A pollution isolation device for a helicopter hydraulic system

Abstract

The present invention relates to a pollution isolation device for a helicopter hydraulic system, which comprises an inlet joint, a housing, a main piston, a spring, a spring seat, a secondary piston, a stop block and an outlet joint; the front end of the inlet joint is an oil inlet P, an oil control port B is opened on the housing, and the outlet joint is connected to a plurality of load ports A; an oil chamber I is formed between the end face of the inlet joint and the main piston, an oil chamber II is formed between the housing and the main piston, and an oil chamber III is formed between the end face of the secondary piston and the outlet joint; it can be installed between the main hydraulic oil tank and the load, and simultaneously realizes the functions of isolating oil, transmitting pressure, absorbing pulses and overpressure protection. It can be used for the design of an oil pollution isolation system. Adding this pollution isolation device before a load with a high risk of pollutant generation or entry can effectively prevent pollutants from entering the main oil tank, and further effectively prevent other circuit failures caused by oil pollution in the main system. The present invention has the characteristics of simple structure, small size, light weight and high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopter hydraulic system design, and particularly relates to a pressure transmission and pollution isolation device for a helicopter hydraulic system. Background Art

[0002] In the design of helicopter hydraulic systems, generally there is a main hydraulic oil tank that simultaneously stores the oil for hydraulic sub-circuits such as the main rotor booster, tail rotor booster, rotor brakes, wheel brakes, and landing gear retraction. However, the situations of generating pollutants in different circuits or load devices vary greatly. Taking the wheel brake device and the rotor brake device as examples, since there are multiple brake actuating cylinders in the brake device and the piston rods are directly exposed to the external environment, with the frequent reciprocating movement of the piston rods, a large amount of external solid dirt is brought into the actuating cylinders and enters the hydraulic system. In addition, during the braking process, the temperature of the brake device is relatively high. Under the action of high temperature and high pressure, the oil in the actuating cylinders will accelerate carbonization and is prone to generate pollutants such as oxides and oil scale. Therefore, the brake device is a key pollution source in the system. In the design of sharing a hydraulic oil tank by multiple sub-circuits, the conventional pollution control method is to use oil filters for filtration. Generally, oil filters are added to each circuit for filtration. However, the filtration accuracy and efficiency of the oil filters are limited, and pollutants will still circulate through all the circuits supplied by this oil tank. Therefore, under the conventional control method of filtering pollutants with oil filters, the replacement cycles of the oil filters and the oil in all circuits are short, the maintenance workload is large, resulting in a huge waste of oil filters and hydraulic oil. Against this background, a device is needed to design the oil fluid isolation control for the key pollution source circuits or key pollution source devices in a hydraulic system with multiple circuits sharing the same oil source, so as to meet the urgent needs of helicopter equipment for reducing the use cost and reducing the maintenance workload. Summary of the Invention

[0003] Object of the present invention: The present invention relates to a pollution isolation device for a helicopter hydraulic system, which can be installed between the main hydraulic oil tank and the load, and simultaneously realizes the functions of isolating the oil fluid, transmitting pressure, absorbing pulses, and overpressure protection. It can be used in the design of oil fluid pollution isolation systems, and has the characteristics of simple structure, small volume, light weight, and high reliability.

[0004] Technical solution: A pollution isolation device for a helicopter hydraulic system, the pollution isolation device for the helicopter hydraulic system includes an inlet joint, a housing, a main piston, a spring, a spring seat, a secondary piston, a stop block, and an outlet joint; the front end of the inlet joint is an oil fluid inlet P, an oil fluid control port B is opened on the housing, and the outlet joint is connected to a plurality of load ports A; an oil chamber I is formed between the end face of the inlet joint and the main piston, an oil chamber II is formed between the housing and the main piston, and an oil chamber III is formed between the end face of the secondary piston and the outlet joint;

[0005] There is a movable fit between the housing and the main piston; both ends of the spring are respectively pressed on the main piston and the spring seat, having a pre-compressive force;

[0006] A small hole is opened on the main piston, which is the pressure relief port C. This pressure relief port C, together with the gap between the end faces of the main and auxiliary pistons, serves as the oil passage between oil chamber II and oil chamber III;

[0007] The auxiliary piston is sleeved on the periphery of the main piston, and the two can slide fit under the action of a certain pressure. The left and right movement spaces of the auxiliary piston are jointly restricted by the boss on the inner wall of the housing and the stopper at the end of the main piston;

[0008] The oil in oil chamber I and the oil in oil chamber II are always in an isolated state; the oil between oil chamber I and oil chamber III is always in an isolated state, but pressure transmission can be achieved; oil chamber I is connected to the main fuel tank of the system, oil chamber III is connected to the key pollution source load and the small fuel tank, and the oil between the main fuel tank and the small fuel tank is isolated to achieve pollution isolation of the main fuel tank;

[0009] The oil in oil chamber II and the oil in oil chamber III are isolated or communicated as the piston moves. When the end faces of the piston and the auxiliary piston are in contact, the third sealing ring plays a role in sealing and isolating the oil between oil chamber II and oil chamber III. When the gap between the end faces of the piston and the auxiliary piston is not enough to cause sufficient compression of the third sealing ring, the oil between oil chamber II and oil chamber III is communicated.

[0010] Further, during pressure supply, after the main piston and the auxiliary piston are in contact, they move together, and the movement stroke depends on the liquid pressure at the oil inlet P; if the liquid pressure at the oil inlet P is high, the movement stroke of the main piston and the auxiliary piston together is large, and the oil in oil chamber III is compressed greatly; if the liquid pressure at the oil inlet P is small, the movement stroke of the main piston and the auxiliary piston together is small, and the oil in oil chamber III is compressed little.

[0011] Further, during the pressure holding process, when the pressure at the load end rises to the set value due to temperature rise or other reasons, the high-pressure oil in oil chamber III will act on the right side of the main piston, overcoming the combined action of the oil inlet P and the spring force, pushing the main piston to the left. Oil chamber II sucks oil from the control port B, a gap is formed between the main piston and the auxiliary piston, and the high-pressure oil in oil chamber III flows through the pressure relief port C on the main piston, the gap between the end faces of the main piston and the auxiliary piston in sequence, and is finally squeezed out through the control port B; oil chamber II and oil chamber III are connected to provide overpressure protection for the system accessories.

[0012] Further, during pressure supply, after the main piston and the auxiliary piston are in contact, the oil in oil chamber III is not connected to the control port B. The main piston and the auxiliary piston move together to compress oil chamber III, and a hydraulic pressure equal to that at the oil inlet P is generated in oil chamber III, realizing the hydraulic pressure transmission from the oil inlet P to the load port A.

[0013] Further, the control port B is connected to the small fuel tank in the system. When the oil at the load end is contaminated, only the oil in the small fuel tank needs to be replaced.

[0014] Further, it can be installed between the main hydraulic fuel tank and the load, and simultaneously realizes the functions of isolating the oil fluid, transmitting pressure, and absorbing pulses.

[0015] Further, the first sealing ring forms a static seal between the inlet joint and the housing; the second sealing ring forms a seal between the housing and the main piston. The second sealing ring moves axially with the main piston and belongs to a dynamic seal; an oil discharge hole D is opened on the main piston; the third sealing ring is installed on the auxiliary piston. When the end faces between the main piston and the auxiliary piston are in close contact, a seal is formed between the main piston and the auxiliary piston; the fourth sealing ring 0 is installed between the auxiliary piston and the housing and moves axially with the auxiliary piston, belonging to a dynamic seal; there is a clearance fit between the auxiliary piston and the main piston; the fifth sealing ring forms a static seal between the housing and the outlet joint.

[0016] Further, the stop block is connected to the main piston by a thread; the stop block is used to limit the displacement of the auxiliary piston relative to the main piston.

[0017] Further, the inlet joint and the housing are connected by a thread, and the outlet joint and the housing are connected by a thread.

[0018] Further, connecting the control port B to the small fuel tank will be beneficial to the automatic exhaust at the load end. If exhaust is not considered, the port B can also be blocked, and the device can still play the role of isolating the oil fluid and transmitting pressure.

[0019] Beneficial technical effects: A pollution isolation device for a helicopter hydraulic system proposed by the present invention can be installed between the main hydraulic fuel tank and the load, and simultaneously realizes the functions of isolating the oil fluid, transmitting pressure, absorbing pulses, and overpressure protection. It can be used for the design of an oil fluid pollution isolation system. Adding this pollution isolation device before a load with a high risk of pollutant generation or entry can effectively prevent pollutants from entering the main fuel tank, and further effectively prevent other circuit failures caused by the pollution of the main system oil fluid. The present invention has the characteristics of simple structure, small size, light weight, and high reliability.

[0020] In a hydraulic system with multiple circuits sharing the same oil source, using this device for the design of oil fluid isolation control for key pollution sources can control the pollution of the oil fluid within the range of the load and the small fuel tank, without causing the pollution of the main fuel tank and other circuit oil fluids, avoiding frequent replacement of oil filters in each circuit and frequent replacement of the oil in the main fuel tank, and avoiding phenomena such as jamming of hydraulic accessories due to pollution. It can greatly reduce the use cost, reduce the maintenance workload, and improve the system reliability. Description of the Drawings

[0021] Figure 1Internal structure diagram of the pollution isolation device of the present invention;

[0022] Figure 2 Schematic diagram of the application scenario of the present invention. Specific implementation manners

[0023] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] A pollution isolation device for a helicopter hydraulic system can be installed between the main hydraulic oil tank and the load, and can simultaneously achieve the functions of isolating the oil fluid, transmitting pressure, absorbing pulses, and overpressure protection. It can be used in the design of an oil fluid pollution isolation system, and has the characteristics of simple structure, small size, light weight, and high reliability. A specific design form includes: an inlet joint (1), a first sealing ring (2), a second sealing ring (3), a housing (4), a main piston (5), a spring (6), a spring seat (7), a third sealing ring (8), a sub-piston (9), a fourth sealing ring (10), a stop block (11), a fifth sealing ring (12), and an outlet joint (13). The main oil fluid flow ports include: an oil fluid inlet P, an oil fluid control port B, a load port A, and a pressure relief port C. The main oil chambers formed are divided into oil chamber I, oil chamber II, and oil chamber III.

[0025] The oil chamber 1 is formed by the cooperation of the piston 5, the inlet joint 1, and the housing 4. The oil chamber II is formed by the cooperation of the housing 4, the piston 5, and the piston block. The oil chamber III is formed by the cooperation of the piston block 9, the piston 5, the housing 4, and the outlet joint. Among them, the oil chamber II and the oil chamber III are communicated through the sliding of the piston block.

[0026] Among them, the inlet joint (1) and the outlet joint (13) are connected to the conduit; the first sealing ring (2) forms a static seal between the inlet joint (1) and the housing (4); the inlet joint (1) and the housing (4) are connected by a thread; the second sealing ring (3) forms a seal between the housing (4) and the main piston (5), and the second sealing ring (3) moves axially with the main piston (5), which belongs to a dynamic seal; there is a clearance fit between the housing (4) and the main piston (5); both ends of the spring (6) are pressed on the main piston (5) and the spring seat (7) respectively, having a pre-compressive force; an oil discharge hole D is opened on the main piston (5); the third sealing ring (8) is installed on the auxiliary piston (9), and when the end faces between the main piston (5) and the auxiliary piston (9) are in close contact, a seal is formed between the main piston (5) and the auxiliary piston (9); the fourth sealing ring (10) is installed between the auxiliary piston (9) and the housing (4), and moves axially with the auxiliary piston (9), which belongs to a dynamic seal; there is a clearance fit between the auxiliary piston (9) and the main piston (5); the fifth sealing ring (12) forms a static seal between the housing (4) and the outlet joint (13). The outlet joint (13) and the housing (4) are connected by a thread; a small hole is opened on the main piston (5), which is the pressure relief port C. The stop block (11) and the main piston (5) are connected by a thread; in the design, at the moment of pressure supply, the spring (6) and the damper will weaken the pressure impact and play a buffering role on the load device.

[0027] The oil inlet P is connected to the main oil tank, the oil control port B is connected to the load small oil tank, the load port A is connected to the load end. When the main piston (5) and the auxiliary piston (9) are not in close contact, the pressure relief port C enables an oil circuit to be formed between the oil control port B and the load port A.

[0028] The oil in the oil chamber I is the oil from the system, the oil in the oil chamber II is the control oil, and the oil in the oil chamber III is the oil at the load end. The oil in the oil chamber I and the oil in the oil chamber II are isolated by the second sealing ring (3); the oil in the oil chamber II and the oil in the oil chamber III are isolated or communicated as the piston (5) moves. When the end faces of the piston (5) and the auxiliary piston (9) are in contact, the third sealing ring (8) plays an oil sealing and isolating role between the oil chamber II and the oil chamber III. When the end face clearance between the piston (5) and the auxiliary piston (9) is not enough to cause sufficient compression of the third sealing ring (8), the oil between the oil chamber II and the oil chamber III is communicated. The oil in the oil chamber I and the oil in the oil chamber III are never communicated.

[0029] When the pressurized oil from the main fuel tank enters the oil chamber I from the oil inlet P, the hydraulic pressure acts on the left end face of the main piston (5). Under the action of the hydraulic pressure, the main piston (5) overcomes the spring force generated by the compression of the spring (6) and moves to the right. At this time, the oil in the oil chamber II is squeezed out through the control port B, and the oil in the oil chamber III is also squeezed. The oil in the oil chamber III flows through the pressure relief port C on the main piston (5), the end face clearance between the main piston (5) and the auxiliary piston (9) in sequence, and finally is squeezed out through the control port B.

[0030] Until the main piston (5) continues to move to the right until it fits with the end face of the auxiliary piston (9). After that, the main piston (5) and the auxiliary piston (9) move to the right together. The third sealing ring (8) forms a seal between the main piston (5) and the auxiliary piston (9). At this time, the oil in the oil chamber II can still be squeezed out through the control port B, but the oil in the oil chamber III is sealed. As the main piston (5) and the auxiliary piston (9) move to the right together, a hydraulic pressure equal to that at the oil inlet P is generated in the oil chamber III, realizing the hydraulic pressure transmission from the oil inlet P to the load port A.

[0031] After that, the main piston (5) and the auxiliary piston (9) move together to a certain position. At this time, the pressure values in the oil chamber III and the oil chamber I reach equilibrium, and the main piston (5) and the auxiliary piston (9) stop moving. Under the condition that the pressure at the oil inlet P remains unchanged: If there is no leakage at the load port and no pressure change caused by factors such as oil expansion due to temperature, the main piston (5) and the auxiliary piston (9) will maintain at this position, keeping the pressure at the load port A constant.

[0032] During the pressure holding process, if the pressure at the oil inlet P remains unchanged and there is oil leakage at the load port resulting in a pressure drop, the main piston (5) and the auxiliary piston (9) will continue to move to the right until the pressure at the load port A is equal to the pressure at the oil inlet P.

[0033] During the pressure holding process, if the pressure at the oil inlet P remains unchanged and the pressure is higher than a certain value due to reasons such as temperature rise after the load port oil circuit is closed, the high-pressure oil in the oil chamber III will act on the right side of the main piston (5), overcoming the combined action of the oil inlet P and the spring force, and pushing the main piston (5) to the left. The oil chamber II sucks oil from the control port B, a gap is formed between the main piston (5) and the auxiliary piston (9), and the high-pressure oil in the oil chamber III flows through the pressure relief port C on the main piston (5), the end face clearance between the main piston (5) and the auxiliary piston (9) in sequence, and finally is squeezed out through the control port B.

[0034] During the pressure holding process, if the pressure at the oil inlet P increases, the main piston (5) and the auxiliary piston (9) will continue to move to the right together, and the oil in the oil chamber III will continue to be compressed until the pressure at the load port A is equal to the pressure at the oil inlet P again, forming a new pressure balance.

[0035] During the pressure holding process, if the pressure at the oil inlet P decreases, the main piston (5) and the auxiliary piston (9) will move to the left together, reducing the compression amount of the oil in oil chamber III until the pressure at the load port A is equal to the pressure at the oil inlet P again, forming a new pressure balance.

[0036] When the hydraulic pressure at the oil inlet P is released, there is no hydraulic pressure on the left end face of the main piston (5). Under the action of the spring force generated by the compression of the spring (6) and the liquid pressure in oil chamber III, the main piston (5) and the auxiliary piston (9) will move to the left together. Oil chamber II sucks oil from the control port B, the compression amount of the oil in oil chamber III decreases, and the pressure is released. Until the piston (9) moves to the limit position of the boss on the housing (4), and then the main piston (5) moves to the left alone under the action of the spring force until the stop block (11) fits against the right end face of the auxiliary piston (9), the main piston (5) returns to its initial position, and the gap between the main piston (5) and the auxiliary piston (9) causes oil chamber III and the control port B to communicate again.

[0037] As Figure 2 shown, in a specific application, among multiple loads, load N is a part where pollutants are generated more in the system. Since the two ends of this pollution isolation device adopt threaded interfaces, it is only necessary to connect this pollution isolation device in series on the pipeline in front of load N, and a small oil cup is connected in parallel to port B. When the pressure enters from port P, the piston is pushed down, and the same pressure as that at port P will be generated at port A. The pressure at port A can then directly act on the load. When the pressure in the blind cavity at the load end needs to be released, the pressure at port P is released, the piston moves up, the pressure between the load and port A is released, and the oil between port A and the load returns to the small oil cup through port B, instead of flowing into the main fuel tank. It can be realized that the contaminated oil at the N end of the load is only limited to flow between the pipeline between the small oil cup and load N, without affecting the oil in the main system, thus avoiding causing failures of other loads.

[0038] The above specific embodiments or cases are only used to explain the technical solutions of the present invention, and do not limit this application. The parts not described in detail are regarded as conventional technical means or common general knowledge in the art. Those of ordinary skill in the art should understand that based on the design concept of this application, the technical solutions recorded in the foregoing embodiments should be adaptively modified, or some or all of the technical features should be equivalently replaced. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of each embodiment of the present invention.

Claims

1. A pollution isolation device for a helicopter hydraulic system, characterized in that, the pollution isolation device includes an inlet joint (1), a housing (4), a main piston (5), a spring (6), a spring seat (7), a secondary piston (9), a stop block (11), and an outlet joint (13); the front end of the inlet joint (1) is the oil inlet P, the housing (4) is provided with an oil control port B, and the outlet joint (13) is connected to multiple load ports A; an oil chamber I is formed between the end face of the inlet joint (1) and the main piston (5), an oil chamber II is formed between the housing (4) and the main piston (5), and an oil chamber III is formed between the end face of the secondary piston (9) and the outlet joint (13); the housing (4) and the main piston (5) are in movable cooperation; the two ends of the spring (6) are respectively pressed on the main piston (5) and the spring seat (7), having a pre-compression force; a small hole is opened on the main piston (5), which is the pressure relief port C; the pressure relief port C and the gap between the end faces of the main and secondary pistons together serve as the oil passage between the oil chamber II and the oil chamber III; the secondary piston (9) is sleeved outside the main piston (5), and the two can slide in cooperation under a certain pressure, and the left and right movement spaces of the secondary piston (9) are jointly restricted by the boss on the inner wall of the housing and the stop block (11) at the end of the main piston (5); the oil in the oil chamber I and the oil in the oil chamber II are always in an isolated state; the oil between the oil chamber I and the oil chamber III is always in an isolated state, but pressure transmission can be achieved; the oil chamber I is connected to the main fuel tank of the system, the oil chamber III is connected to the key pollution source load and the small fuel tank, and the oil between the main fuel tank and the small fuel tank is isolated, realizing the pollution isolation of the main fuel tank; the oil in the oil chamber II and the oil in the oil chamber III are isolated or connected as the main piston (5) moves. When the end faces of the main piston (5) and the secondary piston (9) are in contact, the third sealing ring (8) plays an oil sealing and isolation role between the oil chamber II and the oil chamber III. When the gap between the end faces of the main piston (5) and the secondary piston (9) is not sufficient to cause enough compression of the third sealing ring (8), the oil between the oil chamber II and the oil chamber III is connected.

2. The pollution isolation device for a helicopter hydraulic system according to claim 1, characterized in that, when pressurizing, after the main piston (5) and the secondary piston (9) are in contact, the main piston (5) and the secondary piston (9) move together, and the movement stroke depends on the hydraulic pressure at the oil inlet P; if the hydraulic pressure at the oil inlet P is high, the movement stroke of the main piston (5) and the secondary piston (9) together is large, and the compression amount of the oil in the oil chamber III is large; if the hydraulic pressure at the oil inlet P is small, the movement stroke of the main piston (5) and the secondary piston (9) together is small, and the compression amount of the oil in the oil chamber III is small.

3. The pollution isolation device for a helicopter hydraulic system according to claim 2, characterized in that, when pressurizing, after the main piston (5) and the secondary piston (9) are in contact, the oil in the oil chamber III is not connected to the control port B, and the main piston (5) and the secondary piston (9) move together to compress the oil chamber III, and a hydraulic pressure equal to that at the oil inlet P is generated in the oil chamber III, realizing the hydraulic pressure transmission from the oil inlet P to the load port A.

4. The pollution isolation device of the helicopter hydraulic system according to claim 1, characterized in that, during the pressure holding process, when the pressure at the load end rises to the set value due to temperature rise or other reasons, the high-pressure oil in oil chamber III will act on the right side of the main piston (5), overcoming the combined action of the oil inlet P and the spring force, pushing the main piston (5) to the left. Oil chamber II sucks oil from the control port B. A gap is formed between the main piston (5) and the auxiliary piston (9). The high-pressure oil in oil chamber III flows through the pressure relief port C on the main piston (5), the end face gap between the main piston (5) and the auxiliary piston (9) in sequence, and is finally squeezed out through the control port B; oil chamber II and oil chamber III are connected to achieve overpressure protection for system accessories.

5. The pollution isolation device of the helicopter hydraulic system according to claim 1, characterized in that, the device further includes multiple sealing structures. Among them, the first sealing ring (2) forms a static seal between the inlet joint (1) and the housing (4); the second sealing ring (3) forms a seal between the housing (4) and the main piston (5). The second sealing ring (3) moves axially with the main piston (5) and belongs to a dynamic seal; an oil drain hole D is opened on the main piston (5); the third sealing ring (8) is installed on the auxiliary piston (9). When the end faces of the main piston (5) and the auxiliary piston (9) are in close contact, a seal is formed between the main piston (5) and the auxiliary piston (9); the fourth sealing ring (10) is installed between the auxiliary piston (9) and the housing (4) and moves axially with the auxiliary piston (9), belonging to a dynamic seal; there is a clearance fit between the auxiliary piston (9) and the main piston (5); the fifth sealing ring (12) forms a static seal between the housing (4) and the outlet joint (13).

6. The pollution isolation device of the helicopter hydraulic system according to claim 1, characterized in that, the control port B is connected to a small fuel tank in the system. When the oil at the load end is polluted, only the oil in the small fuel tank needs to be replaced.

7. The pollution isolation device of the helicopter hydraulic system according to claim 1, characterized in that, the stop block (11) is threadedly connected to the main piston (5); the stop block (11) is used to limit the displacement of the auxiliary piston (9) relative to the main piston (5).

8. A helicopter hydraulic system, which includes the pollution isolation device of the helicopter hydraulic system according to any one of claims 1-7, and the pollution isolation device is installed between the main hydraulic fuel tank and the load.

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