CN117681841A - Multi-loop brake hydraulic system of forklift - Google Patents

Abstract

The invention discloses a forklift multi-loop braking hydraulic system which comprises a multi-loop braking valve, wherein the multi-loop braking valve comprises an input end and an output end, the output end is connected with a service brake group, the input end is connected with a plurality of hydraulic oil ways, and each hydraulic oil way works independently. When one of the hydraulic oil ways fails, the service brake group can be continuously controlled through the multi-loop brake valve by the other hydraulic oil way which normally works, so that the safety of the vehicle is controlled, and as the hydraulic oil ways are in independent working states, the failure of one hydraulic oil way does not affect the normal work of the other hydraulic oil way, the fault tolerance of the vehicle is improved, and the running state can be protected when the failure occurs.

Description

Multi-loop brake hydraulic system of forklift

Technical Field

The invention relates to the technical field of vehicle braking, in particular to a multi-loop braking hydraulic system of a forklift.

Background

As is well known, the off-road forklift is four-wheel drive, and the working condition is bad, so that the requirements on the safety, the reliability and the stability of each system of the whole forklift are higher, and a set of stable and reliable braking system is a primary condition for ensuring the working safety of the off-road forklift. If the conventional forklift adopts a front wheel braking mode, the off-road working conditions may include brake oil pipe cracking, brake damage and the like, so that the risk of failure of a brake system can be increased, and for the off-road forklift adopting four-wheel drive, the reliability and safety of the off-road forklift can be greatly improved by a set of safe and reliable four-wheel brake system.

For example, publication number "CN201874905U", discloses an accumulator charging valve of an engineering machinery full hydraulic braking system ", which comprises a charging valve oil inlet, two charging valve working oil ports and a charging valve oil return port, wherein the two charging valve working oil ports are respectively communicated with two accumulators; meanwhile, the working oil ports of the two liquid filling pressure valves are respectively communicated with the oil inlets of the two hydraulic main valves, the liquid filling valves are provided with two-position two-way valves, and the oil outlet of each two-position two-way valve is communicated with an energy accumulator; the connection position of the two-position two-way valve is controlled by oil inlet oil ways of the two-position two-way valve, and the oil inlet oil ways of the two-position two-way valve are communicated; the cut-off position of each two-position two-way valve is controlled by the oil outlet of the two-position two-way valve. However, in practical application, when the oil supply path for supplying oil fails, braking control on the vehicle cannot be realized, and the fault tolerance is low.

Disclosure of Invention

Aiming at the problem that the fault tolerance of a braking system is low in the prior art, the invention provides a multi-loop braking hydraulic system of a forklift, which can improve the fault tolerance of the braking system, and can still realize the braking effect of a vehicle and improve the safety in the running process when an oil supply way fails and cannot supply oil.

In order to achieve the above purpose, the present invention adopts the following technical scheme.

The multi-loop braking hydraulic system of the forklift comprises a multi-loop braking valve, wherein the multi-loop braking valve comprises an input end and an output end, the output end is connected with a service brake group, the input end is connected with a plurality of hydraulic oil ways, and each hydraulic oil way works independently. In this application, be provided with the multiloop brake valve, the multiloop brake valve is including input and output, wherein the output is connected with service brake group, service brake group is the part that control vehicle was braked, when the fluid is exported through the multiloop brake valve, can control service brake group and brake, thereby guarantee stopping of vehicle, the multiloop brake valve still includes the input, wherein the input is then connected with a plurality of hydraulic circuit, each hydraulic circuit independently works, therefore when one of them hydraulic circuit breaks down, can pass through multiloop brake valve through the hydraulic oil way of other normal work and continue to control service brake group, thereby control the security of vehicle, and because for independent operating condition between each hydraulic circuit, therefore the trouble of one hydraulic circuit can not influence the normal work of another hydraulic circuit, improve the fault tolerance of vehicle, can protect the service condition when breaking down.

Preferably, the service brake group comprises a front axle braking unit and a rear axle braking unit, the output end comprises a first output port and a second output port, and the first output port and the second output port are respectively communicated with the front axle braking unit and the rear axle braking unit. The brake system of vehicle self can divide into front brake and back brake, service brake group is including front axle brake unit and rear axle brake unit in this application, and the output then is provided with the export of a export and No. two exports that correspond with front axle brake unit and rear axle brake unit, wherein export and No. two exports are independent work, thereby can independently come front axle brake unit and rear axle brake unit, wherein a plurality of hydraulic circuit can independently with export and No. two exports UNICOM, and then with each hydraulic circuit independent control front axle brake unit and rear axle brake unit, when one of them breaks down of front axle brake unit or rear axle brake unit, also can not lead to the whole brake system of vehicle to break down, still can rely on the front axle/rear axle brake unit of the other half to realize the braking effect to the vehicle, thereby guarantee the security of vehicle.

Preferably, the hydraulic oil way comprises an oil pump, the oil pump is communicated with a charging valve, an accumulator is communicated with the charging valve, and the charging valve is communicated with a multi-loop brake valve. The hydraulic oil is composed of an oil pump, a charging valve and an accumulator, oil is conveyed through the oil pump for the charging valve, and the accumulator is used for assisting, so that braking is realized.

Preferably, the input end comprises a first input port and a second input port, the hydraulic oil circuit comprises a front axle hydraulic oil circuit and a rear axle hydraulic oil circuit, and the first input port and the second input port are respectively communicated with the front axle hydraulic oil circuit and the rear axle hydraulic oil circuit. The input end comprises a first input port and a second input port, wherein the two hydraulic oil ways are respectively a front axle hydraulic oil way and a rear axle hydraulic oil way, the front axle hydraulic oil way and the rear axle hydraulic oil way are respectively communicated with the first input port and the second input port, and are matched with a front axle braking unit and a rear axle braking unit which are respectively communicated with the first output port and the second output port, so that the front axle hydraulic oil way and the rear axle hydraulic oil way are respectively and independently controlled to the front axle braking unit and the rear axle braking unit.

Preferably, the output end is connected with a transfer assembly, the service brake group comprises a plurality of brake units, the transfer assembly comprises brake on-off valves arranged on the brake units, the transfer assembly comprises transfer on-off valves arranged between the brake units, the transfer assembly comprises oil pressure detection units arranged in the brake units, and the oil pressure detection units are communicated with the transfer on-off valves and the brake on-off valves. The output end is provided with a transfer component, wherein the transfer component comprises a brake on-off valve, a transfer on-off valve and an oil pressure detection unit, the brake on-off valves are arranged on each brake unit and can control the on-off of oil in the brake units, the transfer on-off valves are arranged between the brake units, and when the brake units are a front axle brake unit and a rear axle brake unit, the transfer on-off valves are arranged between the front axle brake unit and the rear axle brake unit and can control the oil of the front axle brake unit and the rear axle brake unit to be communicated, so that a certain hydraulic oil circuit can control the front axle brake unit and the rear axle brake unit simultaneously; the control method comprises the following steps: when a front axle braking unit or a rear axle braking unit is damaged, the oil pressure detection unit detects that the oil pressure change on the failed braking unit is abnormal, so that a braking on-off valve on the braking unit is controlled to be closed, oil delivery to the failed braking unit is stopped, when one of the hydraulic oil paths fails, the failed hydraulic oil path cannot deliver oil to the corresponding connected braking unit, the oil pressure detection unit detects that the oil pressure does not change and the standard braking pressure cannot be achieved, so that a transfer on-off valve is controlled to be opened, and the braking unit corresponding to the failed hydraulic oil path is synchronously controlled through another hydraulic oil path; in practical application, when a brake unit is in a problem, generally a pipeline is broken or leaked, when the brake unit is in a braking state, effective oil pressure cannot be formed, leakage can be continuously carried out, at the moment, the oil pressure detection unit can detect that the oil pressure change is abnormal, when a hydraulic oil circuit is in a failure, the hydraulic oil circuit cannot normally carry out oil delivery for the corresponding brake unit through a multi-loop brake valve, a check valve is arranged at an output end, so that the oil pressure on the brake unit is prevented from flowing back, when the hydraulic oil circuit cannot provide oil, the oil pressure in the brake unit is kept unchanged, the oil pressure detection unit can judge that a part at the front end of the brake unit is in a problem, the transfer on-off valve is controlled to be opened, so that the normal hydraulic oil circuit is communicated with each brake unit to realize synchronous control, and when the brake unit is a front axle brake unit and a rear axle brake unit, if the hydraulic oil circuit of the front axle brake unit is controlled to be in a failure, the transfer on-off valve is opened, so that the rear axle hydraulic oil circuit can simultaneously control the front axle brake unit and the rear axle brake unit, and the stable brake of a vehicle is ensured; preferably, the oil pressure detection unit is used for continuously detecting the oil pressure, and is not used for instantaneously detecting, and the brake/transfer on-off valve can be opened only after the abnormal change of the oil pressure or the abnormal change of the oil pressure occurs for a period of time, so that misjudgment can be avoided, and the accuracy of judgment can be improved.

Preferably, each hydraulic oil circuit comprises a secondary output port, each secondary output port is communicated with a shuttle valve, and the shuttle valve is connected with a parking brake assembly. Be provided with vice delivery outlet in the hydraulic pressure oil circuit, vice delivery outlet and shuttle valve UNICOM, wherein the shuttle valve is connected with parking brake subassembly, through shuttle valve control parking brake subassembly to realize parking braking, because the hydraulic pressure oil circuit is provided with a plurality of, so also have more vice delivery outlet relatively, consequently a plurality of hydraulic pressure oil circuits can provide more parking times for shuttle valve and parking brake subassembly, because the stock of fluid is higher than a hydraulic pressure oil circuit among the prior art, consequently can improve the stability of parking brake subassembly in the use.

Preferably, the shuttle valve comprises a plurality of oil inlet channels, each oil inlet channel is communicated with each auxiliary output port, and each oil inlet channel is communicated with each other. Because the shuttle valve is provided with a plurality of hydraulic oil ways and a plurality of auxiliary output ports, a plurality of corresponding oil inlet channels are arranged on the shuttle valve and are communicated with each other through the oil inlet channels so as to control the parking brake assembly at the same time.

Preferably, each of the oil feed passages includes a high pressure oil feed side and a low pressure oil feed side, and the shuttle valve delivers oil from the high pressure oil feed side to the parking brake assembly. Each oil inlet channel comprises a high-pressure oil inlet side and a low-pressure oil inlet side, and because the same oil pressure can not be possessed in practical application, after each oil inlet channel is communicated with each other, the high-pressure oil inlet side and the low-pressure oil inlet side can be relatively generated, in the oil transportation process, the high-pressure oil inlet side can extrude the oil liquid of the low-pressure oil inlet side, and the shuttle valve adaptively selects the oil liquid of the high-pressure oil inlet side to provide the oil liquid for the parking brake assembly, so that the braking performance of the parking brake assembly is more stable, the fault tolerance of the parking brake assembly is improved, and the parking brake can be timely and effectively released when a vehicle breaks down and needs a trailer.

Preferably, the parking brake assembly comprises a manual parking brake valve and a parking brake, and the manual parking brake valve is arranged between the parking brake and the shuttle valve. The manual parking brake valve is used for controlling the parking brake, so that the stability of the parking brake is ensured.

Preferably, the hydraulic oil way comprises a charging valve, the charging valve comprises a main output port, the main output port is communicated with an accumulator, and the auxiliary output port is communicated with the main output port. Through the main delivery outlet UNICOM with vice delivery outlet, simplify the structure, because main delivery outlet and vice delivery outlet can not work at the same time, consequently with main delivery outlet and vice delivery outlet UNICOM, can not produce the interference, can guarantee the stability of two different kinds of brakings simultaneously, the shuttle valve can carry out the self-adaptation to the high-low pressure of energy storage ware simultaneously and select, through main delivery outlet and vice delivery outlet intercommunication for the shuttle valve also can be with the energy storage ware intercommunication of setting on main delivery outlet.

The beneficial effects of the invention are as follows:

(1) The plurality of hydraulic oil ways are matched with the multi-loop brake valve, so that the fault tolerance of a brake system can be improved, the brake control of a vehicle can be still realized under a fault state, and the driving safety is ensured;

(2) The front axle braking unit and the rear axle braking unit are controlled separately by arranging the front axle hydraulic oil way and the rear axle hydraulic oil way, so that the independence of a braking system is ensured, the fault tolerance is improved again, and the safety in a fault state is ensured;

(3) The transfer component is arranged to detect the oil pressure change in the brake unit and control the on-off and transfer, so that the stability and the safety of the vehicle in a fault state are ensured, and the oil leakage caused by the pipeline rupture of the brake unit is avoided;

(4) Set up vice delivery outlet between each hydraulic circuit to with each vice delivery outlet and shuttle valve intercommunication, through the oil pressure of each vice delivery outlet self antagonism, the self-adaptation produces the high pressure oil feed side, thereby provides the fuel feeding for parking brake subassembly, guarantees the braking stability of parking brake subassembly, can improve fault-tolerant rate simultaneously, and can improve the braking number of times.

Drawings

Fig. 1 is a hydraulic schematic of the present invention.

Fig. 2 is a hydraulic schematic diagram of the multi-circuit brake valve of fig. 1.

Fig. 3 is a hydraulic schematic diagram of the hydraulic oil passage in fig. 1.

Fig. 4 is a hydraulic schematic diagram of the shuttle valve of fig. 1.

Fig. 5 is a hydraulic schematic diagram of example 2.

In the figure:

the multi-loop brake valve comprises a multi-loop brake valve 1, an input end 11, an input port 111, an input port 112, an output end 12, an output port 121 and an output port 122;

2 service brake group, 21 front axle brake unit, 22 rear axle brake unit;

3 hydraulic oil ways, 31 main output ports, 32 auxiliary output ports, 33 oil pumps, 34 charging valves, 35 accumulators, 301 front axle hydraulic oil ways and 302 rear axle hydraulic oil ways;

the transfer component, 41 brake on-off valve, 42 transfer on-off valve, 43 communicating oil circuit;

5 a brake unit;

6 parking brake assembly, 61 hand-controlled parking brake valve, 62 parking brake;

a 7 shuttle valve, 71 oil feed passage;

8, a hydraulic oil tank;

9 oil return ports.

Detailed Description

The invention is further described below with reference to the drawings and specific embodiments.

Example 1:

as shown in fig. 1, 2 and 3, a multi-circuit brake hydraulic system of a forklift truck includes a multi-circuit brake valve 1, the multi-circuit brake valve 1 includes an input end 11 and an output end 12, the output end 12 is connected with a service brake set 2, in this embodiment, the input end 11 is connected with two hydraulic oil paths 3, each hydraulic oil path 3 works independently, the service brake set 2 includes a front axle brake unit 21 and a rear axle brake unit 22, the output end 12 includes a first output port 121 and a second output port 122, the first output port 121 and the second output port 122 are respectively communicated with the front axle brake unit 21 and the rear axle brake unit 22, the input end 11 includes a first input port 111 and a second input port 112, the hydraulic oil path 3 includes a front axle hydraulic oil path 301 and a rear axle hydraulic oil path 302, the first input port 111 and the second input port 112 are respectively communicated with the front axle hydraulic oil path 301 and the rear axle hydraulic oil path 302, in this embodiment, the hydraulic oil path 3 includes an oil pump 33, the oil pump 33 is communicated with a charge valve 34, an accumulator 35 is arranged on the charge valve 34, the valve 34 is communicated with the multi-circuit brake valve 1, the oil pump 33 is communicated with the charge valve 8, and the charge valve 9 is also communicated with the charge valve 9.

In this embodiment, a multi-circuit brake valve 1 is provided, the multi-circuit brake valve 1 is a part, when the multi-circuit brake valve 1 is stepped on, the multi-circuit brake valve can realize the in-out oil of multi-circuit brake oil (in this embodiment, the in-out oil of two-circuit brake oil) so as to simultaneously meet the two-circuit braking of a front axle and a rear axle, the multi-circuit service brake valve is installed in a cab, the output of brake valve oil is controlled by stepping on a pedal by a driver, the multi-circuit brake valve 1 in this embodiment comprises an input end 11 and an output end 12, wherein the output end 12 is connected with a service brake group 2, the service brake group 2 is a component for controlling the vehicle to brake, when the multi-circuit brake valve 1 outputs oil, the service brake group 2 is controlled to brake so as to ensure the braking of the vehicle, the multi-circuit brake valve 1 also comprises an input end 11, wherein the input end 11 is connected with a plurality of hydraulic oil ways 3, and each hydraulic oil way 3 works independently, so when one of the hydraulic oil ways 3 breaks down, the other hydraulic oil ways 3 which can work normally can continue to control the service brake group 2 through the multi-circuit brake valve 1, thereby controlling the safety of the vehicle, and the hydraulic oil ways between the hydraulic ways 3 can not work normally when the hydraulic ways break down, and the other hydraulic oil ways can work normally and the fault-tolerant condition can be improved; the braking system of the vehicle can be divided into front braking and rear braking, in the application, the service brake group 2 comprises a front axle braking unit 21 and a rear axle braking unit 22, the output end 12 is provided with a first output port 121 and a second output port 122 which correspond to the front axle braking unit 21 and the rear axle braking unit 22, wherein the first output port 121 and the second output port 122 independently work, so that the front axle braking unit 21 and the rear axle braking unit 22 can be independently separated, a plurality of hydraulic oil ways 3 can be independently communicated with the first output port 121 and the second output port 122, each hydraulic oil way 3 can be used for independently controlling the front axle braking unit 21 and the rear axle braking unit 22, when one of the front axle braking unit 21 or the rear axle braking unit 22 fails, the whole braking system of the vehicle can not fail, and the braking effect of the vehicle can still be realized by means of the other half of the front axle/rear axle braking unit, so that the safety of the vehicle is ensured; the input end 11 comprises a first input port 111 and a second input port 112, wherein the hydraulic oil way 3 is provided with two hydraulic oil ways 301 and 302, which are respectively a front axle hydraulic oil way 301 and a rear axle hydraulic oil way 302, the front axle hydraulic oil way 301 and the rear axle hydraulic oil way 302 are respectively communicated with the first input port 111 and the second input port 112, and are matched with a front axle braking unit 21 and a rear axle braking unit 22 which are respectively communicated with the first output port 121 and the second output port 122, so that the front axle hydraulic oil way 301 and the rear axle hydraulic oil way 302 respectively and independently control the front axle braking unit 21 and the rear axle braking unit 22; the hydraulic oil passage 3 is composed of an oil pump 33, a charge valve 34 and an accumulator 35, and is charged with oil by the oil pump 33 for the charge valve 34 and assisted by the accumulator 35, thereby realizing braking.

As shown in fig. 1, 3 and 4, each hydraulic oil circuit 3 includes a secondary output port 32, each secondary output port 32 is communicated with a shuttle valve 7, the shuttle valve 7 is connected with a parking brake assembly 6, the shuttle valve 7 includes a plurality of oil inlet channels 71, each oil inlet channel 71 is communicated with each secondary output port 32, each oil inlet channel 71 is communicated with each other, each oil inlet channel 71 includes a high-pressure oil inlet side and a low-pressure oil inlet side, the shuttle valve 7 transfers oil from the high-pressure oil inlet side to the parking brake assembly 6, the parking brake assembly 6 includes a manual control brake valve 61 and a parking brake 62, and the manual control parking brake valve 61 is arranged between the parking brake 62 and the shuttle valve 7.

An auxiliary output port 32 is arranged in the hydraulic oil path 3, the auxiliary output port 32 is communicated with the shuttle valve 7, the shuttle valve 7 is connected with the parking brake assembly 6, the parking brake assembly 6 is controlled through the shuttle valve 7, thereby realizing parking brake, more auxiliary output ports 32 are correspondingly arranged because the hydraulic oil path 3 is provided with a plurality of hydraulic oil paths, the plurality of hydraulic oil paths 3 can provide more parking times for the shuttle valve 7 and the parking brake assembly 6, the storage amount of oil is higher than that of one hydraulic oil path 3 in the prior art, the stability of the parking brake assembly 6 in use can be improved, a plurality of corresponding oil inlet channels 71 are arranged on the shuttle valve 7 and are communicated with each other through the oil inlet channels 71, the parking brake assembly 6 is simultaneously controlled, each oil inlet channel 71 comprises a high-pressure oil inlet side and a low-pressure oil inlet side, because the hydraulic oil paths 3 cannot have the same oil pressure in practical application, after the oil inlet channels 71 are communicated with each other, a high-pressure oil inlet side and a low-pressure oil inlet side are relatively generated, in the oil conveying process, the high-pressure oil inlet side can extrude the oil of the low-pressure oil inlet side, the shuttle valve 7 adaptively selects the oil of the high-pressure oil inlet side to provide the oil for the parking brake assembly 6, so that the braking performance of the parking brake assembly 6 is more stable, the fault tolerance of the parking brake assembly 6 is also improved, when a vehicle breaks down and needs a trailer, the parking brake can be timely and effectively released, the parking brake 62 is controlled through the manual brake valve, the stability of the parking brake 62 is ensured, namely, the parking brake 62 is in a parking state when pressure hydraulic oil is not passed, the parking brake 62 has the function of automatic locking and braking due to pressure loss, the safety of the whole vehicle is ensured when the vehicle is at the default position; after the pressure hydraulic oil is introduced, the parking brake is released; wherein the parking brake 62 may be arranged in a position where a parking function is possible, such as at the input shaft of the drive axle, at the output shaft of the gearbox, etc., depending on the situation.

As shown in fig. 3, the hydraulic oil circuit 3 includes a charging valve 34, the charging valve 34 includes a main output port 31, an accumulator 35 is communicated with the main output port 31, and the auxiliary output port 32 is communicated with the main output port 31. Through the main delivery outlet 31 UNICOM with vice delivery outlet 32, simplify the structure, because main delivery outlet 31 and vice delivery outlet 32 can not work at the same time, consequently with main delivery outlet 31 and vice delivery outlet 32 UNICOM, can not produce the interference, can guarantee the stability of two different types of braking simultaneously, the shuttle valve 7 can carry out the self-adaptation to the high low pressure of energy storage ware 35 and select simultaneously, through main delivery outlet 31 and vice delivery outlet 32 intercommunication for the shuttle valve 7 also can communicate with the energy storage ware 35 that sets up on main delivery outlet 31.

The assembly and working process of the forklift multi-loop brake hydraulic system in the embodiment are as follows: in this embodiment, the hydraulic oil circuit 3 comprises two hydraulic oil circuits 3, a charging valve 34, an accumulator 35, an oil pump 33 and a plurality of hydraulic oil tanks 8 are arranged in each hydraulic oil circuit 3, the hydraulic oil circuit 3 comprises a main output port 31 and an auxiliary output port 32, wherein the main output port 31 is communicated with the multi-circuit brake valve 1, the auxiliary output port 32 is communicated with the shuttle valve 7, the multi-circuit brake valve 1 comprises a first input port 111 and a second input port 112 which are communicated with the two hydraulic oil circuits 3, the first input port 111 is communicated with the first output port 121 when a driver steps down the brake, the second input port 112 is communicated with the second output port 122, the multi-circuit brake valve 1 comprises an oil return port 9, the oil return port 9 is communicated with the hydraulic oil tanks 8, the first output port 121 and the second output port 122 are correspondingly connected with the oil return port 9 under a non-braking condition, no back pressure exists on the oil circuit, the other ends of the first output port 121 and the second output port 122 are correspondingly connected with the front axle braking unit 21 and the rear axle braking unit 22 in the service braking assembly, wherein the main output port 31 and the auxiliary output port 32 in the hydraulic oil path 3 are arranged on the charging valve 34, the main output port 31 and the auxiliary output port 32 are mutually communicated, the main output port 31 and the auxiliary output port 32 are both charging ports, the shuttle valve 7 is provided with oil inlet channels 71 communicated with the auxiliary output port 32, two corresponding oil inlet channels 71 are also arranged due to the arrangement of the two hydraulic oil paths 3, the shuttle valve 7 can perform pressure selection on the two accumulators 35 due to the mutual communication of the oil inlet channels 71 and the communication between the main output port 31 and the auxiliary output port 32, so that when the oil pressure in one hydraulic oil path 3 is larger, a high-pressure oil inlet side and a low-pressure oil inlet side can be naturally formed, the high-pressure oil inlet side provides oil pressure for the parking brake assembly 6, wherein the parking brake assembly 6 comprises a manual control parking brake valve 61, an oil return port 9 is arranged on the manual control parking brake valve 61, under normal working conditions, the oil return port 9 is communicated with an oil outlet of the manual control parking brake valve 61, the parking brake 62 has the function of automatically locking the brake under no-pressure, when pressure oil is connected, namely, the oil outlet and the oil inlet of the manual control parking brake valve 61 are communicated, and when the oil on the high-pressure oil inlet side is input to the parking brake 62, the parking brake 62 releases braking, and due to the fact that two energy accumulators 35 are connected, the parking brake can still be contacted during one failure, and the technical scheme is that: the mode of the double pump, the double filling valve and the double loop brake valve is that even if one pump or valve or one of the front and rear axles fails in the running process of the vehicle, the other set of brake system can still effectively and reliably realize the service brake function, the two sets of brake systems are independently controlled, are complementary and do not interfere with each other, the stability and the reliability of the brake systems are greatly provided, the control oil source of the parking brake is derived from the two accumulators 35, and the using times of the parking brake can be greatly improved.

Example 2:

as shown in fig. 5, unlike embodiment 1, in this embodiment, the output end 12 is connected with a relay assembly 4, the service brake set 2 includes two brake units 5, the relay assembly 4 includes a brake on-off valve 41 disposed on the brake units 5, a communication oil path 43 is disposed between each brake unit, the relay assembly 4 includes a relay on-off valve 42 disposed on the communication oil path 43, the relay assembly 4 includes an oil pressure detection unit disposed in each brake unit 5, the oil pressure detection unit communicates the relay on-off valve 42 and the brake on-off valve 41, and the brake on-off valve 41 is disposed on a side of the relay on-off valve 42 away from the multi-circuit brake valve 1.

The output end 12 is provided with a transfer component 4, wherein the transfer component 4 comprises a brake on-off valve 41, a transfer on-off valve 42 and an oil pressure detection unit, the brake on-off valve 41 is arranged on each brake unit 5 and can control the on-off of oil in the brake units 5, the transfer on-off valve 42 is arranged between the brake units 5, and when the brake units 5 are a front axle brake unit 21 and a rear axle brake unit 22, the transfer on-off valve 42 is arranged between the front axle brake unit 21 and the rear axle brake unit 22 and can control the oil in the front axle brake unit 21 and the rear axle brake unit 22 to be communicated, so that a certain hydraulic oil path 3 can simultaneously control the front axle brake unit 21 and the rear axle brake unit 22; the control method comprises the following steps: in a normal state, the brake on-off valve is kept open, and the transfer on-off valve is kept closed, wherein when a certain hydraulic oil line 5 is damaged (in this embodiment, when the front axle brake unit 21 or the rear axle brake unit 22 is damaged), the oil pressure detection unit detects that the oil pressure change on the failed brake unit 5 is abnormal (namely, the pressure in the hydraulic oil line can be input, and even if the pressure changes, the normal brake pressure cannot be formed), so as to control the brake on-off valve 41 on the brake unit 5 to be closed and stop conveying oil to the failed brake unit 5 (can avoid continuous oil leakage in the braking process and ensure the safety); when one of the hydraulic oil paths 3 fails, the failed hydraulic oil path 3 cannot deliver oil to the corresponding connected brake units 5, the oil pressure detection unit detects that the oil pressure does not change and the standard brake pressure cannot be achieved (no pressure oil enters, the pressure is maintained in a stable state and cannot reach the brake pressure standard), so that the transfer on-off valve 42 is controlled to be opened, and the corresponding brake units 5 of the failed hydraulic oil path 3 are synchronously controlled through the other hydraulic oil paths 3 (so that the defect of unsatisfactory brake effect caused by failure of the main brake units is avoided, and the front axle/rear axle braking of the vehicle brake system is also divided into main active braking and auxiliary braking); in practical application, when the brake unit 5 is in a problem, generally a pipeline is broken or leaked, and when the brake is in a braking state, even if the oil in the hydraulic oil way can be input into the brake unit 5, effective oil pressure cannot be formed, leakage can be continuously carried out, the oil pressure detection unit at the moment can detect abnormal oil pressure change, when the hydraulic oil way 3 is in a fault state, the hydraulic oil way 3 cannot normally carry out oil transportation for the corresponding brake unit 5 through the multi-loop brake valve 1, a check valve is arranged at the output end 12, the oil on the brake unit 5 is prevented from flowing back, therefore, when the hydraulic oil way 3 cannot provide oil, the oil pressure in the brake unit 5 is kept unchanged and does not reach the standard brake pressure, the oil pressure detection unit can judge that the part at the front end of the brake unit 5 is in a problem, the transfer on-off valve 42 is controlled, so that the normal hydraulic oil way 3 is communicated with each brake unit 5, synchronous control is realized, when the brake unit 5 is a front axle brake unit 21 and a rear axle brake unit 22, if the hydraulic oil way 3 controlling the front axle brake unit 21 is in a fault state, the transfer on-off valve 42 is opened, and the front axle brake unit 302 can be controlled simultaneously, and the front axle brake unit is controlled stably; preferably, the oil pressure detection unit is used for detecting the oil pressure continuously, and is not used for detecting instantaneously, and the brake/transfer on-off valve 42 is opened only after the abnormal change of the oil pressure or the abnormal change of the oil pressure occurs for a period of time, so that misjudgment can be avoided, the accuracy of judgment is improved, the brake on-off valve is further arranged on the side of the transfer on-off valve, which is far away from the multi-loop brake valve, so that when two brake units are controlled through one hydraulic oil circuit, the oil supply at the position of the failed brake unit can be stably cut off when the brake units fail, and the safety is ensured.

Claims (10)

1. The multi-circuit braking hydraulic system of the forklift truck is characterized by comprising a multi-circuit braking valve (1), wherein the multi-circuit braking valve (1) comprises an input end (11) and an output end (12), the output end (12) is connected with a service brake group (2), the input end (11) is connected with a plurality of hydraulic oil ways (3), and each hydraulic oil way (3) works independently.

2. A multi-circuit brake hydraulic system for a forklift truck according to claim 1, wherein the service brake group (2) comprises a front axle brake unit (21) and a rear axle brake unit (22), the output end (12) comprises a first output port (121) and a second output port (122), and the first output port (121) and the second output port (122) are respectively communicated with the front axle brake unit (21) and the rear axle brake unit (22).

3. A multi-circuit brake hydraulic system for a forklift truck according to claim 1, wherein the hydraulic oil path (3) comprises an oil pump (33), the oil pump (33) is communicated with a charging valve (34), the charging valve (34) is communicated with an accumulator (35), and the charging valve (34) is communicated with the multi-circuit brake valve (1).

4. A multi-circuit brake hydraulic system for a forklift truck according to claim 1, wherein the input end (11) comprises a first input port (111) and a second input port (112), the hydraulic oil path (3) comprises a front axle hydraulic oil path (301) and a rear axle hydraulic oil path (302), and the first input port (111) and the second input port (112) are respectively communicated with the front axle hydraulic oil path (301) and the rear axle hydraulic oil path (302).

5. A multi-circuit brake hydraulic system for a forklift truck according to any one of claims 1-4, wherein the output end (12) is connected with a transfer assembly (4), the service brake group (2) comprises a plurality of brake units (5), the transfer assembly (4) comprises brake on-off valves (41) arranged on the brake units (5), the transfer assembly (4) comprises transfer on-off valves (42) arranged between the brake units (5), the transfer assembly (4) comprises oil pressure detection units arranged in the brake units (5), and the oil pressure detection units are communicated with the transfer on-off valves (42) and the brake on-off valves (41).

6. A multi-circuit brake hydraulic system for a forklift truck according to any one of claims 1 to 4, wherein each hydraulic circuit (3) comprises a secondary outlet (32), each secondary outlet (32) is connected to a shuttle valve (7), and the shuttle valve (7) is connected to a parking brake assembly (6).

7. A multi-circuit brake hydraulic system for a forklift truck according to claim 6, wherein the shuttle valve (7) comprises a plurality of oil feed passages (71), each oil feed passage (71) being in communication with each secondary outlet (32), each oil feed passage (71) being in communication with each other.

8. A multi-circuit brake hydraulic system for a forklift truck as claimed in claim 7, wherein each of said oil feed passages (71) includes a high pressure oil feed side and a low pressure oil feed side, said shuttle valve (7) delivering oil from the high pressure oil feed side to the parking brake assembly (6).

9. A multi-circuit brake hydraulic system for a forklift truck according to claim 6, characterized in that the parking brake assembly (6) comprises a manual parking brake valve (61) and a parking brake (62), the manual parking brake valve (61) being arranged between the parking brake (62) and the shuttle valve (7).

10. A multi-circuit brake hydraulic system for a forklift truck according to claim 6, wherein the hydraulic circuit (3) comprises a charging valve (34), the charging valve (34) comprises a main output port (31), an accumulator (35) is communicated with the main output port (31), and the auxiliary output port (32) is communicated with the main output port (31).