A brake assembly

Abstract

The present invention relates to a brake assembly (100). The brake assembly 100 has a master cylinder (102). The master cylinder (102) includes one or more pistons (110). The one or more pistons (110) are operatively connected to a brake lever (120). Herein, the brake lever (120) is configured to have a first portion (130) and the first portion (130) is configured to have a predetermined profile. In an embodiment, the piston (110) has a first end (110A) and a second end, wherein the first end (110A) is configured to have an oblong profile. Further, the brake assembly (100a) comprises a housing (130a). The housing (130a) is configured to receive a piston (110a) and the piston (110a) moves in a brake operating condition. Herein, the piston (110a) is connected to an elastic member assembly (150), and the elastic member assembly (150) includes a plurality of elastic members (160).

Description

TITLE OF INVENTIONA BRAKE ASSEMBLYFIELD OF THE INVENTION

[0001] The present invention generally relates to a brake assembly. More particularly, the present invention relates to a hydraulic brake assembly.BACKGROUND OF THE INVENTION

[0002] 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.

[0003] 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 deformationof 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.

[0004] Further, in a vehicle, existing hydraulic brake assembly is normally fitted with a single open-coiled compression spring for providing return force for the movement of a brake lever. As a result of provision of the single open- coiled compression spring, the brake lever or brake pedal has a very small amount of movement to actuate in addition to having very small free play. More particularly, after a small free play region or region of ineffective stroke of the movement of the brake lever, wherein the movement of the brake lever is not causing any braking effect.

[0005] Furthermore, Such conventional configurations lead to poor efficiency of transmission in hydraulic braking system, lower brake performance in terms of lever input and brake lever torque, sluggish or vague braking behaviour, delay and poor control in braking response, all of which leads to user safety and fatigue concerns. A poor brake response also makes it difficult for a user to recover from a skid like condition. The safety and fatigueconcerns are especially prominent in high speed, high traffic and poor road conditions. Poor brake returnability, in which a brake does not easily return to its original position, can also cause issues such as excess drag on the vehicle which leads to lowered fuel economy and high temperatures of the brake disc.

[0006] Thus, in brake assemblies use of a single open-coiled compression spring, it becomes necessary to provide a spring which not only has the required stiffness in braking return, while having the required spring preload. Even if the above two characteristics are achieved, the single open-coiled compression spring remains susceptible to buckling, which would severely affect the braking performance.

[0007] 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.

[0008] 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 widevariations 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.

[0009] Thus, there is a need in the art for a brake assembly which addresses at least the aforementioned problems.SUMMARY OF THE INVENTION

[0010] 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.

[0011] 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.

[0012] 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 acentre at a pivot centre of the brake lever and has a central axis of the piston as a tangent.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] In a further embodiment of the invention, the brake lever has a variable curvature profile along a profile length of the brake lever.

[0020] In one aspect, the present invention relates to a brake assembly. The brake assembly has a housing. The housing is configured to receive a piston. The piston moves in a brake operating condition, wherein the piston is connected to an elastic member assembly. The elastic member assembly includes a plurality of elastic members.

[0021] In a further embodiment of the invention, the elastic member assembly is provided in the compression chamber and is operably connected to the piston. The return spring assembly has the plurality of elastic members being connected in series, and one or more connectors. Each connector is provided between adjacent elastic members thereby connecting the plurality of elastic members in a series, wherein each of the plurality of elastic members are disposed along a common axis.

[0022] In a further embodiment of the invention, the plurality of elastic members include a first spring and a second spring connected in series, and the connector is provided between the first spring and the second spring.

[0023] In a further embodiment of the invention, the first spring is connected to the housing and the connector, and the second spring is connected to the connector and the piston.

[0024] In a further embodiment of the invention, the connector has a rim portion having a circular profile, and a hub portion provided radially inward and extending axially from the rim portion.

[0025] In a further embodiment of the invention, the first spring is a telescopic spring having a base end and an apex end. A cross-section area of the first spring at the base end is greater than a cross section area of the first spring at the apex end. In an embodiment, the base end of the first spring is connected to the housing and the apex end of the first spring is connected to the hub portion of the connector. The hub portion extends axially from the rim portion towards the piston.

[0026] In a further embodiment of the invention, the second spring is a telescopic spring having a base end and an apex end. A cross section area of the second spring at the base end is greater than a cross section area of the second spring at the apex end. In an embodiment, the base end of the second spring is connected to the rim portion of the connector, and the apex end of the second spring being connected to the piston.

[0027] In a further embodiment of the invention, the first spring is a barrel spring having a first end and a second end. The first end of the first spring is connected to the housing, and the second end of the first spring is connected to the rim portion of the connector.

[0028] In a further embodiment of the invention, the second spring is a barrel spring having a first end and a second end, and the cross-section area of the second spring is smaller than the first spring. The first end of the second spring is connected to the hub portion of the connector and the hub portion extends axially from the rim portion away from the piston. The second end of the second spring is connected to the piston.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.Figure 6 illustrates a sectional view of a brake assembly, in accordance with an embodiment of the invention.Figure 7A illustrates a sectional view of an elastic member assembly of the brake assembly, in accordance with an embodiment of the invention.Figure 7B illustrates an exploded view of an elastic member assembly of the brake assembly, in accordance with an embodiment of the invention.Figure 8 illustrates an exploded sectional view of the brake assembly, in accordance with an another embodiment of the invention.Figure 9A-9E illustrate graphical representation of lever load vs lever travel in the present invention in comparison to the conventional system, in accordance with an embodiment of the present invention.Figure 10 illustrates another sectional view of the brake assembly, in accordance with an embodiment of the invention.Figure 11 illustrates another sectional view of the brake assembly, in accordance with an embodiment of the invention.DETAILED DESCRIPTION OF THE INVENTION

[0031] 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.

[0032] 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.

[0033] 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 mastercylinder 102 to move, for application of the brake. Herein, the one or more pistons 1 10 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.

[0034] 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.

[0035] 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.

[0036] In another embodiment, as illustrated in Figure 1 , Figure 2A and Figure 2B, the piston 110 is configured to move translationally for displacing abrake 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.

[0037] 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 linecontact 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 lengthand is obtained by connecting loci of ends of a continuously varying tangentline (T1 , Tn) of the imaginary circle (X) about pivot centre 122 of the brake lever 120.

[0038] 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.

[0039] 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 brakelever 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’).

[0040] 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.

[0041] 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 predeterminedprofile 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.

[0042] 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 1 10A 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 1 10A 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 1 10 is housed, is minimised.

[0043] In an embodiment, the first end 110A of the piston 1 10 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 portion130. 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.

[0044] Figure 6 illustrates a sectional view of a brake assembly 100a in accordance with an embodiment of the present invention. As illustrated in Figure 6, the brake assembly 100a comprises a housing 130a. The housing 130a houses all the components of the brake assembly 100a and is provided at a position which is close to a brake lever position. For example, in a two wheeled vehicle, the housing 130a is provided on a handlebar of the two wheeled vehicle.

[0045] As illustrated, the housing 130a is configured to receive a piston 1 10a, wherein the piston 110a moves in a brake operating condition. Thus, whenever the brake is to be operated, the piston 1 10a moves thereby allowing a brake fluid present inside the different parts of the housing to move, for application of the hydraulic brake (not shown). For facilitating the smooth movement and the return movement of the piston 110a, the piston110a is connected to an elastic member assembly 150. The elastic member assembly 150 includes a plurality of elastic members 160. Herein, when the piston 110a moves in a braking operation, the plurality of elastic members 160 get compressed and provide the required resistance and smoothness in the movement of the piston 110a. When the piston 110a is to move to its original position, the compression force of the plurality of elastic members 160 provide expansion force to the piston 110a, as the elastic members 160 return to their normal state. As a result of provision of a plurality of elastic members 160, a free play time and range in the movement of the piston 110a is increased and improved, thereby improving overall braking characteristics.

[0046] In an embodiment of the invention, the piston 110a is connected to a brake lever (not shown), and the piston 110a is configured to move in response to the movement of the brake lever for displacing brake fluid. Thus, whenever the user desires to apply brakes, the user moves the brake lever, in response to which the piston 110a moves, thereby displacing brake fluid for a braking operation. As further illustrated in the embodiment depicted in Figure 6, the housing 130a includes a compression chamber 120. During a braking operation, the compression chamber 120 is configured for receiving brake fluid from a reservoir chamber 140 and transmitting brake fluid to an outlet port 132a. The compressed or pressurised brake fluid is then transmitted to abrake calliper through the outlet port 132ato activate the brake calliper and perform the braking operation.

[0047] As further illustrated in the embodiment depicted in Figure 6 and Figure 7A, the elastic member assembly 150 is provided in the compression chamber 120 and being operably connected to the piston 110a. Thus, for the movement of the piston 110a, the elastic member assembly 150 gets compressed and relaxed inside the compression chamber 120. As illustrated, the elastic member assembly 150 has the plurality of elastic members 160 being connected in series. The elastic member assembly 150 further comprises one or more connectors 170. In that, each connector 170 is provided between adjacent elastic members 160 thereby connecting the plurality of elastic members 160 in a series. By virtue of the plurality of elastic members 160 being connected in series, a higher overall length of elastic members 160 is achieved, which allows for a higher range of free play. As illustrated in Figure 7A, each of the plurality of elastic members 160 are disposed along a common axis X-X’.

[0048] As further illustrated in Figure 6 and Figure 7A, in an embodiment, the plurality of elastic members 160 comprise a first spring 162 and a second spring 164 connected in series. Herein, the connector 170 is provided between the first spring 162 and the second spring 164. As illustrated, the first spring 162 is connected to the housing 130a and the connector 170, andthe second spring 164 is connected to the connector 170 and the piston 110a. Thus, the movement of the brake lever is transmitted to the piston 110a, and the movement of the piston 110a causes compression in the second spring 164. The compression in the second spring 164 is transmitted to the first spring 162 through the connector 170. The spring connector 170 ensures that the first spring 162 and the second spring 164 to have deflection without buckling and thereby accommodates a longer overall free length of combined first spring 162 and the second spring 164. This allows for higher overall compression / deflection ratios.

[0049] To further provide sufficient support to the first spring 162 and the second spring 164, as illustrated in Figure 2B, the connector 170 comprises a rim portion 172 having a circular profile, and a hub portion 174 provided radially inward and extending axially from the rim portion 172. One out of the first spring 162 or the second spring 164 is supported on the rim portion 172, and the other of the first spring 162 or the second spring 164 is supported on the radially inward hub portion 174. Such a configuration ensures that the compression from the second spring 164 is evenly distributed along the connector 170 and then transmitted to the first spring 162 or vice versa. This also ensures that neither of the first spring 162 or the second spring 164 remain susceptible to buckling.

[0050] In an embodiment, as depicted in Figure 6 and Figure 7A, the first spring 162 is a telescopic spring having a base end 162A and an apex end 162A’, wherein a cross section area of the first spring 162 at the base end 162A is greater than a cross section area of the first spring 162 at the apex end 162A’. In this embodiment, the base end 162A of the first spring 162 being connected to the housing 130a and the apex end 162A’ of the first spring 162 is connected to the hub portion 174 of the connector 170. As illustrated, the hub portion 174 extends axially from the rim portion 172 towards the piston 1 10a.

[0051] Further, the second spring 164 is a telescopic spring having a base end 164A and an apex end 164A’, wherein a cross section area of the second spring 164 at the base end 164A is greater than a cross section area of the second spring 164 at the apex end 164A’. In this embodiment, the base end 164A of the second spring 164 is connected to the rim portion 172 of the connector 170 and the apex end 164A’ of the second spring 164 is connected to the piston 110a. Thus, in this configuration, the connector 170 supports the apex end 162A’ of the first spring 162 at the axially extending hub portion 174, and the supports the base end 164A of the second spring at the rim portion 172.

[0052] Such a configuration allows for some overlap between the first spring 162 and the second spring 164, while ensuring that both the hub portion 174and the rim portion 172 of the connector 170 provide support, which further reduces the chances of buckling of the springs. For example, if the first spring 162 starts to buckle, the resultant twisting movement of the hub portion 174 would be resisted by the second spring 164 connected to the rim portion 172. Similarly, if the second spring 164 starts to buckle, the resultant twisting movement of the rim portion 172 would be resisted by the first spring 162 connected to the hub portion 172.

[0053] In an embodiment as referenced in Figure 10 , the connector 170 further comprises an anti friction or resilient guide member 180. The guide member 180 is configured to be in contact with the inner wall of the compression chamber 120 for resisting the movement of the connector 170 or any rotation of the connector 170, thereby preventing buckling of the first spring 162 and the second spring 164. In an alternate embodiment as referenced in Figure 11 , the connector 170 comprises double anti friction or resilient guide members 180 for resisting the movement of the connector 170 or any rotation of the connector 170, thereby preventing buckling of the first spring 162 and the second spring 164.

[0054] In an alternative embodiment of the invention, as illustrated in Figure 8, the first spring 162 is a barrel spring having a first end 162B and a second end 162B’. Herein the first end 162B of the first spring 162 is connected to thehousing 130a and the second end 162B’ of the first spring 162 is connected to the rim portion 172 of the connector 170.

[0055] Further, the second spring 164 is a barrel spring having a first end 164B and a second end 162B’. As illustrated, in this embodiment, the cross section area of the second spring 164 is smaller than the first spring 162. As illustrated in Figure 8, the first end 164B of the second spring 164 is connected to the hub portion 174 of the spring connector 170. Herein, the hub portion 174 extends axially from the rim portion 172 away from the piston 110a. As illustrated in Figure 8, the connector 170 in this embodiment has a substantially U-shaped cross section. Further, the second end 164B’ of the second spring 164 being connected to the piston 110a. Such a configuration allows for some overlap between the first spring 162 and the second spring 164, while ensuring that both the hub portion 174 and the rim portion 172 of the connector 170 provide support, which further reduces the chances of buckling of the springs, while ensuring uniform transfer of compression force between the first spring 162 and the second spring 164.

[0056] As a result of the present invention, as can be seen in Figures 7A-7E, which illustrates a curve between the brake lever travel and brake lever load. Herein, curve L1 illustrates the curve for the prior art and the curve L2 represents the curve for the present invention. The free play of the brake lever, i.e. the range of motion of the brake lever for the braking operation tostart, is higher in the present invention (illustrated as X2) as compared to the prior art (illustrated as X1 ), as a result of which the braking characteristics are improved. Specifically, as illustrated in Figure 7A, in the present invention, not only is the free play of the brake lever increased as compared to the prior art, but also the level of lever load (represented by A1 for prior art and A2 for the present invention) required for actuation of the brakes is minimised in the present invention as compared to the prior art thus reducing the effort required for braking and stress on the brake lever.

[0057] Further, as specifically illustrated in Figure 7B, the brake is actuated or the braking operation is started at a higher level of lever travel in the present invention as compared to the prior art, thereby leading to lower loss (represented by B1 for prior art and B2 for the present invention) for braking operation in the present invention as compared to the conventional system. The higher level of lever travel minimises the risk of sudden braking or jerks, but also provides more predictable and consistent braking feel. Further, as specifically illustrated in Figure 7C, in case of a sudden or hard braking, the lever load in case of hard braking is lower in the present invention, thereby leading to lower lever load (represented by C1 for prior art and C2 for the present invention) and less stress on the braking system in braking operation for sudden or hard braking.

[0058] As specifically illustrated in Figure 7D and 7E, in the present invention, to initiate the braking operation, a higher lever travel is required and a lower lever of lever load is sufficient, as compared to the prior art wherein only a lower lever travel is achieved, and the lever load is also higher. Thus, the loss of energy in actuation of the brakes (represented by D1 for prior art and D2 for the present invention in Figure 7D, and represented by E1 for prior art and E2 for the present invention in Figure 4E) in the present invention is also lower than loss of energy in actuation of brakes in the prior art.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] Furthermore, a brake assembly in which a connector is provided to bridge a plurality of springs to compress. It allows an increase in overall number of coils, free spring length and pre-compression, and in increasing overall compression ratio. The present invention allows for very low overall spring stiffness, which results in enhancement or increasing of range of continuous movement of the brake lever and a higher range of free play.

[0063] Further, the present invention also achieves elimination of any buckling effect by lateral guiding support provided by the connector. This ensures maintenance of higher transmission efficiency, positive brake returnability, and compact packaging in size.

[0064] As a result, better efficiency in the transmission of the brake system is achieved, in addition to improved brake performance in terms of brake torqueand braking force. This also leads to elimination of sluggish or vague braking feel, reduces delay in braking response and improves user control in braking. Thus, better user comfort and reduction in user fatigue is also achieved by the present invention. The consistent braking feel also improvise user confidence and allows the user to recover from a skid like situation with more ease, thus leading to improved user safety. Further, the adequate return of the brake lever also ensures that the brakes are fully disengaged, and there is no unnecessary drag on the vehicle, thus preventing overheating of brakes and improving fuel efficiency.

[0065] 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 Numerals100: Brake Assembly102: Master Cylinder110: Piston110A: First End of the Piston120: Brake Lever122: Pivot Centre of the Brake Lever130: First Portion of the Brake LeverX: Imaginary CircleA-A’: Central Axis of the PistonT1 , Tn: TangentsL1 , Ln: Variable Lengths of Tangents T1 , Tn100a: Brake Assembly110a: Piston120a: Compression Chamber130a: Housing132a: Outlet Port140: Reservoir Chamber150: Elastic Member Assembly160: Plurality of Elastic Members162: First Spring162A: Base End of First Spring162A’: Apex End of First Spring162B: First End of First Spring162B’: Second End of First Spring164: Second Spring164A: Base End of Second Spring164A’: Apex End of Second Spring164B: First End of Second Spring164B’: Second End of Second Spring170: Connector172: Rim Portion 174: Hub Portion180: Guide Members

Claims

WE CLAIM: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); wherein, 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.

6. 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);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).

7. 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).

8. 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).

9. A brake assembly (100a), comprising: a housing (130a), said housing (130a) being configured to receive a piston (110a), said piston (110a) moving in a brake operating condition, wherein said piston (110a) being connected to an elastic member assembly (150a), said elastic member assembly (150a) includes a plurality of elastic members (160a).

10. The brake assembly (100a) as claimed in claim 9, wherein the elastic member assembly (150) being provided in the compression chamber (120a) and being operably connected to the piston (110a), the elastic member assembly (150) comprising the plurality of elastic members (160)being connected in series; and one or more connectors (170), each connector (170) being provided between adjacent elastic members (160) thereby connecting the plurality of elastic members (160) in a series, wherein each of the plurality of elastic members (160) are disposed along a common axis (X-X’).

11. The brake assembly (100a) as claimed in claim 10, wherein the plurality of elastic members (160) comprises a first spring (162) and a second spring (164) connected in series, and the connector (170) being provided between the first spring (162) and the second spring (164).

12. The brake assembly (100a) as claimed in claim 10, wherein the first spring (162) is connected to the housing (130a) and the connector (170), and the second spring (164) is connected to the connector (170) and the piston (110a).

13. The brake assembly (100a) as claimed in claim 12, wherein the connector (170) comprises a rim portion (172) having a circular profile, and a hub portion (174) provided radially inward and extending axially from the rim portion (172).

14. The brake assembly (100a) as claimed in claim 13, wherein the first spring (162) is a telescopic spring having a base end (162A) and an apex end (162A’), wherein a cross-section area of the first spring (162) at the base end (162A) is greater than a cross-section area of the first spring (162) at the apex end (162A’).

15. The brake assembly (100a) as claimed in claim 14, wherein the base end (162A) of the first spring (162) being connected to the housing (130a) and the apex end (162A’) of the first spring (162) being connected to the hub portion (174) of the connector (170), wherein the hub portion (174) extends axially from the rim portion (172) towards the piston (110a).

16. The brake assembly (100a) as claimed in claim 13, wherein the second spring (164) is a telescopic spring having a base end (164A) and an apex end (164A’), wherein a cross-section area of the second spring (164) at the base end (164A) is greater than a cross-section area of the second spring (164) at the apex end (164A’).

17. The brake assembly (100a) as claimed in claim 16, wherein the base end (164A) of the second spring (164) being connected to the rim portion (172) of the connector (170), and the apex end (164A’) of the second spring (164) being connected to the piston (110a).

18. The brake assembly (100a) as claimed in claim 13, wherein the first spring(162) is a barrel spring having a first end (162B) and a second end (162B’), wherein the first end (162B) of the first spring (162) being connected to the housing (130), and the second end (162B’) of the first spring (162) being connected to the rim portion (172) of the connector (170).

19. The brake assembly (100a) as claimed in claim 13, wherein the second spring (164) is a barrel spring having a first end (164B) and a second end (162B’), and the cross section area of the second spring (164) being smaller than the first spring (162), and wherein the first end (164B) of the second spring (164) being connected to the hub portion (174) of the connector (170), wherein the hub portion (174) extends axially from the rim portion (172) away from the piston (110a), and the second end (164B’) of the second spring (164) being connected to the piston (110a).

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