GB2588187A

GB2588187A - Braking system

Info

Publication number: GB2588187A
Application number: GB1914782.6A
Authority: GB
Inventors: David Mitchell Michael; Lewis Gerber Joshua; Randall Melchiori Shaun; A Robinson Mark; Berning Beau
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2019-10-11
Filing date: 2019-10-11
Publication date: 2021-04-21
Also published as: GB201914782D0

Abstract

A braking system 200 for a machine, for example a wheel loader or a tractor, includes an accumulator 210 for storing oil under pressure, at least one brake pack 212 in selective fluid communication with accumulator 210 and a hydraulic tank 214 in selective fluid communication with brake pack 212. A brake valve 208 allows oil to flow from accumulator 210 towards brake pack 212 in an opened state and from brake pack 212 towards hydraulic tank 214 in a closed state. A control module 206 is communicably coupled with brake valve 208, and transmits control signals to brake valve 208 for opening and closing the valve at least once to reduce oil pressure in accumulator 210 below a predetermined threshold. The system may allow accumulator 210 to be efficiently drained, for example during or after shutdown of the machine.

Description

BRAKING SYS IEM

Technical Field

100011 The present disclosure relates to a braking system for a machine Particularly, the present disclosure relates to automatic reduction of a hydraulic pressure in a braking system of a machine, during shut-down of the machine.

Background

100021 A braking system, such as an electro-hydraulic braking system, associated with a machine typically includes an accumulator that stores oil under pressure. In some situations, it is desirable to quickly dissipate hydraulic energy stored in the accumulator during or after a shut-down of the machine in order to ensure safe servicing of the braking system and operator or technician safety. Currently, oil pressure in the accumulator is released by manually pressing of a brake pedal in an operator cab of the machine. Further, automated processes of releasing the oil pressure that are currently available in the market are costly, require installation of additional hardware in the braking system, and increase a complexity of the braking system.

100031 U.S. Patent Number 8,123,304 describes a hydraulic system and method for controlling the brake of a wind turbine. During operation of the wind turbine, pressurized working fluid in the hydraulic system is blocked from being supplied to the brake. Even if some of this fluid does reach the brake, it is drained to prevent a pressure build-up and activation. To activate the brake, this drainage is stopped and the pressurized fluid is supplied to the brake. The blocking and unblocking of the pressurized working fluid may be controlled by first and second activation valves arranged in parallel in a supply line that communicates the working fluid to the brake.

Summary of the Disclosure

10004] In an aspect of the present disclosure, a braking system for a machine is provided. The braking system includes an accumulator for storing oil under pressure. The braking system also includes at least one brake pack in selective fluid communication with the accumulator and adapted to receive oil from the accumulator. The braking system further includes a hydraulic tank in selective fluid communication with the at least one brake pack and adapted to receive oil from the brake pack. The braking system includes a brake valve adapted to allow oil to flow from the accumulator towards the at least one brake pack in an opened state. The brake valve is further adapted to allow oil to flow from the at least one brake pack towards the hydraulic tank in a closed state. The braking system also includes a control module communicably coupled with the brake valve. The control module is configured to transmit control signals to the brake valve for opening and closing the brake valve at least once for reducing a pressure of oil in the accumulator below a predetermined threshold.

100051 Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

100061 FIG. 1 is a perspective view of a machine, according to an embodiment

of the present disclosure;

100071 FIG. 2 is a schematic view of a braking system associated with the machine of FIG. 1, according to an embodiment of the present disclosure; 100081 FIG. 3 is a flowchart for a process of draining an accumulator associated with the braking system of FIG. 2; [0009] FIG. 4 is a schematic view of another braking system associated with the machine of FIG. 1, according to an embodiment of the present disclosure; and 100101 FIG. 5 is a schematic view of yet another braking system associated with the machine of FIG. 1, according to an embodiment of the present disclosure.

Detailed Description

100111 Reference numerals appearing in more than one figure indicate the same or corresponding parts in each of them. References to elements in the singular may also be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims.

100121 FIG. 1 illustrates a perspective view of a machine 100, according to an embodiment of the present disclosure. In the illustrated embodiment, the machine 100 is embodied as a wheel loader. In alternative embodiments, the machine 100 may include a track type tractor, an excavator, a dozer, a harvester, a backhoe loader, a skid steer loader, or any other type of machine known in the art. The machine 100 may perform one or more than one type of operations associated with an industry, such as mining, construction, farming, transportation, or any other industry known in the art.

100131 The machine 100 includes a frame 102. Further, an implement 104 is disposed at a front end of the machine 100. The implement 104 is embodied as a bucket. The machine 100 includes an engine (not shown) that provides power to the machine 100 for operational and mobility requirements. The engine is supported by the frame 102 and is mounted within an enclosure formed in the frame 102. The engine may embody an internal combustion engine, such as a diesel engine, a gasoline engine, a gaseous fuel-powered engine, or any other combustion engine. Further, the machine 100 includes an operator cab 106 mounted on the frame 102. An operator of the machine 100 may be present within the operator cab 106 for operating the machine 100.

100141 The frame 102 rotatably supports a set of wheels 108, 110 in the illustrated embodiment of FIG. 1. More particularly, the machine 100 includes a pair of front wheels 108 and a pair of rear wheels 110. The wheels 108, 110 rotate about their respective axes thereby propelling the machine 100 on a ground surface. Alternatively, it can be contemplated to embody the set of ground engaging members in the form of tracks (not shown) such that the tracks propel the machine 100. Further, the machine 100 includes a front axle 112 and a rear axle 114 (shown in hidden lines herein), such that the front wheels 108 are connected to the front axle 112, whereas the rear wheels 110 are connected to the rear axle 114.

[0015] The machine 100 further includes a braking system 200 (shown in FIG. 2). The braking system 200 is used to control braking of one or more wheels 108, 110 of the machine 100 in order to stop a movement of the machine 100. In the illustrated example, the braking system 200 is used to control braking of the rear wheels 110 of the machine 100 Alternatively, the braking system 200 may be used to control braking of the rear wheels 110 as well as the front wheels 108 of the machine 100, as per application requirements. The braking system 200 illustrated herein is embodied as an electro-hydraulic braking system.

100161 As shown in FIG. 2, the braking system 200 includes a brake pedal 202 that is disposed within the operator cab 106 (see FIG. 1) of the machine 100 (see FIG. 1). When the operator of the machine 100 depresses the brake pedal 202, the braking system 200 causes the rear wheels 110 (see FIG. I) of the machine 100 to come to a halt. The brake pedal 202 is associated with a sensor 204 for acquisition of the operator's braking demand. The operator' s braking demand is transferred to a control module 206, evaluated there, and used as a source for generation of control signals by the control module 206 for controlling a brake valve 208.

100171 The braking system 200 includes an accumulator 210 for storing oil under pressure. The accumulator 210 is embodied as a variable volume fluid reservoir for containing oil which is maintained at a slightly elevated pressure. The accumulator 210 may embody a bladder type accumulator, a piston actuated accumulator, or a diaphragm actuated accumulator. Further, an accumulator pressure sensor 216 is associated with the braking system 200. The accumulator pressure sensor 216 is disposed in a first fluid line 222. The accumulator pressure sensor 216 generates a signal corresponding to a pressure of oil in the accumulator 210.

[0018] Further, the braking system 200 includes one or more brake packs 212 in selective fluid communication with the accumulator 210 and receives oil from the accumulator 210. In the illustrated example, the braking system 200 includes a pair of brake packs 212. The pair of brake packs 212 are disposed in the rear axle 114. Upon depression of the brake pedal 202, oil flows from the accumulator 210 towards the brake packs 212 that effects hydraulic actuation of the brake packs 212 to reduce a speed of the machine 100 or to stop the machine 100. The brake packs 212 includes a brake caliper assembly that is generally known in the art. The brake caliper assembly may include one or more pistons, brake pads, and a brake disc or drum attached to the rear axle 114. Further, a brake pressure sensor 218 is associated with the braking system 200. The brake pressure sensor 218 is disposed in a fourth fluid line 228. The brake pressure sensor 218 generates a signal corresponding to a pressure of oil in the brake packs 212.

[0019] The braking system 200 includes a hydraulic tank 214 in selective fluid communication with the brake packs 212 and receives oil from the brake packs 212. More particularly, oil drains from the brake packs 212 into the hydraulic tank 214 when the brake pedal 202 is released. The hydraulic tank 214 includes a reservoir or tank that is generally known in the art for receiving oil from the brake packs 212 and delivering oil to the accumulator 210. A pump (not shown) may be used to pressurize oil and deliver oil from the hydraulic tank 214 to the accumulator 210.

[0020] Further, the braking system 200 includes the brake valve 208. The brake valve 208 is embodied as an electro-hydraulic valve. The brake valve 208 may be actuated by an electro-hydraulic solenoid (not shown). In an example, the brake valve 208 may be embodied as a 3/2 way solenoid valve, without any limitations. In the illustrated example, the brake valve 208 is in selective fluid communication with each of the accumulator 210, the hydraulic tank 214, and the brake packs 212. The accumulator 210 is fluidly connected with the brake valve 208 via the first fluid line 222. Further, the brake valve 208 is fluidly connected with the brake pack 212 via a second fluid line 224 and a third fluid line 226. The brake valve 208 is fluidly connected with the brake pack 212 via the second fluid line 224 and the fourth fluid line 228. Moreover, the brake valve 208 is fluidly connected with the hydraulic tank 214 via a fifth fluid line 230.

[0021] When the brake valve 208 is opened, the accumulator 210 is in fluid communication with the brake packs 212 via the brake valve 208. The brake valve 208 allows oil to flow from the accumulator 210 towards the one or more brake packs 212 in an opened state. More particularly, in the opened state of the brake valve 208, oil from the accumulator 210 flows towards the brake packs 212 via the first, second, third, and fourth fluid lines 222, 224, 226, 228. Further, when the brake valve 208 is closed, the brake packs 212 are in fluid communication with the hydraulic tank 214 via the brake valve 208. The brake valve 208 allows oil to flow from the one or more brake packs 212 towards the hydraulic tank 214 in a closed state. More particularly, in the closed state of the brake valve 208, oil from the brake pack 212 flows towards the hydraulic tank 214 via the third, second, and fifth fluid lines 226, 224, 230. Moreover, oil from the brake pack 212 flows towards the hydraulic tank 214 via the fourth, second, and fifth fluid lines 228, 224, 230. [0022] The brake valve 208 opens and closes based on operation of the brake pedal 202. The brake valve 208 opens based on depression of the brake pedal 202. When the brake pedal 202 is pressed, the brake valve 208 opens and allows oil to leave the accumulator 210 and flow towards the brake packs 212. It should be noted that the brake valve 208 opens and closes based on signals received from the control module 206. Further, increase of the pressure in the brake packs 212 due to the flow of oil into the brake packs 212 causes the rear wheels 110 to come to a halt. Moreover, the brake valve 208 closes when the brake pedal 202 is released and no pressure is applied on the brake pedal 202. When the brake valve 208 closes, oil from the brake packs 212 drains towards the hydraulic tank 214.

[0023] Further, the braking system 200 includes the control module 206 The control module 206 is communicably coupled with the brake valve 208. The control module 206 is also communicably coupled with the sensor 204. Based on the signal received from the sensor 204, the control module 206 generates the control signals to open or close the brake valve 208. More particularly, when the brake pedal 202 is depressed, the sensor 204 generates a signal indicating depression of the brake pedal 202 that is received by the control module 206. The control module 206 in turn generates the control signal to open the brake valve 208. Further, when the brake pedal 202 is released, the sensor 204 generates a signal indicating release of the brake pedal 202 that is received by the control module 206. The control module 206 in turn generates the control signal to close the brake valve 208. It should be noted that an architecture of the braking system 200 described herein is exemplary in nature, and the braking system 200 may include additional or fewer components that are arranged in a different configuration to fulfill the function of the braking system 200.

[0024] Further, it is desirable to drain oil from the accumulator 210 of the braking system 200 during or after a shut-down of the machine 100. The present disclosure provides a technique of draining oil from the accumulator 210 based on opening and closing of the brake valve 208 once or more than once, based on application requirements. More particularly, the control module 206 transmits the control signals to the brake valve 208 for opening and closing the brake valve 208 one or more times for reducing a pressure of oil in the accumulator 210 below a predetermined threshold. The control module 206 initiates one or more drain cycles to reduce the pressure of oil in the accumulator 210 when a signal to drain the accumulator 210 is received by the control module 206. In an example, the signal to drain the accumulator 210 may be provided to the control module 206 by the operator of the machine 100.

100251 In one example, the control module 206 receives the signal pertaining to the pressure in the brake packs 212 from the brake pressure sensor 218. The control module 206 also receives the signal pertaining to the pressure in the accumulator 210 from the accumulator pressure sensor 216. Further, the control module 206 transmits the control signal to the brake valve 208 for opening the brake valve 208 so that oil from the accumulator 210 enters the brake packs 212 via the brake valve 208. The control module 206 monitors the pressure in the brake packs 212 and when the pressure in the brake packs 212 is greater than a predetermined pressure threshold that can be applied to the brake packs 212, the control module 206 transmits the control signal to the brake valve 208 for closing the brake valve 208. It should be noted that the term "predetermined pressure threshold" used herein may refer to an allowable pressure that can be exerted on the brake packs 212. As the brake valve 208 is closed, oil from in the brake packs 212 drains to the hydraulic tank 214. This completes a first drain cycle that reduces some amount of oil from the accumulator 210. It should be noted that an amount of oil that reduces from the accumulator 210 during each drain cycle is dependent on the predetermined pressure threshold to which the brake packs 212 can be subjected.

100261 Further, the control module 206 receives the signal pertaining to the pressure in the accumulator 210 after the first drain cycle. Based on the pressure in the accumulator 210, the control module 206 initiates a second drain cycle in which the brake valve 208 opens and closes similar to the first drain cycle in order to further reduce the pressure of oil from the accumulator 210. The control module 206 also receives the signal pertaining to the pressure in the accumulator 210 after the second drain cycle and accordingly decides if a third drain cycle needs to be initiated. Although only two drain cycles have been described herein, it should be noted that the control module 206 may initiate multiple drain cycles until the pressure of oil in the accumulator 210 reduces below the predetermined threshold. [0027] In another example, the braking system 200 may omit the brake pressure sensor 218 and the accumulator pressure sensor 216. In such an example, the control module 206 may initiate one or more drain cycles based on data that may be prestored in a memory of the control module 206. For example, the control module 206 may store information pertaining to the number of drain cycles that may have to be initiated to reduce the pressure of oil below the predetermined threshold. Further, the control module 206 may also store information pertaining to a time duration between opening and closing of the brake valve 208 for each drain cycle. It should be noted that the information related to the number of drain cycles and the time duration between opening and closing of the brake valve 208 may be calculated based on the predetermined pressure threshold of the brake packs 212, a volume of the accumulator 210, and the predetermined threshold of the accumulator 210, without any limitations.

[0028] FIG. 3 illustrates a flowchart for a process 300 (algorithm) for reducing the pressure of oil in the accumulator 210. The process 300 is implemented by the control module 206 and may be stored in the memory of the control module 206. Alternatively, the process 300 may be stored and implemented by an Electronic Control Module (ECM) present on-board the machine 100. The process 300 is executed by the control module 206 when the signal to drain the accumulator 210 is received by the control module 206. It should be noted that the process 300 described herein uses data from the brake pressure sensor 218 and the accumulator pressure sensor 216 for reducing the pressure of oil in the accumulator 210. However, it may be contemplated that a similar process may be applied by the control module 206 when the braking system 200 omits the brake pressure sensor 218 and the accumulator pressure sensor 216, without any limitations.

[0029] The process 300 begins at block 302 in which the method implemented by the control module 206 starts or begins operation. At block 304, the control module 206 determines if the engine has been turned off If the control module 206 detects that the engine is running, the process 300 moves to block 306. At block 306, the control module 206 waits until the engine has been turned off However, if the engine is in an off state, the process 300 moves to block 308. At the block 308, the control module 206 transmits the control signal for opening the brake valve 208. The opening of the brake valve 208 causes increase in the pressure of the brake packs 212 due to flow of oil from the accumulator 210 towards the brake packs 212.

100301 The process 300 then moves to block 310. At the block 310, the control module 206 determines if the pressure in the brake packs 212 is greater than the predetermined pressure threshold. If the pressure in the brake packs 212 is not greater than the predetermined pressure threshold, the process 300 moves to step 312. At the block 312, the control module 206 transmits the control signal to keep the brake valve 208 open until the pressure in the brake packs 212 is greater than the predetermined pressure threshold. However, if the pressure in the brake packs 212 is greater than the predetermined pressure threshold, the process 300 moves to block 314, At the block 314, the control module 206 transmits the control signal to the brake valve 208 for closing the brake valve 208. The process 300 then moves to block 316. At the block 316, the control module 206 determines if the pressure of oil in the accumulator 210 is below the predetermined threshold.

100311 If the control module 206 determines that the pressure of oil in the accumulator 210 is below the predetermined threshold, the process 300 moves to block 318. The process 300 terminates operation at the block 320. However, if the control module 206 determines that the pressure in the accumulator 210 is above the predetermined threshold, the process 300 moves to the block 306 to initiate another drain cycle for further reducing the pressure of oil in the accumulator 210 below the predetermined threshold.

100321 FIG. 4 illustrates another braking system 400, according to an embodiment of the present disclosure. The braking system 400 is associated with the machine 100 (see FIG. 1). The braking system 400 is used to control braking of one or more wheels 108, 110 (see FIG. 1) of the machine 100 in order to stop the movement of the machine 100. In the illustrated example, the braking system 400 is used to control braking of the rear wheels 110 of the machine 100. Alternatively, the braking system 400 may be used to control braking of the rear wheels 110 and the front wheels 108 of the machine 100 or the front wheels 108 of the machine 100, as per application requirements.

[0033] The braking system 400 illustrated herein is embodied as an electro-hydraulic braking system. The braking system 400 includes a brake pedal 402 that is disposed within the operator cab 106 (see FIG. 1) of the machine 100. When the operator of the machine 100 depresses the brake pedal 402, the braking system 400 controls braking of the rear wheels 110 of the machine 100. The brake pedal 402 is associated with a sensor 404 for acquisition of the operator's braking demand. The operator's braking demand is transferred to a control module 406, evaluated there, and used as a source for generation of control signals by the control module 406 for controlling a brake valve 408.

[0034] The braking system 400 includes an accumulator 410. The accumulator 410 is similar to the accumulator 210 described in relation to FIG. 2. An accumulator pressure sensor 416 is associated with the braking system 400. The accumulator pressure sensor 416 is disposed in a second fluid line 430. The accumulator pressure sensor 416 generates a signal corresponding to a pressure of oil in the accumulator 410. Further, the braking system 400 includes one or more brake packs 412 in selective fluid communication with the accumulator 410 and receives oil from the accumulator 410. In the illustrated example, the braking system 400 includes a pair of brake packs 412. Oil received from the accumulator 410 effects hydraulic actuation of the brake packs 412 in response to continued depression of the brake pedal 402. The brake packs 412 are similar to the brake packs 212 described in relation to FIG. 2. Further, a brake pressure sensor 418 is associated with the braking system 400. The brake pressure sensor 418 is disposed in a third fluid line 432. The brake pressure sensor 418 generates a signal corresponding to a pressure of oil in the brake packs 412.

100351 The braking system 400 includes a hydraulic tank 414 in selective fluid communication with the brake packs 412 and receives oil from the brake packs 412. More particularly, oil drains from the brake packs 412 into the hydraulic tank 414 after releasing the brake pedal 402. The hydraulic tank 414 is similar to the hydraulic tank 214 described in relation to FIG. 2. A pump (not shown) may be used to deliver oil from the hydraulic tank 414 to the accumulator 410.

100361 Further, the braking system 400 includes a main brake valve 422. The main brake valve 422 is embodied as a hydraulic valve. In an example, the main brake valve 422 may be embodied as a 3/2 way valve, without any limitations. The accumulator 410 is fluidly connected with the main brake valve 422 via a first fluid line 428 and the second fluid line 430. Further, the main brake valve 422 is fluidly connected to the brake packs 412 via the third fluid line 432 and a fourth fluid line 434. Moreover, the main brake valve 422 is fluidly connected to the hydraulic tank 414 via a fifth fluid line 436.

100371 The main brake valve 422 is opened to allow oil to flow from the accumulator 410 towards the brake packs 412. The main brake valve 422 opens based on the hydraulic signal received from a brake valve 408. More particularly, when the brake pedal 402 is pressed, the control module 406 transmits the control signals to open the brake valve 408 which in turn causes the main brake valve 422 to open thereby allowing oil to leave the accumulator 410 and flow towards the brake packs 412. In an opened state of the main brake valve 422, oil from the accumulator 410 flows towards the brake packs 412 via the first, second, third and fourth fluid lines 428, 430, 432, 434.

100381 Further, increase of the pressure in the brake packs 412 due to the flow of oil into the brake packs 412 causes the rear wheels 110 to come to a halt. Moreover, the main brake valve 422 closes when the brake pedal 402 is released and no pressure is applied on the brake pedal 402. When the brake valve 408 closes, oil from the brake packs 412 drains towards the hydraulic tank 414 via the main brake valve 422. More particularly, in a closed state of the main brake valve 422, oil from the brake packs 412 flows towards the hydraulic tank 414 via the third, fourth, and fifth fluid lines 432, 434, 436.

100391 The braking system 400 also includes the brake valve 408, a pilot accumulator 424, and a check valve 426. The brake valve 408, the pilot accumulator 424, and the check valve 426 are disposed in a fluid line 420. The fluid line 420 is in fluid communication with the first fluid line 428. It should be noted that the pilot accumulator 424 and the check valve 426 are used to maintain a minimum hydraulic pressure for the brake valve 408 to actuate the main brake valve 422 as the accumulator 410 is drained. The brake valve 408 is embodied as an electro-hydraulic valve. The brake valve 408 may be actuated by an electrohydraulic solenoid (not shown). In an example, the brake valve 408 may be embodied as a 2/2 way solenoid valve, without any limitations.

[0040] The brake valve 408 is in selective fluid communication with the main brake valve 422. The brake valve 408 is in fluid communication with the main brake valve 422 via a fluid line 438. Further, the brake valve 408 is in fluid communication with the pilot accumulator 424 and receives fluid from the pilot accumulator 424. However, in some examples, the braking system 400 may omit the pilot accumulator 424 and the check valve 426. In such an example, the brake valve 408 may be in selective fluid communication with the accumulator 410 and may receive oil directly from the accumulator 410, without any limitations.

100411 The brake valve 408 allows oil to flow from the accumulator 410 towards the one or more brake packs 412 in an opened state. Further, the brake valve 408 allows oil to flow from the brake packs 412 towards the hydraulic tank 414 in a closed state. The brake valve 408 opens and closes based on operation of the brake pedal 402. It should be noted that the brake valve 408 opens and closes based on signals received from the control module 406. When the brake valve 408 is opened, the accumulator 410 is in fluid communication with the brake packs 412 via the main brake valve 422. More particularly, the opening of the brake valve 408 causes the main brake valve 422 to open. The brake valve 408 opens based on depression of the brake pedal 402. More particularly, when the brake pedal 402 is pressed, the brake valve 408 opens and allows flow of oil towards the main brake valve 422. Oil flowing towards the main brake valve 422 applies hydraulic pressure on the main brake valve 422. As the hydraulic pressure increases, the main brake valve 422 opens and allows oil to leave the accumulator 410 and flow towards the brake packs 412. Thus, the brake valve 408 is opened to allow oil to flow from the accumulator 410 towards the brake packs 412.

[0042] Further, when the brake valve 408 is closed, the brake packs 412 are in fluid communication with the hydraulic tank 414 via the main brake valve 422. The brake valve 408 closes when the brake pedal 402 is released and no pressure is applied on the brake pedal 402. The closing of the brake valve 408 also causes the main brake valve 422 to close. More particularly, when the pressure from the brake pedal 402 is released, the brake valve 408 closes and restricts flow of oil towards the main brake valve 422. Thus, the hydraulic pressure on the main brake valve 422 reduces which causes the main brake valve 422 to close and restrict oil to leave the accumulator 410 and flow towards the brake packs 412. Thus, when the brake valve 408 doses, oil from the brake packs 412 drains towards the hydraulic tank 414.

[0043] Further, the braking system 400 includes the control module 406. The control module 406 is communicably coupled with the brake valve 408. The control module 406 is communicably coupled with the sensor 404. Based on the signal received from the sensor 404, the control module 406 generates the control signals to open or dose the brake valve 408. More particularly, when the brake pedal 402 is depressed, the sensor 404 generates the signal indicating depression of the brake pedal 402 that is received by the control module 406. The control module 406 in turn generates the control signal to open the brake valve 408. Further, when the brake pedal 402 is released, the sensor 404 generates the signal indicating release of the brake pedal 402 that is received by the control module 406. The control module 406 in turn generates the control signal to close the brake valve 408. It should be noted that an architecture of the braking system 400 described herein is exemplary in nature, and the braking system 400 may include additional or fewer components that are arranged in a different configuration to fulfill the function of the braking system 400.

[0044] Further, it is desirable to drain oil from the accumulator 410 of the braking system 400 during or after the shut-down of the machine 100. The present disclosure provides a technique of draining oil from the accumulator 410 based on opening and closing of the brake valve 408 once or more than once, based on application requirements. More particularly, the control module 406 transmits the control signals to the brake valve 408 for opening and closing the brake valve 408 one or more times for reducing the pressure of oil in the accumulator 410 below a predetermined threshold. The control module 406 initiates one or more drain cycles to reduce the pressure of oil in the accumulator 410 when a signal to drain the accumulator 410 is received by the control module 406. In an example, the signal to drain the accumulator 410 may be provided to the control module 406 by the operator of the machine 100.

[0045] In one example, the control module 406 receives the signal pertaining to the pressure in the brake packs 412 from the brake pressure sensor 418. The control module 406 also receives the signal pertaining to the pressure in the accumulator 410 from the accumulator pressure sensor 416. Further, the control module 406 transmits the control signal to the brake valve 408 for opening the brake valve 408. The opening of the brake valve 408 causes the main brake valve 422 to open. The opening of the main brake valve 422 allows flow of oil from the accumulator 410 towards the brake packs 412 via the main brake valve 422.

[0046] Further, the control module 406 monitors the pressure in the brake packs 412 and when the pressure in the brake packs 412 is greater than a predetermined pressure threshold that can be applied to the brake packs 412, the control module 406 transmits the control signal to the brake valve 408 for closing the brake valve 408. It should be noted that the term "predetermined pressure threshold-used herein may refer to an allowable pressure that can be exerted on the brake packs 412. As the brake valve 408 is closed, the main brake valve 422 also closes and oil from the brake packs 412 drains to the hydraulic tank 414 via the main brake valve 422. This completes a first drain cycle that reduces some amount of oil from the accumulator 410. It should be noted that an amount of oil that reduces from the accumulator 410 during each drain cycle is dependent on the predetermined pressure threshold to which the brake packs 412 can be subjected.

[0047] Further, the control module 406 receives the signal pertaining to the pressure in the accumulator 410 after the first drain cycle. Based on the pressure in the accumulator 410, the control module 406 initiates a second drain cycle in which the brake valve 408 opens and closes in order to open and close the main brake valve 422 similar to the first drain cycle for further reducing the pressure of oil from the accumulator 410. The control module 406 receives the signal pertaining to the pressure in the accumulator 410 after the second drain cycle and accordingly decides if a third drain cycle needs to be initiated. Although only two drain cycles have been described herein, it should be noted that the control module 406 may initiate multiple drain cycles until the pressure of oil in the accumulator 410 reduces below the predetermined threshold.

[0048] In another example, the braking system 400 may omit the brake pressure sensor 418 and the accumulator pressure sensor 416. In such an example, the control module 406 may initiate one or more drain cycles based on data that may be prestored in a memory of the control module 406. For example, the control module 406 may store information pertaining to the number of drain cycles that may have to be initiated to reduce the pressure of oil below the predetermined threshold. Further, the control module 406 may also store information pertaining to a time duration between opening and closing of the brake valve 408 for each drain cycle that effects the opening and closing of the main brake valve 422. It should be noted that the information related to the number of drain cycles and the time duration between opening and closing of the brake valve 408 may be calculated based on the predetermined pressure threshold of the brake packs 412, an amount of time required to open the main brake valve 422, a volume of the accumulator 410, and the predetermined threshold of the accumulator 410, without any limitations.

[0049] FIG. 5 illustrates another braking system 500, according to an embodiment of the present disclosure. The braking system 500 is associated with the machine 100 (see FIG. 1). The braking system 500 is used to control braking of one or more wheels 108, 110 (see FIG. 1) of the machine 100 in order to stop the movement of the machine 100. In the illustrated example, the braking system 500 is used to control braking of the rear wheels 110 of the machine 100. Alternatively, the braking system 500 may be used to control braking of the rear wheels 110 and the front wheels 108 of the machine 100 or the front wheels 108 of the machine 100, as per application requirements.

100501 The braking system 500 illustrated herein is embodied as a parallel electro-hydraulic braking system. The braking system 500 includes a brake pedal 502 that is disposed within the operator cab 106 (see FIG. 1) of the machine 100. When the operator of the machine 100 depresses the brake pedal 502, the braking system 500 controls braking of the rear wheels 110 of the machine 100.

100511 The braking system 500 includes an accumulator 510 for storing oil under pressure. The accumulator 510 is similar to the accumulator 210 described in relation to FIG. 2. An accumulator pressure sensor 516 is associated with the braking system 500. The accumulator pressure sensor 516 generates a signal corresponding to a pressure of oil in the accumulator 510. Further, the braking system 500 includes one or more brake packs 512 in selective fluid communication with the accumulator 510 and receive oil from the accumulator 510. In the illustrated example, the braking system 500 includes a pair of brake packs 512. Oil received from the accumulator 510 effects hydraulic actuation of the brake packs 512 in response to continued depression of the brake pedal 502. The brake packs 512 are similar to the brake packs 212 described in relation to FIG. 2. Further, a brake pressure sensor 518 is associated with the braking system 500. The brake pressure sensor 518 generates a signal corresponding to a pressure of oil in the brake packs 512 100521 The braking system 500 includes a hydraulic tank 514 in selective fluid communication with the brake packs 512 and receives oil from the brake packs 512. More particularly, oil drains from the brake packs 512 into the hydraulic tank 514 after releasing the brake pedal 502. The hydraulic tank 514 is similar to the hydraulic tank 214 described in relation to FIG. 2. A pump (not shown) may be used to deliver oil from the hydraulic tank 514 to the accumulator 510.

[0053] Further, the braking system 500 includes a brake pedal valve 501. The brake pedal 502 is mechanically linked to the brake pedal valve 501 such that depression of the brake pedal 502 causes the brake pedal valve 501 to open. The brake pedal valve 501 is embodied as a hydraulic valve. In an example, the brake pedal valve 501 may be embodied as a 5/2 way valve, without any limitations. The accumulator 510 is fluidly connected with the brake pedal valve 501. Further, the brake pedal valve 501 is in selective fluid communication with a main valve 532. When the brake pedal 502 is depressed, the brake pedal valve 501 opens causing oil flow from the accumulator 510 to flow towards the main valve 532 in order to apply a first pilot pressure on the main valve 532. The first pilot pressure is a hydraulic pressure that is applied on the main valve 532 based on an opening of the brake pedal valve 501.

[0054] The braking system 500 also includes the brake valve 508. The brake valve 508 allows oil to flow from the accumulator 510 towards the one or more brake packs 512 in an opened state. More particularly, the opening of the brake valve 508 causes the main valve 532 to open to allow flow of oil from the accumulator 510 towards the brake packs 512. Further, the brake valve 508 allows oil to flow from the one or more brake packs 512 towards the hydraulic tank 514 in a closed state. More particularly, the closing of the brake valve 508 causes the main valve 532 to close and oil from the brake packs 512 is allowed to flow towards the hydraulic tank 514. The brake valve 508 is embodied as an electro-hydraulic valve. The brake valve 508 may be actuated by an electro-hydraulic solenoid (not shown). The brake valve 508 is in selective fluid communication with the main valve 532. The brake valve 508 opens and closes based on signals received from the control module 506. When the brake valve 508 opens, oil is allowed to flow in order to apply a second pilot pressure on the main valve 532. The second pilot pressure is a hydraulic pressure that is applied that is applied on the main valve 532 based on an opening of the brake valve 508.

[0055] In the illustrated example, the brake valve 508 is in selective fluid communication with the accumulator 510 to receive oil from the accumulator 510 for actuating the main valve 532. Alternatively, a pilot accumulator (not shown) that is similar to the pilot accumulator 424 illustrated in FIG. 4 may be associated with the braking system 500. It should be noted that the pilot accumulator may be used to maintain a minimum hydraulic pressure for the brake valve 508 to actuate the main valve 532.

[0056] Further, the braking system 500 includes the main valve 532. The main valve 532 is embodied as a hydraulic valve. In an example, the brake valve 508 may be embodied as a 3/2 way valve, without any limitations. In the illustrated example, the main valve 532 is in selective fluid communication with each of the brake pedal valve 501, the brake valve 508, the accumulator 510, the hydraulic tank 514, and the brake packs 512. The accumulator 510 is fluidly connected with the main valve 532 via a first fluid line 522. Further, the main valve 532 is fluidly connected with the brake pack 512 via a second fluid line 524 and a third fluid line 526. The main valve 532 is fluidly connected with the brake pack 512 via the second fluid line 524 and a fourth fluid line 528. Moreover, the main valve 532 is fluidly connected with the hydraulic tank 514 via a fifth fluid line 530.

[0057] The main valve 532 opens based on the first pilot pressure or the second pilot pressure that is received from the brake pedal valve 501 or the brake valve 508, respectively. More particularly, if the first pilot pressure is higher than the second pilot pressure, the main valve 532 opens based on the application of the first pilot pressure that is received from the brake pedal valve 501. However, if the second pilot pressure is higher than the first pilot pressure, the main valve 532 opens based on the application of the second pilot pressure that is received from the brake valve 508. Further, the opening of the main valve 532 causes oil to leave the accumulator 510 and flow towards the brake packs 512. In an opened state of the main valve 532, oil from the accumulator 510 flows towards the brake packs 512 via the first, second, third and fourth fluid lines 522, 524, 526, 528. Further, increase of the pressure in the brake packs 512 due to the flow of oil into the brake packs 512 causes the rear wheels 110 to come to a halt.

[0058] Moreover, the main valve 532 closes when the brake pedal 502 is released and no pressure is applied on the brake pedal 502. More particularly, when the pressure on the brake pedal 502 is released, the brake pedal valve 501 closes and no pilot pressure is applied on the main valve 532. Thus, the main valve 532 closes thereby restricting oil to leave the accumulator 510 and flow towards the brake packs 512. Further, when the main valve 532 is closed, the brake packs 512 are in fluid communication with the hydraulic tank 514 via the main valve 532. More particularly, when the main valve 532 closes, oil from the brake packs 512 drains towards the hydraulic tank 514 via the main valve 532. It should be noted that oil from the brake packs 512 flows towards the hydraulic tank 514 via the fluid lines 528, 526, 524, 530.

100591 Further, the braking system 500 includes the control module 506. The control module 506 is communicably coupled with the brake valve 508. The control module 506 generates the control signals to open or close the brake valve 508. It should be noted that an architecture of the braking system 500 described herein is exemplary in nature, and the braking system 500 may include additional or fewer components that are arranged in a different configuration to fulfill the function of the braking system 500.

[0060] Further, it is desirable to drain oil from the accumulator 510 of the braking system 500 during or after the shut-down of the machine 100. The present disclosure provides a technique of draining oil from the accumulator 510 based on opening and closing of the brake valve 508 once or more than once, based on application requirements. The control module 506 transmits the control signals to the brake valve 508 for opening and closing the brake valve 508 one or more times for reducing the pressure of oil in the accumulator 510 below a predetermined threshold. Further, the brake valve 508 in turn causes the main valve 532 to open and close to allow flow of oil from the accumulator 510 towards the brake packs 512. The control module 506 initiates one or more drain cycles to reduce the pressure of oil in the accumulator 510 when a signal to drain the accumulator 510 is received by the control module 506. In an example, the signal to drain the accumulator 510 may be provided to the control module 506 by the operator of the machine 100.

[0061] In one example, the control module 506 receives the signal pertaining to the pressure in the brake packs 512 from the brake pressure sensor 518. The control module 506 also receives the signal pertaining to the pressure in the accumulator 510 from the accumulator pressure sensor 516. Further, the control module 506 transmits the control signal to the brake valve 508 for opening the brake valve 508. The opening of the brake valve 508 causes the main valve 532 to open. The opening of the main valve 532 allows flow of oil from the accumulator 510 towards the brake packs 512 via the main valve 532.

[0062] Further, the control module 506 monitors the pressure in the brake packs 512 and when the pressure in the brake packs 512 is greater than a predetermined pressure threshold that can be applied to the brake packs 512, the control module 506 transmits the control signal to the brake valve 508 for closing the brake valve 508. It should be noted that the term "predetermined pressure threshold-used herein may refer to an allowable pressure that can be exerted on the brake packs 512. As the brake valve 508 is closed, the main valve 532 also closes and oil from the brake packs 512 drains to the hydraulic tank 514 via the main valve 532. This completes a first drain cycle that reduces some amount of oil from the accumulator 510. It should be noted that an amount of oil that reduces from the accumulator 510 during each drain cycle is dependent on the predetermined pressure threshold to which the brake packs 512 can be subjected.

100631 Further, the control module 506 receives the signal pertaining to the pressure in the accumulator 510 after the first drain cycle. Based on the pressure in the accumulator 510, the control module 506 initiates a second drain cycle in which the brake valve 508 opens and closes in order to open and close main valve 532 similar to the first drain cycle for further reducing the pressure of oil from the accumulator 510. The control module 506 receives the signal pertaining to the pressure in the accumulator 510 after the second drain cycle and accordingly decides if a third drain cycle needs to be initiated. Although only two drain cycles have been described herein, it should be noted that the control module 506 may initiate multiple drain cycles until the pressure of oil in the accumulator 510 reduces below the predetermined threshold.

100641 In another example, the braking system 500 may omit the brake pressure sensor 518 and the accumulator pressure sensor 516. In such an example, the control module 506 may initiate one or more drain cycles based on data that may be prestored in a memory of the control module 506. For example, the control module 506 may store information pertaining to the number of drain cycles that may have to be initiated to reduce the pressure of oil below the predetermined threshold. Further, the control module 506 may also store information pertaining to a time duration between opening and closing of the brake valve 508 for each drain cycle that effects the opening and closing of the main valve 532. It should be noted that the information related to the number of drain cycles and the time duration between opening and closing of the brake valve 508 may be calculated based on the predetermined pressure threshold of the brake packs 512, an amount of time required to open the main valve 532, a volume of the accumulator 510, and the predetermined threshold of the accumulator 510, without any limitations.

100651 The control modules 206, 406, 506 may embody a single microprocessor or multiple microprocessors for receiving signals from various components of the machine 100. Numerous commercially available microprocessors may be configured to perform the functions of the control modules 206, 406, 506. It should be appreciated that the control modules 206, 406, 506 may embody a machine microprocessor capable of controlling numerous machine functions. A person of ordinary skill in the art will appreciate that the control modules 206, 406, 506 may additionally include other components and may also perform other functions not described herein.

[0066] It is to be understood that individual features shown or described for one embodiment may be combined with individual features shown or described for another embodiment. The above described implementation does not in any way limit the scope of the present disclosure. Therefore, it is to be understood although some features are shown or described to illustrate the use of the present disclosure in the context of functional segments, such features may be omitted from the scope of the present disclosure without departing from the spirit of the present disclosure as defined in the appended claims

Industrial Applicability

[0067] The present disclosure relates to the braking system 200, 400, 500. The braking system 200, 400, 500 allows automation of the process of draining the accumulator 210, 410, 510 based on opening and closing the valve 208, 422, 532 as many times as required until the pressure of oil in the accumulator 210, 410, 510 drops below the predetermined threshold. Thus, a need of manual depression of the brake pedal 202, 402, 502 several times for reducing the pressure of oil in the accumulator 210, 410, 510 may be eliminated.

[0068] The braking system 200, 400, 500 is simple in operation and includes fewer components. Further, the braking system 200, 400, 500 makes use of components that are already present on the machine for draining the accumulator 210, 410, 510, thereby eliminating any additional operational or installation cost. The braking system 200, 400, 500 also improves safety by allowing quick dissipation of the accumulator 210, 410, 510. Further, the braking system 200, 400, 500 can be easily retrofitted on existing machines without modifying hardware associated with the machine.

Claims

Claims What is claimed is: 1 A braking system for a machine, the braking system comprising: an accumulator for storing oil under pressure; at least one brake pack in selective fluid communication with the accumulator and adapted to receive oil from the accumulator; a hydraulic tank in selective fluid communication with the at least one brake pack and adapted to receive oil from the brake pack; a brake valve adapted to allow oil to flow from the accumulator towards the at least one brake pack in an opened state, wherein the brake valve is further adapted to allow oil to flow from the at least one brake pack towards the hydraulic tank in a closed state; and a control module communicably coupled with the brake valve, wherein the control module is configured to transmit control signals to the brake valve for opening and closing the brake valve at least once for reducing a pressure of oil in the accumulator below a predetermined threshold.