Forklift hydraulic system with efficient potential energy recovery function and forklift

Abstract

The utility model discloses a forklift hydraulic system with an efficient potential energy recovery function, which comprises an oil tank, a pump motor capable of being used as a hydraulic pump, a motor generator capable of being used as a motor, a double pump driven by the motor, a brake oil way, a steering oil way, a lifting oil way and an inclined oil way, the rotating end of the motor generator is connected with the pump motor, an oil inlet of the pump motor is communicated with the interior of the oil tank, an oil outlet of the pump motor is connected with a first lifting and descending control valve, the first lifting and descending control valve comprises a first hydraulic control one-way valve, an oil outlet of the pump motor is connected with an oil port a of the first hydraulic control one-way valve, and an oil port b of the first hydraulic control one-way valve is connected with an oil port b of the second hydraulic control one-way valve. An oil port b of the first hydraulic control one-way valve is connected with the lifting oil way. Braking, steering, lifting and inclining actions of the forklift can be achieved through the combination of the duplex pump and the pump motor, and the potential energy recovery efficiency of the forklift can be further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a forklift hydraulic system technical field especially relates to a kind of forklift hydraulic system and forklift with high-efficiency potential energy recovery. BACKGROUND

[0002] In recent years, forklift is used more and more widely in logistics industry, and forklift needs to complete braking, steering, lifting and tilting during work. Among them, a large amount of potential energy is contained in the process of forklift picking up goods, and the traditional hydraulic system consumes potential energy in the throttle valve port, which undoubtedly causes a lot of potential energy waste for forklifts that need to lift frequently. In the existing forklift potential energy recovery technical scheme, the pressure oil of the lifting cylinder in patent application numbers CN201110037639.3 and CN202411102812.7 needs to pass through the pump motor, the internal oil passage of the multi-way valve and the oil tank, and the internal oil passage of the multi-way valve causes large pressure loss, which affects the efficiency of potential energy recovery. SUMMARY

[0003] The utility model aims at at least one of the technical problems in the related art to some extent. Therefore, one purpose of the utility model is to provide a forklift hydraulic system with high-efficiency potential energy recovery, which avoids the pressure oil of the lifting cylinder returning to the oil tank through the internal oil passage of the multi-way valve, and designs a forklift hydraulic system with high-efficiency potential energy recovery.

[0004] In the first aspect, the utility model provides a forklift hydraulic system with high-efficiency potential energy recovery, which comprises an oil tank, a pump motor that can be used as a hydraulic pump, a motor generator that can be used as an electric motor, a double pump driven by the motor, a brake oil circuit, a steering oil circuit, a lifting oil circuit and a tilting oil circuit. The rotating end of the motor generator is connected with the pump motor, the oil inlet of the pump motor is communicated with the inside of the oil tank, the oil outlet of the pump motor is connected with a lifting and descending control valve one, the lifting and descending control valve one comprises a hydraulic control check valve one, the oil outlet of the pump motor is connected with the oil port a of the hydraulic control check valve one, the oil port b of the hydraulic control check valve one is connected with the lifting oil circuit, the oil inlet of the first oil pump P3 and the second oil pump P2 of the double pump are both communicated with the inside of the oil tank, the oil outlet of the first oil pump P3 of the double pump is connected with the brake oil circuit, the oil outlet of the second oil pump P2 of the double pump is connected with the steering oil circuit through a multi-way valve, the oil port A1 of the multi-way valve is connected with the lifting oil circuit, the oil port A2 and the oil port B2 of the multi-way valve are connected with the tilting oil circuit, and the oil return port T of the multi-way valve is communicated with the inside of the oil tank.

[0005] Preferably, the lifting and lowering control valve one comprises a two-position two-way electromagnetic reversing valve one, the oil port c of the hydraulic control check valve one is connected with the oil port g of the electromagnetic reversing valve one, the oil port h of the electromagnetic reversing valve one is communicated with the inside of the oil tank, the oil port A1 of the multi-way valve is connected with the lifting oil circuit, and the oil port b of the hydraulic control check valve one is connected with the oil port A1 of the multi-way valve.

[0006] Preferably, the multi-way valve comprises a priority valve and a lifting spool valve, the oil port P of the priority valve is connected with the second oil pump P2 outlet of the double pump, the oil port EF of the priority valve is connected to port A, the oil port F of the lifting spool valve is connected with port A through a lifting check valve, the oil port G of the lifting spool valve is directly connected with port A, the oil port E of the lifting spool valve is connected with the oil return port T of the multi-way valve, the oil port D of the lifting spool valve is provided with a plug for plugging the oil channel, the oil port H of the lifting spool valve is connected with the oil return port T of the multi-way valve, the oil port J and the oil port K of the lifting spool valve are connected with a lifting and lowering control valve two, the lifting and lowering control valve two comprises a hydraulic control check valve two and a two-position two-way electromagnetic reversing valve two, the oil port J of the lifting spool valve and the oil port d of the hydraulic control check valve two are connected, the oil port K of the lifting spool valve is connected with the oil port k of the electromagnetic reversing valve two, the oil port e of the hydraulic control check valve two is connected with the oil port A1 of the multi-way valve, and the oil port f of the hydraulic control check valve two is connected with the oil port j of the electromagnetic reversing valve two.

[0007] Preferably, a displacement sensor for detecting the motion state of the lifting spool valve is installed at the position of the lifting spool valve.

[0008] Preferably, the multi-way valve comprises an inclined spool valve, the oil port G2 of the inclined spool valve is connected with the oil port O of the lifting spool valve, the oil port E2 of the inclined spool valve is connected to port B through an inclined check valve, one end of the port B is connected with the port A, the oil port F2 and the oil port O2 of the inclined spool valve are respectively connected with the oil return port T of the multi-way valve, the oil port J2 of the inclined spool valve is connected with the oil port A2 of the multi-way valve, and the oil port K2 of the inclined spool valve is connected with the oil port B2 of the multi-way valve.

[0009] Preferably, the multi-way valve comprises an OPS function valve block, the OPS function valve block comprises an oil return on-off valve and a two-position two-way electromagnetic reversing valve two which is electrified when the driver sits on the seat coil, the port B is connected with the oil port m of the oil return on-off valve, the oil port m of the oil return on-off valve is respectively connected with the oil port v of the oil return on-off valve, the oil port s of the oil return on-off valve and the oil port p of the electromagnetic reversing valve two, the oil port n of the oil return on-off valve is connected with the oil return port T of the multi-way valve, and the oil port q of the electromagnetic reversing valve two is connected with the oil return port T of the multi-way valve.

[0010] Preferably, the oil port CF and the oil port LS of the priority valve are connected with the oil inlet of the steering oil circuit respectively, and the oil return port of the steering oil circuit is communicated with the inside of the oil tank.

[0011] Preferably, the oil port a of the hydraulic control one-way valve one is communicated with the inside of the oil tank through a lifting safety valve, the oil port LS of the priority valve is connected with the oil return port T of the multi-way valve through a steering safety valve, a port C is arranged on the pipeline connected with the port A and the port B, and the port C is connected with the oil return port T of the multi-way valve through a main safety valve.

[0012] Preferably, a filter one is arranged on the pipeline through which the first oil pump P3 inlet and the second oil pump P2 inlet of the duplex pump are communicated with the oil tank, and a filter two with bypass is arranged on the pipeline through which the oil return port of the steering oil circuit is communicated with the oil tank.

[0013] In the second aspect, the utility model provides a fork truck which contains any one of the above fork truck hydraulic systems with high efficient potential energy recovery.

[0014] The utility model discloses the beneficial effect is:

[0015] Adopt the multi-pump system, and the first oil pump P3 of duplex pump supplies braking, and the independent oil source of braking oil circuit ensures that the quick and accurate braking effect can be realized when braking. The second oil pump P2 of duplex pump supplies steering, lifting and tilting, and when the pump motor functions as a gear pump, the pump motor supplies lifting, and when the mast lifting action with larger flow demand is carried out, the second oil pump P2 of duplex pump and the pump motor work together, and when the mast tilting action with smaller flow demand is carried out, only the second oil pump P2 of duplex pump works, and energy consumption is reduced.

[0016] When the mast descends, the pump motor functions as a motor, the motor generator functions as a generator, the pressure oil of the lifting oil circuit returns to the oil tank directly through the lifting descent control valve one and the pump motor, the backflow pressure oil drives the motor to rotate, thereby driving the generator to generate electricity, the generated electric energy is stored in the battery, the pressure oil of the lifting oil circuit does not return to the oil tank through the internal oil channel of the multi-way valve, pressure loss is reduced, and potential energy recovery efficiency is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The utility model discloses the frame schematic diagram of a kind of fork truck hydraulic system with high efficient potential energy recovery proposed by the utility model.

[0018] Figure 2 The frame schematic diagram of the multi-way valve proposed by the utility model.

[0019] In the figure: 1-oil tank, 2-pump motor, 3-motor generator, 4-motor, 5-filter one, 6-duplex pump, 7-filter two, 8-brake oil circuit, 9-lift down control valve one, 10-steering oil circuit, 11-lift oil circuit, 12-tilt oil circuit, 13-multiple valve; 9.1-electromagnetic reversing valve one, 9.2-liquid control check valve one, 9.3-lift safety valve; 13.1-priority valve, 13.2-steering safety valve, 13.3-lift spool valve, 13.4-lift down control valve two, 13.5-tilt spool valve, 13.6-OPS function valve block, 13.7-tilt check valve, 13.8-lift check valve, 13.9-main safety valve, 13.10-displacement sensor; 13.4.1-liquid control check valve two, 13.4.2-electromagnetic reversing valve two; 13.6.1-oil return on-off valve, 13.6.2-electromagnetic reversing valve three. DETAILED DESCRIPTION

[0020] Reference Figure 1 A forklift hydraulic system with high-efficiency potential energy recovery, comprising an oil tank 1, a pump motor 2 that can be used as a hydraulic pump, a motor generator 3 that can be used as a motor, a duplex pump 6 driven by a motor 4, a brake oil circuit 8, a steering oil circuit 10, a lift oil circuit 11, and a tilt oil circuit 12, the rotating end of the motor generator 3 is connected with the pump motor 2, the oil inlet of the pump motor 2 is communicated with the inside of the oil tank 1, the oil outlet of the pump motor 2 is connected with a lift down control valve one 9, the lift down control valve one 9 comprises a liquid control check valve one 9.2, the oil outlet of the pump motor 2 is connected with the oil port a of the liquid control check valve one 9.2, the oil port b of the liquid control check valve one 9.2 is connected with the lift oil circuit 11, the oil inlets of the first oil pump P3 and the second oil pump P2 of the duplex pump 6 are both communicated with the inside of the oil tank 1, the oil outlet of the first oil pump P3 of the duplex pump 6 is connected with the brake oil circuit 8, the oil outlet of the second oil pump P2 of the duplex pump 6 is connected with the steering oil circuit 10 through a multiple valve 13, the oil port A1 of the multiple valve 13 is connected with the lift oil circuit 11, the oil port A2 and the oil port B2 of the multiple valve 13 are connected with the tilt oil circuit 12, and the oil return port T of the multiple valve 13 is communicated with the inside of the oil tank 1.

[0021] Obviously, based on the above, the system adopts a multiple pump system, the second oil pump P2 of the duplex pump 6 supplies steering, lifting, and tilting, the pump motor 2 supplies lifting when the pump motor 2 acts as a gear pump, the second oil pump P2 of the duplex pump 6 and the pump motor 2 work together when a mast lifting action with large flow demand is performed, only the second oil pump P2 of the duplex pump 6 works when a mast tilting action with small flow demand is performed, thereby reducing energy consumption, the first oil pump P3 of the duplex pump 6 supplies braking, the brake oil circuit has an independent oil source, and fast and accurate braking effect can be achieved during braking.

[0022] In this embodiment, reference is made to Figure 1The lifting and lowering control valve 9 includes a two-position two-way electromagnetic reversing valve 9.1, and a hydraulic control check valve 9.2. The oil port c of the hydraulic control check valve 9.2 is connected to the oil port g of the electromagnetic reversing valve 9.1, the oil port h of the electromagnetic reversing valve 9.1 is communicated with the inside of the oil tank 1, the oil port A1 of the multi-way valve 13 is connected to the lifting oil circuit 11, and the oil port b of the hydraulic control check valve 9.2 is connected to the oil port A1 of the multi-way valve 13.

[0023] Obviously, based on the above, by the setting of the electromagnetic reversing valve 9.1, when the lifting oil circuit 11 controls the fork to rise, the coil Y1 of the electromagnetic reversing valve 9.1 loses electricity, the oil port g and the oil port h of the electromagnetic reversing valve 9.1 are disconnected, the motor generator 3 acts as a motor, the pump motor 2 acts as a hydraulic pump, the pressure oil output by the pump motor 2 reaches the oil port a of the hydraulic control check valve 9.2, pushes the valve core of the hydraulic control check valve 9.2 to move to connect the oil port a and the oil port b of the hydraulic control check valve 9.2, and the hydraulic oil reaches the lifting oil circuit 11 through the oil port b of the hydraulic control check valve 9.2. When the lifting oil circuit 11 controls the fork to descend, the coil Y1 of the electromagnetic reversing valve 9.1 is electrified, the electromagnetic reversing valve 9.1 is reversed to the upper position, the oil port g and the oil port h of the electromagnetic reversing valve 9.1 are connected, at this time, the pressure oil of the oil port c of the hydraulic control check valve 9.2 is unloaded to connect the oil port b and the oil port a of the hydraulic control check valve 9.2. The pressure oil of the lifting oil circuit 11 reaches the oil port b and the oil port a of the hydraulic control check valve 9.2, and is directly returned to the oil tank through the pump motor 2. At this time, the pump motor 2 acts as a motor, the motor generator 3 acts as a generator, and the returned pressure oil drives the motor to rotate, thereby driving the generator to generate electricity.

[0024] In the embodiment, the multi-way valve 13 includes a priority valve 13.1 and a lifting spool valve 13.3. The oil port P of the priority valve 13.1 is connected to the oil outlet of the second oil pump P2 of the double pump 6, the oil port EF of the priority valve 13.1 is connected to the port A, the oil port F of the lifting spool valve 13.3 is connected to the port A through a lifting check valve 13.8, the oil port G of the lifting spool valve 13.3 is directly connected to the port A, the oil port E of the lifting spool valve 13.3 is connected to the oil return port T of the multi-way valve 13, the oil port D of the lifting spool valve 13.3 is provided with a plug for plugging the oil channel, the oil port H of the lifting spool valve 13.3 is connected to the oil return port T of the multi-way valve 13, the oil port J and the oil port K of the lifting spool valve 13.3 are connected to a second lifting and lowering control valve 13.4, the second lifting and lowering control valve 13.4 includes a second hydraulic control check valve 13.4.1 and a two-position two-way electromagnetic reversing valve 13.4.2, the oil port J of the lifting spool valve 13.3 is connected to the oil port d of the second hydraulic control check valve 13.4.1, the oil port K of the lifting spool valve 13.3 is connected to the oil port k of the electromagnetic reversing valve 13.4.2, the oil port e of the second hydraulic control check valve 13.4.1 is connected to the oil port A1 of the multi-way valve, and the oil port f of the second hydraulic control check valve 13.4.1 is connected to the oil port j of the electromagnetic reversing valve 13.4.2.

[0025] Specifically, when the lifting slice valve 13.3 is in the middle position, the oil port G and the oil port O are communicated, and the oil port D and the oil port H are communicated; when the lifting slice valve 13.3 is in the lower position, the oil port F and the oil port J are communicated, and the oil port G and the oil port D are communicated; when the lifting slice valve 13.3 is in the upper position, the oil port D and the oil port H are communicated, the oil port J and the oil port E are communicated, the oil port K and the oil port E are communicated, and the oil port G and the oil port O are communicated.

[0026] Obviously, based on the above, when the lifting oil circuit 11 controls the fork to rise, the coil Y2 of the electromagnetic reversing valve two 13.4.2 loses power, the oil port j and the oil port k of the electromagnetic reversing valve two 13.4.2 are disconnected, and the pressure oil output by the double pump 6 second oil pump P2 enters the lifting oil circuit 11; when the lifting oil circuit 11 controls the fork to descend, the coil Y2 of the electromagnetic reversing valve two 13.4.2 loses power, the oil port j and the oil port k of the electromagnetic reversing valve two 13.4.2 are disconnected, and the oil port e and the oil port d of the hydraulic control one-way valve two 13.4.1 are not communicated, so that the backflow pressure oil cannot flow back to the oil tank 1 through the multi-way valve 13.

[0027] In this embodiment, with reference to Figure 2 , a displacement sensor 13.10 for detecting the movement state of the lifting slice valve 13.3 is installed at the position of the lifting slice valve 13.3.

[0028] Obviously, based on the above, the movement signal of the lifting slice valve 13.3 can be converted into an electrical signal by the displacement sensor 13.10.

[0029] In this embodiment, with reference to Figure 2 , the multi-way valve 13 includes an inclination slice valve 13.5, the oil port G2 of the inclination slice valve 13.5 is connected with the oil port O of the lifting slice valve 13.3, the oil port E2 of the inclination slice valve 13.5 is connected to the port B through an inclination one-way valve 13.7, one end of the port B is connected with the port A, the oil port F2 and the oil port O2 of the inclination slice valve 13.5 are respectively connected with the oil return port T of the multi-way valve 13, the oil port J2 of the inclination slice valve 13.5 is connected with the oil port A2 of the multi-way valve 13, and the oil port K2 of the inclination slice valve 13.5 is connected with the oil port B2 of the multi-way valve 13.

[0030] Specifically, when the inclination slice valve 13.5 is in the middle position, the oil port G2 and the oil port O2 are communicated; when the inclination slice valve 13.5 is in the lower position, the oil port E2 and the oil port J2 are communicated, and the oil port K2 and the oil port F2 are communicated; when the inclination slice valve 13.5 is in the upper position, the oil port E2 and the oil port K2 are communicated, and the oil port J2 and the oil port F2 are communicated.

[0031] Obviously, based on the above, the control of the inclination oil circuit 12 is realized through the multi-way valve 13.

[0032] In this embodiment, with reference to Figure 2The multi-way valve 13 comprises an OPS function valve block 13.6, the OPS function valve block 13.6 comprising an oil return on-off valve 13.6.1 and a two-position two-way electromagnetic reversing valve two 13.6.2 which is powered when the driver sits on the seat coil, the port B is connected with an oil port m of the oil return on-off valve 13.6.1, the oil port m of the oil return on-off valve 13.6.1 is connected with an oil port v of the oil return on-off valve 13.6.1, an oil port s of the oil return on-off valve 13.6.1 and an oil port p of the electromagnetic reversing valve two 13.6.2 respectively, and an oil port n of the oil return on-off valve 13.6.1 is connected with an oil return port T of the multi-way valve 13, and an oil port q of the electromagnetic reversing valve two 13.6.2 is connected with the oil return port T of the multi-way valve 13.

[0033] Obviously, based on the above, through the setting of the OPS function valve block 13.6, only when the driver sits on the seat, the hydraulic system can work.

[0034] In the embodiment, referring to Figure 1 and Figure 2 , the oil port CF and the oil port LS of the priority valve 13.1 are connected with the oil inlet of the steering oil circuit 10 respectively, and the oil return port of the steering oil circuit 10 is connected with the inside of the oil tank 1.

[0035] Obviously, based on the above, through the multi-way valve 13, the control of the steering oil circuit 10 can be realized.

[0036] In the embodiment, referring to Figure 1 and Figure 2 , the oil port a of the hydraulic control check valve one 9.2 is connected with the inside of the oil tank 1 through the lifting safety valve 9.3, the oil port LS of the priority valve 13.1 is further connected with the oil return port T of the multi-way valve 13 through the steering safety valve 13.2, the pipeline connected with the port A and the port B is provided with a port C, and the port C is connected with the oil return port T of the multi-way valve 13 through the main safety valve 13.9.

[0037] Obviously, based on the above, through the setting of the safety valve, the excess flow pressure oil can be returned to the oil tank 1, and the overload buffering protection effect can be achieved.

[0038] In the embodiment, referring to Figure 1 and Figure 2 , the pipeline connected with the oil inlet of the first oil pump P3 and the oil inlet of the second oil pump P2 of the duplex pump 6 and the oil tank 1 is provided with a filter one 5, and the pipeline connected with the oil return port of the steering oil circuit 10 and the oil tank 1 is provided with a filter two 7 with a bypass.

[0039] Obviously, based on the above, through the setting of the filter, the impurities in the pressure oil can be effectively filtered out, and the damage of the impurities to the oil circuit can be avoided.

[0040] As another embodiment of the present application, the embodiment proposes a forklift truck comprising any one of the above-mentioned solutions of the forklift truck hydraulic system with high-efficiency potential energy recovery.

[0041] In order to more clearly illustrate the embodiments and effects of the present application, examples are combined with the accompanying drawings:

[0042] Referring to the accompanying Figures 1-2 When the driver sits on the seat, the electromagnetic reversing valve three 13.6.2 coil Y3 is powered, the electromagnetic reversing valve three 13.6.2 is reversed to the left position, the oil port p and the oil port q of the electromagnetic reversing valve three 13.6.2 are disconnected, and the oil port m and the oil port n of the oil return on-off valve 13.6.1 are disconnected. At this time, the hydraulic system establishes the working pressure, and the hydraulic system can work.

[0043] When the forklift truck starts to work, the first oil pump P3 of the duplex pump 6 supplies oil to the brake oil circuit 8, and the independent oil source supplies oil to the brake oil circuit 8, so as to realize the fast and accurate braking effect; the oil of the second oil pump P2 of the duplex pump 6 enters the priority valve 13.1. When the forklift truck does not turn, the oil passes through the oil port EF of the priority valve 13.1 to the lifting piece valve 13.3 and the tilting piece valve 13.5, respectively controlling the lifting oil circuit 11 and the tilting oil circuit 12; when the forklift truck turns, the oil preferentially flows to the steering oil circuit 10 through the oil port CF of the priority valve 13.1, realizing the priority steering.

[0044] When the fork of the operating valve lifts the goods, the lifting slice valve 13.3 is reversed to the lower position, the coil Y2 of the electromagnetic reversing valve two 13.4.2 is de-energized, the oil port j and the oil port k of the electromagnetic reversing valve two 13.4.2 are disconnected, the pressure oil output by the second oil pump P2 of the double pump 6 passes through the oil port EF, the oil port A of the priority valve 13.1, the lifting one-way valve 13.8, reaches the oil port F of the lifting slice valve 13.3, reaches the oil port d of the hydraulic control one-way valve two 13.4.1 through the oil port J of the lifting slice valve 13.3, pushes the valve core of the hydraulic control one-way valve two 13.4.1 to move to make the oil port d and the oil port e connected, the hydraulic oil passes through the oil port e, the oil port A1 of the multi-way valve to the lifting oil circuit 11; the coil Y1 of the electromagnetic reversing valve one 9.1 is de-energized, the oil port g and the oil port h of the electromagnetic reversing valve one 9.1 are disconnected, at this time, the motor generator 3 acts as a motor, the pump motor 2 acts as a hydraulic pump, the pressure oil output by the pump motor 2 reaches the oil port a of the hydraulic control one-way valve one 9.2, pushes the valve core of the hydraulic control one-way valve one 9.2 to move to make the oil port a and the oil port b connected, the hydraulic oil passes through the oil port b to the lifting oil circuit 11; when the gantry lifting action with large flow demand is performed, the pressure oil output by the second oil pump P2 of the double pump 6 and the pressure oil output by the pump motor 2 are combined to flow to the lifting oil circuit 11, to provide higher lifting speed for the gantry; when the gantry tilting action with small flow demand is performed, only the second oil pump P2 of the double pump 6 works, to reduce energy consumption. When the gantry is lifted to the top, the excess flow provided by the second oil pump P2 of the double pump 6 flows back to the oil tank T from the main safety valve 13.9, the excess flow provided by the pump motor 2 flows back to the oil tank T from the lifting safety valve 9.3, to play an overload buffer protection role.

[0045] When the fork of the operating valve lowers the goods, the lifting slice valve 13.3 is reversed to the upper position, the displacement sensor 13.10 detects that the lifting slice valve 13.3 in the multi-way valve is in the lowering position, the coil Y2 of the electromagnetic reversing valve two 13.4.2 is de-energized, the oil port j and the oil port k of the two-position two-way electromagnetic reversing valve two 13.4.2 are disconnected, the oil port e and the oil port d of the hydraulic control one-way valve two 13.4.1 are not connected; the coil Y1 of the electromagnetic reversing valve one 9.1 is energized, the electromagnetic reversing valve one 9.1 is reversed to the upper position, the oil port g and the oil port h of the electromagnetic reversing valve one 9.1 are connected, at this time, the pressure oil of the oil port c of the hydraulic control one-way valve one 9.2 is unloaded to make the oil port b and the oil port a of the hydraulic control one-way valve one 9.2 connected. The pressure oil of the lifting oil circuit 11 passes through the oil port b, the oil port a of the hydraulic control one-way valve one 9.2, directly returns to the oil tank through the pump motor 2, at this time, the pump motor 2 acts as a motor, the motor generator 3 acts as a generator, the pressure oil returning to the oil tank drives the motor to rotate, thereby driving the generator to generate electricity, the generated electric energy is stored in the storage battery, the pressure oil returns to the oil tank without passing through the internal oil channel of the multi-way valve, reduces the pressure loss, and realizes efficient recovery of potential energy.

[0046] When the forklift is not working, the second oil pump P2 of the double pump 6 outputs pressure oil through the priority valve 13.1, the tilt one-way valve 13.7 to the oil port E2 of the tilt flap valve 13.5, the tilt flap valve 13.5 is switched to the upper position or the lower position, the oil port G2 of the tilt flap valve 13.5 and the oil port O2 of the tilt flap valve 13.5 are disconnected, the oil reaches the tilt oil way 12, and the front and rear tilting of the gantry is realized.

Claims

1. A forklift hydraulic system with high efficiency potential energy recovery, characterized by: The hydraulic system comprises an oil tank (1), a pump motor (2) used as a hydraulic pump, a motor generator (3) used as an electric motor, a double pump (6) driven by a motor (4), a brake oil circuit (8), a steering oil circuit (10), a lifting oil circuit (11) and a tilting oil circuit (12), the rotating end of the motor generator (3) is connected with the pump motor (2), the oil inlet of the pump motor (2) is communicated with the inside of the oil tank (1), the oil outlet of the pump motor (2) is connected with a lifting and lowering control valve one (9), the lifting and lowering control valve one (9) comprises a hydraulic control check valve one (9.2), the oil outlet of the pump motor (2) is connected with the oil port a of the hydraulic control check valve one (9.2), the oil port b of the hydraulic control check valve one (9.2) is connected with the lifting oil circuit (11), the oil inlets of the first oil pump P3 and the second oil pump P2 of the double pump (6) are communicated with the inside of the oil tank (1), the oil outlet of the first oil pump P3 of the double pump (6) is connected with the brake oil circuit (8), the oil outlet of the second oil pump P2 of the double pump (6) is connected with the steering oil circuit (10) through a multi-way valve (13), the oil port A1 of the multi-way valve (13) is connected with the lifting oil circuit (11), the oil port A2 and the oil port B2 of the multi-way valve (13) are connected with the tilting oil circuit (12), and the oil return port T of the multi-way valve (13) is communicated with the inside of the oil tank (1).

2. The forklift hydraulic system with high efficient potential energy recovery according to claim 1, characterized in that: The lifting and lowering control valve one (9) comprises a two-position two-way electromagnetic reversing valve one (9.1), the oil port c of the hydraulic control check valve one (9.2) is connected with the oil port g of the electromagnetic reversing valve one (9.1), the oil port h of the electromagnetic reversing valve one (9.1) is communicated with the inside of the oil tank (1), the oil port A1 of the multi-way valve (13) is connected with the lifting oil circuit (11), and the oil port b of the hydraulic control check valve one (9.2) is connected with the oil port A1 of the multi-way valve (13). The multi-way valve (13) comprises a priority valve (13.1) and a lifting spool valve (13.3), the oil port P of the priority valve (13.1) is connected with the oil outlet of the second oil pump P2 of the double pump (6), the oil port EF of the priority valve (13.1) is connected to port A, the oil port F of the lifting spool valve (13.3) is connected with port A through a lifting check valve (13.8), the oil port G of the lifting spool valve (13.3) is directly connected with port A, the oil port E of the lifting spool valve (13.3) is connected with the oil return port T of the multi-way valve (13), the oil port D of the lifting spool valve (13.3) is provided with a plug for plugging an oil channel, the oil port H of the lifting spool valve (13.3) is connected with the oil return port T of the multi-way valve (13), the oil port J and the oil port K of the lifting spool valve (13.3) are connected with a lifting and lowering control valve two (13.4), the lifting and lowering control valve two (13.4) comprises a hydraulic control check valve two (13.4.1) and a two-position two-way electromagnetic reversing valve two ( 3. The forklift hydraulic system with high efficient potential energy recovery according to claim 2, characterized in that: ​ The oil port J of the lifting spool valve (13.3) and the oil port d of the second hydraulic control check valve (13.4.1) are connected, the oil port K of the lifting spool valve (13.3) and the oil port k of the second electromagnetic reversing valve (13.4.2) are connected, the oil port e of the second hydraulic control check valve (13.4.1) and the oil port A1 of the multi-way valve are connected, the oil port f of the second hydraulic control check valve (13.4.1) and the oil port j of the second electromagnetic reversing valve (13.4.2) are connected.

4. The forklift hydraulic system with high efficiency potential energy recovery according to claim 3, wherein: A displacement sensor (13.10) for detecting the movement state of the lifting spool valve (13.3) is installed at the position of the lifting spool valve (13.3).

5. The fork truck hydraulic system with high efficiency potential energy recovery according to claim 3, wherein: The multi-way valve (13) comprises a tilt spool valve (13.5), the oil port G2 of the tilt spool valve (13.5) is connected with the oil port O of the lifting spool valve (13.3), the oil port E2 of the tilt spool valve (13.5) is connected to the port B through a tilt check valve (13.7), one end of the port B is connected with the port A, the oil port F2 and the oil port O2 of the tilt spool valve (13.5) are respectively connected with the oil return port T of the multi-way valve (13), the oil port J2 of the tilt spool valve (13.5) is connected with the oil port A2 of the multi-way valve (13), and the oil port K2 of the tilt spool valve (13.5) is connected with the oil port B2 of the multi-way valve (13).

6. The fork truck hydraulic system with high efficiency potential energy recovery according to claim 5, wherein: The multi-way valve (13) comprises an OPS function valve block (13.6), the OPS function valve block (13.6) comprises an oil return on-off valve (13.6.1) and a two-position two-way electromagnetic reversing valve (13.6.2) which is electrified when the driver sits on the seat coil, The port B is connected with the oil port m of the oil return on-off valve (13.6.1), the oil port m of the oil return on-off valve (13.6.1) is respectively connected with the oil port v of the oil return on-off valve (13.6.1), the oil port s of the oil return on-off valve (13.6.1) and the oil port p of the second electromagnetic reversing valve (13.6.2), the oil port n of the oil return on-off valve (13.6.1) is connected with the oil return port T of the multi-way valve (13), and the oil port q of the second electromagnetic reversing valve (13.6.2) is connected with the oil return port T of the multi-way valve (13). The oil port CF and the oil port LS of the priority valve (13.1) are respectively connected with the oil inlet of the steering oil way (10), and the oil return port of the steering oil way (10) is communicated with the inside of the oil tank (1). The oil port a of the first hydraulic control check valve (9.2) is communicated with the inside of the oil tank (1) through a lifting safety valve (9.3), the oil port LS of the priority valve (13.1) is also connected with the oil return port T of the multi-way valve (13) through a steering safety valve (13.2), a port C is arranged on the pipeline connecting the port A and the port B, and the port C is connected with the oil return port T of the multi-way valve (13) through a main safety valve (13.9). ​ ​ ​ ​ 7. The fork truck hydraulic system with high efficiency potential energy recovery according to claim 5, wherein: ​ 8. The fork truck hydraulic system with high efficiency potential energy recovery according to claim 7, wherein: ​ 9. The fork truck hydraulic system with high efficiency potential energy recovery according to claim 7, wherein: The first oil pump P3 inlet and the second oil pump P2 inlet of the double pump (6) are provided with filter one (5) on the pipeline communicated with the oil tank (1), and the return oil port of the steering oil way (10) is provided with filter two (7) with bypass on the pipeline communicated with the oil tank (1).

10. A fork truck characterized by: A fork truck hydraulic system with high efficient potential energy recovery comprising the features of any one of claims 1-9.

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