High-horsepower tractor flow sharing hydraulic system

Abstract

The utility model relates to the technical field of tractor hydraulic control systems, in particular to a high-horsepower tractor flow sharing hydraulic system. The hydraulic control system comprises a variable pump and a proportional multi-way valve used for controlling hydraulic output, a head link, a lifting link, a tail link and a plurality of machine tool using links are arranged in the proportional multi-way valve, an oil way on the lifting link is connected to a tractor lifting oil cylinder, and oil ways on the machine tool using links are connected to a machine tool motor and a machine tool oil cylinder respectively; a tractor lifting oil cylinder control unit is arranged in the lifting unit, and a machine tool motor control unit and a machine tool oil cylinder control unit are arranged in the machine tool using unit. According to the multi-way valve, the tractor lifting oil cylinder and the machine tool hydraulic actuator share the flow of the variable pump in proportion, and when the flow of the variable pump cannot meet the requirements of a plurality of actuators, a hydraulic system can distribute the flow of the variable pump according to the opening degree and proportion of valve elements of different control units in the multi-way valve, so that all the actuators act in a coordinated mode at the same time.

Description

Technical Field

[0001] This utility model relates to the field of tractor hydraulic control system technology, specifically to a flow-sharing hydraulic system for high-horsepower tractors. Background Technology

[0002] In heavy equipment such as agricultural machinery and construction machinery, the hydraulic system is the core component for achieving power transmission and precise control. Traditional hydraulic systems typically use a fixed displacement pump with a throttle valve or a common multi-way valve, which has certain drawbacks. For example, the fixed displacement pump always supplies oil at its maximum displacement, while the flow demand of the actuators varies with operating conditions. Excess flow is lost through the relief valve or throttle valve, leading to severe system overheating and significant energy waste. Common multi-way valves lack pressure compensation functionality. When multiple actuators operate simultaneously, the actuator with the lower load pressure will receive priority flow, while the actuator with the higher load will experience sluggishness or stagnation due to insufficient flow, affecting operational accuracy. Traditional electromagnetic directional valves can only achieve on / off control and cannot steplessly adjust the speed and force of the actuators, making it difficult to meet the precision operation requirements of modern agricultural machinery. Utility Model Content

[0003] The purpose of this utility model is to address the defects and shortcomings of the existing technology by providing a reasonably designed high-horsepower tractor flow-sharing hydraulic system that can solve the aforementioned defects.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: it includes a variable pump and a proportional multi-way valve connected thereto for controlling hydraulic output. The proportional multi-way valve is provided with a head connection, a lifting connection, a tail connection, and multiple implement use connections. The oil circuit on the lifting connection is connected to the tractor lifting cylinder, and the oil circuit on the implement use connections is respectively connected to the implement motor and the implement cylinder. The lifting connection is provided with a tractor lifting cylinder control connection, and the implement use connections are respectively provided with a implement motor control connection and a implement cylinder control connection.

[0005] The inlet of the variable pump is connected to the oil tank, and the outlet is connected to a high-pressure filter. It is then connected to the head unit, lifting unit, tail unit, and multiple implement use units via the main high-pressure oil circuit. The variable pump is also equipped with a variable pump displacement control piston. The variable pump is equipped with a variable pump load-sensitive valve and a variable pump pressure shut-off valve. The tractor lifting cylinder control unit, implement motor control unit, and implement cylinder control unit in the proportional multi-way valve are connected to a load-sensitive oil circuit (LS). This oil circuit is connected to the variable pump load-sensitive valve for load pressure feedback. The variable pump load-sensitive valve is connected to one end of the variable pump displacement control piston via the variable pump pressure shut-off valve.

[0006] Preferably, the proportional multi-way valve is provided with a return oil line connected to the oil tank, and a return oil filter is provided on the return oil line.

[0007] Preferably, the two ends of the tractor lifting cylinder control link, the implement motor control link, and the implement cylinder control link are respectively connected to a multi-way valve pilot control proportional pressure reducing valve one and a multi-way valve pilot control proportional pressure reducing valve two, and the multiple multi-way valve pilot control proportional pressure reducing valve one and multi-way valve pilot control proportional pressure reducing valve two are all connected in parallel.

[0008] Preferably, a pilot control pressure reducing valve is connected to the main high-pressure oil line inside the proportional multi-way valve. The pilot control pressure reducing valve is installed in the tail section, and the oil outlet of the pilot control pressure reducing valve is connected to the first pilot control proportional pressure reducing valve and the second pilot control proportional pressure reducing valve of the multi-way valve.

[0009] Preferably, the two oil ports of the tractor lifting cylinder are respectively provided with a lifting cylinder buffer valve one and a lifting cylinder buffer valve two connected to the return oil circuit.

[0010] Preferably, an LS pressure relief valve is connected between the return oil circuit and the load-sensitive oil circuit (LS).

[0011] Preferably, a pressure compensation valve is provided between the tractor lifting cylinder control line, the implement motor control line, and the implement cylinder control line and the load-sensitive oil circuit (LS).

[0012] Preferably, the oil circuit in the lifting linkage connected to one end of the tractor lifting cylinder is equipped with a load holding valve.

[0013] The beneficial effects of this utility model after adopting the above structure are:

[0014] 1. In this utility model, the tractor lifting cylinder and the implement hydraulic actuator share the variable pump flow rate proportionally. When the variable pump flow rate cannot meet the needs of multiple actuators, the hydraulic system can proportionally distribute the variable pump flow rate according to the valve core opening degree of different control links in the multi-way valve, so that each actuator can act in a coordinated manner at the same time, thus solving the defect that it can only prioritize the operation of lightly loaded actuators.

[0015] 2. In this utility model, the variable pump adjusts the output flow rate as needed, resulting in less energy waste.

[0016] 3. When the variable pump has sufficient flow, for example, when only one hydraulic actuator is in motion, the flow ratio of the actuator (tractor lifting cylinder or implement hydraulic actuator) can be adjusted to accurately meet the action requirements of the tractor lifting cylinder or implement hydraulic actuator. At the same time, the variable pump supplies oil on demand, the hydraulic system is energy-saving, and the system pressure loss is small. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the hydraulic system of this utility model;

[0018] Figure 2This is a schematic diagram of the hydraulic principle of the tractor lifting cylinder when it rises in this utility model;

[0019] Figure 3 This is a schematic diagram of the flow-sharing hydraulic principle of this utility model.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. Variable displacement pump; 2. High-pressure filter; 3. Proportional multi-way valve; 4. Return oil filter; 5. Oil tank; 6. Tractor lifting cylinder; 7. Implement motor one; 8. Implement cylinder one; 9. Implement cylinder two; 10. Implement motor two;

[0022] 101. Variable pump load-sensitive valve; 102. Variable pump pressure shut-off valve; 103. Variable pump displacement control piston; 301. LS oil circuit pressure relief valve; 302. Lifting cylinder buffer valve one; 303. Lifting cylinder buffer valve two; 304. Pressure compensation valve; 305. Tractor lifting cylinder control link; 306. Implement motor control link one; 307. Implement cylinder control link one; 308. Implement cylinder control link two; 309. Implement motor control link two; 3010. Multi-way valve pilot control proportional pressure reducing valve one; 3011. Multi-way valve pilot control proportional pressure reducing valve two; 3012. Load holding valve; 3013. Pilot control pressure reducing valve;

[0023] A. Header link; B. Lifting link; C. Equipment usage link; D. Tail link. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] See Figure 1 As shown, it includes a variable displacement pump 1 and a proportional multi-way valve 3 connected thereto for controlling hydraulic output. The proportional multi-way valve 3 has a head connection, a lifting connection, a tail connection, and four implement use connections. The oil circuit on the lifting connection is connected to the tractor lifting cylinder 6. The four implement use connections are respectively equipped with implement motor control connection 1 306, implement cylinder control connection 1 307, implement cylinder control connection 2 308, and implement motor control connection 2 309, and are respectively connected to implement motor 1 7, implement cylinder 1 8, implement cylinder 2 9, and implement motor 2 10; the lifting connection is equipped with tractor lifting cylinder control connection 305.

[0026] The inlet of variable pump 1 is connected to oil tank 5, and the outlet is connected to high-pressure filter 2. It then connects to the head unit, lifting unit, tail unit, and multiple implement use units via the main high-pressure oil circuit. Variable pump 1 also includes a variable pump displacement control piston 103. Variable pump 1 is equipped with a variable pump load-sensitive valve 101 and a variable pump pressure shut-off valve 102. The tractor lifting cylinder control unit 305, implement motor control unit 1 306, implement cylinder control unit 1 307, implement cylinder control unit 2 308, and implement motor control unit 2 309 in the proportional multi-way valve 3 are connected to load-sensitive oil circuits (LS). The oil circuit is connected to the variable pump load sensing valve 101 for load pressure feedback. The variable pump load sensing valve 101 is connected to one end of the variable pump displacement control piston 103 through the variable pump pressure shut-off valve 102. When the system pressure is higher than the set value, the valve is opened to introduce pressure into one end of the variable pump displacement control piston 103, forcing the swashplate of the variable pump 1 to rotate to a small displacement or 0, thereby achieving protection. The proportional multi-way valve 3 is provided with a return oil circuit connected to the oil tank 5. A return oil filter 4 is provided on the return oil circuit. An LS oil circuit pressure relief valve 301 is connected between the return oil circuit and the load sensing oil circuit (LS).

[0027] Both ends of the tractor lifting cylinder control link 305, implement motor control link 1 306, implement cylinder control link 1 307, implement cylinder control link 2 308, and implement motor control link 2 309 are connected to a multi-way valve pilot control proportional pressure reducing valve 1 3010 and a multi-way valve pilot control proportional pressure reducing valve 2 3011. All the multi-way valve pilot control proportional pressure reducing valve 1 3010 and multi-way valve pilot control proportional pressure reducing valve 2 3011 are connected in parallel.

[0028] A pilot control pressure reducing valve 3013 is connected to the main high-pressure oil line inside the proportional multi-way valve 3. The pilot control pressure reducing valve 3013 is installed in the tail section. The pilot control pressure reducing valve 3013 is connected to the oil outlet of the multi-way valve pilot control proportional pressure reducing valve one 3010 and the multi-way valve pilot control proportional pressure reducing valve two 3011. Pressure compensation valves 304 are provided between the tractor lifting cylinder control line 305, implement motor control line one 306, implement cylinder control line one 307, implement cylinder control line two 308, and implement motor control line two 309 and the load sensitive oil line (LS). The pilot control pressure reducing valve 3013 ensures the pilot pressure for the switching of each control line.

[0029] Therefore, the proportional multi-way valve 3 is controlled by the multi-way valve pilot-controlled proportional pressure reducing valve 1 3010 and the multi-way valve pilot-controlled proportional pressure reducing valve 2 3011. The valve core opening is changed proportionally. With the cooperation of the pressure compensation valve 304, the flow rate can be proportionally adjustable. When multiple actuators act synchronously and the flow rate is saturated, the flow rate of variable pump 1 can be shared according to the valve opening.

[0030] The tractor lifting cylinder 6 has two oil ports equipped with lifting cylinder buffer valve 302 and lifting cylinder buffer valve 303, which are connected to the return oil circuit, to absorb oil pressure fluctuations caused by bumps, provide protection, and prevent cavitation. The oil circuit connected to one end of the tractor lifting cylinder 6 in the lifting link is equipped with a load holding valve 3012 to maintain the lifting state of the implement during transportation without starting the equipment, ensuring that the ground clearance and static settlement meet the standard requirements.

[0031] Example of the working principle of this embodiment:

[0032] like Figure 2 As shown, the multi-way valve pilot control proportional pressure reducing valve 3011 below the tractor lifting cylinder control link 305 receives an electrical signal, and the tractor lifting cylinder control link 305 moves to the lower position. The standby pressure oil at the pump port passes through the tractor lifting cylinder control link 305, then through the pressure compensation valve 304 into the LS oil circuit, and is subsequently transmitted to the variable pump load sensitive valve 101. After receiving the pressure signal, variable pump 1 ends its standby state; the pump displacement changes from zero to a suitable position according to the flow required by the multi-way valve, and the pump starts supplying oil. The pressure oil at the pump port passes sequentially through the tractor lifting cylinder control link 305 and the pressure compensation valve 304, reaching... The load holding valve 3012 (the pressure oil in the control chamber of this valve is unloaded through the control link, and the valve core opens) then enters the lower chamber of the tractor lifting cylinder 6, pushing the cylinder to rise; at the same time, the oil in the upper chamber of the tractor lifting cylinder 6 passes through the lifting cylinder control link and then returns to the oil tank 5 through the return oil filter 4, completing the predetermined action; the opening degree of the control link valve port determines the flow rate of the lifting cylinder, and the pressure difference at both ends of the valve core opening of the tractor lifting cylinder control link 305 is fed back to both ends of the valve core of the load sensitive valve. The variable pump 1 adjusts the pump displacement according to the pressure difference at both ends of the valve core of the load sensitive valve to achieve on-demand oil supply, realize energy saving and avoid energy loss.

[0033] This embodiment demonstrates the principle of shared hydraulic pressure:

[0034] like Figure 3As shown, the analysis is based on two actuators: tractor lifting cylinder 6 and implement cylinder 9. Assume that tractor lifting cylinder 6 has a small load, so its corresponding control valve opens first, and the cylinder moves first. Implement cylinder 9 has a large load, so its corresponding control valve opens later, and the cylinder moves later. During the independent operation of tractor lifting cylinder 6, the flow rate of variable pump 1 meets the cylinder's requirements. When the control valve of implement cylinder 9 opens, assuming that the flow rate of variable pump 1 cannot simultaneously meet the combined action requirements of tractor lifting cylinder 6 and implement cylinder 9, the outlet pressure of variable pump 1 passes sequentially through tractor lifting cylinder control link 305, implement motor control link 1 306, implement cylinder control link 1 307, and implement cylinder control link 2 308, reaching the implement cylinder. The pressure compensation valve 304 on the implement cylinder 9 then acts on the lower end of the pressure compensation valve 304 on the tractor lifting cylinder 6, causing it to close and the system to hold pressure. When the pressure rises to a level that can drive the cylinder to its maximum load, the pressure compensation valve 304 on the tractor lifting cylinder 6 opens again. At this time, the tractor lifting cylinder 6 and the implement cylinder 9 operate simultaneously. The pressure loss across the pressure compensation valve 304 is the pressure of the implement cylinder 9 minus the pressure of the tractor lifting cylinder 6. The inlet pressure of the valve ports of the tractor lifting cylinder control link 305 and the implement cylinder control link 308 are both equal to the outlet pressure of the variable pump 1. The outlet pressure of the valve ports is equal to the pressure corresponding to the maximum load of the cylinder. The pressure loss of the two proportional throttle valve ports is the same, and they share the flow rate of the variable pump 1 according to the valve port opening ratio.

[0035] It should be understood that the above-described specific embodiments of this utility model are merely illustrative or explanatory of the principles of this utility model and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this utility model should be included within the protection scope of this utility model. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A high horse power tractor flow sharing hydraulic system comprising a variable pump (1), characterized in that: Variable pump (1) is connected with proportional multi-way valve (3) for controlling hydraulic output, proportional multi-way valve (3) is equipped with head connection, lifting connection, tail connection and multiple implement use connections, oil passage on lifting connection is connected to tractor lifting oil cylinder (6), and oil passage on implement use connection is respectively connected to implement motor and implement oil cylinder;Lifting connection is equipped with tractor lifting oil cylinder control connection (305), and implement use connection is respectively equipped with implement motor control connection and implement oil cylinder control connection; Variable pump (1) is connected to oil tank (5) in oil inlet, and high pressure filter (2) is connected to oil outlet, and then is connected to head connection, lifting connection, tail connection and multiple implement use connections through main high pressure oil passage, and variable pump (1) is also equipped with variable pump displacement control piston (103), variable pump load sensitive valve (101) and variable pump pressure cut-off valve (102) are installed on variable pump (1), tractor lifting oil cylinder control connection (305), implement motor control connection and implement oil cylinder control connection in proportional multi-way valve (3) are connected with load sensitive oil passage (LS), which is connected to variable pump load sensitive valve (101) for load pressure feedback, and variable pump load sensitive valve (101) is connected to one end of variable pump displacement control piston (103) through variable pump pressure cut-off valve (102).

2. A high horsepower tractor flow sharing hydraulic system as claimed in claim 1 characterized by: The proportional multi-way valve (3) is provided with a return oil passage connected to the oil tank (5), and a return oil filter (4) is arranged on the return oil passage.

3. A high horsepower tractor flow sharing hydraulic system as claimed in claim 1, wherein: Both ends of the tractor lifting oil cylinder control connection (305), the implement motor control connection and the implement oil cylinder control connection are respectively connected with a multi-way valve pilot control proportional pressure reducing valve one (3010) and a multi-way valve pilot control proportional pressure reducing valve two (3011), and the plurality of multi-way valve pilot control proportional pressure reducing valve one (3010) and multi-way valve pilot control proportional pressure reducing valve two (3011) are connected in parallel.

4. A high horsepower tractor flow sharing hydraulic system as claimed in claim 3, characterized in that: The proportional multi-way valve (3) is provided with a pilot control pressure reducing valve (3013) connected to the main high pressure oil passage, which is installed in the tail connection, and the pilot control pressure reducing valve (3013) is connected to the oil outlet of the multi-way valve pilot control proportional pressure reducing valve one (3010) and the multi-way valve pilot control proportional pressure reducing valve two (3011).

5. A high horsepower tractor flow sharing hydraulic system as claimed in claim 2, wherein: The tractor lifting oil cylinder (6) is provided with a lifting oil cylinder buffer valve one (302) and a lifting oil cylinder buffer valve two (303) connected to the return oil passage.

6. A high horsepower tractor flow sharing hydraulic system as claimed in claim 2, wherein: The LS oil passage pressure limiting valve (301) is connected between the return oil passage and the load sensitive oil passage (LS).

7. A high horsepower tractor flow sharing hydraulic system as claimed in claim 1, wherein: The pressure compensating valve (304) is arranged between the tractor lifting oil cylinder control connection (305), the implement motor control connection and the implement oil cylinder control connection and the load sensitive oil passage (LS).

8. A high horsepower tractor flow sharing hydraulic system as claimed in claim 1, wherein: The load holding valve (3012) is arranged in the oil passage connected to one end of the tractor lifting oil cylinder (6) in the lifting connection.

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