DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
A HYDRAULIC BRAKE CONTROL SYSTEM WITH ACCUMULATORS FOR EFFECTIVE BRAKING ON WHEEL LOADER
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
BEML LIMITED IN BEML Soudha, No 23/1, 4th Main S.R. Nagar, Bengaluru- 560027, Karnataka, India.
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION

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

FIELD OF INVENTION:
[001] The present invention relates to the field of braking system of heavy vehicle. The present invention in particular relates to a hydraulic brake control system with accumulators for effective braking on wheel loader.
DESCRIPTION OF THE RELATED ART:
[002] In a normal working condition of a wheel loader, the operator stops the equipment by pressing the brake pedal by foot. The brake pedal (1) is connected to actuation rod (7) by using diversion plate (4), Fork clevis (5) and lock nut (6) which in turn connected to the brake valve (8), which is assisted by hydraulic system in which the pressure oil is supplied from the gear pump, which is coupled to the engine through power take off system. The pressurized oil from the pump is supplied to the brake valve which assists the brake system and reduces operator’s effort on the brake pedal, as well as reduces operator fatigue to make ease of operation and holds the brake with less effort from the operator. The brake pedal stroke is adjustable by setscrew (2 and 3).
[003] When engine shut down due to various problems, the application of the brakes will be very difficult as the hydraulic assistance is not available during engine off condition / pump failure condition. The above reason leads us to think further and invent solution for secondary braking system positively by providing accumulator backup system in brake hydraulic circuit, where the pressure energy will be available continuously for brake application during engine shut off / pump failure condition also.
[004] Reference may be made to the following:
[005] Publication No. CN207484544 relates to a bull -dozer safe parking hydraulic system. It includes hydraulic tank, the slippage pump links to each other with hydraulic tank, be equipped with the first pipeline rather than linking to each other on the slippage pump, the one end and the first pipeline parallel connection of second pipeline, the other end of second pipeline links to each other with brake solenoid valve's t mouth, brake solenoid valve's a mouth passes through the third pipeline and links to each other with the left cavity of brake cylinder upper piston, brake cylinder shang rod links to each other with the stopper, the one end of the 7th pipeline links to each other with hydraulic tank, the other end of the 7th pipeline links to each other with pilot solenoid valve's t mouth, pilot solenoid valve's p mouth is through the 5th pipeline and first pipeline parallel connection, pilot solenoid valve's a mouth links to each other with the k1 mouth of cushion valve, the p mouth that the p mouth of cushion valve passes through fourth pipeline and brake solenoid valve links to each other, a mouth of cushion valve is through the 6th pipeline and the 7th pipeline parallel connection. The utility model discloses can realize that the parking is steadily braked to the bull -dozer when taking place the electrical accident, improve the security of traveling of all -hydraulic bull -dozer.
[006] The above Publication no. CN207484544 relates to safe parking hydraulic system by use of brake solenoid valves. However, in the present invention Braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal, the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stops. So, energy stored in accumulators is used for applying service brakes. The present application is for Service brake not for parking brake.
[007] Publication No. CN204821532 provides a tracked vehicle is with turning to stopper, it includes the casing, be provided with the braking assembly that is used for driving rocker arm mechanism in the casing, the braking assembly is including piston A who arranges the A intracavity in and the piston B who arranges the B intracavity in, rocker arm mechanism is connected in the drive of piston A's one end, the other end is connected with the guiding valve, and leaves one section and the communicating start -up chamber D in A chamber with the guiding valve link in the A chamber, the guiding valve run through piston B and with casing sliding fit, and the B intracavity keep away from the stopper live A's one end be provided with piston B complex spring. The stopper is normal making brake, stopper oil -break promptly, and the vehicle is in braking state, and the solve stopper is the unable shortcoming that apply the brake under the oil -break state, has improved vehicle nature.
[008] The above Publication no. CN204821532 relates to use of rocker mechanism for control of steering brake application. In this case steering brake is applied in neutral condition and it gets released when started. However, in the present invention, braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes. In this case, in neutral condition, brake is not in applied condition.
[009] Publication No. CN208069630 provides a novel turn to braking control mechanism, including brake control valve, rocker arm mechanism, brake band, brake drum, the brake control valve is installed on brake assembly, braking control valve bond rocker arm mechanism, rocker arm mechanism connects the brake band, and the brake band is located the brake drum periphery, the brake control valve includes case, valve body, valve barrel, dish spring, sleeve pipe, and case, valve body, valve barrel, dish spring, sleeve pipe are all installed inside the valve body, and valve barrel, dish spring, sleeve pipe are installed on the case, in the brake control valve left side, form the A oil pocket between case and the valve body, an oil pocket intercommunication has the steering pump oil circuit, forms the B oil pocket between case and the valve barrel, and Boil pocket intercommunication has the steering clutch oil circuit. Novel turn to braking control mechanism makes the driving safer, brake control valve and the integrated design of brake assist mechanism, the structure is compacter, through turning to pressure variation control arrestment mechanism to the control bull -dozer turns to braking state, modern design.
[010] The above Publication no. CN208069630 relates to use of rocker mechanism for control of steering and brake application. In this case, steering and brake is applied in neutral condition and it gets released when started. However, in the present invention, braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes. In this case, in neutral condition, brake is not in applied condition.
[011] Publication No. CN205737494 discloses a novel bull -dozer braking system, include the relief pressure valve, turn to the braking valves, the relief pressure valve turns to the braking valves through the oil circuit connection, it passes through the right stopper of oil circuit connection, right clutch, left clutch and left stopper to turn to the braking valves, right side stopper, right clutch, left clutch and left stopper pass through oil circuit intercommunication oil tank, relief pressure valve and turn to that a check valve is set up between the valves to the braking and the interface is installed fast to the energy storage ware. This bull -dozer braking system can be under the engine failure condition, and convenient quick separation brake strip accomplishes broken -down car's quick transition maintenance, improves work efficiency, the also economic loss under reducible some dangerous operating mode.
[012] The above Publication no. CN205737494 relates to use of pressure reducing valve and steering brake valve for bull dozer. Whenever engine fails, brake is applied automatically and vehicle cannot be moved. So stored energy accumulators are used to release the brake and move the machine. However, in the present invention, braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes. Here the stored energy accumulators are used to supply the oil to apply the service brake not for releasing the brake.
[013] Publication No. CN102926418 discloses a brake device for a hybrid power dozer. The brake device comprises a driving motor, wherein the driving motor comprises an armature shaft used for outputting power to drive wheels to rotate; and an electromagnetic brake is arranged on the armature shaft. Compared with the prior art, the brake device for the hybrid power dozer has the advantages that the electromagnetic brake is arranged on the armature shaft of the driving motor, the characteristic of the electromagnetic brake that a driving part and a driven part are controlled to be rapidly combined with and separated from each other through power-on/off is utilized, the corresponding brake time of the dozer in case of emergency is shortened, so that the operating reliability and safety of the dozer are improved. On the basis, the invention also discloses a hybrid power dozer comprising the brake device.
[014] The above Publication no. CN102926418 includes a driving motor, and the driving motor has an armature shaft for outputting power to drive the wheels to rotate, and the armature shaft is provided with an electromagnetic brake. However, in the present invention Braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes. No hydraulic motor, electromagnetic brake is used for application of brake.
[015] Publication No. CN207812534 relates to a hydrostatic bull -dozer brake control system, speed transmitter sets up on variable hydraulic motor, sets up synchronization module in the intelligent control ware, and speed transmitter and synchronization module are connected, and engine, brake pedal, brake valve lever and parking pull -rod operator are connected with the signal input part of intelligent control ware respectively, and volume adjustable hydraulic pump, variable hydraulic motor and variable hydraulic motor 1 are connected with the variable hydraulic motor 3 of intelligent control ware respectively. The utility model has the advantages of it influences life's problem because of frequently moving generating heat of bringing, wearing and tearing etc. To reduce brake solenoid valve, great impact to arresting gear produces is effectively alleviated and can effectively prolong its life, decreasing failure rate, the sloping automated inspection function of swift current of development has improved the security and the reliability of bull -dozer brake control, the nature controlled, travelling comfort and the security of hydrostatic bull -dozer can improve greatly.
[016] The above Publication no. CN207812534 includes a variable hydraulic motor and pumps with brake solenoid valves and braking is controlled through intelligent controller with the help of sensors and current input signal to pump and motor. However, in the present invention, braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes. No hydraulic motor, solenoid vales, intelligent controller, sensor, current signals used for application of brake.
[017] IN Publication No. 201841030487 relates to a braking system for a dozer comprising a brake pedal and a rod assembly. The brake pedal is linked with a brake lever by means of a brake linkage. The rod assembly is connected to a first lever at one end, and the brake lever at another end, thereby connected to the brake pedal. The rod assembly facilitates reduction of engine Revolutions Per Minute (RPM) upon application of the brake pedal by pulling the rod assembly inwardly as a result of an outward push received by the brake linkage. Subsequently, a second lever via the first lever is pushed to limit fuel flowing into a Fuel Injection Pump (FIP) when the brake pedal is pressed thereby bringing down the engine RPM below a predefined threshold.
[018] In the above Publication no. IN201841030487, the braking is by pressing mechanical linkages and claim is for reducing wear on brake bands and reduce fuel consumption. However, in the present invention. Braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes.
[019] Publication No. CN102839701 relates to a braking system of a bulldozer. The braking system comprises a steering clutch, a brake-type steering machine and a step less speed regulation hydraulic steering motor, wherein the steering clutch is connected with the brake-type steering machine, so that the pivot steering of a mechanism is realized, the radius of the steering range is small, and the steering is flexible; and the step less speed regulation hydraulic steering motor is connected with a speed-variable control lever, so that different steering radiuses and rotating speeds can be realized. The braking system of the bulldozer, provided by the invention, can be used for assisting a driver to easily control the driving, ensuring easiness in driving and high-standard safety function, and simultaneously realizing energy conservation and consumption reduction.
[020] In the above Publication no. CN102839701, the braking is by using speed change joystick, stepless speed-regulating hydraulic steering motor, and the steering clutch is connected with the brake-type steering gear. However, in the present invention, braking of wheel loader is through hydraulic system which consists of pressure reducing valve, Brake pedal, Brake valve and accumulators. The required flow from these aggregates flow to axles chamber. By pressing the brake pedal the wet multiple disc brakes are applied which is provided in axles. Whenever engine fails, the flow from pump to hydraulic system stop. So, energy stored in accumulators is used for applying service brakes.
[021] The powertrain system of wheel loader consists of Engine, Torque converter, Transmission and final drive with brake system. Hydraulic cylinders for lift and lower and tilt up/down of bucket attachment. The wheel loader equipment works gradients up to 25 deg in the field. When working in gradients due to inertia of the equipment it tends to move along the down gradient. To control this movement of equipment operator has to use service brake to stop the machine when engine is running. If engine stops, the service brakes are not efficient and effective and as there is no pressure oil from the gear pump supplied to the brake valve and in order to avoid toppling due to self weight (>20000 kg) the brake has to be applied as a safety feature.
[022] In order to overcome above listed prior art, the present invention aims to provide a hydraulic brake control system with accumulators for effective braking on wheel loader. The secondary braking system the hydraulic assistance of braking provided continuously by accumulator backup system, which makes the operator to perform the braking function even during the engine off condition. By using this system, the operator can apply brake at emergency condition and makes+ the system safer without accidents.
OBJECTS OF THE INVENTION:
[023] The principal object of the present invention is to provide a hydraulic brake control system with accumulators for effective braking on wheel loader.
[024] Another object of the present invention is to provide an improved braking system which makes vehicle safer for operating the equipment on different gradient work locations.
SUMMARY:
[025] The present invention relates to the hydraulic brake control system with accumulators for effective braking on wheel loader. The secondary hydraulic assisted braking system uses the energy stored in the accumulator provided in the brake hydraulic system that will be available at the brake valve while braking and there by stops the machine to avoid fatal accidents.
[026] The invention provides secondary braking system positively by using the available stored energy in the accumulator of the brake hydraulic circuit. The invention provides the pressurized oil to the brake valve at engine off condition, the pressurized oil is stored in the accumulator as a backup system which is provided in the brake hydraulic circuit. During normal operation, the inside of the accumulator contains Nitrogen gas it is compressed and it stores the hydraulic oil at the required pressure. During the sudden engine switch off and at emergency, this pressurized oil in the accumulator will be available at the brake valve while braking and there by stops the machine to avoid fatal accidents in wheel loader as foolproof technology this will serves as backup system for brake circuit.
BREIF DESCRIPTION OF THE INVENTION
[027] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[028] Figure 1 shows hydraulic brake control system according to the present invention;
[029] Figure 2 shows block diagram of hydraulic brake control system according to the present invention;
[030] Figure 3 shows flowchart according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION:
[031] The present invention provides hydraulic brake control system with accumulators 1 for effective braking on wheel loader. The secondary hydraulic assisted braking system uses the energy stored in the accumulator provided in the brake hydraulic system that will be available at the brake valve while braking and there by stops the machine to avoid fatal accidents. The system comprises hydraulic pump (1), priority valve (2), reducing valve (3), brake valve with inbuilt dual check valve (4), accumulators (5), brake pedal (6), hydraulic tank (7) and hoses and pipes for connections (8) as shown in figure 1 and 2.
[032] The flow from pump (1) flows to priority valve (2) and then to pressure reducing valve (3). The flow from pressure reducer valve (3) is diverted to brake valve circuit .The brake valve circuit is given the first priority so that oil reaches the hydraulic accumulators (5) connected in the line. Once the set charging pressure for the hydraulic accumulators is reached, the accumulator charging valve supplies the entire pump delivery volume to brake circuit.
[033] The two service brake circuits are separated by a brake valve with dual check valve (4). Therefore, if one brake circuit fails, the other remains operational. If the service brake is actuated, the brake valve regulates the pressure to be applied to brake chamber of axle in proportion to the actuating force and actuating path of the brake pedal (6).
[034] The vehicle is decelerated by the wheel brakes. When the braking process is completed, the hydraulic fluid flows back into the tank (7). If one of the brake circuits fails, the other one remains operational due to the mechanical contact of the two control spools in the brake valve and the circuit separation of the two hydraulic accumulators. The check valve prevents pressure reduction in the system and the actuating force remains unchanged. Thus meeting the secondary brake function.
[035] The invention provides secondary braking system positively by using the available stored energy in the accumulator of the brake hydraulic circuit. The invention provides the pressurized oil to the brake valve at engine off condition, the pressurized oil is stored in the accumulator as a backup system which is provided in the brake hydraulic circuit. During normal operation, the inside of the accumulator contains Nitrogen gas it is compressed and it stores the hydraulic oil at the required pressure. During the sudden engine switch off and at emergency, this pressurized oil in the accumulator will be available at the brake valve while braking and there by stops the machine to avoid fatal accidents in wheel loader as foolproof technology this will serves as backup system for brake circuit.
[036] By application of this system fatal accidents is prevented totally in the above said operating conditions and the system proves to be safer for operating the equipment on different gradient work locations.
[037] The system consists of pressure reducer valve for which flow is provided from the pump. The flow from pressure reducer valve is diverted to brake valve circuit. The brake valve circuit is given the first priority so that oil reaches the hydraulic accumulators connected in the line. Once the set charging pressure for the hydraulic accumulators is reached, the accumulator charging valve supplies the entire pump delivery volume to brake circuit The two service brake circuits are separated by a dual check valve. Therefore, if one brake circuit fails, the other remains operational. If the service brake is actuated, the brake valve regulates the pressure to be applied to brake chamber of axle in proportion to the actuating force and actuating path of the pedal.
[038] The vehicle is decelerated by the wheel brakes. When the braking process is completed, the hydraulic fluid flows back into the tank. If one of the brake circuits fails, the other one remains operational due to the mechanical contact of the two control spools in the brake valve and the circuit separation of the two hydraulic accumulators. The check valve prevents pressure reduction in the system and the actuating force remains unchanged. Thus, meeting the secondary brake function. The brake light of the vehicle is controlled via the pressure switch provided in the brake valve.
[039] In addition, brake valve is provided with parking brake circuit. When the parking brake switch is OFF, the parking brake is in released condition. Parking brake is applied when vehicle is stationary position. In the equipment, parking brake provided at the transmission front output drive shaft.
[040] Figure 2 shows flowchart according to the present invention When the wheel loader engine is started, the pump coupled with the transmission delivers pressurized oil to both steering, work attachment and brake valve. The pressure oil is tapped from the pump line and is stored in the accumulator as back up energy for emergency braking purpose during normal operation. The inside of the accumulator contains Nitrogen gas and it is compressed, it stores the hydraulic oil at the required pressure. When the equipment is working on a gradient or when the equipment has to be stopped during an emergency condition the brake pedal needs to be engaged to apply the brakes. While engine ON condition, when brake pedal (6) is depressed (brake applied), the linkage connecting to brake valve (4) pushes the spool in the brake valve and flow connects from pressure reducing valve (3) to brake valve via dual check valve and simultaneously the accumulator (5) gets charged during this process and it will be available as stored energy source.
[041] When the engine is OFF condition, when brake pedal (6) is depressed (brake applied), the linkage connecting to brake valve (4) pushes the spool in the brake valve and flow connects from the accumulator (5) there by stops the machine to avoid fatal accidents in wheel loader during working.
[042] The accumulator stored energy source serves as fail-safe technology and provide backup system for braking and the system proves to be safer for operating the equipment on different gradient work locations.
[043] This hydraulic brake system is applicable for any capacity of wheeled models as a safety feature.
[044] The two service brake circuits are separated by a brake valve with dual check valve (4). Therefore, if one brake circuit fails, the other remains operational. If the service brake is actuated, the brake valve regulates the pressure to be applied to brake chamber of axle in proportion to the actuating force and actuating path of the brake pedal (6).
[045] The vehicle is decelerated by the wheel brakes by using brake pedal. When the braking process is completed, the hydraulic fluid flows back into the tank (7). If one of the brake circuits fails, the other one remains operational due to the mechanical contact of the two control spools in the brake valve and the circuit separation of the two hydraulic accumulators. The check valve prevents pressure reduction in the system and the actuating force remains unchanged. Thus meeting the secondary brake function.
[046] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention. ,CLAIMS:WE CLAIM:
1. A hydraulic brake control system with accumulators for effective braking on wheel loader comprises-
a) reducing valve (3), wherein the flow from pump (1) flows to priority valve (2) and then to pressure reducing valve (3) and flow from pressure reducer valve (3) is diverted to brake valve circuit which is circuit is given the first priority so that oil reaches the hydraulic accumulators (5) connected in the line and once the set charging pressure for the hydraulic accumulators is reached, the accumulator charging valve supplies the entire pump delivery volume to brake circuit;
b) brake valve with inbuilt dual check valve (4) to separate two service brake circuits, of pressure reducer valve for which flow is provided from the pump wherein flow from pressure reducer valve is diverted to brake valve circuit (4) so that oil reaches the hydraulic accumulators connected in the line and once the set charging pressure for the hydraulic accumulators is reached, the accumulator charging valve supplies the entire pump delivery volume to brake circuit;
c) The two service brake circuits are separated by a dual check valve so that if one brake circuit fails, the other remains operational and if the service brake is actuated, the brake valve regulates the pressure to be applied to brake chamber of axle in proportion to the actuating force and actuating path of the pedal;
d) accumulators (5);
e) brake pedal (6);
f) hydraulic tank (7);
g) hoses and pipes for connections (8).
2. The hydraulic brake control system with accumulators, as claimed in claim 1, wherein the pressurized oil is supplied to the brake valve at engine off condition, the pressurized oil is stored in the accumulator as a backup system which is provided in the brake hydraulic circuit and during normal operation, the inside of the accumulator contains Nitrogen gas it is compressed and it stores the hydraulic oil at the required pressure and during the sudden engine switch off and at emergency, this pressurized oil in the accumulator will be available at the brake valve while braking and there by stops the machine to avoid fatal accidents in wheel loader as foolproof technology this will serves as backup system for brake circuit.
3. The hydraulic brake control system with accumulators, as claimed in claim 1, wherein the two service brake circuits are separated by a brake valve with dual check valve (4) and if one brake circuit fails, the other remains operational.
4. The hydraulic brake control system with accumulators, as claimed in claim 3, wherein if the service brake is actuated, the brake valve regulates the pressure to be applied to brake chamber of axle in proportion to the actuating force and actuating path of the brake pedal (6).
5. The hydraulic brake control system with accumulators, as claimed in claim 3, wherein When the braking process is completed, the hydraulic fluid flows back into the tank (7) and if one of the brake circuits fails, the other one remains operational due to the mechanical contact of the two control spools in the brake valve and the circuit separation of the two hydraulic accumulators and the check valve prevents pressure reduction in the system and the actuating force remains unchanged meeting the secondary brake function.
6. The hydraulic brake control system with accumulators, as claimed in claim 1, wherein the hen the braking process is completed, the hydraulic fluid flows back into the tank and if one of the brake circuits fails, the other one remains operational due to the mechanical contact of the two control spools in the brake valve and the circuit separation of the two hydraulic accumulators.
7. The hydraulic brake control system with accumulators, as claimed in claim 3, wherein the check valve prevents pressure reduction in the system and the actuating force remains unchanged and meets the secondary brake function.
8. The hydraulic brake control system with accumulators, as claimed in claim 1, wherein the brake light of the vehicle is controlled via the pressure switch provided in the brake valve.
9. The hydraulic brake control system with accumulators, as claimed in claim 1, wherein when the parking brake switch is OFF, the parking brake is in released condition and parking brake is applied when vehicle is stationary position. In the equipment,
10. The hydraulic brake control system with accumulators, as claimed in claim 6, wherein parking brake provided at the transmission front output drive shaft.