Safety valve for fuel pump regulator

Abstract

The application discloses a safety valve of fuel pump regulator. The application comprises a second shell, a second safety valve bushing arranged in the second shell, a second safety valve arranged in the second safety valve bushing, a second spring, a left end of the second spring abutting against the second safety valve, a right end of the second spring abutting against a second spring seat, and the second spring seat being arranged in a second cover; a high-pressure fuel Pg after the pump being communicated with a left end of the second safety valve and a type hole of the second safety valve bushing, a return oil Ph being communicated with the type hole of the second safety valve bushing, and a constant-pressure oil Py being communicated with the type hole of the second safety valve bushing; and a force area A2 of the left end of the second safety valve being smaller than a force area A3 of the right end of the second safety valve. According to the structure of the application, the spring force required by the valve is greatly reduced, the design length of the spring can be shortened, the requirement of the spring is reduced, the valve is simple in design, the overall length of the whole assembly is correspondingly shortened, the space occupied is less, and the weight and volume of the airplane are reduced.

Description

Technical Field

[0001] This invention relates to the field of fuel pump regulators for aircraft engines or gas turbines, and in particular to a safety valve for a fuel pump regulator. Background Technology

[0002] Throughout the entire operation of the fuel pump regulator, especially in the event of a malfunction, it is necessary to ensure that the pressure after the pump does not exceed a certain value to guarantee the safety of the fuel pump regulator. This function is usually achieved using a safety valve.

[0003] The safety valve of a certain type of fuel pump regulator is as follows: Figure 1 As shown, the first safety valve 1 is located inside the first safety valve bushing 2. One end of the first spring 3 abuts against the first safety valve 1, and the other end abuts against the first spring seat 4, which is installed inside the first cover. The high-pressure fuel Pg after the pump communicates with the left cavity of the first safety valve 1 and the type hole XK2 of the first safety valve bushing 2. The return oil Ph communicates with the type hole XK1 of the first safety valve bushing 2, and the low-pressure oil Pd communicates with the type hole XK3 of the first cover 5. When the pressure of the high-pressure fuel Pg after the pump increases, the first safety valve 1 moves to the right. When Pg is greater than 8 MPa, Pg passes through XK2 and communicates with XK1 from the annular cavity on the first safety valve, allowing the fuel Pg to be discharged into Ph. When the amount of fuel discharged into Ph through XK2 is greater than or equal to the newly added amount of fuel from the high-pressure fuel Pg after the pump, the first safety valve stabilizes in this position. When the pressure of Pg decreases, the first safety valve 1 moves to the left. As the pressure of Pg drops below 8 MPa, XK2 closes.

[0004] Based on this structure, Equation 1 is established according to the force analysis at both ends of the first safety valve 1:

[0005] Pg·A1=Pd·A1+F1

[0006] Where F1 is the spring force.

[0007] Based on the force analysis of the first spring 3, Equation 2 is established:

[0008] F1 = F0 + k1·x

[0009] Where F0 is the initial installation preload of the first spring 3, k1 is the stiffness of the first spring 3, and x is the movement distance of the safety valve.

[0010] Taking the aforementioned fuel pump regulator as an example, it is required that the first safety valve bushing type 2 hole XK2 is open at 8MPa and that the type hole XK2 is fully open at 9MPa.

[0011] Since the force area of the first safety valve 1 at both ends is A1, the pressure difference at both ends when the XK2 type hole starts to open is 7.8 MPa, and the pressure difference at both ends when the XK2 type hole starts to open is 8.8 MPa. In order to ensure that the product can quickly release the high-pressure fuel Pg to Ph under any condition, the diameters of the XK2 and XK1 type holes are 4 mm, and the number is 4.

[0012] The following difficulties exist in the design of the valve:

[0013] 1. Since the pressure difference at both ends of the valve is large, and at the same time, the first safety valve bushing 2 type hole XK2 needs to be opened to fully open, the first safety valve 1 moves a distance x=4, and the pressure rises by 9-8=1 MPa, so 4×k1=1×A1. Therefore, when designing the spring, there is a certain difficulty in matching the spring and the valve. When the spring force is large, the spring design is difficult, and the higher the pressure, the more difficult it is to design. The larger the spring stiffness, the larger the spring length and size, so according to the existing product design, the spring length must be very long, which affects the stability of the spring.

[0014] 2. Because the spring length is long, the first cover 5 and the first spring seat 4 are relatively long, which makes the overall size and weight of the assembly larger, which is not conducive to the weight and size reduction of the aircraft. SUMMARY

[0015] To solve the valve design difficulty problem in the background art, the present application provides a safety valve of a fuel pump regulator.

[0016] The technical scheme of the present application: a safety valve of a fuel pump regulator, comprising a second housing, a second safety valve bushing is arranged in the second housing, a second safety valve is arranged in the second safety valve bushing, a left end of a second spring abuts against the second safety valve, a right end of the second spring abuts against a second spring seat, and the second spring seat is installed in a second cover; the high-pressure fuel Pg after the pump is communicated with a type hole of the second safety valve bushing and a left end of the second safety valve, the oil return Ph is communicated with the type hole of the second safety valve bushing, and the constant-pressure oil Py is communicated with the type hole of the second safety valve bushing; the force area A2 of the left end of the second safety valve is smaller than the force area A3 of the right end of the second safety valve.

[0017] In the foregoing safety valve of a fuel pump regulator, the second safety valve is in the shape of a stepped cylinder, and from left to right, it is a small-diameter section cylinder, a medium-diameter section cylinder, and a large-diameter section cylinder.

[0018] In the foregoing safety valve of a fuel pump regulator, the large-diameter section cylinder is provided with a spring groove; and the left part of the second spring is arranged in the spring groove.

[0019] In the foregoing safety valve of a fuel pump regulator, the medium-diameter section cylinder is provided with a cavity.

[0020] In the aforementioned safety valve of fuel pump regulator, the inner left end of the bushing is provided with a small-diameter section cavity, and the inner right end is provided with a large-diameter section cavity; the small-diameter section cylinder is arranged in the small-diameter section cavity; and the medium-diameter section cylinder and the large-diameter section cylinder are arranged in the large-diameter section cavity.

[0021] In the aforementioned safety valve of fuel pump regulator, the second shell is provided with a valve cavity at the left end of the second safety valve.

[0022] Beneficial effects

[0023] Under the structure of the application, Py uses constant-pressure oil, the pressure is generally about 2 MPa, and by adjusting the area ratio of A2 and A3, the hydraulic pressure of Pg on the second safety valve is mostly offset by the hydraulic pressure of Py on the second safety valve, so that the required spring force is greatly reduced, the spring design length can be shortened, the spring requirement is reduced, the valve design is simple, and the overall length of the entire assembly is also shortened accordingly, the space occupied is less, and the weight and volume of the aircraft are reduced. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0025] Figure 1 is a schematic diagram of a safety valve of a certain type of existing product;

[0026] Figure 2 is a schematic diagram of the structure of the present application;

[0027] Figure 3 is a schematic diagram of the structure of the second safety valve bushing;

[0028] Figure 4 is a schematic diagram of the structure of the second safety valve.

[0029] The marks in the drawings are: 1-first safety valve, 2-first safety valve bushing, 3-first spring, 4-first spring seat, 5-first cover, 6-first shell, 7-second shell, 8-second safety valve bushing, 9-second safety valve, 10-second spring, 11-second spring seat, 12-second cover; 71-valve cavity; 81-small-diameter section cavity; 82-large-diameter section cavity; 91-small-diameter section cylinder; 92-medium-diameter section cylinder; 93-large-diameter section cylinder; 94-spring groove; 95-cavity; Pg-high-pressure fuel after the pump, Ph-oil return, Pd-low-pressure oil, Py-constant-pressure oil. DETAILED DESCRIPTION

[0030] In order to make the person skilled in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0031] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0032] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For the person skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0033] In addition, the terms "mount", "set", "provided with", "connect", "connect", "socket" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication between two devices, elements or components. For the person skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific situation.

[0034] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0035] Embodiment. A safety valve of a fuel pump regulator, the structure is as follows Figures 2-4As shown, the second housing 7 is provided with the second safety valve sleeve 8, the second safety valve sleeve 8 is provided with the second safety valve 9, the left end of the second spring 10 abuts against the second safety valve 9, the right end abuts against the second spring seat 11, and the second spring seat 11 is installed in the second cover 12; the high-pressure fuel Pg after the pump is communicated with the left end of the second safety valve 9 and the type hole XK5 of the second safety valve sleeve 8, the return oil Ph is communicated with the type hole XK4 of the second safety valve sleeve 8, and the constant-pressure oil Py is communicated with the type hole XK6 of the second safety valve sleeve 8; the left end force area A2 of the second safety valve 9 is smaller than the right end force area A3 of the second safety valve 9.

[0036] The second safety valve 9 is in the shape of a stepped cylinder, and sequentially comprises a small-diameter section cylinder 91, a medium-diameter section cylinder 92 and a large-diameter section cylinder 93 from left to right. The step of the medium-diameter section cylinder 92 larger than the small-diameter section cylinder 91 serves to limit, and the limiting is achieved by cooperating with the step formed by the small-diameter section cavity 81 and the large-diameter section cavity 82. The stop structure is arranged in the middle of the valve, which has the advantage of shortening the length of the valve compared with the valve before the improvement; and the large-diameter section cylinder 93 is arranged to change the force area of the second safety valve 9.

[0037] The large-diameter section cylinder 93 is provided with a spring groove 94; and the left part of the second spring 10 is arranged in the spring groove 94. After the spring groove 94 is arranged, the overall length of the safety valve and the product volume and weight can be further reduced.

[0038] The medium-diameter section cylinder 92 is provided with a cavity 95. The cavity 95 can reduce the weight.

[0039] The inside left end of the sleeve 8 is provided with a small-diameter section cavity 81, and the inside right end is provided with a large-diameter section cavity 82; the small-diameter section cylinder 91 is arranged in the small-diameter section cavity 81; and the medium-diameter section cylinder 92 and the large-diameter section cylinder 93 are arranged in the large-diameter section cavity 82.

[0040] The second housing 7 is provided with a valve cavity 71 at the left end of the second safety valve 9. The stop point of the existing valve is at the right end, and the stop structure is arranged in the middle in the structure of the valve, which aims to shorten the length of the valve. The valve cavity 71 is arranged to ensure that the second safety valve 9 is always not communicated between Pg and Ph when moving to the right.

[0041] The working principle of the present application is as follows:

[0042] When the high pressure Pg after the pump rises, the second safety valve (9) moves to the right, when Pg is greater than 8 MPa, Pg passes through XK5, communicates with XK4 from the annular cavity on the second safety valve, so that Pg fuel is discharged into Ph. When the amount of fuel discharged into Ph through XK5 is greater than or equal to the newly added fuel amount of high pressure Pg after the pump, the second safety valve is stable at this position. When Pg pressure drops, the second safety valve (9) moves to the left, and when Pg pressure drops to 8 MPa or less, XK5 is closed.

[0043] According to the force analysis of the two ends of the second safety valve, equation 3 is established:

[0044] Pg·A2+ (A3-A2) ·Ph=Py·A3+F1

[0045] Wherein the pressure Pg> Py> Ph.

[0046] Because Py uses constant pressure oil, the pressure is generally about 2 MPa, and the area ratio of A2 and A3 can be adjusted to make the hydraulic pressure of Pg on the second safety valve (9) mostly offset by the hydraulic pressure of Py on the second safety valve (9), so the spring design length can be shortened, and the design is simple, the overall length of the entire assembly is also shortened, and the space occupied is less, which is beneficial to the weight and volume reduction of the aircraft.

[0047] Wherein, Py can also be selected according to the actual situation, when selecting a lower pressure, such as Py=Pd, Pg*A2=A2*Py+F1 is brought into equation 3, that is, the actual force area is A2, which is used to offset a part of the force area, and the actual force area of the valve is only related to the area of A2; When Py is constant pressure oil, Py is greater than Pd, in order to facilitate understanding, it is assumed that Pd pressure is 0.2 MPa, A3=4A2, Py=2 MPa, Pg=8 MPa. For the original scheme, 8A1=F1, and the present scheme is 0.6A2=F1, which greatly reduces the spring force F1.

[0048] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art within the technical scope disclosed in the present application, according to the technical scheme and concept of the present application, equivalent replacement or change, should be covered in the protection scope of the present application.

Claims

1. A safety valve for a fuel pump regulator, characterized by: The second shell (7) is provided with a second safety valve bushing (8) inside, the second safety valve bushing (8) is provided with a second safety valve (9) inside, the left end of the second spring (10) abuts against the second safety valve (9), the right end abuts against the second spring seat (11), and the second spring seat (11) is installed in the second cover (12); the high-pressure fuel Pg after the pump is communicated with the left end of the second safety valve (9) and the XK5 hole of the second safety valve bushing (8), the return oil Ph is communicated with the XK4 hole of the second safety valve bushing (8), and the constant-pressure oil Py is communicated with the XK6 hole of the second safety valve bushing (8); the left end of the second safety valve (9) has a force area A2 smaller than the right end of the second safety valve (9) with a force area A3; The second safety valve (9) is a stepped cylinder, and from left to right, it is a small-diameter section cylinder (91), a medium-diameter section cylinder (92) and a large-diameter section cylinder (93); The large-diameter section cylinder (93) is provided with a spring groove (94); and the left part of the second spring (10) is arranged in the spring groove (94); The medium-diameter section cylinder (92) is provided with a cavity (95); The second safety valve bushing (8) is provided with a small-diameter section cavity (81) at the left end inside and a large-diameter section cavity (82) at the right end inside; the small-diameter section cylinder (91) is arranged in the small-diameter section cavity (81); and the medium-diameter section cylinder (92) and the large-diameter section cylinder (93) are arranged in the large-diameter section cavity (82); The second shell (7) is provided with a valve cavity (71) at the left end of the second safety valve (9).

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