Description:FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003

COMPLETE SPECIFICATION
[See section 10; rule 13]

TITLE: “PARKING BRAKE SYSTEM OF A VEHICLE”

Name and Address of the Applicant: TATA MOTORS LIMITED; Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India.

Nationality: IN

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

TECHNICAL FIELD

[001] Present disclosure generally relates to a field of automobiles. Particularly, but not exclusively, the present disclosure relates to a brake system of a vehicle. Further, embodiments of the present disclosure discloses a parking brake system of the vehicle.

BACKGROUND OF THE DISCLOSURE

[002] Vehicles are commonly equipped with braking systems for slowing and stopping the vehicle. Further, vehicles are equipped with parking brake systems which are adapted to keep the vehicle motionless in parked conditions. Generally, the parking brake systems adapt brake-by-wire/cable mechanism, which includes a brake wire/cable extending between a parking brake lever and brake units associated with wheels of the vehicle. Relative to actuation of the parking brake lever, the brake wire/cable displaces to actuate and de-actuate the brake units.

[003] With increase in size and load carrying capacity of the vehicle, force or the effort required to operate the parking brake system having brake-by-wire/cable mechanism, is high. That is, the effort of the operator to operate the parking brake lever to pull the brake wire/cable is high, which is undesired. At some instances where the operator fails to apply sufficient force to operate the parking brake lever, it may lead to improper application of brake force on to wheels, leading to roll down or roll forward of the vehicle in parked condition, leading to accidents.

[004] Considering the above, a brake booster is usually adapted in the parking brake systems to minimize the effort of the operator in actuating the parking brake lever. However, in case of failure of the brake booster, the effort requirement by the operator to actuate the parking brake lever increases, thereby leading to ineffective braking, which is undesired.

[005] The present disclosure is directed to overcome one or more limitations stated above or other limitations associated with the existing art.

SUMMARY OF THE DISCLOSURE

[006] One or more shortcomings of conventional parking brake systems are overcome, and additional advantages are provided through the system as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered as a part of the claimed disclosure.

[007] In one non-limiting embodiment of the disclosure, a parking brake system of a vehicle is disclosed. The parking brake system includes a first booster coupled to a parking brake lever of the vehicle and a second booster coupled to the first booster. Further, parking brake system includes a vacuum pump fluidly coupled to the first booster and a hydraulic fluid reservoir fluidly connected to a pump and the second booster. The vacuum pump is structured to supply vacuum to the first booster for first brake force amplification and the pump is adapted to supply hydraulic fluid from the hydraulic fluid reservoir to the second booster for second brake force amplification, corresponding to actuation of the parking brake lever. Furthermore, the parking brake system includes an auxiliary vacuum reservoir fluidly coupled to the first booster. The auxiliary vacuum reservoir is adapted to supply vacuum to the first booster and regulate hydraulic pressure in the second booster, upon operation of one of the auxiliary vacuum source and the vacuum pump at predefined threshold conditions. Additionally, the parking brake system includes a brake unit provided to one or more wheels of the vehicle. The brake unit is adapted to apply the brake force to the one or more wheels, corresponding to actuation of the parking brake lever. The configuration of the parking brake system aids is reducing the effort of the user to operate the parking brake system since the first booster and the second booster amplifies the brake force. Further, the configuration of the parking brake system aids in brake force amplification even in case of operation of the vacuum pump at the predefined threshold conditions or failure to the vacuum pump through the auxiliary vacuum reservoir. Further, the auxiliary vacuum reservoir also regulates (thus, increases) hydraulic pressure in the second booster for producing first brake force amplification along with second brake force amplification, thereby reducing the effort of the user in applying the parking brake, in case of failure of the first booster.

[008] In an embodiment of the disclosure, the parking brake system includes a plurality of levers. At least one lever of the plurality of levers are is coupled to at least one plunger of the first booster and the second booster. The at least one lever is adapted to transfer brake force to the first booster and the second booster, corresponding to operation of the parking brake lever.

[009] In an embodiment of the disclosure, the parking brake system includes an auxiliary hydraulic fluid reservoir which is adapted to supply hydraulic fluid to the second booster, upon operation of the pump at the predefined threshold conditions. In an embodiment of the disclosure, the parking brake system includes a regulating valve disposed in fluid communication between the hydraulic fluid reservoir and the second booster. Further, the parking brake system includes a vacuum cylinder fluidly coupled to the auxiliary vacuum reservoir and the regulating valve. The vacuum cylinder is adapted to displace and actuate the regulating valve, corresponding to operation of the auxiliary vacuum reservoir and the vacuum pump at the predefined threshold conditions.

[010] In an embodiment of the disclosure, actuating the regulating valve corresponds to increasing pressure of the hydraulic fluid to regulate pressure in the second booster, for both first brake force amplification and second brake force amplification.

[011] In an embodiment of the disclosure, the parking brake system an equalizer disposed between the second booster and the brake unit, the equalizer is adapted to distribute equal brake force to the brake unit.

[012] In an embodiment of the disclosure, the first booster is a vacuum booster and second booster is a hydraulic booster.

[013] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined together to form a further embodiment of the disclosure.

[014] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[015] The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with reference to the accompanying drawings wherein like reference numerals represent like elements and in which:

[016] Figure. 1 is a schematic view of a parking brake system of a vehicle, in accordance to an embodiment of the present disclosure.

[017] The figure depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

[018] While the embodiments in the disclosure are subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the figure and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.

[019] It is to be noted that a person skilled in the art would be motivated from the present disclosure and modify various features of a parking brake system of a vehicle, without departing from the scope of the disclosure. Therefore, such modifications are considered to be part of the disclosure. Accordingly, the drawings show only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skilled in the art having benefit of the description herein.

[020] The terms “comprises”, “comprising”, or any other variations thereof used in the disclosure, are intended to cover a non-exclusive inclusion, such that a system that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such system. In other words, one or more elements in a system or device proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or device.

[021] The following paragraphs describe the present disclosure with reference to Figure. 1. In the figure, the same element or elements which have similar functions are indicated by the same reference signs.
[022] Figure. 1 illustrates a schematic view of a parking brake system (100) [hereinafter referred as “brake system (100)”] of a vehicle. In an embodiment, the parking brake system (100) may include a brake-by-wire/cable mechanism for transferring brake force. The brake system (100) may include a parking brake lever (103) which may be positioned in a cabin of the vehicle and proximal to an operator (thus, the driver). The operator may actuate the parking brake lever (103) for applying brake force on to wheels [not shown in figures] of the vehicle for keeping the vehicle motionless in a parked condition.

[023] As apparent from Figure. 1, the brake system (100) may further include a first booster (101), which may be coupled to the parking brake lever (103) and a second booster (102), which may be coupled to the first booster (101). In an embodiment, the first booster (101) may be coupled to the parking brake lever (103) and the second booster (102), through a brake wire (104), which may be made of metallic materials. As an example, the first booster (101) may be but not limiting to a vacuum booster and the second booster (102) may be but not limiting to a hydraulic booster. The first booster (101) may be configured to provide first brake force amplification and the second booster (102) may be configured to provide second brake force amplification, corresponding to actuation of the parking brake lever (103). The first brake force amplification and second brake force amplification by the first booster (101) and the second booster (102), respectively aids in decreasing the effort by the operator in actuating the parking brake system (100), and also results effective application of the brake force on to the one or more wheels. Further, the brake system (100) may include a brake unit (110) provided to the one or more wheels of the vehicle. The brake unit (110) is adapted to apply the brake force to the one or more wheels of the vehicle, corresponding to actuation of the parking brake lever (103). As an example, the brake unit (110) may be one of a drum brake unit and a disc brake unit.

[024] In an embodiment, the brake system (100) may include a plurality of levers (105a, 105b, 105c). At least one lever (105a) of the plurality of levers (105a, 105b, 105c) may be coupled to a plunger (116a) of the first booster (101) and the at least one lever (105b) may be coupled to a plunger (116b) of the second booster (102). At least one lever of the plurality of levers (105a, 105b, 105c) may be adapted to transfer the brake force generated as a result of actuation of the parking brake lever (103), to the first booster (101) (by the lever 105a), the second booster (102) (by the lever 105b) and to the brake unit (110) (by the lever 105c). The at least one lever of the plurality of levers (105a, 105b, 105c) may pivot corresponding to actuation of the parking brake lever (103) for transferring the brake force from the parking brake lever (103) to the first booster (101) (by the lever 105a), to the second booster (102) (by the lever 105) and thereafter to the brake unit (110) (by the lever 105c) provided to one or more wheels of the vehicle.

[025] Referring further to Figure. 1, the brake system (100) may include a vacuum pump (106) which may be fluidly coupled to the first booster (101) and a hydraulic fluid reservoir (108) which may be fluidly connected to a pump (114) and the second booster (102). The vacuum pump (106) may be configured to supply vacuum to the first booster (101) for first brake force amplification and the pump (114) may be configured to supply hydraulic fluid from the hydraulic fluid reservoir (108) to the second booster (102) for second brake force amplification, corresponding to actuation of the parking brake lever (103). Additionally, the brake system (100) may include an auxiliary vacuum source which may be fluidly coupled to the first booster (101). The auxiliary vacuum source may be adapted to supply vacuum to the first booster (101), upon operation of the vacuum pump (106) at the predefined threshold conditions. The predefined threshold conditions of the vacuum pump (106) may correspond to but not limiting to operation of the vacuum below its fully operational capacity or failure of the vacuum pump (106). In an embodiment, the auxiliary vacuum reservoir (107) supplies vacuum to the first booster (101) to keep the first booster (101) functional even upon failure of the vacuum pump (106), thereby providing uninterrupted first brake force amplification corresponding to actuation of the parking brake lever (103).

[026] In an embodiment, the auxiliary vacuum reservoir (107) may be adapted to regulate hydraulic pressure of the second booster (102), upon operation of one of the vacuum pump (106) and the auxiliary vacuum reservoir (107) at the predefined threshold conditions. The predefined threshold conditions of the auxiliary vacuum reservoir (107) may correspond to decreasing vacuum level or empty of the auxiliary vacuum reservoir (107). That is, upon failure or partial operation of the vacuum sources of the first booster (101), the auxiliary vacuum reservoir (107) regulates (thus, increases) hydraulic pressure in the second booster (102) such that, the second booster (102) compensates the partial or non-operation of the first booster (101), thereby producing both the first brake force amplification and second brake force amplification. Thus, the configuration of the brake system (100) of the present disclosure aids in catering to both the first brake force amplification and second brake force amplification, even in case of or partial operation or failure of the first brake booster (thus, the vacuum pump (106) and the auxiliary vacuum reservoir (107)).

[027] In an embodiment, the braking system may include a pressure regulating valve (111), which may be disposed in fluid communication between the hydraulic fluid reservoir (108) and the second booster (102). As an example, the pressure regulating valve (111) may be but not limiting to load conscious pressure regulating valve (LCRV). The pressure regulating valve (111) may be adapted to regulate (thus, increase or decrease) pressure of the hydraulic fluid supplied from the hydraulic fluid reservoir (108) to the second booster (102). Further, the brake system (100) may include a vacuum cylinder (112) which may be fluidly coupled to the auxiliary vacuum reservoir (107) and the pressure regulating valve (111). The vacuum cylinder (112) may be configured to modulate the pressure regulating valve (111) corresponding to operation of the auxiliary vacuum reservoir (107) and the vacuum pump (106) at the predefined threshold conditions. In other words, the vacuum cylinder (112) may displace in response to decrease in vacuum levels in the auxiliary vacuum reservoir (107) to modulate the pressure regulating valve (111) for increasing the pressure of the hydraulic fluid, such that the second booster (102) may compensate for the partial or failure of the first booster (101) and thereby producing both the first brake force amplification and second brake force amplification, thus providing same convenience (i.e., minimized force) of the operator even after failure or partial operation of the first brake booster.

[028] In an embodiment, the brake system (100) may include a pressure control valve (115) (PCRV) which may be fluidly connected between the pump (114) and the second booster (102). The pressure control valve (115) may be configured to control pressure of the hydraulic fluid being supplied to the second booster (102).

[029] In an embodiment, as apparent from Figure. 1, the brake system (100) may include an auxiliary hydraulic fluid reservoir (109). The auxiliary hydraulic fluid reservoir (109) may be adapted to supply the hydraulic fluid to the second booster (102), upon operation of the pump (114) at the predefined threshold conditions or damage to the hydraulic fluid reservoir (108). The predefined threshold conditions of the pump (114) may corresponds to but not limiting to operation of the pump (114) below its fully operational capacity or failure of the pump(114). The auxiliary hydraulic fluid reservoir (109) aids in supplying the hydraulic fluid to the second booster (102) to keep the second booster (102) functional even upon partial or failure of the pump (114) or the hydraulic fluid reservoir (108), thereby providing uninterrupted second brake force amplification corresponding to actuation of the parking brake lever (103).

[030] In an embodiment, the brake system (100) may include an equalizer (113) which may be disposed between the second booster (102) and the brake unit (110). The equalizer (113) may be adapted to distribute equal brake force to the brake unit (110) provided to one or more wheels of the vehicle for effective braking of the vehicle in the parked condition.

[031] In an operational embodiment, to keep the vehicle motionless in the parked condition, the operator may actuate the parking brake lever (103). In response to actuation of the parking brake lever (103), the first booster (101) may produce first brake force amplification and consequently the second booster (102) may produce second brake force amplification. The amplified brake force may thereafter be transferred to the brake unit (110) through the brake wire (104) for providing brake force to the one or more wheels of the vehicle. The first brake force amplification and second brake force amplification may aid in minimizing the force to be applied by the operator to actuate the parking brake lever (103).

[032] Further, as an example, if the vacuum pump (106) operates at the predefined threshold conditions, the auxiliary vacuum reservoir (107) may supply vacuum to the first booster (101) for producing first brake force amplification. Likewise, if the pump (114) or the hydraulic fluid reservoir (108) operates at the predefined threshold conditions, the auxiliary hydraulic fluid reservoir (109) may supply hydraulic fluid to the second booster (102) for producing second brake force amplification. Furthermore, in another example, if vacuum level in the auxiliary vacuum reservoir (107) decreases or at zero or if operation of the vacuum pump (106) is at the predefined threshold conditions, the auxiliary vacuum reservoir (107) may modulate the pressure regulating valve (111), such that, the pressure regulating valve (111) increases pressure of the hydraulic fluid thereby increasing pressure in the second booster (102) such that, the second booster (102) compensates for the pressure required for operation of the first booster (101), by producing both first brake force amplification and second brake force amplification, thus providing the same convenience [i.e., reduced effort or force] required by the operator during actuation of the parking brake system (100).

[033] In an embodiment, the parking brake system (100) is simple in construction and includes a fail-safe mechanism, which may compensate in case of operation of few components at predefined threshold conditions.

[034] It is to be understood that a person of ordinary skill in the art may develop a parking brake system (100) similar configuration without deviating from the scope of the present disclosure. Such modifications and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the present disclosure covers such modifications and variations provided they come within the ambit of the appended claims and their equivalents.

Equivalents:

[035] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

[036] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting.

Referral Numerals:

Particular Reference number
Parking brake system 100
First booster 101
Second booster 102
Parking brake lever 103
Brake wire / cable 104
Plurality of Levers 105a, 105b, 105c
Vacuum pump 106
Auxiliary vacuum reservoir 107
Hydraulic fluid reservoir 108
Auxiliary hydraulic fluid reservoir 109
Brake unit 110
Pressure regulating valve 111
Vacuum cylinder 112
Equalizer 113
Pump 114
Pressure control valve 115
Plunger 116a, 116b
, Claims:We Claim:

1. A parking brake system (100) of a vehicle, the brake system comprising:

a first booster (101) coupled to a parking brake lever (103) of the vehicle;
a second booster (102) coupled to the first booster (101);
a vacuum pump (106) fluidly coupled to the first booster (101);
a hydraulic fluid reservoir (108) fluidly connected to a pump (114) and the second booster (102);
wherein, the vacuum pump (106) is structured to supply vacuum to the first booster (101) for producing first brake force amplification and the pump (114) is adapted to supply hydraulic fluid from the hydraulic fluid reservoir (108) to the second booster (102) for producing second brake force amplification, corresponding to actuation of the parking brake lever (103);
an auxiliary vacuum reservoir (107) fluidly coupled to the first booster (101), the auxiliary vacuum reservoir (107) is adapted to supply vacuum to the first booster (101), upon operation of the vacuum pump (106) at predefined threshold conditions, and regulate hydraulic pressure in the second booster (102), upon operation of one of the auxiliary vacuum reservoir (107) and the vacuum pump (106) at the predefined threshold conditions; and
a brake unit (110) provided to one or more wheels of the vehicle, wherein the brake unit (110) is adapted to apply brake force to the one or more wheels, corresponding to actuation of the parking brake lever (103).

2. The brake system (100) as claimed in claim 1, comprises a plurality of levers (105a, 105b, 105c), wherein at least one lever (105a) is coupled to at least one plunger (116a) of the first booster (101) and the at least one lever (105b) is coupled to the at least one plunger (116b) to the second booster (102).

3. The brake system (100) as claimed in claim 1, comprises an auxiliary hydraulic fluid reservoir (109), adapted to supply hydraulic fluid to the second booster (102), upon operation of the pump (114) at the predefined threshold conditions.

4. The brake system (100) as claimed in claim 1, comprises a pressure regulating valve (111) disposed in fluid communication between the hydraulic fluid reservoir (108) and the second booster (102).

5. The brake system (100) as claimed in claims 1 and 4, comprises a vacuum cylinder (112) coupled to the auxiliary vacuum reservoir (107) and the pressure regulating valve (111), the vacuum cylinder (112) is adapted to displace and modulate the pressure regulating valve (111) corresponding to operation of the auxiliary vacuum reservoir (107) and the vacuum pump (106) at the predefined threshold conditions.

6. The brake system (100) as claimed in claim 5, wherein actuating the regulating valve corresponds to increasing pressure of the hydraulic fluid to regulate pressure in the second booster (102), for producing both first brake force amplification and second brake force amplification.

7. The brake system (100) as claimed in claim 1, comprises an equalizer (113) disposed between the second booster (102) and the brake unit (110), the equalizer (113) is adapted to distribute equal brake force to the brake unit (110).

8. The brake system (100) as claimed in claim 1, wherein the first booster (101) is a vacuum booster.

9. The brake system (100) as claimed in claim 1, wherein the second booster (102) is a hydraulic booster.

10. The brake system (100) as claimed in claim 1, wherein the brake unit (110) is one of a drum brake unit and a disc brake unit.

Dated this 23rd day of September, 2022

Nikhil SRINIVASA REDDY
IN/PA 2127
OF K & S PARTNERS
AGENT FOR THE APPLICANT