A filter device integrating a high-pressure filter and an oil return filter

Abstract

This invention belongs to the field of civil aircraft hydraulic system design technology. Specifically, it proposes a filtration device integrating a high-pressure filter and a return oil filter. It comprises a pressure oil filter assembly, a return oil filter assembly, a return oil check valve, a system safety valve, a pressure sensor, and a differential pressure indicator. During aircraft hydraulic system operation, high-pressure oil enters the filtration device through the pressure inlet, is filtered by the high-pressure filter element, and then flows out through the pressure outlet into the downstream system. Oil from the hydraulic system's return oil line enters the filtration device through the return oil inlet, passes through the return oil check valve, and then is filtered by the return oil filter element before flowing out into the downstream oil tank. When the hydraulic system pressure exceeds the designed pressure limit, the system safety valve opens, allowing high-pressure oil to directly reach the return oil filter inlet, and ultimately the return oil filter outlet and the oil tank, protecting the hydraulic system from excessive pressure. This reduces system complexity and cost, and improves the maintainability of the hydraulic system.

Description

Technical Field

[0001] This invention relates to a filtration device for a civil aircraft hydraulic system, belonging to the technology of integrated design of high-pressure filters and return oil filters for civil aircraft hydraulic systems, and involving the combined and lightweight design of high-pressure filters at the pump outlet and return oil filters at the front end of the oil tank in aircraft hydraulic systems. Background Technology

[0002] In typical civil aircraft hydraulic systems, high-pressure filters and return oil filters are usually two separate devices performing their respective functions. They are located in different parts of the hydraulic system. High-pressure filters filter the oil entering the hydraulic system to remove impurities and protect hydraulic components sensitive to contaminants. Return oil filters filter the oil flowing out of the hydraulic system to remove impurities and contaminants, thereby ensuring oil quality and extending system lifespan. However, distributed high-pressure and return oil filters increase system weight, complexity, and cost. They not only occupy more aircraft space but also require multiple maintenance windows on the aircraft skin for filter replacement, resulting in poor maintainability and indirectly increasing operating costs. Summary of the Invention

[0003] The purpose of this invention is:

[0004] This invention proposes a filtration device that integrates high-pressure filtration and return oil filtration into one unit. It has a high degree of integration and is lightweight. It aims to solve the problem that the high-pressure filter and return oil filter need to be installed in different locations in the prior art, thereby reducing the complexity and cost of the system. Since the two filters are integrated together, the filter element can be replaced more conveniently, reducing maintenance time.

[0005] Technical solution: A filtration device integrating a high-pressure filter and a return oil filter, the filtration device consisting of a pressure oil filter assembly, a return oil filter assembly, a return oil check valve, a system safety valve, a pressure sensor, and a differential pressure indicator functional component;

[0006] When the aircraft hydraulic system is working, high-pressure oil enters the filter device from the pressure inlet, is filtered by the high-pressure filter element, and then flows out from the pressure outlet into the downstream. The oil in the hydraulic system's return oil line enters the filter device from the return oil inlet, passes through the return oil check valve, and then is filtered by the return oil filter element before flowing out into the downstream oil tank. When the hydraulic system pressure exceeds the design pressure limit, the system safety valve opens, and the high-pressure oil directly reaches the return oil filter inlet through the safety valve, and finally reaches the return oil filter outlet and the oil tank, to protect the hydraulic system pressure from becoming too high.

[0007] The return oil filter integrates a bypass valve. If the oil filter element is clogged, the bypass valve connected in parallel with the filter element will open, allowing the hydraulic oil to directly reach the return oil outlet. This avoids excessive pressure upstream of the return oil filter due to clogged filter element, which could affect system function.

[0008] When the system pressure exceeds the design pressure limit, the system safety valve opens, and the oil flows directly to the inlet of the return oil filter, and then to the outlet of the return oil filter and the oil tank, in order to protect the hydraulic system pressure from becoming too high.

[0009] Furthermore, the pressure oil filter assembly and the return oil filter assembly are both integrated on the same housing and located on both sides of the housing. The two oil filter assemblies are controlled by a system safety valve. When the pressure value is set, the high-pressure oil inlet of the pressure oil filter assembly flows to the return oil filter assembly.

[0010] Furthermore, in addition to sharing a common housing, the pressure oil filter assembly and the return oil filter assembly also include a bypass valve assembly and a filter element assembly. The housing can be divided into an upper housing and a lower housing. The upper housing has a stepped cavity. The larger diameter cavity is connected to the oil inlet, and a bypass valve seat is provided in the middle section of the inner wall of the larger diameter cavity. The smaller diameter cavity is connected to the oil outlet, and a first sealing structure is provided in the smaller diameter cavity near the larger diameter cavity.

[0011] The filter element assembly is disposed in the lower housing. The filter element assembly includes a frame and an end cap. The frame is a hollow structure that serves as an oil passage. The end cap has an annular boss arranged along the central through hole, and an oil passage is also provided on the edge of the end cap.

[0012] The self-sealing bypass valve assembly is disposed inside the upper housing and includes a bypass valve and a spring. The bypass valve is composed of a cup-shaped base and a shaft segment disposed at the center of the cup-shaped base. The center of the bypass valve is an oil passage, and several oil outlet holes are opened near the end of the shaft segment.

[0013] The spring is fitted onto the shaft section of the bypass valve, with one end of the spring abutting against the middle step of the upper housing and the other end abutting against the inner side of the cup-shaped base.

[0014] During normal operation, the upper and lower housings are fixed together. Under the action of the spring, the end of the bypass valve assembly and the end of the filter element assembly form a contact seal. External oil enters the larger diameter cavity of the upper housing from the oil inlet, and flows into the cavity of the lower housing through the end cover of the filter element assembly. After being filtered, it enters the bypass valve channel through the skeleton channel, and is discharged from the smaller diameter cavity of the upper housing through the oil outlet hole at the end of the self-sealing bypass valve assembly, and then discharged from the oil outlet.

[0015] When the filter element is clogged, the pressure inside the cavity of the lower housing gradually increases. This pressure acts on the outer root of the cup-shaped base to push the self-sealing bypass valve assembly away from the filter element assembly. External oil flows out directly from the outlet without being filtered by the filter assembly, thus achieving the bypass function.

[0016] When the filter element assembly needs to be replaced, unscrew the lower housing. At this time, the spring pushes the self-sealing bypass valve assembly downward, so that the annular boss at the upper end of the cup-shaped base contacts the sealing rubber on the bypass valve seat to form a seal. The two sealing structures cooperate with the bypass valve assembly to ensure that the oil is blocked, thereby realizing the self-sealing function.

[0017] Furthermore, the lower housings of the pressure oil filter assembly and the return oil filter assembly are used to install filter elements. The lower housing of the pressure oil filter assembly is shorter than the lower housing of the return oil filter assembly, and an error-proof design is adopted.

[0018] Furthermore, the filter elements of the pressure oil filter assembly and the return oil filter assembly are the same, allowing for interchangeability.

[0019] Furthermore, a one-way valve is also provided at the oil outlet of the oil return filter assembly.

[0020] Furthermore, the system safety valve consists of a main valve body, a spring, a pilot-operated valve core, and a pilot spring. During normal operation, the main valve core is in a locked state. When the medium pressure reaches the opening pressure, the pilot valve core opens, and the oil flows to the return port through the pressure relief hole of the main valve seat and the pressure relief hole of the safety valve body. The pressure in the main valve chamber decreases, the main valve core moves to the right, the safety valve opens, and the oil flows directly to the return port through the main valve core. When the inlet oil pressure drops to the closing pressure, the pilot valve core closes, the main valve chamber becomes a high-pressure chamber, and the main valve core closes under the action of the spring force.

[0021] Furthermore, the pressure oil filter assembly and the return oil filter assembly each integrate an electromechanical differential pressure indicator; the filter housing is provided with two electromechanical differential pressure indicator mounting holes to monitor the differential pressure between the high-pressure filter element and the return oil filter element, and to indicate the status of the oil filter assembly through the differential pressure.

[0022] Furthermore, the filtration device also integrates a pressure sensor; the pressure sensor is inserted into the filter housing, and the pressure changes inside the filter can be monitored in real time, thereby adjusting the working status of the filter in a timely manner.

[0023] Furthermore, the filter device also integrates a sampling port connector, which facilitates the detection of the internal oil condition during ground maintenance without disassembling the filter assembly.

[0024] Technical effects of the present invention:

[0025] The aforementioned invention integrates a high-pressure filter and a return oil filter into a single filtration device, reducing system complexity and cost while improving the maintainability of the hydraulic system. Simultaneously, the filtration device integrates a mechatronic differential pressure indicator to monitor the filter element's contamination status in real time; it also integrates a bypass and self-sealing device, enabling both self-sealing and bypass oil circuit functions; a pressure sensor is integrated to monitor the hydraulic system pressure in real time; and a system safety valve is integrated, which opens when the system pressure exceeds the designed pressure limit, allowing oil to directly reach the return oil filter inlet, and ultimately the return oil filter outlet and the oil tank, protecting the hydraulic system from excessive pressure. A return oil check valve is integrated between the return oil filter inlet and the filter element to prevent hydraulic oil from flowing back into the mission system from the oil tank, and also to prevent hydraulic oil from flowing into the mission system during ground refueling. This invention can be applied to various types of aircraft hydraulic systems, possessing broad market prospects and economic benefits. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the filtration device of the present invention;

[0028] Figure 2 This is a schematic diagram of the structural principle of the filtration device;

[0029] Figure 3 This is a schematic diagram of the system's safety valve.

[0030] Figure 4 This is a schematic diagram of the operation of the device of the present invention;

[0031] Figure 5 Schematic diagram of bypass self-sealing device;

[0032] Figure 6 This is a schematic diagram of a differential pressure indicator;

[0033] The components include: 1. Pressure oil filter assembly; 2. System safety valve; 3. Sampling port pipe connector; 4. Pressure inlet pipe connector; 5. Pressure sensor; 6. Differential pressure indicator; 7. Pressure outlet pipe connector; 8. Return oil inlet pipe connector; 9. Return oil outlet pipe connector; 10. Ground refueling pipe connector; 11. Return oil check valve; 12. Filter housing; and 13. Return oil filter assembly.

[0034] In the system safety valve structure: 2a-main valve core; 2b-reset spring; 2c-main valve seat; 2d-pilot valve core; 2e-body; 2f-spring; 2g-plug; 2h-nut;

[0035] The pressure oil filter assembly structure includes: a first valve seat assembly 1a, a first spring 1b, a first sealing ring 1c, a self-sealing valve assembly 1d, and a pressure oil filter 1f;

[0036] The oil return filter assembly consists of: gasket 13a, bypass valve assembly 13b, second valve seat assembly 13c, second spring 13d, second sealing ring 13e, upper housing 13f, third sealing ring 13g, and oil return filter 13h.

[0037] The differential pressure indicator structure includes an adjustment seat 6a, a spring 6b, a piston assembly 6c, an indicator housing 6d, an indicator element 6e, a protective cover 6f, a micro switch 6g, and an electrical socket 6h. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0040] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] Figure 1 This is a schematic diagram of an embodiment of the present invention, which integrates a high-pressure filter and a return oil filter into one unit.

[0042] The filtration device designed in this invention integrates a high-pressure filter and a return oil filter, including a pressure oil filter assembly 1, a system safety valve 2, a sampling port pipe connector 3, a pressure inlet pipe connector 4, a pressure sensor 5, a differential pressure indicator 6, a pressure outlet pipe connector 7, a return oil inlet pipe connector 8, a return oil outlet pipe connector 9, a ground refueling pipe connector 10, a return oil check valve 11, a filter housing 12, and a return oil filter assembly 13;

[0043] When the aircraft hydraulic system is working, high-pressure oil enters the filter device from the pressure inlet, is filtered by the high-pressure filter element, and then flows out from the pressure outlet into the downstream. The oil in the hydraulic system's return oil line enters the filter device from the return oil inlet, passes through the return oil check valve, and then is filtered by the return oil filter element before flowing out into the downstream oil tank. When the hydraulic system pressure exceeds the design pressure limit, the system safety valve opens, and the high-pressure oil directly reaches the return oil filter inlet through the safety valve, and finally reaches the return oil filter outlet and the oil tank, to protect the hydraulic system pressure from becoming too high.

[0044] The return oil filter integrates a bypass valve. If the oil filter element is clogged, the bypass valve connected in parallel with the filter element will open, allowing the hydraulic oil to directly reach the return oil outlet. This avoids excessive pressure upstream of the return oil filter due to clogged filter element, which could affect system function.

[0045] When the system pressure exceeds the design pressure limit, the system safety valve opens, and the oil flows directly to the inlet of the return oil filter, and then to the outlet of the return oil filter and the oil tank, in order to protect the hydraulic system pressure from becoming too high.

[0046] refer to Figure 1 and Figure 2 During system operation, high-pressure oil enters the system oil filter assembly through pressure inlet pipe connector 4, and after passing through the pressure oil filter, it enters the downstream system through pressure outlet pipe connector 7. The high-pressure oil circuit of the filtration device does not have a bypass valve to ensure that the oil entering the system must pass through the pressure oil filter, ensuring the cleanliness of the system oil. System return oil enters the filtration device through return oil inlet pipe connector 8, and then returns to the hydraulic oil tank through the return oil check valve and return oil filter. The return oil filter integrates a bypass valve. If the filter element is clogged, the pressure difference between the inlet and outlet of the return oil filter will open the bypass valve, allowing hydraulic oil to return to the tank and preventing excessive return oil pressure due to filter blockage, which could affect system function.

[0047] refer to Figure 3The main valve core of the pressure oil filter assembly 1 is in the locked state. The system safety valve 2 consists of a main valve core 2a, a return spring 2b, a main valve seat 2c, a pilot valve core 2d, a housing 2e, a spring 2f, a plug 2g, and a nut 2h. When the medium pressure reaches the opening pressure, the pilot valve core 2d opens, and the oil flows to the return port through the pressure relief hole of the main valve seat 2c and the pressure relief hole of the safety valve housing 2e. The pressure in the main valve chamber decreases, the main valve core of the pressure oil filter assembly 1 moves to the right, the safety valve opens, and the oil flows directly to the return port through the main valve core of the pressure oil filter assembly 1. When the inlet oil pressure drops to the closing pressure, the pilot valve core 2a closes, the main valve chamber becomes a high-pressure chamber, and the main valve core of the pressure oil filter assembly 1 closes under the action of the spring force.

[0048] refer to Figure 4 The bypass self-cleaning device is divided into a pressure oil filter self-sealing device and a return oil filter self-cleaning bypass device. The pressure oil filter assembly structure includes a first valve seat assembly 1a, a first spring 1b, a first sealing ring 1c, a self-sealing valve assembly 1d, and a pressure oil filter 1f;

[0049] The return oil filter assembly structure includes a gasket 13a, a bypass valve assembly 13b, a second valve seat assembly 13c, a second spring 13d, a second sealing ring 13e, an upper housing 13f, a third sealing ring 13g, and a return oil filter 13h.

[0050] The pressure difference before and after the return oil filter (13h) drives the bypass valve assembly 13b to move upward. This force overcomes the preload of the second spring 13d, causing the bypass valve assembly 13b to move upward and achieve bypass. (Reference) Figure 3 The return oil filter bypass self-cleaning device is in a self-sealing state. The self-sealing valve assembly 1d and the second valve seat assembly 13c are in contact, ensuring that oil will not leak from the filter after the lower housing and filter element are removed. The self-sealing device of the pressure oil filter and the self-sealing bypass device of the return oil filter are identical except for the self-sealing valve assembly 1d and the bypass valve assembly 13b (the purpose being to eliminate the bypass function). All other parts are completely interchangeable. (Reference) Figure 3 , 4 5. The pressure difference across the filter element drives the self-sealing valve assembly 1d downwards. This force is downwards, therefore the self-sealing valve assembly 1d will not move upwards. The self-sealing device of the pressure oil filter is in a self-sealing state. The self-sealing valve assembly 1d is in contact with the first valve seat assembly 1a and is in a self-sealing state, ensuring that oil will not leak from the filter after the lower housing and filter element are removed.

[0051] refer to Figure 6 The differential pressure indicator includes an adjustment seat 6a, a spring 6b, a piston assembly 6c, an indicator housing 6d, an indicator element 6e, a protective cover 6f, a micro switch 6g, and an electrical socket 6h.

[0052] When the product is working normally, the differential pressure indicator senses the inlet pressure in the high-pressure chamber and the outlet pressure in the low-pressure chamber. As the working time increases, the filter element collects more and more pollutants, and the pressure difference across the two ends of the filter element gradually increases. The pressure difference between the high and low pressure chambers gradually increases, and the piston assembly 6c gradually moves downward. When the pressure difference between the high and low pressure chambers reaches the indicated pressure difference, the piston assembly 6c moves downward until the force between it and the indicator changes from attraction to repulsion. The indicator 6e pops out and emits a red mechanical visual indication signal. At the same time, the micro switch 6g contacts change from the normal pressure state to the free state and emit an alarm electrical signal.

[0053] The innovative design features of this invention are as follows:

[0054] Core Innovative Design Technologies: This invention integrates a high-pressure filter and a return oil filter into a single filtration device, mainly composed of functional components such as a pressure oil filter, a return oil filter, a return oil check valve, a system safety valve, a pressure sensor, and a differential pressure indicator. During the design process, the difference in pressure regime between the high-pressure filter and the return oil filter presented some challenges, requiring multiple simulations to overcome. The high-pressure filter is primarily used to filter high-pressure liquids, thus requiring high pressure resistance, while the return oil filter is mainly used to filter reflux liquids, therefore having relatively lower pressure requirements. In traditional designs, high-pressure and return oil filters are typically designed separately, resulting in a fragmented hydraulic system with significant volume and weight, and requiring multiple iterations through simulations and experiments to meet strength requirements. This invention proposes a filtration device integrating a high-pressure filter and a return oil filter to achieve weight reduction while ensuring the device's strength meets requirements. By redesigning the filter structure and selecting materials, the filtration device can withstand the pressure of high-pressure liquids while also meeting the filtration requirements of return oil liquids. During the design process, this invention underwent multiple simulation experiments to verify the device's performance under different pressure conditions. By optimizing the filter structure and selecting appropriate materials, this invention successfully solves the problem of different pressure systems between the high-pressure filter and the return oil filter, ultimately achieving the goal of lightweight yet meeting strength requirements. The advantages of this invention are twofold: firstly, by integrating the high-pressure filter and the return oil filter, the weight and volume of the device are reduced, improving its portability and installation flexibility; secondly, while maintaining a lightweight design, it still meets the filtration requirements for both high-pressure liquids and return oil liquids, ensuring the reliability and efficiency of the device.

[0055] In this field, the pressure systems of high-pressure filters and return oil filters differ greatly, making them difficult to integrate. However, integration can bring significant advantages: 1. It saves on piping, connectors, and other hydraulic components, reducing aircraft weight; 2. It reduces aircraft maintenance windows, improving aircraft maintainability and economy.

[0056] When the aircraft hydraulic system is operating, high-pressure hydraulic fluid (21MPa±1MPa) enters the filter device through the pressure inlet, is filtered by the high-pressure filter element, and then flows out through the pressure outlet into the downstream. Hydraulic fluid (0~10MPa) in the hydraulic system return line enters the filter device through the return inlet, passes through the return check valve, and then flows out through the return filter element into the downstream oil tank. When the hydraulic system pressure exceeds the design pressure limit (generally 23.5MPa), the system safety valve opens, and the high-pressure hydraulic fluid directly reaches the return filter inlet, and ultimately the return filter outlet and the oil tank, protecting the hydraulic system from excessive pressure.

[0057] The return oil filter integrates a bypass valve. If the oil filter element is clogged, the bypass valve connected in parallel with the filter element will open, allowing hydraulic oil to directly reach the return oil outlet. This avoids excessive pressure upstream of the return oil filter due to filter element blockage, which could affect system function.

[0058] When the system pressure exceeds the design pressure limit, the system safety valve opens, and the oil flows directly to the inlet of the return oil filter, and then to the outlet of the return oil filter and the oil tank, in order to protect the hydraulic system pressure from becoming too high.

[0059] A check valve is installed between the return oil filter inlet and the filter element to prevent hydraulic oil in the tank from flowing back into the mission system, and also to prevent hydraulic oil from flowing into the mission system when refueling on the ground.

[0060] When the pressure oil filter element or return oil filter element becomes clogged to a certain extent, the differential pressure indicator will give a mechanical indication and a discrete electrical signal at the same time; the differential pressure indicator can maintain the contamination indication state unless manually reset.

[0061] Both the pressure oil filter and the return oil filter are equipped with self-sealing devices to prevent hydraulic oil from leaking from the system oil filter assembly when the filter element is replaced.

[0062] The pressure sensor provides a variable voltage signal to the hydraulic power control unit (HECU) and EICAS based on the proportion of changes in system pressure.

[0063] Secondary innovative design technology point 1: This filtration device integrates an electromechanical differential pressure indicator. The filter housing is equipped with two electromechanical differential pressure indicator mounting holes to monitor the differential pressure of the high-pressure filter element and the return oil filter element respectively, so as to facilitate the determination of the filter element's dirt status and timely replacement of the filter element. The electromechanical differential pressure indicator includes both mechanical and electrical indications. When the filter element reaches the required differential pressure, it will send an electrical signal to the crew, and at the same time, the mechanical signal will pop up a red indicator rod, which is convenient for maintenance personnel to observe and determine the dirt status of the filter element.

[0064] Secondary innovative design technology point 2: This filtration device integrates a system safety valve. The high-pressure safety valve is inserted into the filter housing. The high-pressure safety valve is designed as a pilot-operated safety valve, mainly composed of a main valve body, spring, pilot valve core, pilot spring, etc. Unlike traditional safety valves, this system safety valve is equipped with a suitable damping orifice. Under the action of the pilot-operated structure, the safety valve can respond and open quickly, with excellent steady-state pressure regulation characteristics, light weight, large flow capacity, and a closing pressure ratio (reset pressure: set pressure) that can reach over 97%.

[0065] Secondary innovative design technology point 3: The return oil filter of this filtration device integrates a bypass self-sealing valve. This valve solves the problems of large space occupation and heavy weight associated with separate bypass valves and self-sealing valves in traditional filters. When the filter element needs to be replaced, after unscrewing the lower housing, the valve can quickly cut off the upstream and downstream oil circuits of the return oil filter, ensuring no oil leakage in the system. When the filter element becomes sufficiently dirty and has not been replaced, the valve can automatically bypass the filter, preventing oil blockage and ensuring it flows back to the oil tank.

[0066] Secondary innovative design technology point 4: The high-pressure filter of this filtration device integrates a self-sealing valve. When the filter element needs to be replaced, after unscrewing the lower housing and the filter element, the valve can quickly cut off the upstream and downstream oil circuits of the high-pressure filter to ensure that the oil in the system does not leak.

[0067] Secondary innovative design technology point 5: The high-pressure filter element and the return oil filter element use the same filter element, and the filtration accuracy can reach 5μm, effectively filtering out small particles and contaminants. At the same time, it reduces the types of filter element spare parts in the hydraulic system, increases the interchangeability of the high-pressure filter element and the return oil filter element, and enhances the maintainability of the filter element.

[0068] Secondary Innovative Design Technology Point 6: This filter device integrates a pressure sensor. The pressure sensor is inserted into the filter housing and can monitor pressure changes inside the filter in real time, thereby adjusting the filter's operating status promptly. Specifically, by monitoring the internal pressure of the filter device in real time, it effectively prevents hydraulic system failures caused by malfunctions in the filter device. Unlike traditional pressure sensors, this pressure sensor has advantages such as fast response, high accuracy, and high reliability, and achieves intelligent interconnection with the control system, resulting in a higher level of intelligence.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A filtration device integrating a high-pressure filter and a return oil filter, characterized in that, The filtration device consists of a pressure oil filter assembly, a return oil filter assembly, a return oil check valve, a system safety valve, a pressure sensor, and a differential pressure indicator. In addition to sharing a common housing, the pressure oil filter assembly and the return oil filter assembly also include a bypass valve assembly and a filter element assembly. The housing can be divided into an upper housing and a lower housing. The upper housing has a stepped cavity. The larger diameter cavity is connected to the oil inlet, and a bypass valve seat is provided in the middle section of the inner wall of the larger diameter cavity. The smaller diameter cavity is connected to the oil outlet, and a first sealing structure is provided in the smaller diameter cavity near the larger diameter cavity. The filter element sub-assembly is disposed in the lower housing. The filter element sub-assembly includes a frame and an end cap. The frame is a hollow structure that serves as an oil passage. The end cap has an annular boss arranged along the central through hole, and an oil passage is also provided on the edge of the end cap. The self-sealing bypass valve assembly is disposed inside the upper housing and includes a bypass valve and a spring. The bypass valve is composed of a cup-shaped base and a shaft segment disposed at the center of the cup-shaped base. The center of the bypass valve is an oil passage, and several oil outlet holes are opened near the end of the shaft segment. The spring is fitted onto the shaft section of the bypass valve, with one end of the spring abutting against the middle step of the upper housing and the other end abutting against the inner side of the cup-shaped base. During normal operation, the upper and lower housings are fixed together. Under the action of the spring, the end of the bypass valve assembly and the end of the filter element assembly form a contact seal. External oil enters the larger diameter cavity of the upper housing from the oil inlet, and flows into the cavity of the lower housing through the end cover of the filter element assembly. After filtration, it enters the bypass valve channel from the skeleton channel, and is discharged from the smaller diameter cavity of the upper housing through the oil outlet hole at the end of the self-sealing bypass valve assembly, and then discharged from the oil outlet. When the filter element is clogged, the pressure inside the cavity of the lower housing gradually increases. This pressure acts on the root of the outer side of the cup-shaped base to push the self-sealing bypass valve assembly away from the filter element sub-assembly. External oil flows out directly from the outlet without being filtered by the filter assembly, thus achieving the bypass function. When the filter element assembly needs to be replaced, unscrew the lower housing. At this time, the spring pushes the self-sealing bypass valve assembly downward, so that the annular boss at the upper end of the cup-shaped base contacts the sealing rubber on the bypass valve seat to form a seal. The two sealing structures cooperate with the bypass valve assembly to ensure that the oil is blocked, thereby achieving the self-sealing function. When the aircraft hydraulic system is working, high-pressure oil enters the filter device from the pressure inlet, is filtered by the high-pressure filter element, and then flows out from the pressure outlet into the downstream. The oil in the hydraulic system's return oil line enters the filter device from the return oil inlet, passes through the return oil check valve, and then is filtered by the return oil filter element before flowing out into the downstream oil tank. When the hydraulic system pressure exceeds the design pressure limit, the system safety valve opens, and the high-pressure oil directly reaches the return oil filter inlet through the safety valve, and finally reaches the return oil filter outlet and the oil tank, to protect the hydraulic system pressure from becoming too high. The return oil filter integrates a bypass valve. If the oil filter element is clogged, the bypass valve connected in parallel with the filter element will open, allowing the hydraulic oil to directly reach the return oil outlet. This avoids excessive pressure upstream of the return oil filter due to clogged filter element, which could affect system function. When the system pressure exceeds the design pressure limit, the system safety valve opens, and the oil flows directly to the inlet of the return oil filter, and then to the outlet of the return oil filter and the oil tank, in order to protect the hydraulic system pressure from becoming too high.

2. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 1, characterized in that, The pressure oil filter assembly and the return oil filter assembly are both integrated on the same housing and located on both sides of the housing. The two oil filter assemblies are controlled by a system safety valve. When the pressure value is set, the high-pressure oil inlet of the pressure oil filter assembly flows to the return oil filter assembly.

3. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 1, characterized in that, The lower housing of the pressure oil filter assembly and the return oil filter assembly is used to install the filter element. The lower housing of the pressure oil filter assembly is shorter than that of the return oil filter assembly, and it adopts an error-proof design.

4. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 3, characterized in that, The filter elements of the pressure oil filter assembly and the return oil filter assembly use the same filter element and can be interchanged.

5. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 4, characterized in that, A one-way valve is also provided at the oil outlet of the oil return filter assembly.

6. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 1, characterized in that, The system safety valve consists of a main valve body, a spring, a pilot-operated valve core, and a pilot spring. During normal operation, the main valve body valve core is in a locked state. When the medium pressure reaches the opening pressure, the pilot valve core opens, and the oil flows to the return port through the pressure relief hole of the main valve seat and the pressure relief hole of the safety valve body. The pressure in the main valve chamber decreases, the main valve body valve core moves to the right, the safety valve opens, and the oil flows directly to the return port through the main valve body valve core. When the inlet oil pressure drops to the closing pressure, the pilot valve core closes, the main valve chamber becomes a high-pressure chamber, and the main valve body valve core closes under the action of the spring force.

7. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 1, characterized in that, The pressure oil filter assembly and the return oil filter assembly each integrate an electromechanical differential pressure indicator; the filter housing is provided with two electromechanical differential pressure indicator mounting holes to monitor the pressure difference between the high-pressure filter element and the return oil filter element, and to indicate the status of the oil filter assembly through the pressure difference.

8. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 1, characterized in that, The filtration device also integrates a pressure sensor; the pressure sensor is inserted into the filter housing, and the pressure changes inside the filter can be monitored in real time, thereby adjusting the working status of the filter in a timely manner.

9. The filtration device integrating a high-pressure filter and a return oil filter as described in claim 1, characterized in that, The filter device also integrates a sampling port connector, which facilitates the detection of the internal oil condition during ground maintenance without disassembling the filter assembly.

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