A differential pressure hysteresis valve assembly in an aircraft engine oil source switching device

Abstract

This invention discloses a differential pressure hysteresis valve assembly in an aero-engine fuel source switching device, comprising a differential pressure hysteresis valve (6), characterized in that: the differential pressure hysteresis valve (6) is installed inside a differential pressure hysteresis valve bushing (7); one end of a spring (4) presses against the differential pressure hysteresis valve (6), and the other end presses against an adjusting shim (3), and together with the adjusting shim (3), is installed on a spring seat (2), which is installed inside a screw cap (1); the screw cap (1) presses the differential pressure hysteresis valve bushing (7) onto a pad (9) through a stop seat (5), and the entire assembly is installed inside a housing (8). The differential pressure hysteresis valve assembly of this invention uses a mechanical valve assembly to output control oil, and utilizes a mechanical seal and a symmetrical double valve core structure to enable the fuel source switching device to stably achieve bidirectional fuel source switching function under high temperature and high pressure conditions, thereby improving the reliability of the engine.

Description

Technical Field

[0001] This invention relates to the field of engine oil source switching technology, and in particular to a differential pressure hysteresis valve assembly in an aircraft engine oil source switching device. Background Technology

[0002] When a certain type of aero-engine undergoes mode switching, the fuel source switching device must achieve bidirectional switching of the fuel source when the pressure difference between the two incoming fuel streams reaches a specific value, and then supply fuel to the nozzle control mechanism. Traditional fuel source switching devices generally use solenoid valves to output control oil to enable the switching mechanism to complete the fuel source switching. However, the reliability of solenoid valves decreases under high temperature and high pressure conditions, and they cannot stably output control oil, making it impossible for the fuel source switching device to reliably achieve the bidirectional fuel source switching function.

[0003] Chinese Patent 201911016003.3 discloses a dual-oil-circuit fuel drain device for an aircraft engine. This device comprises an end cover, an upper valve sleeve, a lower valve sleeve, a valve core, a base, a spring, a throttling element, and a sealing structure. The fuel drain device ensures reliable sealing of each oil circuit through end face sealing rings and radial sealing rings on the valve core. High pressure introduced from the fuel conditioning pump ensures the drain valve remains closed during engine operation. This design employs a single valve core design, using the pressure difference between the two chambers of the throttling element to drive the valve core and achieve dual-oil-circuit fuel drain. The valve core needs to be reset under spring pressure. However, the sealing ring structure between the valve core and the valve sleeve is prone to wear after repeated operation under high pressure and high temperature conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a differential pressure hysteresis valve assembly in an aircraft engine fuel source switching device. By replacing the solenoid valve with this differential pressure hysteresis valve assembly to output control oil, the problem of the fuel source switching device being unable to stably achieve bidirectional fuel source switching under high temperature and high pressure conditions is solved.

[0005] The technical solution of the present invention: A differential pressure hysteresis valve assembly in an aircraft engine oil source switching device includes a differential pressure hysteresis valve, which is installed inside a differential pressure hysteresis valve bushing; one end of a spring presses on the differential pressure hysteresis valve and the other end presses on an adjusting shim, and is installed together with the adjusting shim on a spring seat, which is installed inside a screw cap; the screw cap presses the differential pressure hysteresis valve bushing onto a pad block through a stop seat, and the entire assembly is installed inside a housing.

[0006] The differential pressure hysteresis valve assembly in the aforementioned aero-engine fuel source switching device has a bottom cylinder at the bottom and two middle cylinders in the middle, forming a second annular groove between the two middle cylinders. A first annular groove is formed between the lower middle cylinder and the bottom cylinder. The differential pressure hysteresis valve bushing has a bottom inner hole and a middle inner hole. The inner diameter of the bottom inner hole matches the outer diameter of the bottom cylinder, and the inner diameter of the middle inner hole matches the outer diameter of the middle cylinder. The side wall of the differential pressure hysteresis valve bushing has a first hole, a second hole, and a third hole. The small diameter end of the differential pressure hysteresis valve bushing has grooves evenly distributed in the radial direction.

[0007] In the aforementioned aero-engine oil source switching device, the differential pressure hysteresis valve assembly has a second annular groove of the differential pressure hysteresis valve forming a return oil chamber with the differential pressure hysteresis valve bushing, and a first annular groove forming a control chamber with the differential pressure hysteresis valve bushing. The return oil chamber is connected to the return oil circuit, and the control chamber is connected to the P2 oil supply.

[0008] In the aforementioned aircraft engine oil source switching device, the differential pressure hysteresis valve assembly forms a bottom cavity between the differential pressure hysteresis valve, the housing, and the gasket.

[0009] In the aforementioned aircraft engine oil source switching device, the differential pressure hysteresis valve assembly forms a spring cavity between the screw cap, the stop seat, the differential pressure hysteresis valve, and the housing, and the spring cavity is connected to the oil supply from P1.

[0010] The beneficial effects of this invention: Traditional oil source switching devices generally use solenoid valves to output control oil to complete the oil source switching, which reduces reliability under high temperature and high pressure conditions and cannot stably achieve bidirectional oil source switching. In contrast, the differential pressure hysteresis valve assembly of this invention uses a mechanical valve assembly to output control oil, and employs a mechanical seal and a symmetrical dual-valve core structure to enable the oil source switching device to stably achieve bidirectional oil source switching under high temperature and high pressure conditions, thus improving engine reliability.

[0011] Compared to the dual-oil-circuit fuel drain device for aero-engines described in patent document 201911016003.3, this invention employs a mechanical seal between the valve core and valve sleeve, meeting the requirements of this patent for repeated operation under high pressure and high temperature conditions. Two high-pressure oil streams are introduced into the spring chamber Q1 and control chamber Q3 respectively for pressure comparison. When the pressure difference between the two streams exceeds a specific value, the valve core opens, allowing the control chamber Q3 to communicate with the bottom chamber Q4, outputting control oil. When the pressure difference is less than the specific value, the valve core resets under the combined action of the high-pressure oil in the spring chamber Q1 and the spring, cutting off the control oil in the bottom chamber Q4. A symmetrical dual-valve core structure enables bidirectional switching of the oil source. Attached Figure Description

[0012] Appendix Figure 1 This is a schematic diagram of the structure of the present invention;

[0013] Appendix Figure 2 This is a structural diagram of the differential pressure hysteresis valve of the present invention;

[0014] Appendix Figure 3 This is a structural diagram of the differential pressure hysteresis valve bushing of the present invention.

[0015] Explanation of reference numerals in the attached drawings: 1-Screw cap, 2-Spring seat, 3-Adjusting shim, 4-Spring, 5-Stop seat, 6-Differential pressure hysteresis valve, 7-Differential pressure hysteresis valve bushing, 8-Housing, 9-Pan block, 61-Bottom cylinder, 62-Middle cylinder, 71-Bottom inner hole, 72-Middle inner hole, A-Groove, Ⅰ-First hole, II-Second hole, III-Third hole, Q1-Spring cavity, Q2-Return oil cavity, Q3-Control cavity, Q4-Bottom cavity, First annular groove c1, Second annular groove c2 Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0017] Embodiment 1 of the present invention: A differential pressure hysteresis valve assembly in an aircraft engine oil source switching device includes a differential pressure hysteresis valve 6, which is installed inside a differential pressure hysteresis valve bushing 7; one end of a spring 4 presses on the differential pressure hysteresis valve 6, and the other end presses on an adjusting shim 3, and is installed together with the adjusting shim 3 on a spring seat 2, which is installed inside a screw cap 1; the screw cap 1 presses the differential pressure hysteresis valve bushing 7 onto a pad block 9 through a stop seat 5, and the entire assembly is installed inside a housing 8.

[0018] The differential pressure hysteresis valve 6 has a bottom cylinder 61 at the bottom and two middle cylinders 62 in the middle. A second annular groove c2 is formed between the two middle cylinders 62. A first annular groove c1 is formed between the lower middle cylinder 62 and the bottom cylinder 61. The differential pressure hysteresis valve bushing 7 has a bottom inner hole 71 and a middle inner hole 72. The inner diameter of the bottom inner hole 71 matches the outer diameter of the bottom cylinder 61, and the inner diameter of the middle inner hole 72 matches the outer diameter of the middle cylinder 62. The side wall of the differential pressure hysteresis valve bushing 7 has a first hole I, a second hole II, and a third hole III. The small diameter end of the differential pressure hysteresis valve bushing 7 has grooves A evenly distributed in the radial direction.

[0019] The second annular groove c2 of the differential pressure hysteresis valve 6 and the differential pressure hysteresis valve bushing 7 form a return oil chamber Q2, and the first annular groove c1 and the differential pressure hysteresis valve bushing 7 form a control chamber Q3. The return oil chamber Q2 is connected to the return oil circuit, and the control chamber Q3 is connected to the oil supply from P2.

[0020] A bottom cavity Q4 is formed between the differential pressure hysteresis valve 6, the housing 8, and the pad 9.

[0021] A spring cavity Q1 is formed between the screw cap 1, the stop seat 5, the differential pressure hysteresis valve 6, and the housing 8. The spring cavity Q1 is connected to the oil supply P1.

[0022] The core of this invention is the shape of the differential pressure hysteresis valve assembly. The differential pressure hysteresis valve 6 has the following structure: Figure 2 As shown, the differential pressure hysteresis valve 6 is shaped like several stepped cylinders of different diameters. The bottom of the valve is a bottom cylinder 61 with an outer diameter of d1. Two middle cylinders 62 with an outer diameter of d2 are located in the middle of the valve. These two cylinders, d1 and d2, with different outer diameters, cooperate with the differential pressure hysteresis valve bushing 7 to form the return oil chamber Q2 and the control chamber Q3. The first annular groove c1 is used to compare the pressure difference between oil from P1 and oil from P2, and to facilitate communication between oil from P2 and the control oil. The second annular groove c2 is used to facilitate communication between the control oil and the return oil.

[0023] Differential pressure hysteresis valve bushing 7 structure as follows Figure 3 As shown, the differential pressure hysteresis valve bushing 7 is composed of multiple cylinders of varying sizes connected together. It has two sections with different inner diameters: the bottom inner diameter 71 is D1, and the middle inner diameter 72 is D2. These inner diameters cooperate with the differential pressure hysteresis valve 6 to form the return oil chamber Q2 and the control chamber Q3. The first cylinder H1 of the differential pressure hysteresis valve bushing 7 has several first holes I evenly distributed radially to introduce oil from P2 into the control chamber Q3; the second cylinder H2 has several second holes II evenly distributed radially to connect the control oil with the return oil chamber Q2 or the control chamber Q3; the third cylinder H3 has several third holes III evenly distributed radially to lead the return oil chamber Q2 out to the return oil; the small-diameter end of the differential pressure hysteresis valve bushing 7 has several grooves A evenly distributed radially to connect the control oil with the bottom chamber Q4.

[0024] During operation, oil from P1 enters the spring chamber Q1, and oil from P2 enters the control chamber Q3 through orifice I. When the pressure difference between the oil from P2 and P1 does not reach a specific value, the differential pressure hysteresis valve assembly is in the closed state. Figure 1The state shown is as follows: At this time, control oil communicates with the return oil through the return oil chamber Q2, the differential pressure hysteresis valve assembly does not output control oil, and the oil source switching device does not perform oil source switching. When the pressure difference between the oil from P2 and the oil from P1 reaches a specific value, the differential pressure hysteresis valve 6 compresses the spring 4 under the action of the oil pressure in the control chamber Q3, closing the communication between the control oil and the return oil chamber Q2. Simultaneously, it allows the control oil to communicate with the control chamber Q3 and the bottom chamber Q4, thus keeping the differential pressure hysteresis valve assembly open and outputting control oil, while the oil source switching device performs oil source switching. With the differential pressure hysteresis valve assembly open, when the pressure difference between the oil from P2 and the oil from P1 drops to a specific value, the differential pressure hysteresis valve 6 moves under the action of the oil pressure in the spring chamber Q1 and the spring 4 until the cylindrical section of the differential pressure hysteresis valve 6 with an outer diameter of d3 contacts the large-diameter end face of the differential pressure hysteresis valve bushing 7 and stops. Figure 1 As shown in the diagram; the communication between the control oil and the control chamber Q3 is closed, while the control oil is connected to the return oil chamber Q2, thereby closing the output of the control oil. The oil source switching device then switches the oil source again, completing the bidirectional switching of the oil source.

[0025] Example 2. A differential pressure hysteresis valve 6 of a certain model has a bottom cylinder 61 with an outer diameter d1 of Ф5.5mm, a middle cylinder 62 with an outer diameter d2 of Ф9mm, a first annular groove c1 of Ф4.3mm, and a second annular groove c2 of Ф5mm. The differential pressure hysteresis valve bushing 7 has a bottom inner hole 71 with an inner diameter D1 of Ф5.5mm and a middle inner hole 72 with an inner diameter D2 of Ф9mm; the first cylinder H1 has a diameter of Ф15mm and four first holes I with a diameter of Ф5mm are evenly distributed in the radial direction; the second cylinder H2 has a diameter of Ф13mm and four second holes II with a diameter of Ф5mm are evenly distributed in the radial direction; the third cylinder H3 has a diameter of Ф14mm and four third holes III with a diameter of Ф5mm are evenly distributed in the radial direction; and four square grooves A with a side length of 2mm are evenly distributed in the radial direction at the small diameter end of the bushing.

[0026] During operation, oil from P1 enters the spring chamber Q1 and works with spring 4 to exert an axial force F1 in the closing direction on the differential pressure hysteresis valve 6. Oil from P2 enters the control chamber Q3 through four Ф5mm first holes I on the Ф15mm diameter differential pressure hysteresis valve bushing 7, acting on the two end faces of the first annular groove c1 of the differential pressure hysteresis valve 6. The outer diameters d2 and d1 of the two end faces are Ф9mm and Ф5.5mm respectively. Since the annular area of ​​the outer diameter d2 end face is larger than that of the outer diameter d1 end face, the force exerted by the oil pressure on the outer diameter d2 end face is greater than the force exerted on the outer diameter d1 end face, thus subjecting the differential pressure hysteresis valve 6 to an axial force F2 in the opening direction. When the pressure difference between oil from P2 and P1 does not reach a specific value, the axial force F2 on the differential pressure hysteresis valve 6 is less than F1, and the differential pressure hysteresis valve assembly is in the closed state. Figure 1In the indicated state, the control oil communicates with the return oil through the return oil chamber Q2, the differential pressure hysteresis valve assembly does not output control oil, and the oil source switching device does not perform oil source switching. When the pressure difference between the oil from P2 and the oil from P1 reaches a specific value, the axial force F2 on the differential pressure hysteresis valve 6 is greater than F1, and it begins to move in the valve opening direction, thereby compressing the spring 4, cutting off the communication between the control oil and the return oil, and at the same time, the oil from P2 in the control chamber Q3 enters the bottom chamber Q4 through the four Ф5mm second holes II on the differential pressure hysteresis valve bushing 7 with a diameter of Ф13mm. The differential pressure hysteresis valve assembly outputs control oil, and the oil source switching device performs oil source switching. When the differential pressure hysteresis valve assembly is in the open state, and the differential pressure difference between the oil supply from P2 and P1 drops to a specific value, the axial force F2 on the differential pressure hysteresis valve 6 is less than F1, causing it to begin moving in the valve closing direction. This closes the communication between the control oil and the control chamber Q3, while simultaneously allowing the control oil to communicate with the return oil chamber Q2. This allows the control oil to return through the four Ф14mm diameter third holes III on the differential pressure hysteresis valve bushing 7 (4 Ф5mm holes). The differential pressure hysteresis valve assembly then returns to the closed state. Figure 1 In the indicated state, the control oil output is shut off, and the oil source switching device switches the oil source again, completing the bidirectional switching of the oil source to meet the engine requirements.

Claims

1. A differential pressure hysteresis valve assembly in an aircraft engine fuel source switching device, comprising a differential pressure hysteresis valve (6), characterized in that: The differential pressure hysteresis valve (6) is installed inside the differential pressure hysteresis valve bushing (7); one end of the spring (4) presses on the differential pressure hysteresis valve (6), and the other end presses on the adjusting shim (3), and together with the adjusting shim (3), it is installed on the spring seat (2), which is installed inside the screw cap (1); the screw cap (1) presses the differential pressure hysteresis valve bushing (7) onto the pad (9) through the stop seat (5), and the entire assembly is installed inside the housing (8); the differential pressure hysteresis valve (6) has a bottom cylinder (61) at the bottom. The differential pressure hysteresis valve (6) has two central cylinders (62) in the middle, forming a second annular groove (c2) between the two central cylinders (62). A first annular groove (c1) is formed between the lower central cylinder (62) and the bottom cylinder (61). The differential pressure hysteresis valve bushing (7) has a bottom inner hole (71) and a central inner hole (72). The inner diameter of the bottom inner hole (71) matches the outer diameter of the bottom cylinder (61), and the inner diameter of the central inner hole (72) matches the outer diameter of the central cylinder (62). The differential pressure hysteresis valve bushing (7) has a first hole (I), a second hole (II), and a third hole (III) on its side wall. The small-diameter end of the differential pressure hysteresis valve bushing (7) has grooves (A) evenly distributed radially. The second annular groove (c2) of the differential pressure hysteresis valve (6) and the differential pressure hysteresis valve bushing (7) form a return oil chamber (Q2), and the first annular groove (c1) and the differential pressure hysteresis valve bushing (7) form a control chamber (Q3). The return oil chamber (Q2) is connected to the return oil circuit, and the control chamber (Q3) is connected to… Oil from P2 is supplied; a spring cavity (Q1) is formed between the screw cap (1), the stop seat (5), the differential pressure hysteresis valve (6), and the housing (8), and the spring cavity (Q1) is connected to the oil from P1; the outer diameter of the bottom cylinder (61) is d1, and the outer diameter of the middle cylinder (62) is d2, and the outer diameters d1 and d2 are different; the first hole (I) is used to introduce the oil from P2 into the control cavity (Q3); the second hole (II) is used to connect the control oil with the return oil cavity (Q2) or the control cavity (Q3).

2. The differential pressure hysteresis valve assembly in the aero-engine fuel source switching device according to claim 1, characterized in that: A bottom cavity (Q4) is formed between the differential pressure hysteresis valve (6), the housing (8), and the pad (9).

Images