Engineering machine hydraulic system and engineering machine

Abstract

The invention discloses an engineering machine hydraulic system and an engineering machine, and belongs to the technical field of engineering machine lubrication and control hydraulic systems, the hydraulic system comprises a filter, an oil inlet of the filter is communicated with an outlet of a hydraulic pump, and an oil outlet is connected with a working device; an oil inlet of the constant pressure difference valve is connected with an oil inlet of the filter, an oil outlet of the constant pressure difference valve is connected with an oil inlet of the radiator, a control end of the constant pressure difference valve is communicated with the oil inlet of the filter, and a spring end of the constant pressure difference valve is connected with an oil outlet of the filter; an oil outlet of the radiator is communicated with the oil tank, and an oil inlet of the radiator is communicated with an oil outlet of the working device. According to the invention, unfiltered hydraulic oil is effectively prevented from entering the control system, and the filter is replaced according to the normal maintenance period of the machine without warning and replacing the filter, so that the risks of clamping stagnation and failure of the control system are reduced, and the use and maintenance cost of the filter is relatively low.

Description

Technical Field

[0001] This invention relates to the field of hydraulic systems for lubrication and control of engineering machinery, and more particularly to a hydraulic system and a machine for engineering machinery, specifically a hydraulic lubrication system for gearbox gears of a tractor and hydraulic control system for power reversing of the gearbox. Background Technology

[0002] As global agriculture transitions towards intelligent manufacturing, tractors, as core operating equipment, are undergoing technological innovation. Power steering and power shift technologies significantly improve operating efficiency and have become key technologies for OEMs. Power steering and power shift technologies require corresponding hydraulic control systems. Due to their low oil pressure and low flow requirements, to reduce overall machine space, multi-system integration is common, typically integrating the control system with the gearbox lubrication system or steering and braking systems. Because multiple systems share resources, filters are generally added to the system to ensure oil cleanliness. In traditional designs, one method to prevent filter damage is to add a bypass. When the filter's inlet and outlet pressures exceed the filter element's capacity, the bypass port is opened, allowing hydraulic oil to bypass the filter and directly connect to the filter outlet, protecting the filter element from damage. However, this leads to hydraulic filtration failure, allowing unfiltered oil to enter the control system, potentially causing control valve jamming or malfunction. Another method is to add an alarm function. When the filter inlet pressure exceeds the set pressure, the driver is alerted to replace the filter. However, due to the complexity of tractor operating conditions, the driver cannot replace the filter immediately after the warning. A certain safety margin of usage time needs to be allowed; otherwise, there is still a risk of damage. This reduces the filter's service life, leading to the need for a larger filter design or excessively frequent replacement, resulting in higher operating costs for the customer. Furthermore, regardless of which method is used, low-temperature operating conditions are unavoidable. When encountering relatively low ambient temperatures, the viscosity of the hydraulic oil increases, which can also cause false alarms. Summary of the Invention

[0003] The purpose of this invention is to provide a hydraulic system and a machine for engineering machinery, which effectively prevents unfiltered hydraulic oil from entering the control system. At the same time, there is no need to alarm or remind the filter to be replaced. The filter can be replaced according to the normal maintenance cycle of the tractor, which reduces the risk of control system jamming and failure.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0005] In a first aspect, the present invention provides a hydraulic system for engineering machinery, comprising:

[0006] The filter has an oil inlet connected to the outlet of the hydraulic pump and an oil outlet connected to the working device.

[0007] A constant pressure differential valve, wherein the oil inlet of the constant pressure differential valve is connected to the oil inlet of the filter, the oil outlet is connected to the oil inlet of the radiator, the control end is connected to the oil inlet of the filter, and the spring end is connected to the oil outlet of the filter.

[0008] The oil outlet of the radiator is connected to the oil tank, and the oil inlet is connected to the oil outlet of the working device.

[0009] Furthermore, when the pressure difference between the oil inlet and the oil outlet of the filter is 0, the constant pressure differential valve operates in the shut-off position, at which time hydraulic oil flows out from the oil outlet of the filter.

[0010] Furthermore, when the pressure difference between the filter's inlet and outlet is greater than the retaining force of the spring end of the differential pressure valve, the spring end of the differential pressure valve is compressed, the differential pressure valve operates in the connected position, and hydraulic oil flows out simultaneously from the filter's outlet and the differential pressure valve's outlet.

[0011] Furthermore, if the engineering machine is started for the first time when the ambient temperature is lower than the set value, the pressure difference between the filter's inlet and outlet is greater than the retaining force of the spring end of the differential pressure valve. The spring end of the differential pressure valve is compressed, and the differential pressure valve operates in the connected position. Hydraulic oil flows out simultaneously from the outlets of both the filter and the differential pressure valve. This combination of filter and differential pressure valve effectively prevents unfiltered hydraulic oil from entering the control system, instead directing it back to the oil tank via the differential pressure valve.

[0012] Furthermore, the working device includes a control valve, the oil inlet of which is connected to the inlet of the accumulator, the inlet of the sequence valve, the inlet of the first solenoid directional valve, and the inlet of the second solenoid directional valve, respectively. The first outlet of the sequence valve is connected to the oil outlet of the control valve, and the second outlet of the sequence valve is connected to the oil tank. The accumulator is used to store and release hydraulic energy and release it when needed to balance flow, stabilize pressure, or absorb shock.

[0013] The working ports of the first and second solenoid directional valves are connected to the control system, and the outlet ports of the first and second solenoid directional valves are directly connected to the oil tank.

[0014] Furthermore, when the pressure at the control valve inlet is less than the opening pressure of the sequence valve, if the first and second solenoid directional valves are energized at this time, hydraulic oil flows into the control system through the working ports of the first and second solenoid directional valves to control power reversal or power shifting, etc.

[0015] When the pressure at the inlet of the control valve reaches the opening pressure of the sequence valve, the sequence valve operates in the connected position, and excess hydraulic oil flows out from the outlet of the control valve; the control valve is also equipped with a spare port.

[0016] Furthermore, the radiator includes a cooling unit and a second check valve. The oil inlet of the radiator is connected to the inlet of the cooling unit and the inlet of the second check valve, and the outlet of the cooling unit and the outlet of the second check valve are connected to the outlet of the radiator. The radiator dissipates heat from the hydraulic oil, preventing the oil temperature from becoming too high due to heat generated during system operation, which could affect the performance of the hydraulic oil and the stability of the system.

[0017] Furthermore, a first check valve is provided between the differential pressure valve and the radiator; the inlet of the first check valve is connected to the outlet of the differential pressure valve, and the outlet of the first check valve is connected to the inlet of the radiator. The component characteristics of the check valve ensure that the hydraulic oil will not flow back. Unfiltered hydraulic oil flows back to the oil tank after passing through the differential pressure valve, and there is no possibility of it flowing back into the hydraulic system. This greatly ensures the working stability of the hydraulic system.

[0018] Furthermore, a third check valve is provided between the oil outlet of the working device and the oil inlet of the radiator.

[0019] In a second aspect, the present invention provides an engineering machine equipped with the engineering machine hydraulic system described in any one of the first aspects.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0021] This invention effectively prevents unfiltered hydraulic oil from entering the control system in the hydraulic system. At the same time, compared with the prior art, there is no need for alarm warnings to replace the filter. The filter can be replaced according to the normal maintenance cycle of the tractor. In low temperature environment or in the case of filter blockage, the risk of control system jamming and failure is reduced, and the cost of filter use is also reduced. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a system schematic diagram of the engineering machine control and lubrication system provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the filter principle and structure provided in the embodiments of the present invention;

[0025] Figure 3 This is a schematic diagram of the control valve principle and structure provided in the embodiments of the present invention.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Filter; 2. Differential pressure valve; 3. Control valve; 4. Accumulator; 5. Sequence valve; 6. Radiator; 7. Cooling unit; 8. First check valve; 9. Second check valve; 10. Third check valve; 11. Hydraulic oil pump; 12. First solenoid directional valve; 13. Second solenoid directional valve; 14. Oil tank; 15. Engine; 16. Fourth check valve. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use.

[0029] Example 1:

[0030] like Figures 1-3 As shown, this embodiment provides a hydraulic system for engineering machinery, specifically including:

[0031] Filter 1, with its inlet P1 connected to the outlet of hydraulic pump 11 and its outlet L1 connected to the working device; in this embodiment, the filter can be a wire mesh structure with a filtration capacity of 10 microns. Differential pressure valve 2, with its inlet P1.1 connected to the inlet P1 of filter 1, its outlet L2 connected to the inlet P3 of radiator 6, its control end connected to the inlet P1 of filter 1, and its spring end connected to the outlet L1 of filter 1; the outlet L5 of radiator 6 is connected to oil tank 14, and its inlet P3 is connected to the outlet LQ of the working device. This combination of filter and differential pressure valve design ensures that unfiltered hydraulic oil will not enter the control system.

[0032] When the pressure difference between the oil inlet P1 and the oil outlet L1 of the filter 1 is 0, the constant pressure differential valve 2 operates in the shut-off position, and at this time, hydraulic oil flows out from the oil outlet L1 of the filter 1.

[0033] When the pressure difference between the filter's inlet P1 and outlet L1 exceeds the retaining force of the spring end of the differential pressure valve 2, the spring end of the differential pressure valve 2 is compressed, and the differential pressure valve 2 operates in the connected position. Hydraulic oil flows out simultaneously from the outlet L1 of the filter 1 and the outlet L2 of the differential pressure valve 2. Clean hydraulic oil flows out from outlet L1, while unfiltered hydraulic oil flows out from outlet L2.

[0034] If the engineering machine is started for the first time when the ambient temperature is lower than the set value, the pressure difference between the oil inlet P1 and the oil outlet L1 of filter 1 is greater than the holding force of the spring end of the constant pressure differential valve 2. The spring end of the constant pressure differential valve 2 is compressed, and the constant pressure differential valve 2 works in the connected position. Hydraulic oil flows out from the oil outlet L1 of filter 1 and the oil outlet L2 of constant pressure differential valve 2 at the same time.

[0035] The working device includes a control valve 3. The oil inlet P2 of the control valve 3 is connected to the inlet of the accumulator 4, the inlet of the sequence valve 5, the inlet of the first electromagnetic reversing valve 12, and the inlet of the second electromagnetic reversing valve 13. The first outlet of the sequence valve 5 is connected to the oil outlet LQ of the control valve 3, and its second outlet L4 is connected to the oil tank 14.

[0036] The working port CS1 of the first solenoid directional valve 12 and the working port CS2 of the second solenoid directional valve 13 are connected to the control system. The oil outlet T2.2 of the first solenoid directional valve 12 and the oil outlet T2.3 of the second solenoid directional valve 13 are directly connected to the oil tank 14.

[0037] When the pressure at the oil inlet P2 of control valve 3 is less than the opening pressure of sequence valve 5, if the first solenoid directional valve 12 and the second solenoid directional valve 13 are energized at this time, hydraulic oil flows into the control system through the working oil port CS1 of the first solenoid directional valve 12 and the working oil port CS2 of the second solenoid directional valve 13.

[0038] When the pressure at the oil inlet P2 of control valve 3 reaches the opening pressure of sequence valve 5, sequence valve 5 operates in the connected position, and excess hydraulic oil flows out from the oil outlet LQ of control valve 3. Control valve 3 is also equipped with a spare port MP.

[0039] The radiator 6 includes a cooling unit 7 and a second one-way valve 9;

[0040] The oil inlet P3 of the radiator 6 is connected to the inlet of the cooling unit 7 and the oil inlet of the second check valve 9, and the oil outlet of the cooling unit 7 and the oil outlet of the second check valve 9 are connected to the oil outlet L5 of the radiator 6. The radiator dissipates heat from the hydraulic oil to prevent the oil temperature from becoming too high due to the heat generated by the system operation, which would affect the performance of the hydraulic oil and the normal operation of the system.

[0041] A first check valve 8 is also provided between the constant pressure differential valve 2 and the radiator 6;

[0042] The oil inlet of the first check valve 8 is connected to the oil outlet L2 of the constant pressure differential valve 2, and the oil outlet of the first check valve 8 is connected to the oil inlet P3 of the radiator 6.

[0043] A third check valve 10 is also provided between the oil outlet LQ of the working device and the oil inlet P3 of the radiator 6.

[0044] In addition, a fourth check valve 16 is installed between the radiator and the oil tank to prevent hydraulic oil entering the oil tank from flowing back into the hydraulic circuit.

[0045] The hydraulic system under the first operating condition will be tested below:

[0046] When the ambient temperature is normal (-10~40℃), the hydraulic oil pump 11 draws oil from the oil tank 14 and sends the hydraulic oil into the oil inlet P1 of the filter 1. After being filtered by the filter 1, particles larger than 10 micrometers in the hydraulic oil are blocked, and the clean oil flows out from the oil outlet L1 of the filter 1 and enters the oil inlet P2 of the control valve 3. At this time, the sequence valve 5 in the control valve 3 is closed, and the hydraulic oil rushes into the accumulator 4. At the same time, the pressure increases. If the first solenoid directional valve 12 or the second solenoid directional valve 13 is energized, the pressurized oil flows out from the working oil port CS1 of the first solenoid directional valve 12 or the working oil port CS2 of the second solenoid directional valve 13 and enters the tractor control system to control power reversing or power shifting, etc. When the pressure rises further to the opening pressure of sequence valve 5, sequence valve 5 opens, and excess hydraulic oil flows out from the outlet LQ of control valve 3, enters the inlet P3 of radiator 6 through the third check valve 10, and flows back to oil tank 14 from the outlet L5 of radiator 6 after being cooled by radiator 6.

[0047] Example 2:

[0048] This embodiment uses the same scheme as Embodiment 1, except that it provides a second type of hydraulic system test under different working conditions:

[0049] When the ambient temperature is normal (-10~40℃) and the filter 1 is clogged, the hydraulic oil pump 11 draws oil from the oil tank 14. When the oil is sent into the oil inlet P1 of the filter 1, the inlet pressure of the filter 1 increases due to the blockage. At this time, the bypass port of the constant pressure differential valve 2 opens, and a small amount of oil flows into the control system from the oil outlet L1 of the filter 1 to complete the corresponding work. A large amount of unfiltered oil flows out from the oil outlet L2 of the constant pressure differential valve 2 and enters the oil inlet P3 of the radiator 6 through the first check valve 8. The hydraulic oil flows back to the oil tank 14 through the oil outlet L5 of the radiator 6.

[0050] Example 3:

[0051] This embodiment uses the same scheme as the above embodiment, but differs from the above embodiment in that it provides a third type of hydraulic system test:

[0052] When the ambient temperature is too low (< -20℃), the viscosity of the hydraulic oil increases. When the vehicle is started for the first time, the hydraulic oil pump 11 draws oil from the oil tank 14 and sends the hydraulic oil into the oil inlet P1 of the filter 1. At this time, the pressure difference between the oil inlet P1 and the oil outlet L1 of the filter 1 is greater than the holding force of the spring end of the constant pressure differential valve 2. The spring is compressed, the valve core position is changed, and the bypass port of the constant pressure differential valve 2 opens. Some oil flows out from the oil outlet L1 of the filter 1 and enters the oil inlet P2 of the control valve 3 to ensure the operation of the control system. Some oil flows out from the oil outlet L2 of the constant pressure differential valve 2 and flows back to the oil tank 14 through the oil outlet L5 of the radiator 6. After several working cycles, the oil temperature rises and the system returns to the state described in condition one.

[0053] Example 4:

[0054] This embodiment adopts the same scheme as the above embodiments, except that this embodiment provides an engineering machine, such as a tractor, which is equipped with the engineering machine hydraulic system described in any of the above embodiments.

[0055] Based on the above embodiments, the present invention effectively prevents unfiltered hydraulic oil from entering the control system in the hydraulic system. At the same time, compared with the prior art, there is no need for alarm warnings to replace the filter. The filter can be replaced according to the normal maintenance cycle of the tractor. In low temperature environment or in the case of filter blockage, the risk of control system jamming and failure is reduced, and the cost of filter use is also reduced.

[0056] It should be noted that in the above embodiments, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0057] Furthermore, unless otherwise explicitly specified and limited, the terms "connection" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydraulic system for engineering machinery, characterized in that, include: The filter (1) has an oil inlet P1 connected to the outlet of the hydraulic pump (11) and an oil outlet L1 connected to the working device. The differential pressure valve (2) has its inlet P1.1 connected to the inlet P1 of the filter (1), its outlet L2 connected to the inlet P3 of the radiator (6), its control end connected to the inlet P1 of the filter (1), and its spring end connected to the outlet L1 of the filter (1). The oil outlet L5 of the radiator (6) is connected to the oil tank (14), and the oil inlet P3 is connected to the oil outlet LQ of the working device.

2. The hydraulic system for engineering machinery according to claim 1, characterized in that, When the pressure difference between the oil inlet P1 and the oil outlet L1 of the filter (1) is 0, the constant pressure differential valve (2) is in the shut-off position, and at this time the hydraulic oil flows out from the oil outlet L1 of the filter (1).

3. The hydraulic system for engineering machinery according to claim 1, characterized in that, When the pressure difference between the oil inlet P1 and the oil outlet L1 of the filter is greater than the holding force of the spring end of the differential pressure valve (2), the spring end of the differential pressure valve (2) is compressed, the differential pressure valve (2) works in the connected position, and hydraulic oil flows out from the oil outlet L1 of the filter (1) and the oil outlet L2 of the differential pressure valve (2) at the same time.

4. The hydraulic system for engineering machinery according to claim 1, characterized in that, If the engineering machine is started for the first time when the ambient temperature is lower than the set value, the pressure difference between the oil inlet P1 and the oil outlet L1 of the filter (1) is greater than the holding force of the spring end of the constant pressure differential valve (2). The spring end of the constant pressure differential valve (2) is compressed, and the constant pressure differential valve (2) works in the connected position. Hydraulic oil flows out from the oil outlet L1 of the filter (1) and the oil outlet L2 of the constant pressure differential valve (2) at the same time.

5. A hydraulic system for engineering machinery according to claim 1, characterized in that, The working device includes a control valve (3), the oil inlet P2 of the control valve (3) is connected to the inlet of the accumulator (4), the inlet of the sequence valve (5), the inlet of the first electromagnetic reversing valve (12) and the inlet of the second electromagnetic reversing valve (13), the first outlet of the sequence valve (5) is connected to the oil outlet LQ of the control valve (3), and the second outlet L4 of the sequence valve (5) is connected to the oil tank (14). The working port CS1 of the first electromagnetic directional valve (12) and the working port CS2 of the second electromagnetic directional valve (13) are connected to the control system. The oil outlet T2.2 of the first electromagnetic directional valve (12) and the oil outlet T2.3 of the second electromagnetic directional valve (13) are directly connected to the oil tank (14).

6. A hydraulic system for engineering machinery according to claim 5, characterized in that, When the pressure at the oil inlet P2 of the control valve (3) is less than the opening pressure of the sequence valve (5), if the first solenoid directional valve (12) and the second solenoid directional valve (13) are energized at this time, the hydraulic oil flows into the control system through the working oil port CS1 of the first solenoid directional valve (12) and the working oil port CS2 of the second solenoid directional valve (13). When the pressure at the inlet P2 of the control valve (3) reaches the opening pressure of the sequence valve (5), the sequence valve (5) operates in the connected position, and the excess hydraulic oil flows out from the outlet LQ of the control valve (3).

7. A hydraulic system for engineering machinery according to claim 1, characterized in that, The radiator (6) includes a cooling unit (7) and a second check valve (9); The oil inlet P3 of the radiator (6) is connected to the inlet of the cooling unit (7) and the oil inlet of the second check valve (9), and the outlet of the cooling unit (7) and the oil outlet of the second check valve (9) are connected to the oil outlet L5 of the radiator (6).

8. A hydraulic system for engineering machinery according to claim 1, characterized in that, A first check valve (8) is also provided between the constant pressure differential valve (2) and the radiator (6); The oil inlet of the first check valve (8) is connected to the oil outlet L2 of the constant pressure differential valve (2), and the oil outlet of the first check valve (8) is connected to the oil inlet P3 of the radiator (6).

9. A hydraulic system for engineering machinery according to claim 1, characterized in that, A third check valve (10) is also provided between the oil outlet LQ of the working device and the oil inlet P3 of the radiator (6).

10. An engineering machine, characterized in that, The engineering machine is equipped with the engineering machine hydraulic system as described in any one of claims 1-9.

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