure plate 5 may be a circular annulus plate for applying a pressure on the friction liner 7, and is integrated with a wedge shaped male cam profile 14. The male cam profile 14 are tapering wedges that are placed circumferentially on the pressure plate 5.
[0017] In one aspect, on one side of the housing 1, a plurality of guides 22 may be provided for the pressure plate 5. In one aspect, the pressure plate 5 may have a circular hole provided centrally for a coupler shaft 4 to pass through. A bearing 3 may be used to support the coupler shaft 4 on either side of the electromagnetic braking apparatus 100. In another implementation, the friction liner 7 is sandwiched between the end plate 15 and the pressure plate 5. In one aspect, the friction liner 7 is a plate with an internal splined hub 18 and a frictional material attached to the friction liner on either side. The internal splined hub 18 may slide on an external spline 21 of the coupler shaft 4.
[0018] In yet another implementation, the primary magnetic coil 6 is within the housing 1, and opposite to the friction liner 7. The housing 1 may have a slot inside to place the primary electromagnetic coil 6 within the housing 1.
[0019] In one more implementation, the secondary electromagnetic coil 23 is mounted on a surface of the end plate 15, the secondary electromagnetic coil 23 is located opposite to the primary electromagnetic coil 6, and further, the plurality of permanent magnets 24 are located between the primary electromagnetic coil 6 and the secondary electromagnetic coil 23.
[0020] In another embodiment, during braking operation, a primary magnetic force is generated between the end plate 15 and the pressure plate 5, in turn sandwiching the friction liner 7 between the pressure plate 5 and the end plate 15, when the secondary electromagnetic coil 23 is de-energized. In one aspect, the end plate 15 is attracted towards the pressure plate 5 due to the primary magnetic force generated by the plurality of permanent magnets 24 and the secondary electromagnetic coil 23. Hence, due to the tightly held friction liner 7 between the pressure plate 5 and the end plate 15, the coupler shaft 4 connected to the frictional liner 7 through the internal splined hub 18 is held up thus providing the braking action for a vehicle. In one example, a spring 2 is used to force the pressure plate 5 in order to tightly hold the friction liner 7 between the pressure plate 5 and the end plate 15. Further, a step 12 may be used to accommodate the spring 2. In one aspect, a bigger spline 21 mates with an internal splined hub 18 of the friction liner 7 in order to transfer a braking torque from the friction liner 7 to a transaxle.
[0021] In one another embodiment, during operation of releasing a brake, a repulsive force is generated between the end plate 15 and the pressure plate 5, in turn pushing back the pressure plate 5 and the end plate 15 away from each other, thus releasing the friction liner 7, when the secondary electromagnetic coil 23 is energized. Hence, releasing the friction liner 7 allows a transfer of a torque from a traction motor to the transaxle. The coupler shaft 4 may be used for transferring the torque from the traction motor to the transaxle. The coupler shaft 4 may comprise two external splines (a smaller spline 19 and the bigger spline 21) and one internal spline. The smaller spline 19 mates with internal splines of the traction motor in order to transfer the motion from the traction motor to the transaxle. In one aspect, the internal spline (not shown) of the coupler shaft 4 mates with a transaxle input shaft in order to transfer a traction torque of the traction motor to the transaxle.
[0022] In one implementation, during operation of releasing the brake, a secondary magnetic force is generated between the housing 1 and the pressure plate 5, in turn attracting the pressure plate 5 and the housing 1, when the primary electromagnetic coil 6 is energized. In one example, the secondary magnetic force is generated by the plurality of permanent magnets 24 and the primary electromagnetic coil 6.
[0023] In yet another embodiment, during an emergency braking operation, a movement of the pressure plate 5 is controlled based on controlling a third magnetic force generated between the pressure plate 5 and the end plate 15, when the primary electromagnetic coil 6 is de-energized and the secondary electromagnetic coil 23 is modulated. The secondary electromagnetic coil 23 is modulated may be applying a power supply to the secondary electromagnetic coil in order to create a north pole and a south pole alternatively. The emergency braking operation may be operated by an emergency braking switch (not shown) driver based on the vehicle speed and a logic built in an engine control unit of the vehicle.
[0024] In another implementation, during operation of releasing the brake manually in case of a battery failure, battery drain and the like, a female cam plate 8 is rotated, in turn pushing the pressure plate 5 away from the friction liner 7, when a pulling force is applied on a release lever 11. In one aspect, the release lever 11 may be locked using a suitable mounting mechanism (not shown) to keep the brake disengaged so that the vehicle may be towed away. The release lever 11 may be provided throughout an outer circumference of the female cam plate 8 for actuating the manual release of the brake. A slot may be provided throughout an outer circumference of the female cam plate in order to accommodate the release cable 11.
[0025] In another aspect, due to the rotation of the female cam plate 8, a plurality of recoil springs 9 in the female cam plate recess 16 that were compressed against the retainers 17 on the end plate 15, expands and goes back to a normal position, when the release cable 11 is freed. The retainers 17 may be on other side of the end plate 15 (as shown in figure 3). In one more aspect, the female cam plate 8 may self-lock while manual release operation due to the pressure exerted by the pressure plate 5 via the male cam profile 14. In another aspect, the female cam plate 8 is a plate with a wedge shaped female cam profile 13 on one side matching with a cam profile of the pressure plate 5.
[0026] In one example, in order to reduce friction, an annulus ball bearing 25 placed in between the contact surfaces of the female cam plate 8 and the end plate 15. The annulus ball bearing 25 may be placed inside a plurality of annulus grooves of the female cam plate 8 and the end plate 15, ensuring trouble free movement of the manual release operation of the brake.
[0027] Exemplary embodiments discussed above may provide certain advantages, these advantages may include the following.
[0028] Some embodiments of the electromagnetic braking apparatus 100 provides lesser number of parts for manual release operation of the brake.
[0029] Some embodiments of the electromagnetic braking apparatus 100 provides safety to customers.
[0030] Some embodiments of the electromagnetic braking apparatus 100 provides higher flexibility in manual operation of releasing the brake by means of the release lever 11.
[0031] Some embodiments of the electromagnetic braking apparatus 100 provides controlled gradual braking.
[0032] Some embodiments of the electromagnetic braking apparatus 100 provides controlled gradual disengagement of the brake.

[0033] Although implementations for the electromagnetic braking apparatus 100 have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations for the electromagnetic braking apparatus 100.
,CLAIMS:
1. An electromagnetic braking apparatus (100), the electromagnetic braking apparatus (100) comprises
an end plate (15), wherein the end plate (15) is coupled to a housing (1);
a pressure plate (5), wherein the pressure plate (5) is mounted within the housing (1), wherein a plurality of permanent magnets (24) are mounted along a circumference of the pressure plate (5);
a friction liner (7), wherein the friction liner (7) is sandwiched between the end plate (15) and the pressure plate (5);
a primary electromagnetic coil (6), wherein the primary magnetic coil (6) is within the housing (1), and opposite to the friction liner (7); and
a secondary electromagnetic coil (23), wherein the secondary electromagnetic coil (23) is mounted on a surface of the end plate (15), wherein the secondary electromagnetic coil (23) is located opposite to the primary electromagnetic coil (6), and wherein the plurality of permanent magnets (24) are located between the primary electromagnetic coil (6) and the secondary electromagnetic coil (23).

2. The electromagnetic braking apparatus (100) as claimed in claim 1, wherein during braking operation, a primary magnetic force is generated between the end plate (15) and the pressure plate (5), in turn sandwiching the friction liner (7) between the pressure plate (5) and the end plate (15), when the secondary electromagnetic coil (23) is de-energized.

3. The electromagnetic braking apparatus (100) as claimed in claim 2, wherein the end plate (15) is attracted towards the pressure plate (5) due to the primary magnetic force generated by the plurality of permanent magnets (24) and the secondary electromagnetic coil (23).

4. The electromagnetic braking apparatus (100) as claimed in claim 1, wherein during operation of releasing a brake, a repulsive force is generated between the end plate (15) and the pressure plate (5), in turn pushing back the pressure plate (5) and the end plate (15) away from each other, releasing the friction liner (7), when the secondary electromagnetic coil (23) is energized.

5. The electromagnetic braking apparatus (100) as claimed in claim 1, wherein during operation of releasing the brake, a secondary magnetic force is generated between the housing (1) and the pressure plate (5), in turn attracting the pressure plate (5) and the housing (1), when the primary electromagnetic coil (6) is energized.

6. The electromagnetic braking apparatus (100) as claimed in claim 5, wherein the secondary magnetic force is generated by the plurality of permanent magnets (24) and the primary electromagnetic coil (6).

7. The electromagnetic braking apparatus (100) as claimed in claim 1, during an emergency braking operation, a movement of the pressure plate (5) is controlled based on controlling a third magnetic force generated between the pressure plate (5) and the end plate (15), when the primary electromagnetic coil (6) is de-energized and the secondary electromagnetic coil (23) is modulated.

8. The electromagnetic braking apparatus (100) as claimed in claim 1, wherein during operation of releasing the brake manually, a female cam plate (8) is rotated, in turn pushing the pressure plate (5) away from the friction liner (7), when a pulling force is applied on a release lever (11).