FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION “HYDRAULIC BRAKE SYSTEM WITH AIR BOOSTERS”
APPLICANT(S)
TATA MOTORS LIMITED
Bombay House, 24 Homi Mody Street,
Hutatma Chowk, Mumbai 400 001, Maharashtra, India; an Indian company.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[0001] The present invention relates to pneumatic booster, and more specifically related to pneumatically assisted double diaphragm force boosters.
BACKGROUND OF THE INVENTION
[0002] Pneumatic brake power boosters operating on the basis of pressure in excess of or below atmospheric pressure are known from the prior art. More particularly, low-pressure brake power boosters.
[0003] Conventional vacuum brake boosters for automotive vehicles use vacuum to boost braking force. The vacuum brake boosters uses a pressure gradient between the vacuum prevailing in the intake manifold of the four-stroke engine or vacuum pump and the atmospheric outside pressure as a power source for boosting the hydraulic pressure that is generated in a master cylinder by the driver’s pedal force. But vacuum is limited to 0.85 bar pressure differential, hence boost in force is very small and bigger size booster is required. Using pressurized air instead gives much higher assist even at smaller booster size. This boosted brake force can be used as input to tandem master cylinder for generating pressurized brake fluid for application of hydraulic foundation brakes.
OBJECT OF THE INVENTION
[0004] The principal object of the embodiments herein is to air assisted booster device for amplification of input force with help of pressurized air and rubber diaphragm. The amplification is done by the help of pressure difference between pressurized air and atmospheric air.
[0005] Another object of the embodiments herein is to provide hydraulic brake system with Air booster schematic diagram.

SUMMARY OF THE INVENTION
[0006] In one aspect the object is satisfied by providing air booster device for a hydraulic brake system. The air booster device includes a housing comprising a booster shell, a valve body provided in the housing and is fixed in the booster shell, a diaphragm dividing the booster shell into a high pressure chamber and an atmospheric chamber, an input rod inserted into the valve body and is operable to generate pressurized air into the high pressure chamber, an output rod is connected to the input rod and is operable to generate pressurized air into the atmospheric chamber, a plunger disposed within the valve body and coupled to the input rod, and a reaction member connected to the output rod and the plunger. The plunger is movable in forward and backward direction to introduce and discharge the pressurized air into the high pressure chamber to generate thrust into the atmospheric chamber. The reaction member transmits thrust of diaphragm force to the output rod. When the input rod pushes the plunger against the reaction member, the pressurized air is introduced into the high pressure chamber and pushes the diaphragm against the reaction member to provide the diaphragm force to the output rod.
[0007] In an embodiment, the diaphragm converts the pressure air into force and force pushes the reaction member.
[0008] In an embodiment, the diaphragm is made of rubber material.
[0009] In an embodiment, the plunger is connected to a value for opening and closing by the movement of the plunger to introduce and discharge the pressurized air into the high pressure chamber.
[0010] In an embodiment, the input rod and the output rod are movable forward and backward direction.

[0011] In another aspect the object is satisfied by providing a hydraulic brake system with air boosters. The hydraulic brake system includes a first air tank, a second air tank, an air compressor to provide compressed air, a Drying and Distribution Unit (DDU) connected to the air compressor to receive the compressed air from the air compressor, a primary air booster device connected to the first air tank using a first pressure reduction valve, a secondary air booster device connected to the second air tank using a second pressure reduction valve, and a Tandem master cylinder (TMC). The DDU processes the compressed air and provide to the first air tank and the second air tank. The primary air booster device amplify an input force from the first air tank and output a first air booster output force. The secondary air booster device amplify the first air booster output force from the primary air booster device and output a second air booster output force. Further, the TMC receives the second air booster output force from the secondary air booster device and generate pressure to the hydraulic brake system.
[0012] In an embodiment, the primary air booster device is connected to the first air tank using a first pressure reduction valve. The first pressure reduction valve reduces a pressure of the air receives from the DDU as per system requirement.
[0013] In an embodiment, the secondary air booster device is connected to the second air tank using a second pressure reduction valve. The second pressure reduction valve reduces a pressure of the air receives from the DDU as per system requirement.
[0014] In an embodiment, the TMC includes a primary chamber and a secondary chamber to generate the pressure and provide to the hydraulic brake system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The proposed air assist brake booster for hydraulic brake system are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will

be better understood from the following description with reference to the drawings, in which:
[0016] FIG. 1 illustrates air assist brake booster for hydraulic brake system, according to embodiment as disclosed herein;
[0017] FIG. 2 illustrates vacuum assist brake booster for hydraulic brake system, according to the embodiment as disclosed herein; and
[0018] FIG. 3 illustrates a hydraulic brake system with brake boosters, according to the embodiment as disclosed herein.
DETAILED DESCRIPTION OF INVENTION
[0019] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. The term “or” as used herein, refers to a non-exclusive or, unless otherwise indicated. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein can be practiced and to further enable those skilled in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0020] Referring now to the drawings, and more particularly to FIGS. 1 through 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.

[0021] FIG. 1 illustrates an air assist brake booster for hydraulic brake system, according to embodiment as disclosed herein. The air booster device includes a housing having a booster shell (1), a valve body (2), a diaphragm (3), an input rod (6), an output rod (7), a plunger (8), a reaction member (9), and a poppet assembly (10).
[0022] The valve body (2) is provided in the housing. The valve body (2) is fixed in the booster shell (1). The diaphragm (3) divides the booster shell (1) into a high pressure chamber (4) and an atmospheric chamber (5). The diaphragm (3) is connected to a diagrams hub (12). In an embodiment, the diaphragm (3) is made of rubber material.
[0023] The input rod (6) is inserted into the valve body (2) and is operable to generate pressurized air into the high pressure chamber (4). The output rod (7) is connected to the input rod (6) and is operable to generate pressurized air into the atmospheric chamber (5). The input rod (6) and the output rod (7) are movable forward and backward direction. In an embodiment, a pressurized air pressure (11) is applied when the input rod (6) is operated.
[0024] The plunger (8) is disposed within the valve body (2) and is coupled to the input rod (6). The plunger (8) is movable in forward and backward direction to introduce and discharge the pressurized air into the high pressure chamber (4) to generate thrust into the atmospheric chamber (5). The plunger (8) is connected to a value for opening and closing by the movement of the plunger (8) to introduce and discharge the pressurized air into the high pressure chamber (4). In an embodiment, the plunger (8) has a large diameter portion that is movably guided to the valve body (2) on the rear end side.
[0025] The reaction member (9) is connected to the output rod (7) and the plunger (8). The reaction member (9) transmits thrust of diaphragm (3) force to the output rod (7). When the input rod (6) pushes the plunger (8) against the reaction member (9), the pressurized air is introduced into the high pressure chamber (4) and pushes

the diaphragm (3) against the reaction member to provide the diaphragm (3) force to the output rod (7). The diaphragm (3) converts the pressure air into force and force pushes the reaction member (9). The diaphragm (3) converts the pressure air into force and force pushes the reaction member (9). During the operation, an input force is applied on the input rod (6), it travels towards the reaction member (9) and apply force on the reaction member (9). Simultaneously, the pressurized air is entered into the high pressure chamber (4) and pushes the diaphragm (3). The diaphragm (3) coverts the pressure energy into force and pushes the reaction member (9). The force applied on the input rod (6) is amplified with assistance of the diaphragm force. Subsequently the reaction member (9) transfers amplified force to the output rod (7) for further application.
[0026] The proposed air assist brake booster is a pneumatic booster that uses a pressurized air as a boosting source. In another the vacuum assist brake booster can also be used as shown in the FIG. 2. In this case, the diaphragm (3) divides the booster shell (1) into the atmospheric chamber (5) and the vacuum chamber (13). When the input rod (6) pushes the plunger (8) against the reaction member (9), the air is introduced into the atmospheric chamber (4) through filters (14) and pushes the diaphragm (3) against the reaction member to provide the diaphragm (3) force to the output rod (7).
[0027] FIG. 3 illustrates a hydraulic brake system with brake boosters, according to the embodiment as disclosed herein. The hydraulic brake system includes a first air tank (16), a second air tank (17), an air compressor (18) to provide compressed air, a Drying and Distribution Unit (DDU) (19), a primary air booster device (20), a secondary air booster device (21), a brake fluid reservoir (24), a right front wheel cylinder (25), a left front wheel cylinder (26), a load conscious pressure regulating valve (LCRV) (27), a right front wheel cylinder (28), and a left front wheel cylinder (29).

[0028] The DDU (19) is connected to the air compressor (18) to receive the compressed air from the air compressor (18). The DDU (19) processes the compressed air and provide to the first air tank (16) and the second air tank (17).
[0029] The primary air booster device (20) is connected to the first air tank (16) using a first pressure reduction valve (22). The secondary air booster device (21) is connected to the second air tank (17) using a second pressure reduction valve (23). The first pressure reduction valve (22) and the second pressure reduction valve (23) are used to reduce the pressure as per system requirement. Further the secondary air booster device (21) is connected to a Tandem Master Cylinder (TMC) (30), the right front wheel cylinder (25), the left front wheel cylinder (26), the load conscious pressure regulating valve (LCRV) (27), the right front wheel cylinder (28), and the left front wheel cylinder (29).
[0030] The primary air booster device (20) amplify an input force (F) from the first air tank (16) and output a first air booster output force (F1). The primary air booster device (20) is connected to the first air tank (16) using a first pressure reduction valve (22), wherein the first pressure reduction valve (22) reduces a pressure of the air receives from the DDU (19) as per system requirement.
[0031] The secondary air booster device (21) amplify the first air booster output force (F1) from the primary air booster device (20) and output a second air booster output force (F2). The secondary air booster device (21) is connected to the second air tank (17) using a second pressure reduction valve (23), wherein the second pressure reduction valve (23) reduces a pressure of the air receives from the DDU (19) as per system requirement. The TMC) (30) to receive the second air booster output force from the secondary air booster device (21) and generate pressure to the hydraulic brake system. The TMC (30) includes a primary chamber (P1) and a secondary chamber (P2) to generate the pressure and provide to hydraulic brake system.

[0032] In an embodiment, the primary air booster device (20) and the primary air booster device (20) and the secondary air booster device (21) is described with respect to the FIGS. 1-2. The description is not repeated for sake of brevity in the document.
[0033] Unlike the conventional system, the proposed air assisted booster device is used amplify the input force with help of pressurized air and the diaphragm as indicated in the FIGS. 1-2. Amplification is done by the help of pressure difference between pressurized air and atmospheric air. The diagram separate the booster shell is divided into – High pressure chamber and atmospheric chamber and provide housing to reaction member and valve plunger. The prosed air assisted booster device is reliability and low cost as the installation and operation cost of the equipment is less. The compact size boosters helps for force amplification in many application like automobile brakes and clutch, and manufacturing. Ratio of the amplification can be increased by adding extra diaphragm. The proposed air assisted booster device is environment friendly as no pollutant is released to environment.
[0034] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

List to Reference Numerals:

Sr. No. Description
1 booster shell
2 valve body
3 diaphragm
4 high pressure chamber
5 atmospheric chamber
6 input rod
7 output rod
8 plunger
9 reaction member
10 poppet assembly
11 bar pressure
12 diagrams hub
13 vacuum chamber
14-15 Air filters
16 first air tank
17 second air tank
18 air compressor
19 Drying and Distribution Unit (DDU)
20 primary air booster device
21 secondary air booster device
22 Primary Pressure control valve
23 Secondary Pressure control valve
24 brake fluid reservoir
25 right front wheel cylinder
26 left front wheel cylinder
27 LCRV
28 right front wheel cylinder
29 left front wheel cylinder
30 Tandem master cylinder

We Claim:
1. An air booster device for a hydraulic brake system, wherein the air booster
device comprises:
a housing comprising a booster shell (1);
a valve body (2) provided in the housing, wherein the valve body (2) is fixed in the booster shell (1);
a diaphragm (3) dividing the booster shell into a high pressure chamber (4) and an atmospheric chamber (5);
an input rod (6) inserted into the valve body (2), wherein the input rod (6) is operable to generate pressurized air into the high pressure chamber (4);
an output rod (7) connected to the input rod (6), wherein the output rod (7) is operable to generate pressurized air into the atmospheric chamber (5);
a plunger (8) disposed within the valve body (2) and coupled to the input rod (6), wherein the plunger (8) is movable in forward and backward direction to introduce and discharge the pressurized air into the high pressure chamber (4) to generate thrust into the atmospheric chamber (5); and
a reaction member (9) connected to the output rod (7) and the plunger (8), wherein the reaction member (9) transmits thrust of diaphragm (3) force to the output rod (7),
wherein when the input rod (6) pushes the plunger (8) against the reaction member (9), the pressurized air is introduced into the high pressure chamber (4) and pushes the diaphragm (3) against the reaction member to provide the diaphragm (3) force to the output rod (7).
2. The air booster device as claimed in claim 1, wherein the diaphragm (3) converts the pressure air into force and force pushes the reaction member.
3. The air booster device as claimed in claim 1, wherein the diaphragm (3) is made of rubber material.

4. The air booster device as claimed in claim 1, wherein the plunger (8) is connected to a value for opening and closing by the movement of the plunger (8) to introduce and discharge the pressurized air into the high pressure chamber (4).
5. The air booster device as claimed in claim 1, wherein the input rod (6) and the output rod (7) are movable forward and backward direction.
6. A hydraulic brake system with air boosters, wherein the hydraulic brake system comprises:
a first air tank (16);
a second air tank (17);
an air compressor (18) to provide compressed air;
a Drying and Distribution Unit (DDU) (19) connected to the air compressor
(18) to receive the compressed air from the air compressor (18), wherein the DDU
(19) processes the compressed air and provide to the first air tank (16) and the second air tank (17);
a primary air booster device (20) connected to the first air tank (16) using a first pressure reduction valve (22), wherein the primary air booster device (20) amplify an input force from the first air tank (16) and output a first air booster output force;
a secondary air booster device (21) connected to the second air tank (17) using a second pressure reduction valve (23), wherein the secondary air booster device (21) amplify the first air booster output force from the primary air booster device (20) and output a second air booster output force; and
a Tandem master cylinder (TMC) (30) to receive the second air booster output force from the secondary air booster device (21) and generate pressure to the hydraulic brake system.
7. The hydraulic brake system as claimed in claim 6, wherein the primary air
booster device (20) is connected to the first air tank (16) using a first pressure

reduction valve (22), wherein the first pressure reduction valve (22) reduces a pressure of the air receives from the DDU (19) as per system requirement.
8. The hydraulic brake system as claimed in claim 6, wherein the secondary air booster device (21) is connected to the second air tank (17) using a second pressure reduction valve (23), wherein the second pressure reduction valve (23) reduces a pressure of the air receives from the DDU (19) as per system requirement.
9. The hydraulic brake system as claimed in claim 6, wherein the TMC (30) comprises a primary chamber (P1) and a secondary chamber (P2) to generate the pressure and provide to the hydraulic brake system.
10. The hydraulic brake system as claimed in claim 6, wherein the primary air
booster device (20) comprises:
a housing comprising a booster shell (1);
a valve body (2) provided in the housing, wherein the valve body (2) is fixed in the booster shell (1);
a diaphragm (3) dividing the booster shell (1) into a high pressure chamber (4) and an atmospheric chamber (5);
an input rod (6) inserted into the valve body (2), wherein the input rod (6) is operable to generate pressurized air into the high pressure chamber (4);
an output rod (7) is connected to the input rod (6), wherein the output rod (7) is operable to generate pressurized air into the atmospheric chamber (5);
a plunger (8) disposed within the valve body (2) and coupled to the input rod (6), wherein the plunger (8) is movable in forward and backward direction to introduce and discharge the pressurized air into the high pressure chamber (4) to generate thrust into the atmospheric chamber (5); and
a reaction member (9) connected to the output rod (7) and the plunger (8), wherein the reaction member (9) transmits thrust of diaphragm (3) force to the output rod (7),

wherein when the input rod (6) pushes the plunger (8) against the reaction member (9), the pressurized air is introduced into the high pressure chamber (4) and pushes the diaphragm (3) against the reaction member to provide the diaphragm (3) force to the output rod (7).
11. The hydraulic brake system as claimed in claim 10, wherein the diaphragm (3) converts the pressure air into force and force pushes the reaction member (9), and wherein the diaphragm (3) is made of rubber material.
12. The hydraulic brake system as claimed in claim 10, wherein the plunger (8) is connected to a value for opening and closing by the movement of the plunger (8) to introduce and discharge the pressurized air into the high pressure chamber (4).
13. The hydraulic brake system as claimed in claim 6, wherein the secondary air
booster device (21) comprises:
a housing comprising a booster shell (1);
a valve body (2) provided in the housing, wherein the valve body (2) is fixed in the booster shell (1);
a diaphragm (3) dividing the booster shell (1) into a high pressure chamber (4) and an atmospheric chamber (5);
an input rod (6) inserted into the valve body (2), wherein the input rod (6) is operable to generate pressurized air into the high pressure chamber (4);
an output rod (7) is connected to the input rod (6), wherein the output rod (7) is operable to generate pressurized air into the atmospheric chamber (5);
a plunger (8) disposed within the valve body (2) and coupled to the input rod (6), wherein the plunger (8) is movable in forward and backward direction to introduce and discharge the pressurized air into the high pressure chamber (4) to generate thrust into the atmospheric chamber (5); and
a reaction member (9) connected to the output rod (7) and the plunger (8), wherein the reaction member (9) transmits thrust of diaphragm (3) force to the output rod (7),

wherein when the input rod (6) pushes the plunger (8) against the reaction member (9), the pressurized air is introduced into the high pressure chamber (4) and pushes the diaphragm (3) against the reaction member to provide the diaphragm (3) force to the output rod (7).
14. The hydraulic brake system as claimed in claim 13, wherein the diaphragm (3) converts the pressure air into force and force pushes the reaction member (9), and wherein the diaphragm (3) is made of rubber material.
15. The hydraulic brake system as claimed in claim 13, wherein the plunger (8) is connected to a value for opening and closing by the movement of the plunger (8) to introduce and discharge the pressurized air into the high pressure chamber (4).