Description:FIELD OF THE INVENTION
[001] The present invention generally relates to a brake assembly. More particularly, the present invention relates to a hydraulic brake assembly.

BACKGROUND OF THE INVENTION
[002] Conventionally, in a vehicle, existing hydraulic brake master cylinder assemblies consists of control lever that actuates a piston. The control lever actuates the piston either directly or through a plunger type link mechanism, wherein the plunger type link is connected between the lever and piston. Generally, the plunger type link element has spherical joints on both ends of the link element, wherein one end contacts the lever while the other end contacts the piston.
[003] However, the plunger type link, over a time period, is susceptible to elastic deformation. Thus, usage of such a plunger type link eventually leads to poor braking feel due to excess lever travel due to elastic deformation of plunger link. The poor braking feel appears specifically due to compromise in angular alignment of the piston with the lever during actuation. Further, there is a certain lack of rigidity in the braking system due to the elastic deformation of the plunger type link. This leads to lack of braking bite, and also leads to delay in braking response due to insufficient rigidity of system links. There always remain difficulties in brake system design due to constrains in matching brake effectiveness while managing wheel lock control. This is because of challenges in optimization of overall lever ratio for adequate brake performance/effectiveness while ensuring that this does not lead to any premature wheel lock control.
[004] Such conventional configurations lead to less brake performance at partial braking condition and non-linear behaviour of braking response (deceleration) from a given brake control input (effort). This leads to a long lead time for brake system design and tuning. This also leads to abrupt control in cases of panic braking which leads to safety concerns and poor morale in braking.
[005] A general issue with conventional brake assembly is the high wear and tear in moving parts, due to high number of parts and frictional contact between multiple parts. Further, due to high part count, there is a difficulty in controlling stack up tolerances of all child parts. This causes very wide variations in ineffective stroke of brake system. It becomes a further challenge to control ineffective stroke of the control lever of the in large volume mass production process. This leads to excess free play or wheel drag issue in mass production samples.
[006] Thus, there is a need in the art for a brake assembly which addresses at least the aforementioned problems.

SUMMARY OF THE INVENTION
[007] In one aspect, the present invention relates to a brake assembly. The brake assembly has a master cylinder. The master cylinder includes one or more pistons. The one or more pistons are operatively connected to a brake lever. Herein, the brake lever is configured to have a first portion and the first portion is configured to have a predetermined profile.
[008] In an embodiment of the invention, the piston has a first end and a second end. The first end is configured to have an oblong profile.
[009] In a further embodiment of the invention, the piston is configured to move translationally for displacing a brake fluid. Further, the brake lever is configured to move pivotally for actuating the piston. Further, the first portion is configured to be in contact with the first end of the piston. The predetermined profile of the first portion is defined as a spline controlled by loci of tangents of an imaginary circle. In that, the imaginary circle has a centre at a pivot centre of the brake lever and has a central axis of the piston as a tangent.
[010] In a further embodiment of the invention, the predetermined profile of the first portion has an involute profile. The involute profile of the first portion is defined as involute of the imaginary circle.
[011] In a further embodiment of the invention, the predetermined profile of the first portion is defined by variable lengths of the tangents corresponding to an angle of actuation of the brake lever.
[012] In a further embodiment of the invention, the variable lengths of the tangents of the predetermined profile are equal to a length of the arc travel of a tangent point of the tangents moving in a direction angularly opposite to the direction of actuation of the brake lever.
[013] In a further embodiment of the invention, the oblong cylinder profile of the first end of the piston has a predetermined inclination angle, thereby allowing a single line contact of the piston with the first portion.
[014] In a further embodiment of the invention, the single line of contact of the piston with the first portion overlaps with the central axis of the piston.
[015] In a further embodiment of the invention, the first end of the piston is at a predetermined distance from the pivot centre of the brake lever, thereby allowing a single line of contact of the piston with the first portion.
[016] In a further embodiment of the invention, the brake lever has a variable curvature profile along a profile length of the brake lever.

BRIEF DESCRIPTION OF THE DRAWINGS
[017] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a sectional view of a brake assembly, in accordance with an embodiment of the invention.
Figure 2A illustrates a perspective view of a brake lever of the brake assembly, in accordance with an embodiment of the invention.
Figure 2B illustrates a top view of the brake lever of the brake assembly, in accordance with an embodiment of the invention.
Figure 3 illustrates another top view of the brake lever, in accordance with an alternative embodiment of the invention.
Figure 4 illustrates another sectional view of the brake assembly, in accordance with an embodiment of the present invention.
Figure 5 illustrates a sectional view of the brake assembly, in accordance with an alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION
[018] The present invention relates to a brake assembly. In particular, the present invention relates to a hydraulic brake assembly. The brake assembly of the present invention is typically used in a vehicle such as a two wheeled vehicle. However, it should be understood that the brake assembly as illustrated may find its application in a three wheeled vehicle, or a four wheeled vehicle, or other multi-wheeled vehicles, or any non-automotive application using a hydraulic brake as required.
[019] Figure 1 illustrates a sectional view of a brake assembly 100 in accordance with an embodiment of the invention. As illustrated in Figure 1, the brake assembly 100 comprises a master cylinder 102. The master cylinder 102 houses all the components of the brake assembly 100 and is provided at a position which is accessible to the user for usage of the brake assembly 100 for a braking operation. For example, in a two wheeled vehicle, the master cylinder 102 is provided on a handlebar of the two wheeled vehicle.
[020] As further illustrated in Figure 1, the master cylinder 102 includes one or more pistons 110, wherein the piston 110 moves in a brake operating condition. Thus, whenever the brake is to be operated, the piston 110 moves thereby allowing a brake fluid present inside the different parts of the master cylinder 102 to move, for application of the brake. Herein, the one or more pistons 110 are operatively connected to a brake lever 120. In that, the piston 110 is configured to move in response to the movement of the brake lever 120 for displacing brake fluid. Thus, whenever the user desires to apply brakes, the user moves the brake lever 120, in response to which the piston 110 moves, thereby displacing brake fluid for a braking operation. In an embodiment, the brake lever 120 having a variable curvature profile along a profile length of the brake lever 120.
[021] As further illustrated in Figure 1, the brake lever 120 is configured to have a first portion 130. In the embodiment illustrated in Figure 1, first portion 130 of the brake lever 120 is configured to be in contact with the piston 110. Further, the first portion 130 is configured to have a predetermined profile. As mentioned hereinbefore, the first portion 130 is the portion of the brake lever 120 which is directly in contact with the piston 110 for actuation. In this embodiment, the part of the piston 110 that is in contact with the first portion 130 actuator has a surface that is perpendicular to the axis of the piston 110.
[022] In an embodiment, as illustrated in Figure 1, the piston 110 has a first end 110A and a second end, wherein the first end 110A being configured to have an oblong profile.
[023] In another embodiment, as illustrated in Figure 1, Figure 2A and Figure 2B, the piston 110 is configured to move translationally for displacing a brake fluid. For the movement of the brake lever 120, the brake lever 120 is configured to move pivotally for actuating the piston 110. Herein, the first portion 130 that protrudes from the brake lever 120 is configured to be in contact with the first end 110A of the piston 110. Herein, as illustrated in Figure 3, the predetermined profile of the first portion 130 is defined as a spline controlled by loci of tangents (T1, Tn) of an imaginary circle (X). Herein, the imaginary circle (X) has a centre at a pivot centre 122 of the brake lever 120. Further, the imaginary circle (X) has a central axis (A-A’) of the piston 110 as a tangent.
[024] Herein, the predetermined profile of the first portion 130 ensures that the first portion 130 is always having a line-contact with piston 110. This line-contact is obtained by means of the profile of the first portion, which extends in a direction across or perpendicular (illustrated by YY’ in Figure 1 and Figure 5) to the axis of the piston 110 and along or parallel to the pivot-axis of the brake lever 120. This predetermined profile of the first portion 130 provides a constant lift-ratio, meaning that ratio of lift of the piston 110 to actuation angle of the brake lever 120 remains constant. Also, the predetermined profile of the first portion 130 ensures a fixed line of actuation force exerted by the first portion 130 upon the piston 110, with respect to the piston-axis (A-A’). In that, the predetermined profile of the first portion 130 is in the form of a continuously variable curvature spline along its profile length and is obtained by connecting loci of ends of a continuously varying tangent-line (T1, Tn) of the imaginary circle (X) about pivot centre 122 of the brake lever 120.
[025] In an embodiment, the predetermined profile of the first portion 130 is defined by variable lengths (L1, Ln) of the tangents (T1, Tn) corresponding to an angle of actuation of the brake lever 120. The variable lengths (L1, Ln) of the tangents (T1, Tn) of the predetermined profile are equal to a length of the arc travel of a tangent point of the tangents (T1, Tn) moving in a direction angularly opposite to the direction of actuation of the brake lever 120. In other words, the length of above continuously varying tangent line (T1, Tn) is always directly and linearly proportional to the angular travel or arc travel of a tangent point of the tangent line (T1, Tn) moving in a direction angularly opposite to the direction of actuation of the brake lever 120. Specifically, the length of above tangent line (T1, Tn) is always equal to the arc-travel of the tangent point of the tangent line (T1, Tn) while moving in a direction angularly opposite to the direction of actuation of that brake lever 120.
[026] In an embodiment, the predetermined profile of the first portion 130 comprises an involute profile, wherein the involute profile of the first portion 130 is defined as involute of the imaginary circle (X). Herein, the involute profile of the imaginary circle (X) is always tangent to a surface of the first end 110A of the piston 110 that is in contact with the first portion 130 of the brake lever 120. The imaginary circle (X) which forms this involute profile, is always tangent to the piston axis (A-A’). The piston 110 is actuated with a linear travel ratio by the involute profile of the first portion 130 while actuating the brake lever 120. The actuation force exerted by the first portion 130 upon the piston 110, is always parallel to the piston axis (A-A’). In an embodiment, the line of the actuation force is always colinear with the piston-axis (A-A’).
[027] In the embodiment illustrated in Figure 1 and Figure 4, the oblong cylinder profile of the first end 110A of the piston 110 has a predetermined inclination angle, thereby allowing a single line contact of the piston 110 with the first portion 130. In an embodiment, the predetermined inclination angle of the first end 110A is equal to an angle of a friction-cone formed by actuation force (illustrated by F2 in Figure 4) exerted by the first portion 130 on the first end 110A of the piston 110, and its corresponding friction (illustrated by F1 in Figure 4) generated between the first portion 130 and the first end 110A of the piston 110.
[028] Further, the single line of contact of the piston (110) with the first portion 130 overlaps with the central axis (A-A’) of the piston (110). In the brake assembly 100 of the present invention, in an embodiment, the first end 110A of the piston has the oblong profile while the first portion 130 has a conventional profile. In an alternative embodiment, the first end 110A of the piston has the oblong profile while the first portion 130 has the predetermined profile as explained hereinbefore. In an alternative embodiment as illustrated in Figure 5, the first end 110A of the piston has a conventional profile while the first portion 130 has the predetermined profile as explained hereinbefore.
[029] In the above embodiments, as illustrated in Figure 4, the direction of the actuation force (illustrated by F2 in Figure 4) being exerted by the first portion 130 on to the first end 110A of the piston 110 is perpendicular to the surface of the first end 110A of the piston 110 and the frictional force (illustrated by F1 in Figure 4) between the first portion 130 and the first end 110A of the piston is along the surface of the first end 110A of the piston. Accordingly, the resultant force (illustrated by F3 in Figure 4) exerted on the first end 110A of the piston 110 is along or collinear or overlapping with the central axis (A-A’) of the piston 110, thus ensuring linear travel of the piston 110. This ensures that any lateral load on the piston 110 during actuation of the brake lever 120 is nullified, thus reducing any tilting tendency or the load or stress on the piston 110. The resultant force being collinear with the central axis (A-A’) of the piston 110 also ensures that any friction between the piston 110 and a bore of the master cylinder 102 inside which the piston 110 is housed, is minimised.
[030] In an embodiment, the first end 110A of the piston 110 is at a predetermined distance from the pivot centre 122 of the brake lever 120, thereby allowing a single line of contact of the piston 110 with the first portion 130. In that, the contact point of the involute profile of the first portion 130 with the first end 110A of the piston 110 is in the vicinity of the start of the involute profile from the imaginary circle (X) before the brake lever 120 is actuated, i.e. starting of actuation of the brake lever 120 or resting position. This helps in maintaining less spline travel over the contact point of the involute profile of the first portion 130 with the first end 110A of the piston 110. As a result of this, the sliding force between the first portion 130 and first end 110A of the piston 110 is also kept minimum during start of actuation of brake lever.
[031] Advantageously, the present invention provides a brake assembly in which the predetermined profile of the first portion ensures fixed contact line between the first portion and the first end of the piston during entire range of actuation of the brake lever. This also ensures the line of action of resultant force of the first portion upon the first end of the piston is always collinear with the central axis of the piston. As a result, it is ensured that there is no lateral or eccentric loading on the piston.
[032] Further, owing to the predetermined profile of the first portion, it is also ensured that ratio of lift of the piston to actuation angle of the brake lever remains constant. This provides improved efficiency of transmission in the brake assembly and linear control in braking response. This ensures that the brake performance in terms of braking torque and deceleration are improved, thus reducing delay in braking response time and improving braking response.
[033] Furthermore, the present invention provides a smooth braking feel, that improves rider morale in the braking, thus enhancing safety especially in cases of panic braking. In addition, the present invention eliminates the requirement of a plunger type link for connecting the brake lever to the piston, which reduces part count and wear and tear, as a result of which overall performance and durability of the vehicle is improved. Due to lower part count, the ease of manufacturing and serviceability is also increased.
[034] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals
100: Brake Assembly
102: Master Cylinder
110: Piston
110A: First End of the Piston
120: Brake Lever
122: Pivot Centre of the Brake Lever
130: First Portion of the Brake Lever
X: Imaginary Circle
A-A’: Central Axis of the Piston
T1, Tn: Tangents
L1, Ln: Variable Lengths of Tangents T1, Tn
, Claims:1. A brake assembly (100), comprising:
a master cylinder (102), said master cylinder (102) including one or more pistons (110), said one or more pistons (110) being operatively connected to a brake lever (120), wherein said brake lever (120) being configured to have a first portion (130), said first portion (130) being configured to have a predetermined profile.

2. The brake assembly (100) as claimed in claim 1, wherein said piston (110) having a first end (110A) and a second end, said first end (110A) being configured to have an oblong profile.

3. The brake assembly as claimed in claim 1, wherein the piston (110) being configured to move translationally for displacing a brake fluid; the brake lever (120) being configured to move pivotally for actuating the piston (110), and said first portion (130) being configured to be in contact with the first end (110A) of the piston (110), , and the predetermined profile of the first portion (130) being defined as a spline controlled by loci of tangents (T1, Tn) of an imaginary circle (X), wherein the imaginary circle (X) having a centre at a pivot centre (122) of the brake lever (120) and having a central axis (A-A’) of the piston (110) as a tangent.

4. The brake assembly (100) as claimed in claim 3, wherein the predetermined profile of the first portion (130) comprises an involute profile, the involute profile of the first portion (130) being defined as involute of the imaginary circle (X).

5. The brake assembly (100) as claimed in claim 3, wherein the predetermined profile of the first portion (130) being defined by variable lengths (L1, Ln) of the tangents (T1, Tn) corresponding to an angle of actuation of the brake lever (120).

6. The brake assembly (100) as claimed in claim 5, the variable lengths (L1, Ln) of the tangents (T1, Tn) of the predetermined profile are equal to a length of the arc travel of a tangent point of the tangents (T1, Tn) moving in a direction angularly opposite to the direction of actuation of the brake lever 120.

7. The brake assembly (100) as claimed in claim 2, wherein the oblong cylinder profile of the first end (110A) of the piston (110) has a predetermined inclination angle, thereby allowing a single line contact of the piston (110) with the first portion (130).

8. The brake assembly (100) as claimed in claim 7, wherein the single line of contact of the piston (110) with the first portion (130) overlaps with the central axis (A-A’) of the piston (110).

9. The brake assembly (100) as claimed in claim 3, wherein the first end (110A) of the piston (110) being at a predetermined distance from the pivot centre (122) of the brake lever (120), thereby allowing a single line of contact of the piston (110) with the first portion (130).

10. The brake assembly (100) as claimed in claim 1, wherein the brake lever (120) having a variable curvature profile along a profile length of the brake lever (120).