Push shovel hydraulic system

Abstract

The utility model discloses a push shovel hydraulic system which comprises a first working oil way and a second working oil way which are used for being connected with a rod cavity and a rodless cavity of an oil cylinder, a first pump oil way connected with a working pump, two oil return oil ways connected with an oil tank and a control valve, and the control valve is provided with a first position, a third position and a fourth position. When the control valve is located at the first position, the first pump oil way is connected with the first working oil way, and the second working oil way is connected with one of the two oil return oil ways. When the control valve is located at the third position, the first pump oil way is connected with the second working oil way, and the first working oil way is connected with one of the two oil return oil ways; when the control valve is located at the fourth position, the first pump oil way and the first working oil way are simultaneously connected with the second working oil way. Only a fourth position is added to the control valve, so that the first working oil way and the first pump oil way converge and flow to a rodless cavity, a regeneration loop is formed, and the push shovel rapidly descends; the first working oil way and the second working oil way are connected with the oil tank at the same time, push shovel floating is achieved, and the device is suitable for rugged working conditions.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of hydraulic control systems, especially a kind of push shovel hydraulic system. BACKGROUND

[0002] Backfill compactor is generally used in garbage landfill or soil compaction working condition, and the tonnage and push shovel capacity of these use scenes are relatively large. To improve work efficiency, the speed of push shovel descending needs to be accelerated, and the floating function of push shovel needs to be increased. The common push shovel hydraulic system lifting speed scheme is to increase the flow of working pump and control valve, which inevitably causes the cost and installation size of hydraulic components to be greatly improved.

[0003] The patent application for invention with publication number CN 111033056 A discloses a kind of hydraulic circuit, the big cavity (no rod) of hydraulic cylinder, small cavity (have rod) are connected cylinder bottom oil circuit, cylinder rod oil circuit respectively, cylinder bottom oil circuit connects bypass oil circuit, reversing valve connects cylinder bottom oil circuit, cylinder rod oil circuit, bypass oil circuit, two oil tank oil circuit, pump oil circuit, when reversing valve controls pump oil circuit and cylinder bottom oil circuit connection, cylinder rod oil circuit is divided into two branches by reversing valve, one branch connects big cavity through bypass oil circuit and cylinder bottom oil circuit, the remaining one branch connects oil tank, when the working oil of cylinder bottom chamber is insufficient, the arm of engineering machinery can be quickly operated (regeneration circuit);Pilot control valve is connected on bypass oil circuit, pilot control valve is controlled to open by the pilot oil pressure of reversing valve or is controlled to open by the pressure feedback of cylinder rod cavity (small cavity), thereby, when forming regeneration circuit, cylinder rod chamber supplies oil to cylinder bottom chamber unidirectionally. In the scheme, the way of forming regeneration oil circuit is complex, and when forming regeneration circuit, the resistance of cylinder rod oil circuit to oil tank needs to be greater than the pressure resistance to cylinder bottom, and pressure oil will pass from cylinder rod chamber to cylinder bottom chamber, which contributes less to cylinder rod cavity. In addition, to simplify the control system, the pilot control valve provided on bypass oil circuit is linked with reversing valve, and the working position of reversing valve needs to be symmetrically arranged, which is difficult to increase floating position. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a kind of push shovel hydraulic system of simplifying oil circuit connection mode.

[0005] Technical scheme: the utility model's the push shovel hydraulic system, including the first working oil circuit, second working oil circuit for connecting the rod cavity, rodless cavity of oil cylinder, the first pump oil circuit of connecting working pump, two back oil oil circuits of connecting oil tank, and control valve, the control valve has first position, third position, fourth position;When control valve is in first position, first pump oil circuit connects first working oil circuit, and second working oil circuit connects one of two back oil oil circuits;When control valve is in third position, first pump oil circuit connects second working oil circuit, and first working oil circuit connects one of two back oil oil circuits;When control valve is in fourth position, first pump oil circuit and first working oil circuit connect second working oil circuit simultaneously.

[0006] Preferably, the reversing valve is provided with a one-way valve, the control valve is in the fourth position, and the first working oil path is one-way connected to the second working oil path.

[0007] Preferably, the control valve has a fifth position, the control valve is in the fifth position, and the second working oil path and the first working oil path are connected to two oil return paths respectively.

[0008] Preferably, the control valve has a second position, the control valve is in the second position, and the first pump oil path and the two oil return paths are disconnected from the first working oil path and the second working oil path.

[0009] Preferably, the control valve is provided with a damper, the control valve is in the first position, the damper reduces the flow rate of the second working oil path, and the control valve is in the third position or the fourth position, the damper reduces the flow rate of the first working oil path.

[0010] Preferably, the first pump oil path is connected to the working pump through a pressure compensation valve, a control valve and a second pump oil path, and the pressure compensation valve is a valve pressure compensation valve.

[0011] Preferably, the first working oil path and the second working oil path are respectively provided with an oil tank connected oil supplement overflow valve.

[0012] Advantages: Compared with the prior art, the utility model has the following remarkable advantages: 1, simplify the system oil path connection: only in the control valve increases the fourth position, can realize the first working oil path and the first pump oil path confluence flow direction rodless chamber, forms the regenerative circuit, realizes the push shovel quick drop, thereby improves the construction efficiency;2, increase the oil flow of entering the push shovel oil cylinder: the control valve is in the fourth position, the first working oil path is directly connected to the rodless chamber, and there is no need to shunt flow direction oil tank, improves the regenerative circuit efficiency;3, it is convenient to increase the floating position to adapt to the uneven work object in the operation process. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a structural schematic view of the utility model. DETAILED DESCRIPTION

[0014] The technical scheme of the utility model will be further described below with reference to the drawings.

[0015] As Figure 1The hydraulic system of the push shovel mainly comprises an oil tank 1, a working pump 2, a control valve group 3 and an oil cylinder 4. The working pump 2 is a power source, the oil suction port S of the working pump 2 is connected with the oil tank 1, the oil discharge port of the working pump 2 is connected with the oil tank 1, the oil outlet port P of the working pump 2 is connected with the P1 port of the control valve group 3, and the load sensitive signal port X of the working pump 2 is connected with the LS port of the control valve group 3. The control valve group 3 comprises a pump oil path 31, two oil return paths 32 and 33, two working oil paths 36 and 35, a control valve 5 connected between the control oil paths, the pump oil path 31 is connected with the P1 port of the control valve group 3, the two oil return paths 32 and 33 are connected with the oil tank 1 through the T1 port of the control valve group 3, the two working oil paths 36 and 35 are connected with the large cavity (rodless cavity) and the small cavity (rod cavity) of the oil cylinder 4 respectively, and the L1 port of the control valve group 3 is also connected with the oil tank 1. The control valve 5 is an electro-hydraulic proportional multi-way valve, has five valve positions, is controlled by two proportional electromagnets a and b, the valve position and the flow rate of the control valve 5 can be controlled by the electrification and the current value of the proportional electromagnet a, and the valve position of the control valve 5 is sequentially recorded as the first position, the second position, the third position, the fourth position and the fifth position (close to the proportional electromagnet b end) from the start end close to the proportional electromagnet a end, and the structure and working process are:

[0016] The proportional electromagnet a is electrified, the control valve 5 is in the first position, the control valve 5 controls the pump oil path 31 to be connected with the working oil path 35, controls the working oil path 36 and any one of the two oil return paths 32 and 33 to be communicated, the pump oil path 31 supplies oil to the small cavity of the oil cylinder 4, the large cavity of the oil cylinder 4 returns oil to the oil tank 1, the oil cylinder 4 is retracted, and the corresponding push shovel ascending movement is realized, and the specific flow path is that: the pressure oil output by the working pump 2 passes through the pump oil path 31, the control valve 5, the working oil path 35, the B interface of the control valve group 3, enters the small cavity of the oil cylinder 4 through the interface B1, the oil in the large cavity of the oil cylinder 4 passes through the A1 interface, the A interface of the control valve group 3, the working oil path 36, the control valve 5, any one of the two oil return paths 32 and 33, and the T1 port of the control valve group 3, and returns to the oil tank 1, and the current value of the proportional electromagnet a is from small to large in the specified range, and the corresponding push shovel ascending movement is from slow to fast.

[0017] The proportional electromagnet b is electrified, the control valve 5 is in the third position, the control valve 5 controls the pump oil way 31 to connect the working oil way 36, the working oil way 35 is communicated with any one of the two oil return ways 32 and 33, the pump oil way 31 supplies oil to the large cavity of the oil cylinder 4, the small cavity of the oil cylinder 4 returns oil to the oil tank 1, the oil cylinder 4 extends, corresponding to the lowering action of the push shovel, and the specific flow path is: the pressure oil output by the working pump 2 passes through the pump oil way 31, the control valve 5, the working oil way 36, the A port and the A1 port, enters the large cavity of the oil cylinder 4, the oil in the small cavity of the oil cylinder 4 passes through the B1 port, the B port, the working oil way 35, the control valve 5, any one of the two oil return ways 32 and 33 and the T1 port, and returns to the oil tank 1, and the current value of the proportional electromagnet b is from small to large within a specified range, corresponding to the slow to fast lowering action of the push shovel.

[0018] When the current of the proportional electromagnet b reaches the specified range, the control valve 5 is in the fourth position, the pump oil way 31 is connected with the working oil way 36, and the working oil way 35 is combined with the pump oil way 31 in the control valve 5 to connect the working oil way 36, that is, the pressure oil of the pump oil way 31 and the oil from the small cavity of the oil cylinder 4 flow to the large cavity through the working oil way 36 at the same time, forming a regenerative oil way, and this part of the regenerative oil accelerates the extension of the oil cylinder 4, corresponding to the rapid lowering action of the push shovel. The control valve 5 is provided with a one-way valve, and the one-way valve enables the working oil way 35 to flow to the working oil way 36 in one direction.

[0019] When neither of the proportional electromagnets a and b is electrified, the control valve 5 is in the second position, which is a disconnected position, at this time, the working oil way 35 and the working oil way 36 are disconnected with the pump oil way and the two oil return ways 32 and 33, no oil enters the oil cylinder 4, the oil cylinder 4 has no action, and the push shovel has no action.

[0020] When the current of the proportional electromagnet b reaches the specified range, the control valve 5 is in the fifth position, the working oil way 35 and the working oil way 36 are respectively connected with the oil return way 32 and the oil return way 33, the large cavity and the small cavity of the oil cylinder 4 are connected with the oil tank 1, and flow back to the oil tank, which is equivalent to that the two cavities of the oil cylinder 4 are communicated, and the push shovel is in a floating state.

[0021] The control valve 5 is provided with a damper, when the control valve 5 is in the first position, the damper reduces the flow rate of the oil in the working oil way 36 flowing to the oil return way 32 or 33, that is, the return speed of the large cavity of the oil cylinder 4 is slowed down, when the control valve 5 is in the third position or the fourth position, the damper reduces the flow rate of the oil in the working oil way 35 flowing to the oil return way 32 or 33, that is, the return speed of the small cavity of the oil cylinder 4 is slowed down.

[0022] The P1 port pump oil way 34 of the control valve group 3, the control valve 5, the oil way 37, the pressure compensation valve 6 and the pump oil way 31 are connected, so that the pressure compensation valve 6 is a valve rear pressure compensation valve, and the flow through the control valve 5 is stabilized. The working oil ways 35 and 36 are respectively provided with the oil supplement overflow valve 8 connected with the T1 port, the oil supplement overflow valve 8 includes a one-way valve and a one-way overflow valve in parallel, the one-way valve controls the oil to flow from the oil tank 1 to the working oil way in one direction, the one-way overflow valve controls the oil in the working oil way to flow to the oil tank 1 in one direction, and pressure protection and anti-vacuum are performed when the push shovel oil cylinder executes an action. The pilot oil source valve 9 provides a pilot control pressure for the control valve 5, and the overflow valve 7 functions as pressure protection of the control valve group LS oil way.

Claims

1. A hydraulic system of a push shovel, comprising a first working oil passage (35) connecting a rod chamber and a rodless chamber of a cylinder, a second working oil passage (36), a first pump oil passage (31) connecting a working pump, two return oil passages connecting a tank, and a control valve (5), characterized in that, The control valve (5) has a first position, a third position, and a fourth position; when the control valve (5) is in the first position, the first pump oil way (31) is connected to the first working oil way (35), and the second working oil way (36) is connected to one of the two return oil ways; when the control valve (5) is in the third position, the first pump oil way (31) is connected to the second working oil way (36), and the first working oil way (35) is connected to one of the two return oil ways; when the control valve (5) is in the fourth position, the first pump oil way (31) and the first working oil way (35) are simultaneously connected to the second working oil way (36).

2. The hydraulic system of a push shovel according to claim 1, wherein The control valve (5) is provided with a one-way valve; when the control valve (5) is in the fourth position, the first working oil way (35) is one-way connected to the second working oil way (36).

3. The hydraulic system of claim 2, wherein, The control valve (5) has a fifth position; when the control valve (5) is in the fifth position, the second working oil way (36) and the first working oil way (35) are respectively connected to the two return oil ways.

4. The hydraulic system of claim 1, 2 or 3, wherein: The control valve (5) has a second position; when the control valve (5) is in the second position, the first pump oil way (31) and the two return oil ways are disconnected from the first working oil way (35) and the second working oil way (36).

5. The hydraulic system of claim 1, wherein, The control valve (5) is provided with a damper; when the control valve (5) is in the first position, the damper reduces the flow rate of the second working oil way (36); when the control valve (5) is in the third position or the fourth position, the damper reduces the flow rate of the first working oil way (35).

6. The hydraulic system of claim 1, wherein, The first pump oil way (31) is connected to the working pump through a pressure compensation valve (6), the control valve (5), and the second pump oil way (34); the pressure compensation valve (6) is a valve-after pressure compensation valve.

7. The hydraulic system of claim 1, wherein, The first working oil way (35) and the second working oil way (36) are respectively provided with oil tank-connected oil supplement overflow valves (8).

Images