A small negative feedback constant flow starting valve assembly

Abstract

The application provides a small negative feedback constant flow starting valve assembly, and belongs to the field of structural design of aerospace mechanical hydraulic control systems, which comprises a valve bushing, a starting valve, an adjusting spring and a throttle nozzle. The starting valve is arranged in the valve bushing, and the inside of the valve bushing is divided into a spring cavity and a control cavity by the starting valve. The adjusting spring is arranged in the spring cavity. The starting valve is further provided with a flow guide channel, and the throttle nozzle is arranged in the flow guide channel. An oil inlet bushing type hole and an oil outlet hole are arranged on the side wall of the valve bushing, and a first flow guide hole is arranged on the side wall of the starting valve, the oil inlet bushing type hole is connected with the control cavity through the first flow guide hole, and the oil outlet hole is connected with the spring cavity. The small negative feedback constant flow starting valve assembly can ensure that the pressure difference on both sides of the throttle nozzle is basically constant, and a stable flow supply effect is formed.

Description

Technical Field

[0001] This invention belongs to the field of structural design of hydraulic control systems for aerospace machinery, and in particular relates to a small negative feedback constant flow starting valve assembly. Background Technology

[0002] In the field of aero-engines, the main function of fuel metering devices is to provide the engine with fuel flow throughout its entire operating state, from start-up to maximum. If the control accuracy of the output flow decreases under a certain condition, it may lead to problems such as lean-fuel shutdown or rich-fuel overheating, which in turn may adversely affect the engine's safety.

[0003] To meet the engine's operating requirements, fuel metering devices are generally designed with a secondary fuel line (or standby fuel line) for providing starting fuel. In systems with lower control precision requirements, starting fuel is typically controlled using a constant-sized orifice. However, since the orifice is usually located on the distribution valve, the pressure difference across the orifice cannot be separately controlled during operation. The starting flow rate is significantly affected by the pressure before the orifice and the combustion chamber back pressure, leading to unstable flow during operation. Furthermore, during manufacturing, high dimensional accuracy of the orifice is required to ensure relatively precise starting flow. Dimensional deviations during manufacturing will render the entire distribution valve unusable, resulting in economic losses. Moreover, once the orifice is formed, the resulting starting flow rate cannot be adjusted by other means. This increases the difficulty and time required for overall product debugging, making it unsuitable for practical applications. Summary of the Invention

[0004] In view of this, the present invention aims to provide a small negative feedback constant flow starting valve assembly to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution created by this invention is implemented as follows:

[0006] A small negative feedback constant flow starting valve assembly includes: a valve bushing, a starting valve, an adjusting spring, and a throttle nozzle; the valve bushing includes a bushing body and a valve cover, with the valve cover disposed at one end of the bushing body; the starting valve is disposed inside the valve bushing, dividing the interior of the valve bushing into a spring cavity and a control cavity, with the spring cavity located on the side of the starting valve closer to the valve cover, and the control cavity located on the side of the starting valve farther from the valve cover; the adjusting spring is disposed inside the spring cavity, for adjusting... The first end of the spring abuts against the valve cover, and the second end of the adjusting spring abuts against the starting valve. A flow guide channel is also provided on the starting valve, and the throttle nozzle is located inside the flow guide channel. A throttle orifice is provided on the throttle nozzle, and the control chamber is connected to the spring chamber through the throttle orifice. An oil inlet bushing-shaped hole and an oil outlet hole are provided on the side wall of the valve bushing. A first flow guide hole is provided on the side wall of the starting valve. The oil inlet bushing-shaped hole is connected to the control chamber through the first flow guide hole, and the oil outlet hole is connected to the spring chamber.

[0007] Furthermore, a filter screen is provided inside the flow channel, and the filter screen is located on the side of the throttle nozzle close to the control cavity.

[0008] Furthermore, a pad is provided inside the flow channel. The pad is located on the side of the filter screen away from the throttling nozzle. A connecting channel is provided on the pad, and the throttling orifice is connected to the control cavity through the connecting channel. A second flow guide hole is also provided on the side wall of the pad, and the first flow guide hole is connected to the connecting channel through the second flow guide hole.

[0009] Furthermore, a second flow guide groove is provided on the outer wall of the pad, and the second flow guide hole is disposed inside the second flow guide groove, and the width of the second flow guide groove is greater than the inner diameter of the second flow guide hole.

[0010] Furthermore, the inner diameter of the second guide hole is larger than the inner diameter of the first guide hole, and the inner diameter of the first guide hole is larger than the inner diameter of the oil inlet bushing type hole.

[0011] Furthermore, the flow channel is also provided with a first adjusting washer and a retaining ring, with the first adjusting washer located on the side of the pad block away from the filter screen, and the retaining ring located on the side of the first adjusting washer away from the pad block.

[0012] Furthermore, a second adjusting washer is provided inside the spring cavity, and the second adjusting washer is located between the second end of the adjusting spring and the starting valve.

[0013] Furthermore, the outer wall of the starting valve is provided with a first flow guide groove, the first flow guide hole is disposed inside the first flow guide groove, and the width of the first flow guide groove is greater than the inner diameter of the first flow guide hole.

[0014] Furthermore, the oil inlet bushing orifice is a curved orifice.

[0015] Furthermore, the outer wall of the valve bushing is also provided with a first sealing ring, a second sealing ring and a third sealing ring arranged along the axis of the valve bushing, the oil outlet is located between the first sealing ring and the second sealing ring, and the oil inlet bushing orifice is located between the second sealing ring and the third sealing ring; the outer wall of the throttle nozzle is also provided with a sealing ring groove, and a fourth sealing ring is provided inside the sealing ring groove.

[0016] Compared with existing technologies, the small negative feedback constant flow starting valve assembly described in this invention has the following advantages:

[0017] This invention discloses a small negative feedback constant flow starting valve assembly. The starting valve forms a spring cavity and a control cavity within its bushing. The bushing has an inlet bushing-shaped hole communicating with the control cavity and an outlet hole communicating with the spring cavity. A throttling nozzle is located within the flow guide channel of the starting valve, and a first guide hole is provided on the starting valve. When the pressure at the outlet hole or the inlet bushing-shaped hole changes, the starting valve can move within the bushing, adjusting the area of ​​the starting valve blocking the inlet bushing-shaped hole. This changes the area of ​​the inlet passage formed by the first guide hole and the inlet bushing-shaped hole, ensuring a relatively constant pressure difference across the throttling nozzle and achieving a stable flow supply. Furthermore, since an adjusting spring is located within the spring cavity, the pressure difference across the throttling nozzle is related to the elastic force of the adjusting spring. Operators can adjust the elastic force of the adjusting spring according to actual flow requirements, thus meeting different usage needs. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 A cross-sectional structural schematic diagram of the small negative feedback constant flow starting valve assembly described in an embodiment of the present invention.

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

[0021] 11-Bushing body; 12-Valve cover; 13-Spring cavity; 14-Control cavity; 15-Oil inlet bushing type hole; 16-Oil outlet hole; 2-Starting valve; 21-Guide channel; 22-First guide hole; 23-First guide ring groove; 3-Adjusting spring; 4-Throttle nozzle; 41-Throttle hole; 5-Filter screen; 6-Pan block; 61-Connecting channel; 62-Second guide hole; 63-Second guide ring groove; 71-First adjusting washer; 72-Second adjusting washer; 8-Snap ring; 91-First sealing ring; 92-Second sealing ring; 93-Third sealing ring; 94-Fourth sealing ring. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] A small negative feedback constant flow starting valve assembly, the structure of which can be made from Figure 1 The following is an illustration. In this embodiment, the small negative feedback constant flow starting valve assembly includes: a valve bushing, a starting valve 2, an adjusting spring 3, and a throttle nozzle 4.

[0027] Specifically, the valve bushing includes a bushing body 11 and a valve cover 12, with the valve cover 12 located at one end of the bushing body 11. In use, the valve cover 12 is used to connect the entire starting valve assembly to the fuel metering device. Operators can adjust the shape and type of the valve cover 12 according to actual needs to meet the assembly requirements of the fuel metering device.

[0028] The starting valve 2 is located inside the valve bushing, dividing the interior of the valve bushing into a spring cavity 13 and a control cavity 14. The spring cavity 13 is located on the side of the starting valve 2 closest to the valve cover 12, while the control cavity 14 is located on the side of the starting valve 2 furthest from the valve cover 12. A flow guide channel 21 is also provided on the starting valve 2, and a throttle nozzle 4 is located inside the flow guide channel 21. The throttle nozzle 4 has a throttle orifice 41, and the control cavity 14 is connected to the spring cavity 13 through the throttle orifice 41. Correspondingly, to facilitate fuel entry and exit from this valve assembly, the side wall of the valve bushing should have an inlet bushing-shaped hole 15 and an outlet hole 16, and a first flow guide hole 22 is provided on the side wall of the starting valve 2. After the assembly of the starting valve 2 and the valve bushing is completed, the inlet bushing-shaped hole 15 will connect to the control cavity 14 through the first flow guide hole 22, and the outlet hole 16 will connect to the spring cavity 13.

[0029] During operation, fuel enters the control chamber 14 through the inlet bushing orifice 15 and the first guide hole 22, then flows into the spring chamber 13 through the throttle orifice 41, and finally exits the starting valve assembly through the outlet hole 16 to enter the fuel metering device's fuel circuit. When the pressure in the inlet bushing orifice 15 increases / decreases (i.e., the valve assembly is affected by pressure fluctuations on the inlet side), the starting valve 2 moves inside the valve bushing towards / away from the valve cover 12, thereby adjusting the area of ​​the starting valve 2 blocking the inlet bushing orifice 15. This reduces / increases the area of ​​the fuel inlet passage formed by the first guide hole 22 and the inlet bushing orifice 15, thus ensuring that the pressure in the control chamber 14 remains relatively constant. Correspondingly, when the pressure at the oil outlet 16 increases / decreases (i.e., the valve assembly is affected by pressure fluctuations on the oil outlet side), the starting valve 2 will move away from / closer to the valve cover 12 inside the valve bushing, thereby adjusting the area of ​​the starting valve 2 blocking the oil inlet bushing orifice 15. This increases / decreases the area of ​​the oil inlet passage formed by the first guide hole 22 and the oil inlet bushing orifice 15. At this time, only the oil inlet volume in the control chamber 14 will increase / decrease accordingly, so that the pressure in the control chamber 14 and the pressure in the spring chamber 13 can increase / decrease synchronously. Through the above negative feedback process, the valve assembly can ensure that the pressure difference before and after the throttle nozzle 4 remains basically constant regardless of pressure changes on the oil inlet or outlet side, thus forming a stable fuel flow supply effect.

[0030] Optionally, to facilitate the smooth flow of fuel into the first guide hole 22 along the fuel inlet bushing orifice 15, a first guide ring groove 23 may be provided on the outer wall of the starter valve 2. The first guide hole 22 is located inside the first guide ring groove 23, and the width of the first guide ring groove 23 should be greater than the inner diameter of the first guide hole 22, so that the first guide ring groove 23 can collect the fuel leaving the fuel inlet bushing orifice 15 into the first guide hole 22.

[0031] As an optional implementation of this embodiment, the oil inlet bushing orifice 15 can be machined into a curved orifice. When the starting valve 2 moves inside the valve bushing, the curved orifice makes the change in the blocking area of ​​the starting valve 2 on the oil inlet bushing orifice 15 more continuous and smooth, thereby preventing sudden changes in pressure and flow.

[0032] To properly adjust the pressure difference across the throttle nozzle 4, the adjusting spring 3 in this embodiment should be located inside the spring cavity 13. After assembly, the first end of the adjusting spring 3 abuts against the valve cover 12, and the second end of the adjusting spring 3 abuts against the starting valve 2. In practical applications, the magnitude of the pressure difference across the throttle nozzle 4 will be related to the elastic force of the adjusting spring 3. Operators can adjust the elastic force of the adjusting spring 3 according to the actual flow requirements to meet different usage needs.

[0033] Optionally, to facilitate adjustment of the elastic force of the adjusting spring 3, a second adjusting washer 72 may be provided inside the spring cavity 13. For example... Figure 1 As shown, the second adjusting washer 72 should be located between the second end of the adjusting spring 3 and the starting valve 2. Since the elastic force of the adjusting spring 3 is generally positively correlated with the degree of deformation, the greater the thickness of the second adjusting washer 72 installed in this valve assembly, the shorter the initial length of the adjusting spring 3. Consequently, during subsequent use, the elastic force of the adjusting spring 3 when it undergoes the same deformation will be greater. In this way, operators can install second adjusting washers 72 of different thicknesses into the valve assembly according to the elastic force requirements of the adjusting spring 3, thereby reducing the difficulty of adjusting the elastic force.

[0034] In practical applications, a small amount of solid impurities may be trapped inside the fuel. To prevent solid impurities from clogging the valve assembly, a filter screen 5 can be provided inside the flow channel 21. The filter screen 5 is located on the side of the throttle nozzle 4 near the control chamber 14, thereby filtering the fuel entering the throttle orifice 41 with the help of the filter screen 5.

[0035] Optionally, to facilitate the limiting of the flow nozzle 4 and the filter screen 5, the flow channel 21 may also be equipped with a pad 6, a first adjusting washer 71, and a retaining ring 8. Figure 1As shown, the pad 6 is located on the side of the filter 5 away from the throttle nozzle 4, the first adjusting washer 71 is located on the side of the pad 6 away from the filter 5, and the retaining ring 8 is located on the side of the first adjusting washer 71 away from the pad 6. Accordingly, to facilitate the flow of fuel inside this valve assembly, the pad 6 may be provided with a connecting channel 61, and the throttle orifice 41 is connected to the control chamber 14 through the connecting channel 61. A second guide hole 62 may also be provided on the side wall of the pad 6, and the first guide hole 22 should be connected to the connecting channel 61 through the second guide hole 62. During use, the fuel will flow sequentially through the fuel inlet bushing orifice 15, the first guide hole 22, the second guide hole 62, and the connecting channel 61 to enter the control chamber 14 and the throttle orifice 41.

[0036] It should be noted that, in order to avoid the fuel flow being unduly affected by the flow inside this valve assembly, the inner diameter of the second guide hole 62 should be larger than the inner diameter of the first guide hole 22, and the inner diameter of the first guide hole 22 should be larger than the inner diameter of the oil inlet bushing type hole 15.

[0037] Similar to the structure near the first guide hole 22, this embodiment may also provide a second guide ring groove 63 on the outer side wall of the pad 6. The second guide hole 62 is disposed inside the second guide ring groove 63, and the width of the second guide ring groove 63 should be greater than the inner diameter of the second guide hole 62, so as to facilitate the collection of fuel leaving the first guide hole 22 into the interior of the second guide hole 62 through the second guide ring groove 63.

[0038] As another optional implementation of this embodiment, to achieve isolation between the oil passages of this valve assembly, a first sealing ring 91, a second sealing ring 92, and a third sealing ring 93 are also provided on the outer wall of the valve bushing, arranged along the axis of the valve bushing. The oil outlet hole 16 is located between the first sealing ring 91 and the second sealing ring 92, and the oil inlet bushing-type hole 15 is located between the second sealing ring 92 and the third sealing ring 93. After the valve assembly and fuel metering device are assembled, the cooperation of the first sealing ring 91, the second sealing ring 92, and the third sealing ring 93 can achieve isolation between the inlet and outlet oil passages. In addition, to improve the sealing effect around the throttle nozzle 4, a sealing ring groove can be provided on the outer wall of the throttle nozzle 4, and a fourth sealing ring 94 is provided inside the sealing ring groove, thereby sealing the gap between the throttle nozzle 4 and the guide channel 21 by means of the fourth sealing ring 94.

[0039] The effects of the above solution are explained below:

[0040] This embodiment provides a small negative feedback constant flow starting valve assembly. By moving the starting valve, the obstruction area of ​​the starting valve on the inlet bushing orifice is adjusted, causing a change in the area of ​​the inlet passage formed by the first guide orifice and the inlet bushing orifice. This ensures that the pressure difference across the throttle nozzle remains essentially constant, resulting in a stable flow supply. Furthermore, this valve assembly can also adjust the pressure difference across the throttle nozzle by adjusting the elastic force of the spring, thereby meeting different practical application requirements.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A small negative feedback constant flow starting valve assembly, characterized in that, include: The valve includes a valve bushing, a starting valve (2), an adjusting spring (3), and a throttle nozzle (4). The valve bushing includes a bushing body (11) and a valve cover (12), with the valve cover (12) located at one end of the bushing body (11). The starting valve (2) is located inside the valve bushing, dividing the interior of the valve bushing into a spring cavity (13) and a control cavity (14). The spring cavity (13) is located on the side of the starting valve (2) closer to the valve cover (12), and the control cavity (14) is located on the side of the starting valve (2) away from the valve cover (12). The adjusting spring (3) is located inside the spring cavity (13), with the first end of the adjusting spring (3) connected to the valve cover (12). The second end of the adjusting spring (3) abuts against the starting valve (2); a guide channel (21) is also provided on the starting valve (2), the throttle nozzle (4) is set inside the guide channel (21), a throttle hole (41) is provided on the throttle nozzle (4), and the control cavity (14) is connected to the spring cavity (13) through the throttle hole (41); an oil inlet bushing type hole (15) and an oil outlet hole (16) are provided on the side wall of the valve bushing, a first guide hole (22) is provided on the side wall of the starting valve (2), the oil inlet bushing type hole (15) is connected to the control cavity (14) through the first guide hole (22), and the oil outlet hole (16) is connected to the spring cavity (13); The flow channel (21) is also equipped with a filter screen (5), and the filter screen (5) is located on the side of the throttle nozzle (4) near the control cavity (14); The flow channel (21) is provided with a pad (6) inside. The pad (6) is located on the side of the filter screen (5) away from the throttle nozzle (4). A connecting channel (61) is provided on the pad (6), and the throttle hole (41) is connected to the control cavity (14) through the connecting channel (61). A second flow hole (62) is also provided on the side wall of the pad (6). The first flow hole (22) is connected to the connecting channel (61) through the second flow hole (62). The inner diameter of the second guide hole (62) is larger than the inner diameter of the first guide hole (22), and the inner diameter of the first guide hole (22) is larger than the inner diameter of the oil inlet bushing type hole (15); The starting valve (2) has a first flow guide ring groove (23) on its outer side wall, and the first flow guide hole (22) is located inside the first flow guide ring groove (23), and the width of the first flow guide ring groove (23) is greater than the inner diameter of the first flow guide hole (22).

2. The small negative feedback constant flow starting valve assembly according to claim 1, characterized in that: The outer wall of the pad (6) is provided with a second flow guide groove (63), and the second flow guide hole (62) is located inside the second flow guide groove (63), and the width of the second flow guide groove (63) is greater than the inner diameter of the second flow guide hole (62).

3. The small negative feedback constant flow starting valve assembly according to claim 1, characterized in that: The flow channel (21) is also provided with a first adjusting washer (71) and a retaining ring (8), and the first adjusting washer (71) is located on the side of the pad (6) away from the filter screen (5), and the retaining ring (8) is located on the side of the first adjusting washer (71) away from the pad (6).

4. A small negative feedback constant flow starting valve assembly according to claim 1, characterized in that: The spring cavity (13) is also provided with a second adjusting washer (72), and the second adjusting washer (72) is located between the second end of the adjusting spring (3) and the starting valve (2).

5. A small negative feedback constant flow starting valve assembly according to claim 1, characterized in that: The oil inlet bushing orifice (15) is a curved orifice.

6. A small negative feedback constant flow starting valve assembly according to claim 1, characterized in that: The outer wall of the valve bushing is also provided with a first sealing ring (91), a second sealing ring (92) and a third sealing ring (93) arranged along the axis of the valve bushing. The oil outlet hole (16) is located between the first sealing ring (91) and the second sealing ring (92). The oil inlet bushing type hole (15) is located between the second sealing ring (92) and the third sealing ring (93). The outer wall of the throttle nozzle (4) is also provided with a sealing ring groove, and a fourth sealing ring (94) is provided inside the sealing ring groove.

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