CN103629175B - working bucket hydraulic control system and engineering vehicle - Google Patents

Abstract

The invention discloses a working bucket hydraulic control system and an engineering vehicle. The control system includes a leveling oil cylinder (4) and a leveling control circuit, a luffing oil cylinder (5) and a luffing control circuit, a booster oil cylinder (7) and a booster Pressure oil circuit (V1), the rod cavity oil circuit of the booster cylinder is connected to the main oil inlet circuit (P); the first switch control valve (11) is installed in the booster oil circuit and has a hydraulic connection to the luffing cylinder The first bypass oil passage (V2) of the rod cavity and the second bypass oil passage (V3) hydraulically connected to the system oil tank (15) and the second switch control valve (8) are installed therein. Due to the addition of a pressurized oil circuit in the present invention, during the self-weight recovery process of the boom, the hydraulic oil in the rodless chamber of the luffing cylinder can pass through the pressurized oil circuit, the pressurized oil cylinder, the main oil inlet circuit and the leveling control circuit Supply oil to the leveling cylinder to level the working bucket in real time. During this process, there is no need to frequently start the emergency pump power unit to level the working bucket, saving energy.

Description

Working Bucket Hydraulic Control System and Engineering Vehicle

technical field

The present invention relates to a hydraulic control system in an engineering vehicle, in particular, to a hydraulic control system for a working bucket.

Background technique

Working buckets are installed in various engineering vehicles such as aerial ladder fire trucks, climbing fire trucks, and aerial work vehicles to be used as loading platforms or standing platforms for operators. As shown in Figure 1, the turntable 3 of the engineering vehicle is hinged with a jib 2, and the jib 2 performs pivotal luffing motion relative to the turntable 3 under the push of the luffing cylinder 5, driving the working bucket hinged at the top of the jib 2 1 lift or lower. During the lifting or lowering process of the working bucket 1, the working bucket 1 is leveled by the leveling cylinder 4, so that it is always kept in a horizontal position, so as to avoid adverse effects on the people or objects loaded in the working bucket.

However, after the jib 2 is extended, if the main hydraulic pump of the whole vehicle system or the power device driving the main hydraulic pump fails to move, the jib 2 needs to be withdrawn urgently. On some engineering vehicles, DC emergency pumps, AC emergency pumps or small gasoline engines are installed as power emergency pump devices for this purpose, so that the boom 2 can be retracted smoothly, and the emergency pump devices provide power for the leveling cylinder 4 in real time. Leveling bucket 1. Furthermore, in order to save energy and avoid energy shortage caused by long-term use of the emergency pump device, it is more convenient to use the principle of the self-gravity of the boom 2, under the action of the self-weight of the boom 2, the compression becomes The hydraulic oil in the rodless chamber of the oil cylinder 5 is evenly released back to the oil tank, thereby achieving the purpose of automatically recovering the boom 2, which is the so-called "recovery of the boom's own weight". At this time, it is difficult for the working bucket 1 to keep level in real time during the lowering process of the boom 2 due to gravity. If people or objects are loaded in the working bucket, it is necessary to start the emergency pump power unit very frequently to level the working bucket 1 while realizing the automatic lowering of the boom gravity, which not only seriously affects the work efficiency, but also wastes the energy of the power unit.

Contents of the invention

The purpose of the present invention is to provide a working bucket hydraulic control system and an engineering vehicle with the working bucket hydraulic control system, which can automatically level the working bucket during the gravity lowering process of the boom without starting the emergency pump power unit.

To achieve the above object, the present invention provides a working bucket hydraulic control system, the system includes: a leveling cylinder and a leveling control circuit for leveling the working bucket, a luffing cylinder and a luffing control circuit And the main oil inlet oil circuit and the main oil return oil circuit respectively provide oil inlet and oil return for each circuit. The luffing oil cylinder is used to control the amplitude of the boom and thus drive the working bucket connected to the boom lifting; and

The pressurized oil cylinder and the pressurized oil passage connected between the rodless chamber of the pressurized oil cylinder and the rodless chamber of the luffing oil cylinder, the first switch control valve is arranged in the pressurized oil passage, and the pressurized oil passage The rod cavity oil circuit of the oil cylinder is connected to the main oil inlet oil circuit to supply oil to the leveling control circuit;

Wherein, the pressurized oil passage has a first bypass oil passage hydraulically connected to the rod chamber of the luffing cylinder and a second bypass oil passage hydraulically connected to the system oil tank, and the second bypass oil passage A second switch control valve is provided.

Preferably, the luffing cylinder balance valve group is set in the luffing control circuit, and the first bypass oil passage is connected to the connection oil between the luffing cylinder balancing valve group and the rod cavity of the luffing cylinder. On the road, and the first bypass oil passage is provided with a first one-way valve, so that the hydraulic oil can flow to the rod chamber of the luffing cylinder through the first bypass oil passage and reversely cut off.

Preferably, the amplitude control circuit is further provided with an amplitude main operation valve, which is respectively connected to the active cylinder of the amplitude oil cylinder through the connecting oil circuit of the rod cavity and the connecting oil circuit of the rodless cavity. On the rod chamber and the rodless chamber, the luffing cylinder balance valve group includes a first externally controlled balance valve and a second externally controlled balance valve with the same structure, and the first externally controlled balance valve is arranged on the The rod chamber is connected to the oil passage and the pilot control oil passage is connected to the rodless chamber connection oil passage, the second external control balance valve is set in the rodless chamber connection oil passage and the pilot control oil passage is connected to the active The rod chamber is connected to the oil passage, wherein the first bypass oil passage is connected to the part of the rod chamber connecting oil passage between the first externally controlled balance valve and the rod chamber of the luffing cylinder.

Preferably, the system further includes a second one-way valve, the rod cavity oil circuit of the booster cylinder is connected to the connection point in the main oil inlet circuit, and the second one-way valve is arranged on the part of the main oil inlet line on one side of the connection point, so that the hydraulic oil in the booster cylinder flows to the leveling control through the part of the main oil inlet line on the other side of the connection point circuit.

Preferably, the system further includes a first relief valve, and the first relief valve is arranged on the connecting oil passage between the pressurized oil passage and the system oil tank.

Preferably, the first on-off control valve is linked with the second on-off control valve, so that one of the pressurized oil passage and the second bypass oil passage is turned on while the other is blocked.

Preferably, a throttle valve is provided in the pressurized oil circuit.

Preferably, the system further includes a control unit and an inclination sensor installed in the working bucket, the leveling control circuit is provided with a leveling control valve group, the leveling control valve group includes an electric proportional control valve, the The control unit is used for controlling the electric proportional control valve according to the signal of the inclination sensor to adjust the hydraulic oil flow to the leveling oil cylinder.

Preferably, the leveling control valve group further includes a second overflow valve for limiting the supply oil pressure in the leveling control circuit.

In addition, the present invention also provides an engineering vehicle, which includes the hydraulic control system of the working bucket according to the present invention.

According to the above-mentioned technical solution, since the pressurized oil cylinder and the first and second switch control valves are added in the working bucket hydraulic control system of the present invention, the rodless cavity of the luffing oil cylinder is compressed during the self-weight recovery process of the boom. Therefore, part of the pressure oil in the rodless chamber flows back to the rod chamber of the luffing cylinder through the first bypass oil passage, and the other part flows to the rodless chamber of the booster cylinder, so that the rod of the booster cylinder The oil in the cavity is pressurized, and the pressurized oil is supplied to the leveling cylinder through the main oil inlet circuit and the leveling control circuit, thus realizing the circulation of hydraulic oil among multiple oil cylinders and enabling automatic leveling work fight.

Other features and advantages of the present invention will be described in detail in the following detailed description.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention. In the attached picture:

Figure 1 is a schematic diagram of the installation structure of a common working bucket and its driving device in an engineering vehicle;

Fig. 2 is a hydraulic schematic diagram of the working bucket hydraulic control system according to a preferred embodiment of the present invention, wherein the booster cylinder is in a non-working state;

Fig. 3 is the working bucket hydraulic control system shown in Fig. 2, the difference is that the booster cylinder is in working state.

Explanation of reference signs

1 working bucket 2 boom

3 turntable 4 leveling cylinder

5 luffing cylinder

7 booster cylinder 8 second switch control valve

9 First relief valve 10 Throttle valve

11 The first switch control valve 12 The first one-way valve

13 luffing cylinder balance valve group 14 luffing main operating valve

15 system oil tank 16 back pressure valve

17 Second one-way valve 18 Leveling control valve group

19 leveling cylinder balance valve group 181 electric proportional control valve

182 first function module 183 second function module

V1 booster oil circuit V2 first bypass oil circuit

V3 second bypass oil circuit A connection point

P Main oil inlet circuit T Main oil return circuit

detailed description

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

In the present invention, in the case of no contrary description, the used orientation words such as "up, down, left and right" usually refer to the up, down, left and right shown in the accompanying drawings; "inside and outside" Refers to the inside and outside of the outline of each part itself. The technical term "boom self-weight recovery" used in the present invention refers to that after the main hydraulic pump of the system stops working, the boom stops working, and the boom is recovered toward the turntable luffing by using its own gravity, and then the luffing is compressed. The hydraulic oil in the rodless cavity of the oil cylinder is evenly released back to the oil tank, so as to achieve the purpose of recovering the self-weight of the boom.

As shown in Figure 1 and Figure 2, the present invention provides a working bucket hydraulic control system, the working bucket 1 is hinged on the top end of the arm frame 2, and the bottom end of the boom frame 2 is hinged on the turntable 3, wherein the working bucket The bucket hydraulic control system includes: the leveling cylinder 4 and the leveling control circuit for leveling the working bucket 1, the luffing cylinder 5 and the luffing control circuit of the boom 2, and providing oil inlet and oil return for each circuit respectively. The main oil inlet oil circuit P and the main oil return oil circuit T; and the booster oil cylinder 7 and the booster oil circuit V1 connected between the rodless cavity of the booster cylinder 7 and the rodless cavity of the luffing cylinder 5, The booster oil circuit V1 is provided with a first switch control valve 11 (a two-position two-way electromagnetic reversing valve in the figure), and the rod chamber oil circuit of the booster cylinder 7 is connected to the main oil inlet circuit P to adjust Oil supply to the flat control circuit; wherein, the pressurized oil circuit V1 has a first bypass oil circuit V2 hydraulically connected to the rod chamber of the luffing cylinder 5 and a second bypass oil circuit V3 hydraulically connected to the system oil tank 15, the A second switch control valve 8 (a two-position three-way electromagnetic reversing valve in the figure) is provided in the second bypass oil passage V3. As a general inventive concept, by adding a pressurized oil passage V1 between the rodless chamber of the booster cylinder 7 and the rodless chamber of the luffing cylinder 5, the rodless cylinder of the luffing cylinder 5 will The hydraulic oil in the chamber can flow to the rodless chamber of the booster cylinder 7 through the pressurized oil passage V1, thereby pushing the pressure of the oil in the rod chamber of the pressurized cylinder 7 to rise and output to the main oil inlet passage P, and then through The leveling control circuit supplies oil to the leveling oil cylinder 4, so that the working bucket 1 can be leveled in real time. In this way, the hydraulic oil circulation between multiple oil cylinders can be realized, and the working bucket can be automatically leveled, and there is no need to frequently start the emergency pump power unit to level the working bucket, saving power energy and avoiding corresponding complicated controls.

Wherein, the luffing cylinder 5 as the main luffing cylinder is generally installed between the turntable 3 and the boom 2 as shown in Fig. The No. 2 arm and the No. 1 arm include multi-section telescopic arms. When the No. 2 arm is hinged on the top segment telescopic arm of the No. 1 arm, the luffing cylinder 5 can also be arranged between the No. 2 arm and the top segment telescopic arm of the No. 1 arm. During the period, as long as the automatic recovery of the boom can be satisfied, the piston rods of the luffing cylinder 5 are compressed and retracted. Those skilled in the art can understand that, generally speaking, the volume of the piston chamber of the luffing cylinder 5 is much larger than that of the leveling cylinder 4, and the stroke of the luffing cylinder 5 is also greater than that of the leveling cylinder 4 during the self-weight recovery process of the boom. The flow of oil flowing out of the rodless chamber of the luffing cylinder 5 far exceeds the required flow of the leveling cylinder 4 . At the same time, it is considered that the rod cavity of the luffing cylinder 5 needs to be replenished with oil to prevent air suction, which is unfavorable to the use of hydraulic components. Therefore, part of the oil flowing out of the rodless cavity of the luffing cylinder 5 can also be replenished into the rod cavity through the first bypass oil passage V2, and the hydraulic oil of the volume difference between the two cavities of the luffing cylinder 5 should be guaranteed to be able to Meet the needs of leveling oil cylinder 4. The second bypass oil passage V3 is used to release the hydraulic oil in the pressurized oil passage V1 when the boom 2 is working normally, so that the piston rod in the pressurized oil cylinder 7 moves to the left under the pressure oil of the main oil inlet passage P Move to the bottom of the cylinder to reserve enough piston stroke for booster oil cylinder 7 when working.

As shown in Figure 2, the luffing control circuit is provided with a luffing cylinder balance valve group 13 and a luffing main operating valve 14, the luffing main operating valve 14 includes a functional module and a main reversing valve, etc. The two working oil ports are respectively connected to the rod chamber and the rodless chamber of the luffing cylinder 5 through the connecting oil circuit of the rod cavity and the connecting oil circuit of the rodless cavity, so as to switch and control the extension or retraction of the luffing cylinder 5 . The luffing cylinder balance valve group 13 is used to control the oil inlet and oil return of the rod chamber of the luffing cylinder 5, and lock the piston rod to prevent the piston rod from being damaged due to sudden loss of pressure and drop. On the basis of the luffing cylinder balance valve group 13, the first bypass oil circuit V2 is connected to the connection oil circuit between the luffing cylinder balance valve group 13 and the rod cavity of the luffing cylinder 5 (that is, there is The rod cavity is connected to the oil passage), that is, the K2 point in Figure 2 or Figure 3. Specifically, the luffing cylinder balance valve group 13 includes a first externally controlled balance valve and a second externally controlled balance valve with the same structure. The rodless cavity is connected to the oil circuit, the second external control balance valve is arranged in the rodless cavity connecting oil circuit and the pilot control oil circuit is connected to the rod cavity connecting oil circuit. In this way, the first bypass oil passage V2 is preferably connected to the rod chamber connecting oil passage part between the first externally controlled balance valve and the rod chamber of the luffing cylinder 5 . Since each externally controlled balance valve includes a sequence valve and a check valve connected in parallel, the hydraulic oil in the first bypass oil circuit V2 cannot flow to the system due to the reverse cut-off effect of the check valve in the externally controlled balance valve. Fuel tank 15, and can only flow to rod cavity. Further, a first one-way valve 12 is also provided in the first bypass oil passage V2, and the reverse port of the first one-way valve 12 is connected with a rod cavity, so that hydraulic oil can pass through the first bypass oil passage V2 Flow to the rod chamber of the luffing cylinder 5 and reversely cut off.

In addition, although the outlet of the oil pump connected to the main oil inlet oil passage P is generally provided with a one-way valve to prevent backflow to the hydraulic pump, it is more preferable to ensure that the pressure oil flowing out of the rod chamber of the booster cylinder 7 can All flow to the leveling control circuit, as shown in Figure 2, the rod chamber oil circuit of the pressurized cylinder 7 in this embodiment is connected to the connection point A in the main oil inlet circuit P, and there is a second check valve 17 is set in the part of the main oil inlet oil passage P on the side of the connection point A, and the reverse port of the second check valve 17 is hydraulically connected to the rod chamber of the booster cylinder 7, so that the hydraulic oil in the rod chamber passes through the connection The main oil inlet oil circuit P on the other side of point A flows to the leveling control circuit. Of course, the second one-way valve 17 can also be, for example, an electromagnetic switch valve, etc., which can also achieve the above effects.

In addition, when the stroke of the luffing oil cylinder 5 is relatively large, the hydraulic oil in the pressurized oil circuit V1 is released excessively, and when the pressure is too large, it is necessary to release the pressure. For this reason, the hydraulic control system of the present invention preferably also includes a first relief valve 9, which serves as a safety relief valve for the pressurized oil circuit V1, and is set at the pressurized stage as shown in FIG. The connecting oil circuit between the oil circuit V1 and the system oil tank 15 . In addition, a throttle valve 10 is preferably provided in the pressurized oil passage V1, and the boom 2 can be lowered evenly and steadily by adjusting the opening of the throttle valve 10 . A back pressure valve 16 is provided between the system oil tank 15 and the main oil return circuit T to maintain a certain back pressure in the main oil return circuit T. The hydraulic oil in will not be able to flow back in the system oil tank 15 of getting off part side completely because of self gravity.

In the leveling control circuit, there are generally a leveling control valve group 18 and a leveling cylinder balance valve group 19 as shown in Figure 2. The structure and function of the leveling cylinder balance valve group 19 are similar to the luffing cylinder balance valve group 13. No longer. The working bucket hydraulic control system in this embodiment also includes a control unit and an inclination sensor (not shown) installed in the working bucket 1. The leveling control valve group 18 includes an electric proportional control valve 181. The control unit is used to The signal controls the electric proportional control valve 181 to adjust the hydraulic oil flow to the leveling oil cylinder 4 . In this embodiment, as shown in FIG. 2 , the leveling control valve group 18 generally also has a second functional module 183 that works in cooperation with the electric proportional control valve 181 and other first functional modules 182, etc., so the control unit can Control the electric proportional control valve 181 and combine with the second function module 183 to jointly control the hydraulic oil flow to the leveling cylinder 4 . The control unit may be an independent controller, or may include a control circuit or a control program. In addition, the leveling control valve group 11 preferably also includes a second relief valve (not shown in the figure) for limiting the oil supply oil pressure in the leveling control circuit. The second relief valve is generally set at an electric proportional In the first functional module 182 before the control valve 181 . When the oil supply oil pressure of the pressurized oil cylinder 7 is too high, it can be released from the second relief valve in the first function module 182 . It should be noted that the leveling control valve group 18 in this embodiment shown in FIG. 2 is a common leveling control valve group. The structural composition is well known to those skilled in the art and does not belong to the gist of the present invention, so it will not be described in detail here.

The above working bucket hydraulic control system can be applied to various engineering vehicles with working buckets such as aerial ladder fire trucks, climbing fire trucks, aerial work vehicles, etc. It can maintain the real-time level of the working bucket, save energy consumption, and avoid frequent activation of emergency pump power unit. The working process of the working bucket hydraulic control system will be described below in conjunction with FIG. 2 and FIG. 3 .

When the boom 2 is working normally, as shown in Figure 2, the first switch control valve 11 is closed to disconnect the pressurized oil circuit V1, the second switch control valve 8 is opened to conduct the second bypass oil circuit V3, At this time, the booster oil circuit does not work, the leveling cylinder 4 and the luffing cylinder 5 are normally driven by the main hydraulic pump of the system, and at the same time, the hydraulic oil in the rodless chamber of the booster cylinder 7 is completely returned through the second bypass oil circuit V3 To the system fuel tank 15, the piston of the pressurized oil cylinder 7 moves to the bottom of the cylinder to the left.

When the self-weight of the boom needs to be recovered, the power source of the main hydraulic pump and the power source of the hydraulic emergency pump are both in a stopped state, as shown in Figure 3. At this time, the first switch control valve 11 is opened to conduct the booster oil circuit V1 , the second on-off control valve 8 is turned off so that the second bypass oil passage V3 is disconnected. At this time, due to the gravity of the boom 2 itself, the hydraulic oil in the rodless chamber of the luffing cylinder 5 has a certain pressure, so the hydraulic oil in the rodless chamber flows to the booster oil circuit V1, the oil cylinder retracts, and the boom 2 to achieve the purpose of self-recycling. Wherein, the presence of the throttle valve 10 can prevent the recovery speed of the boom 3 from being too fast, so that the boom 2 can be lowered evenly and steadily. During the retraction process of the luffing cylinder 5, hydraulic oil needs to be replenished in the rod cavity in time, otherwise it will be sucked out, which is unfavorable to the use of hydraulic components, and during the descending process of the luffing cylinder, the working bucket 1 cannot be automatically leveled. As the jib 2 descends, the bucket 1 tilts. Therefore, in the present invention, the hydraulic oil in the rodless cavity of the luffing cylinder 5 flows through the first on-off control valve 11 and the throttle valve 10, and then a part of the hydraulic oil passes through the first side with the first one-way valve 12. The oil connecting circuit V2 is supplemented to the rod cavity of the luffing cylinder 5, and another part of the hydraulic oil flows to the rodless cavity of the booster cylinder 7. The hydraulic oil pushes the piston rod of the pressurized cylinder 7 to move outward. Due to the existence of the piston rod, there is a volume difference between the rod chamber and the rodless chamber, so that during the extension of the piston rod, the oil pressure in the rod chamber As the force continues to rise, the hydraulic oil in the rod chamber flows out to the main oil inlet circuit P. Because the second check valve 17 is set in the main oil inlet circuit P, the pressure of the rod chamber flowing out of the booster cylinder 7 Oil is forced to flow to the leveling control valve bank 18 . The leveling control valve group 18 controls the supply of appropriate hydraulic oil to the leveling cylinder 4 of the working bucket 1 to keep the working bucket 1 in a horizontal state.

If the output pressure of the rod chamber of the booster cylinder 7 is P1, then P1 should be greater than the maximum working pressure of the leveling cylinder 4, and at the same time less than the second relief built in the first functional module 182 of the leveling control valve group The overflow pressure of the valve not only ensures that the leveling cylinder 4 can operate smoothly in any state, but also ensures that the hydraulic oil in the rod cavity of the booster cylinder 7 does not overflow.

In addition, in the design, it should be ensured that the supply of hydraulic oil in the rod chamber of booster cylinder 7 is greater than the demand of hydraulic oil in leveling cylinder 4, so as to ensure sufficient oil supply even when there is a small amount of hydraulic oil leakage. In addition, the second switch control valve 8 shown in Fig. 2 and Fig. 3 is a normally open type, and may also be designed as a normally closed type.

In the present invention, it can be ensured that the working bucket 1 can be automatically leveled and kept in a horizontal state during the self-weight recovery process of the boom. Compared with the prior art, the energy of the emergency power unit is saved. In the case of working bucket 1 carrying people or objects, it can greatly improve the safety of the boom 2 during the lowering process, and also greatly shorten the recovery time of the boom 2. At the same time, it avoids the adverse effects on the machine caused by frequent activation of the emergency power unit. influences. Wherein, due to the use of the second on-off control valve 8 in FIG. 2 , it is ensured that the pressure in the rod chamber of the pressurized cylinder 7 is successfully built up when the self-weight is recovered. At the same time, it is ensured that under the normal working condition that the hydraulic system adopts the main oil pump to drive the boom to move up and down, the piston rod of the booster cylinder 7 can be recovered smoothly to the end, so that the rod chamber of the booster cylinder 7 is filled with hydraulic oil, which is ready for gravity lowering Prepare.

The preferred embodiment of the present invention has been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the specific details of the above embodiment, within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, These simple modifications all belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (9)

1. a working bucket hydraulic control system, wherein, described system comprises:

For described working bucket (1) being carried out to the leveling cyclinder (4) and leveling control loop, change of levelingWidth oil cylinder (5) and luffing control loop and be respectively each loop the main oil-feed oil of oil-feed and oil return is providedRoad (P) and main oil return circuit (T), described amplitude oil cylinder (5) is for controlling the luffing of jib (2)Thereby and drive described working bucket (1) lifting that is connected with this jib (2); And

Pressurizing cylinder (7) and the rodless cavity and the described amplitude oil cylinder (5) that are connected to this pressurizing cylinder (7)Rodless cavity between Pressure Increasing Oil-Line (V1), in this Pressure Increasing Oil-Line (V1), be provided with the first switching control pilot(11), the rod chamber oil circuit of described pressurizing cylinder (7) connects described main oil-feed oil circuit (P) with to instituteState leveling control loop fuel feeding;

Wherein, described Pressure Increasing Oil-Line (V1) has the have bar of hydraulic connecting to described amplitude oil cylinder (5)First side in chamber connects oil circuit (V2) and hydraulic connecting connects oil circuit (V3) to the second side of system fuel tank (15),This second other connecing is provided with second switch control valve (8) in oil circuit (V3); Described the first switching control pilot (11)Control with described second switch control valve (8) interlock, to make described Pressure Increasing Oil-Line (V1) and secondWhen connecing the one conducting in oil circuit (V3), side blocks another one.

2. working bucket hydraulic control system according to claim 1, wherein, described luffing controlIn loop, be provided with amplitude oil cylinder balanced valve group (13), described the first other connecing described in oil circuit (V2) is connected toBeing connected on oil circuit between the rod chamber of amplitude oil cylinder balanced valve group (13) and amplitude oil cylinder (5), andAnd the described first other connecing in oil circuit (V2) is provided with the first check valve (12), so that hydraulic oil can be led toCross the described first other oil circuit (V2) that connects and flow to the rod chamber of described amplitude oil cylinder (5) and oppositely cut-off.

3. working bucket hydraulic control system according to claim 2, wherein, described luffing controlIn loop, be also provided with luffing main operation valve (14), this luffing main operation valve (14) passes through respectively rod chamberConnect oil circuit and be connected with rodless cavity that oil circuit is corresponding is connected to the rod chamber of described amplitude oil cylinder (5) and without barOn chamber, described amplitude oil cylinder balanced valve group (13) comprises the first external control type balanced valve and that structure is identicalTwo external control type balanced valves, described the first external control type balanced valve be arranged on that described rod chamber connects in oil circuit andPilot control oil circuit connects described rodless cavity and connects oil circuit, described in described the second external control type balanced valve is arranged onRodless cavity connects in oil circuit and pilot control oil circuit connects described rod chamber connection oil circuit, wherein, described inThe first other oil circuit (V2) that connects is connected to described the first external control type balanced valve and described amplitude oil cylinder (5)Rod chamber between rod chamber connects in oil circuit part.

4. working bucket hydraulic control system according to claim 1, wherein, this system also comprisesThe second check valve (17), the rod chamber oil circuit of described pressurizing cylinder (7) is connected to described main oil-feed oil circuit(P) tie point (A) in is upper, and described the second check valve (17) is arranged on described tie point (A)In described main oil-feed oil circuit (P) part of one side, to make the hydraulic oil in described pressurizing cylinder (7)Described main oil-feed oil circuit (P) part by described tie point (A) opposite side flows to described leveling controlLoop processed.

5. working bucket hydraulic control system according to claim 1, wherein, this system also comprisesThe first overflow valve (9), this first overflow valve (9) is arranged on described Pressure Increasing Oil-Line (V1) and described systemOn connection oil circuit between system fuel tank (15).

6. working bucket hydraulic control system according to claim 1, wherein, described Pressure Increasing Oil-Line(V1) in, be provided with choke valve (10).

7. working bucket hydraulic control system according to claim 1, wherein, this system also comprisesControl module and be arranged on the obliquity sensor in described working bucket (1), in described leveling control loopBe provided with leveling control valve group (18), this leveling control valve group (18) comprises electric proportional control valve (181),Described control module is used for according to electric proportional control valve (181) described in the signal controlling of described obliquity sensorTo regulate the hydraulic fluid flow rate that flows to described leveling cyclinder (4).

8. working bucket hydraulic control system according to claim 7, wherein, described leveling controlIn valve group (11), also comprise the second overflow valve of the fuel feeding oil pressure for limiting described leveling control loop.

9. an engineering truck, wherein, this project vehicle comprises according in claim 1-8 any oneWorking bucket hydraulic control system described in.