Hydraulic system with movable arm floating regeneration function and excavator

Abstract

The utility model discloses a hydraulic system with a movable arm floating regeneration function and an excavator, and belongs to the technical field of engineering machinery. The defects that in a traditional excavator movable arm control system in the prior art, when an operator continuously controls a movable arm, fatigue is prone to being generated, and the working effect is affected are overcome. The main structure of the hydraulic system comprises a main pump, a pilot pump, a movable arm descending proportional valve, a movable arm lifting proportional valve and a movable arm oil cylinder, an oil outlet of the main pump is connected with the movable arm oil cylinder through a movable arm reversing valve, and an oil outlet of the pilot pump is connected with oil inlets of the movable arm descending proportional valve and the movable arm lifting proportional valve. An oil outlet of the movable arm descending proportional valve is connected with a right pilot oil port of the movable arm reversing valve, an oil outlet of the movable arm lifting proportional valve is connected with a left pilot oil port of the movable arm reversing valve, and a regeneration control assembly is further arranged between a rod cavity and a rodless cavity of the movable arm oil cylinder. The utility model is mainly applied to engineering machinery such as excavators and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of engineering machinery, and in particular relates to a hydraulic system and an excavator with a movable arm floating regeneration function. Background Art

[0002] Excavators play a vital role in engineering construction. The complex and diverse operating conditions encountered by excavators require not only excellent performance from the excavator's own systems but also high operator skills and expertise. Typical operating conditions, such as leveling and deep excavation, require a higher level of operator skill. Leveling operations require the boom and dipper arm to work together. Deep excavation, with the bucket digging deep, requires constant raising and lowering of the boom to maximize digging force and achieve optimal results. These two operating conditions require the operator to constantly control the boom, which can lead to fatigue and compromise performance. To address these issues, the boom needs to be kept in a floating position during hammering or leveling operations.

[0003] Existing excavator boom control systems such as Figure 2 As shown, the fourth working position of the control main valve is the boom bidirectional floating working position, the oil channel in the third working position is provided with a boom downward floating oil circuit, and a fourth working position enabling control device is provided to limit the travel of its valve core; the oil outlet of the right pump is connected to the oil inlet of the control main valve through an oil inlet shut-off valve; the oil inlet shut-off valve is only cut off when the boom is lowered and the one-way or two-way floating mode is working, otherwise it is in a conducting state, and the fourth working position enabling control device is only enabled when the boom is lowered and the two-way floating mode is working, otherwise it is in a disabled state; the oil inlet shut-off and the fourth working position enabling control device are controlled by a solenoid valve. However, the above scheme has the following shortcomings: it uses a four-position six-way boom reversing valve with a floating function, the valve stem and valve body are difficult to manufacture, the versatility is poor, and it is equipped with multiple solenoid valves to achieve the corresponding floating function, which increases the difficulty of debugging. Utility Model Content

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a hydraulic system and an excavator with a movable arm floating regeneration function.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A hydraulic system with a boom floating regeneration function includes a main pump, a pilot pump, a boom lowering proportional valve, a boom lifting proportional valve and a boom cylinder. The oil outlet of the main pump is connected to the boom cylinder through a boom reversing valve, the oil outlet of the pilot pump is connected to the oil inlets of the boom lowering proportional valve and the boom lifting proportional valve respectively, the oil outlet of the boom lowering proportional valve is connected to the right pilot oil port of the boom reversing valve, and the oil outlet of the boom lifting proportional valve is connected to the left pilot oil port of the boom reversing valve. A regeneration control component is also provided between the rod chamber and the rodless chamber of the boom cylinder.

[0007] Preferably, the regeneration control component includes an electro-hydraulic compound control valve and a regeneration check valve. The oil inlet of the regeneration check valve is connected in parallel to the rodless chamber of the boom cylinder and then connected to the oil outlet of the boom reversing valve. The oil outlet of the regeneration check valve is connected to the rod chamber of the boom cylinder through the electro-hydraulic compound control valve, and the oil outlet of the boom lowering proportional valve is also connected to the hydraulic control port of the electro-hydraulic compound control valve.

[0008] Preferably, the oil outlet of the electro-hydraulic composite control valve is further connected to a switch valve, and the oil outlet of the switch valve is connected to the hydraulic oil tank.

[0009] Preferably, a small-cavity port overflow valve and a large-cavity port overflow valve are also connected to the oil outlet of the boom reversing valve, and the small-cavity port overflow valve is connected in parallel with the rod chamber of the boom cylinder and then connected to the F port of the boom reversing valve, and the large-cavity port overflow valve is connected in parallel with the rodless chamber of the boom cylinder and then connected to the E port of the boom reversing valve.

[0010] Preferably, the oil outlet of the main pump is connected to the A port and the B port of the boom reversing valve respectively, and a load check valve is further provided between the B port of the boom reversing valve and the main pump.

[0011] Preferably, a controller is further included, which is electrically connected to the signal ends of the boom lowering proportional valve, the boom raising proportional valve, the electro-hydraulic composite control valve and the switch valve respectively.

[0012] Preferably, the controller is also electrically connected to a floating button.

[0013] Preferably, the oil drain ports of the boom-down proportional valve and the boom-up proportional valve are respectively connected to the hydraulic oil tank.

[0014] Preferably, the boom-down proportional valve and the boom-up proportional valve are electrically connected to an electric control handle.

[0015] An excavator is provided with a hydraulic system with a boom floating regeneration function as described in any one of the above items.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. The regeneration check valve and the electro-hydraulic compound control valve can be used to regenerate the flow rate of the boom during its descent. On the one hand, due to the effect of gravity, the pressure in the large chamber of the boom cylinder is greater than the pressure in the small chamber of the cylinder when the boom is descending. The oil can pass through the regeneration check valve and the electro-hydraulic compound control valve to supply part of the pressure oil in the large chamber of the cylinder and the pressure oil output by the pump to the small chamber of the cylinder at the same time, which can speed up the boom descent and improve work efficiency. On the other hand, when the boom's own weight and load accelerate the descent, the descent speed may be too fast, and the pump's oil supply may be insufficient, resulting in cavitation. At this time, through regeneration control, the return oil of the boom cylinder will flow back to the small chamber of the boom cylinder to prevent the boom cylinder from being sucked empty when the boom is descending.

[0018] 2. The boom floating function can be realized through the electronic control logic of the electro-hydraulic composite control valve and the switch valve. When the excavator is performing special working conditions such as deep digging and leveling, the boom can freely adjust its posture due to the addition of the boom floating function. The operator does not need to accurately control the boom position and operate frequently, which reduces the driver's workload and operational difficulty when performing leveling or deep digging operations. At the same time, since the utility model only uses the electro-hydraulic composite control valve and the switch valve, the system structure is simple and easy to debug.

[0019] 3. Since most systems in the existing technology use hydraulic control to control the movement of the boom-link reversing valve core, and the hydraulic control method has a slow response and relatively low control accuracy, and at the same time increases many pilot lines to produce a certain pressure loss and difficulty in design and assembly, the utility model adopts an electric control method and uses a proportional solenoid valve to control the reversing of the boom-link valve core, changing the pilot hydraulic control to electric control, thereby enhancing the response time and control accuracy of the boom-link operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the hydraulic principle diagram of the utility model;

[0021] Figure 2 This is a diagram of the existing excavator boom control system.

[0022] In the figure: 1. Hydraulic oil tank; 2. Engine; 3. Main pump; 4. Load check valve; 5. Pilot pump; 6. Boom reversing valve; 7. Boom lowering proportional valve; 8. Boom raising proportional valve; 9. Electric control handle; 10. Controller; 11. Floating button; 12. Boom cylinder; 13. Electro-hydraulic compound control valve; 14. Regeneration check valve; 15. Small cavity port overflow valve; 16. Large cavity port overflow valve; 17. Switch valve. DETAILED DESCRIPTION

[0023] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0024] Example 1:

[0025] like Figure 1-2 As shown, a hydraulic system with a boom floating regeneration function includes a main pump 3, a pilot pump 5, a boom lowering proportional valve 7, a boom lifting proportional valve 8 and a boom cylinder 12, the oil outlet of the main pump 3 is connected to the boom cylinder 12 through the boom reversing valve 6, the oil outlet of the pilot pump 5 is connected to the oil inlets of the boom lowering proportional valve 7 and the boom lifting proportional valve 8 respectively, the oil outlet of the boom lowering proportional valve 7 is connected to the right pilot oil port of the boom reversing valve 6, the oil outlet of the boom lifting proportional valve 8 is connected to the left pilot oil port of the boom reversing valve 6, and a regeneration control component is further provided between the rod chamber and the rodless chamber of the boom cylinder 12; the oil drain ports of the boom lowering proportional valve 7 and the boom lifting proportional valve 8 are respectively connected to the hydraulic oil tank 1.

[0026] Example 2:

[0027] A hydraulic system with a boom floating regeneration function, which is different from Example 1 in that the regeneration control component includes an electro-hydraulic compound control valve 13 and a regeneration check valve 14, the oil inlet of the regeneration check valve 14 is connected in parallel with the rodless chamber of the boom cylinder 12 and then connected to the oil outlet of the boom reversing valve 6, the oil outlet of the regeneration check valve 14 is connected to the rod chamber of the boom cylinder 12 through the electro-hydraulic compound control valve 13, and the oil outlet of the boom lowering proportional valve 7 is also connected to the hydraulic control port of the electro-hydraulic compound control valve 13; the oil outlet of the electro-hydraulic compound control valve 13 is also connected to a switch valve 17, and the oil outlet of the switch valve 17 is connected to the hydraulic oil tank 1.

[0028] Furthermore, the oil outlet of the boom reversing valve 6 is also connected to a small-cavity port relief valve 15 and a large-cavity port relief valve 16. The small-cavity port relief valve 15 is connected in parallel with the rod chamber of the boom cylinder 12 and then connected to the F port of the boom reversing valve 6. The large-cavity port relief valve 16 is connected in parallel with the rodless chamber of the boom cylinder 12 and then connected to the E port of the boom reversing valve 6. The function of the small-cavity port relief valve 15 and the large-cavity port relief valve 16 is to limit the maximum operating pressure of the boom cylinder 12 to ensure that the boom cylinder 12 is not damaged.

[0029] Furthermore, the oil outlet of the main pump 3 is connected to the A port and the B port of the boom reversing valve 6 respectively, and a load check valve 4 is further provided between the B port of the boom reversing valve 6 and the main pump 3 .

[0030] Furthermore, it also includes a controller 10, which is electrically connected to the signal ends of the boom lowering proportional valve 7, the boom raising proportional valve 8, the electro-hydraulic compound control valve 13 and the switch valve 17 respectively; the controller 10 is also electrically connected to the floating button 11.

[0031] Furthermore, the boom lowering proportional valve 7 and the boom raising proportional valve 8 are electrically connected to an electric control handle 9 .

[0032] Specifically, the engine 2 is coaxially connected to the main pump 3 and the pilot pump 5 to provide power for them and drive their rotation; after the oil suction port of the main pump 3 draws oil from the hydraulic oil tank 1, the pressure oil is output through the oil outlet of the main pump 3 and is divided into two paths, one path directly leads to the oil inlet A of the boom reversing valve 6, and the other path is connected to the oil inlet B of the boom reversing valve 6 through the load check valve 4. The working oil port E of the boom reversing valve 6 is connected to the rodless chamber of the boom cylinder 12 through a hydraulic pipeline, and the working oil port F of the boom reversing valve 6 is connected to the rod chamber of the boom cylinder 12 through a hydraulic pipeline; the large chamber port overflow valve 16 is connected in parallel with the hydraulic pipeline entering the rodless chamber of the boom cylinder 12, and the small chamber port overflow valve 15 is connected in parallel with the hydraulic pipeline entering the rod chamber of the boom cylinder 12; at the same time, the oil inlet of the regeneration check valve 14 is connected in parallel with the rodless chamber of the boom cylinder 12, and the oil outlet of the regeneration check valve 14 is connected to the oil inlet of the electro-hydraulic compound control valve 13, and the oil outlet of the electro-hydraulic compound control valve 13 is divided into two paths, one path is connected to the rod chamber of the boom cylinder 12, and the other path is connected to the oil inlet of the switch valve 17, and the oil outlet of the switch valve 17 is connected to the hydraulic oil tank 1.

[0033] In addition, the pilot pump 5's suction port is connected to the hydraulic oil tank 1, and its outlet is connected to the oil inlets of the boom-down proportional valve 7 and boom-up proportional valve 8, respectively. The drain ports of the boom-down proportional valve 7 and boom-up proportional valve 8 are also connected to the hydraulic oil tank 1. The boom-down proportional valve 7's outlet is divided into two routes: one route is connected to the right pilot oil port of the boom reversing valve 6, and the other route is connected to the hydraulic control port of the electro-hydraulic compound control valve 13. The boom-up proportional valve 8's outlet is connected to the left pilot oil port of the boom reversing valve 6. The electric control handle 9 is electrically connected to the boom-down proportional valve 7 and boom-up proportional valve 8. The floating button 11 is electrically connected to the controller 10, which sends control signals to the boom-down proportional valve 7, boom-up proportional valve 8, electro-hydraulic compound control valve 13, and the on-off valve 17.

[0034] Example 3:

[0035] An excavator is provided with a hydraulic system with a boom floating regeneration function as described in Example 1 or Example 2.

[0036] The working principle of this utility model is:

[0037] The boom reversing valve 6 is divided into left position, middle position and right position, which correspond to boom lifting, boom holding and boom lowering respectively; when the boom reversing valve 6 is in the middle position, the hydraulic oil output by the main pump 3 flows to other functional oil ports through the central bypass circuit to perform other operations.

[0038] Boom lifting action: The pilot oil output by the pilot pump 5 is supplied to the boom lifting proportional valve 8. The operator pushes the electric control handle 9. The stroke displacement of the electric control handle 9 determines the current of the boom lifting proportional valve 8 (the greater the stroke of the electric control handle 9, the greater the control current of the boom lifting proportional valve 8), thereby controlling the pilot pressure of the boom lifting. The pilot pressure oil output by the boom lifting proportional valve 8 pushes the valve core of the boom reversing valve 6 to the right, and the boom reversing valve 6 operates in the left position. The hydraulic oil output by the main pump 3 enters the rodless chamber of the boom cylinder 12. The oil in the rodless chamber returns to the hydraulic oil tank 1, thus completing the boom lifting action. At this time, the electromagnets of the electro-hydraulic compound control valve 13 and the switch valve 17 are both de-energized.

[0039] Boom lowering action: The pilot oil output by the pilot pump 5 is supplied to the boom-lowering proportional valve 7. The operator pushes the electric control handle 9. The stroke displacement of the electric control handle 9 determines the current level of the boom-lowering proportional valve 7 (the greater the stroke of the electric control handle 9, the greater the control current of the boom-lowering proportional valve 7), thereby controlling the pilot pressure for boom lifting. The pilot pressure oil output by the boom-lowering proportional valve 7 pushes the spool of the boom reversing valve 6 to the left, and the boom reversing valve 6 operates in the right position. The hydraulic oil output by the main pump 3 enters the rod chamber of the boom cylinder 12, and the oil in the rodless chamber returns to the hydraulic oil tank 1, thus completing the boom lowering action. At this time, the electromagnets of the electro-hydraulic compound control valve 13 and the switch valve 17 are both de-energized, but since the oil outlet of the boom lowering proportional valve 7 will output pressure oil connected to the control oil port of the electro-hydraulic compound control valve 13, the pressure oil will overcome the spring force of the return spring of the electro-hydraulic compound control valve 13, causing the electro-hydraulic compound control valve 13 to work in the upper position, and the oil in the rodless chamber of the boom cylinder 12 passes through the regeneration one-way valve 14 and the electro-hydraulic compound control valve 13 into the rod chamber of the boom cylinder 12, thereby realizing the regeneration control of the boom lowering flow. On the one hand, due to the action of gravity, when the boom is lowered, the pressure in the large chamber of the boom cylinder 12 is greater than the pressure in the small chamber of the boom cylinder 12. The oil passes through the regeneration one-way valve 14 and the electro-hydraulic compound control valve 13, and can supply part of the pressure oil in the large chamber of the boom cylinder 12 and the pressure oil output by the main pump 3 to the small chamber of the boom cylinder 12 at the same time, which can speed up the boom lowering speed and improve work efficiency; on the other hand, when the boom's own weight and load accelerate the fall, the falling speed may be too fast, and the pump's oil supply is insufficient, resulting in cavitation. At this time, through regeneration control, the return oil of the boom cylinder 12 will flow back to the small chamber of the boom cylinder 12 to prevent the boom cylinder 12 from being sucked into the air when the boom is lowered.

[0040] When performing leveling operations or hammering operations, first, according to the above principle, the boom is lifted or lowered to a suitable height. After reaching a floating position suitable for the operation, the floating button 11 is activated, and the controller 10 sends an electric control signal to the electro-hydraulic compound control valve 13 and the switch valve 17 to be energized. At this time, the electro-hydraulic compound control valve 13 works in the upper position, and the switch valve 17 works in the right position. As a result, the oil in the rod chamber and the rodless chamber of the boom cylinder 12 is connected through the regeneration one-way valve 14 and the electro-hydraulic compound control valve 13, and then returns to the hydraulic oil tank 1 through the switch valve 17 to realize the floating function. When the rod chamber and the rodless chamber of the boom cylinder 12 are both connected to the hydraulic oil tank 1, the boom can float freely according to changes in the ground shape or the deadweight load, which can reduce the operator's special control of the boom.

Claims

1. A hydraulic system with boom floating regeneration function, characterized by: The invention comprises a main pump (3), a pilot pump (5), a boom lowering proportional valve (7), a boom raising proportional valve (8) and a boom oil cylinder (12), wherein the oil outlet of the main pump (3) is connected to the boom oil cylinder (12) via the boom reversing valve (6), the oil outlet of the pilot pump (5) is connected to the oil inlets of the boom lowering proportional valve (7) and the boom raising proportional valve (8), respectively, the oil outlet of the boom lowering proportional valve (7) is connected to the right pilot oil port of the boom reversing valve (6), the oil outlet of the boom raising proportional valve (8) is connected to the left pilot oil port of the boom reversing valve (6), and a regeneration control component is further provided between the rod chamber and the rodless chamber of the boom oil cylinder (12).

2. The hydraulic system with boom floating regeneration function according to claim 1, characterized in that: The regeneration control component includes an electro-hydraulic composite control valve (13) and a regeneration check valve (14). The oil inlet of the regeneration check valve (14) is connected in parallel with the rodless cavity of the boom oil cylinder (12) and then connected to the oil outlet of the boom reversing valve (6). The oil outlet of the regeneration check valve (14) is connected to the rod cavity of the boom oil cylinder (12) through the electro-hydraulic composite control valve (13). The oil outlet of the boom lowering proportional valve (7) is also connected to the hydraulic control port of the electro-hydraulic composite control valve (13).

3. The hydraulic system with boom floating regeneration function according to claim 2, characterized in that: The oil outlet of the electro-hydraulic composite control valve (13) is also connected to a switch valve (17), and the oil outlet of the switch valve (17) is connected to the hydraulic oil tank (1).

4. The hydraulic system with boom floating regeneration function according to claim 3, characterized in that: The oil outlet of the boom reversing valve (6) is also connected to a small cavity port relief valve (15) and a large cavity port relief valve (16), and the small cavity port relief valve (15) is connected in parallel with the rod cavity of the boom oil cylinder (12) and then connected to the F port of the boom reversing valve (6), and the large cavity port relief valve (16) is connected in parallel with the rodless cavity of the boom oil cylinder (12) and then connected to the E port of the boom reversing valve (6).

5. The hydraulic system with boom floating regeneration function according to claim 3, characterized in that: The oil outlet of the main pump (3) is connected to the A port and the B port of the boom reversing valve (6) respectively, and a load check valve (4) is provided between the B port of the boom reversing valve (6) and the main pump (3).

6. The hydraulic system with boom floating regeneration function according to any one of claims 3 to 5, characterized in that: The device further comprises a controller (10), which is electrically connected to the signal ends of the boom lowering proportional valve (7), the boom raising proportional valve (8), the electro-hydraulic composite control valve (13) and the switch valve (17).

7. The hydraulic system with boom floating regeneration function according to claim 6, characterized in that: The controller (10) is also electrically connected to a floating button (11).

8. The hydraulic system with boom floating regeneration function according to any one of claims 1 to 5, characterized in that: The oil drain ports of the boom lowering proportional valve (7) and the boom raising proportional valve (8) are respectively connected to the hydraulic oil tank (1).

9. The hydraulic system with boom floating regeneration function according to any one of claims 1 to 5, characterized in that: The boom lowering proportional valve (7) and the boom raising proportional valve (8) are electrically connected to an electric control handle (9).

10. An excavator, characterized in that: The excavator is provided with a hydraulic system with a boom floating regeneration function as described in any one of claims 1 to 5.

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