A three-stage throttle for crashworthy landing gear

Abstract

The application provides a three-stage throttle valve for an anti-crash landing gear, which comprises a valve body, a first plane, a second plane, an upper circumferential surface and an upper counterbore; the upper circumferential surface is arranged between the first plane and the second plane, and the upper counterbore is arranged on the second plane; a first oil hole is arranged on the first plane; a second oil hole is arranged on the upper circumferential surface; and a third oil hole is arranged on the circumferential surface of the upper counterbore; the first plane and the second plane are both circular ring surfaces, and the outer diameter of the first plane is larger than that of the second plane; the three-stage throttle valve can meet the load control requirements in the large-span sinking speed range, has a low installation space, controllable damping effect, no strict requirement on the buffer assembly and can be used for the design of the anti-crash landing gear.

Description

Technical Field

[0001] This application belongs to the field of landing gear structural design technology, and in particular relates to a three-stage throttle valve for crash-resistant landing gear. Background Technology

[0002] As the military's requirements for the survivability of military helicopters continue to increase, new military helicopters are generally designed with crash-resistant landing gear to improve their survivability in the event of a crash. Generally, when designing crash-resistant helicopters, it is required that the landing gear absorb as much crash energy as possible; therefore, the design of crash-resistant landing gear is quite critical.

[0003] Current crash-resistant landing gear typically employs a hydropneumatic design, absorbing crash-resistant energy through two methods: throttling of hydraulic fluid to dissipate energy and storing energy in compressed gas. The landing gear generally uses throttle valves to restrict the flow of hydraulic fluid within the buffer, thereby dissipating landing energy. Crash-resistant landing gear typically employs dual throttle valves or needle valve designs to meet the requirements of a wide range of descent speeds. Dual throttle valves generally use two throttle valves connected in series, typically no more than two stages, and are well-suited for multi-chamber or tandem dual-chamber buffer designs.

[0004] The dual-throttle valve design requires an oil chamber between the two air chambers, resulting in a relatively large distance between them, making maintenance of the upper air chamber inconvenient; furthermore, this design requires a larger installation space for the throttle valve. The needle valve achieves load control by designing different throttling surfaces corresponding to different strokes. The needle valve has high requirements for the cross-section of the needle, as well as high requirements for the coaxiality and stiffness of the needle during movement; its annular throttling orifice damping effect is relatively uncontrollable. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a three-stage throttle valve for crash-resistant landing gear, the three-stage throttle valve comprising:

[0006] The valve body includes a first plane, a second plane, an upper circumferential surface, and an upper countersunk hole; wherein the upper circumferential surface is disposed between the first plane and the second plane, and the upper countersunk hole is disposed on the second plane;

[0007] A primary oil hole is located on the first plane;

[0008] Secondary oil holes are provided on the upper circumferential surface;

[0009] A three-stage oil hole is provided on the circumferential surface of the upper countersunk hole; wherein the first plane and the second plane are both annular surfaces, and the outer diameter of the first plane is larger than the outer diameter of the second plane.

[0010] Preferably, the third-level oil hole is coaxial with the second-level oil hole.

[0011] Preferably, a pin hole is provided on the second plane.

[0012] The three-stage throttle valve also includes:

[0013] The first ejector pin is disposed within the ejector pin hole;

[0014] A secondary hole cover is disposed at the secondary oil hole; wherein, one end of the first ejector pin abuts against the secondary hole cover;

[0015] A secondary hole retaining ring is disposed below the secondary hole cover; wherein, the secondary hole retaining ring is used to limit the travel of the secondary hole cover;

[0016] A secondary hole spring, one end of which contacts the secondary hole cover, and the other end of which contacts the secondary hole retaining ring.

[0017] Preferably, the three-stage throttle valve further includes:

[0018] The second ejector pin is disposed inside the ejector pin hole;

[0019] A third-stage orifice cover is disposed at the third-stage oil hole; wherein, one end of the second ejector pin abuts against the third-stage orifice cover;

[0020] A three-stage hole retaining ring is disposed below the three-stage hole cover;

[0021] A three-stage hole spring, one end of which contacts the three-stage hole cover, and the other end of which contacts the three-stage hole retaining ring.

[0022] Preferably, the three-stage throttle valve further includes:

[0023] A hole cover baffle is disposed between the third-level hole cover and the third-level hole retaining ring; wherein the hole cover baffle is used to limit the travel of the third-level hole cover.

[0024] Preferably, the secondary and tertiary orifice covers are provided with oil passages.

[0025] Preferably, the valve body further includes:

[0026] First inner cavity;

[0027] The second inner cavity is connected to the first inner cavity; wherein the primary oil hole is connected to the first inner cavity; and the secondary oil hole and the tertiary oil hole are connected to the second inner cavity.

[0028] Preferably, the secondary hole cover, secondary hole retaining ring, secondary hole spring, tertiary hole cover, tertiary hole retaining ring, tertiary hole spring and hole cover baffle are all disposed in the second inner cavity.

[0029] The beneficial technical effects of this application are as follows:

[0030] The three-stage throttle valve provided in this application can meet the load control requirements of a large span sinking speed range. It does not require much installation space, has controllable damping effect, and does not have strict requirements for buffer assembly. It can be used in crash-resistant landing gear design. Attached Figure Description

[0031] Figure 1 A schematic diagram of a three-stage throttle valve provided in an embodiment of this application;

[0032] Figure 2 This is a cross-sectional view of the three-stage throttle valve provided in the embodiments of this application;

[0033] Figure 3 This is a schematic diagram of the three-stage throttle valve body provided in the embodiments of this application;

[0034] Figure 4 This is a schematic diagram of the opening of the secondary oil hole provided in an embodiment of this application;

[0035] Figure 5 This is a schematic diagram of the opening of the second and third stage oil holes provided in the embodiments of this application;

[0036] Figure 6 This is a schematic diagram of the installation of a three-stage throttle valve provided in an embodiment of this application;

[0037] Wherein, 1-valve body; 2-first ejector pin; 3-second ejector pin; 4-secondary hole cover; 5-tertiary hole cover; 6-secondary hole retaining ring; 7-secondary hole spring; 8-retaining ring; 9-tertiary hole spring; 10-tertiary hole retaining ring; 11-hole cover baffle; 21-first plane; 22-upper circumferential surface; 23-second plane; 24-first ejector pin hole; 5-second ejector pin hole; 26-upper countersunk hole; 27-second cavity; 28-first cavity; 30-outer cylinder; 31-pressure oil chamber; 32-tertiary throttle valve; 33-return oil chamber; 34-air chamber; 35-piston rod. Detailed Implementation

[0038] In this embodiment, the invention features a primary oil orifice, a secondary oil orifice, and a tertiary oil orifice. A pin design controls the opening and closing of the secondary and tertiary oil orifices, thereby achieving throttling orifices of different areas to control the oil damping force corresponding to different sinking velocities. The throttling valve of this invention mainly consists of a valve body 1, a first pin 2, a second pin 3, a secondary orifice cover 4, a tertiary orifice cover 5, a secondary orifice retaining ring 6, a secondary orifice spring 7, a retaining ring 8, a tertiary orifice spring 9, a tertiary orifice retaining ring 10, an orifice cover baffle 11, a washer, a nut, and a cotter pin.

[0039] It should be noted that the working principle of forward compression is as follows: When the buffer's compression speed is low, the pressure in the pressure chamber is low. Under the pressure of the pressure chamber, the first ejector pin cannot push the secondary orifice cover 4 and the tertiary orifice cover 5. The oil in the pressure chamber only flows from the primary oil hole to the return oil chamber, forming an oil damping force that consumes energy. When the buffer's compression speed reaches a certain level, the pressure in the pressure chamber is high. The secondary orifice cover 4 is pushed open by the first ejector pin 2, while the tertiary orifice cover 5 is not pushed open by the second ejector pin 3. The oil in the pressure chamber flows from the primary and secondary oil holes to the return oil chamber, forming an oil damping force that consumes energy. The first ejector pin 2 achieves reciprocating motion through the pressure difference between the upper and lower oil (see...). Figure 4 During the crash, both the secondary borehole cover 4 and the tertiary borehole cover 5 were forced open, and the primary, secondary, and tertiary oil holes were activated simultaneously (see...). Figure 5 The oil in the pressure chamber flows from the primary oil hole, secondary oil hole, and tertiary oil hole to the return oil chamber, forming an oil damping force that consumes energy.

[0040] It should be noted that the principle of preventing helicopter ground resonance is as follows: When the helicopter is in a ground vibration environment, the speed of the shock absorber compression movement is relatively small, the secondary hole cover 4 and the tertiary hole cover 5 are always in the closed state, and the oil in the pressure oil chamber flows only from the primary oil hole to the return oil chamber. Therefore, it can provide greater damping to prevent the helicopter from ground resonance.

[0041] It should be noted that the principle of preventing the buffer from suddenly extending is as follows: When the buffer extends, under the combined action of the oil force and the spring force, the secondary orifice cover 4 and the tertiary orifice cover 5 block the secondary oil hole and the tertiary oil hole respectively, so only the primary oil hole is active. This can effectively control the speed at which the oil flows from the return oil chamber back to the pressure oil chamber, thereby controlling the rebound speed of the buffer.

[0042] In other embodiments of this application,

[0043] 1) It is designed with three-stage throttling orifices;

[0044] 2) The opening timing of the second and third stage oil holes is guaranteed by the matching design of the ejector pin and spring;

[0045] 3) The third-level oil hole and the second-level oil hole are designed with the same axis to ensure the machinability of the third-level oil hole;

[0046] 4) Both the second and third stage oil holes are designed with a limiting structure to ensure that the oil holes remain open under high pressure.

[0047] The technology provided in this application has been applied to the design of landing gear test pieces for a certain type of aircraft. Through landing gear performance simulation analysis, this patented technology can meet the load control requirements for crash-resistant landing gear.

[0048] In other embodiments of this application, a three-stage throttle valve is installed between the pressure oil chamber and the return oil chamber (see...). Figure 6This is used to control the damping force generated by the back-and-forth flow of oil between the return oil chamber and the pressure oil chamber. After the components of the three-stage throttle valve are assembled, the upper and lower movements of the secondary orifice cover 4 and the tertiary orifice cover 5 need to be run-in to ensure that there is no jamming. The valve body of the three-stage throttle valve is pre-set with mounting holes, and the three-stage throttle valve is connected to the piston rod by a pin, moving up and down together with the piston rod.

Claims

1. A three-stage throttle valve for crash-resistant landing gear, characterized in that, The three-stage throttle valve includes: The valve body includes a first plane, a second plane, an upper circumferential surface, and an upper countersunk hole; wherein the upper circumferential surface is disposed between the first plane and the second plane, and the upper countersunk hole is disposed on the second plane; A primary oil hole is located on the first plane; Secondary oil holes are provided on the upper circumferential surface; A three-stage oil hole is provided on the circumferential surface of the upper countersunk hole; wherein, the first plane and the second plane are both annular surfaces, and the outer diameter of the first plane is larger than the outer diameter of the second plane; The third-level oil hole is coaxial with the second-level oil hole; The second plane is provided with a pin hole; the three-stage throttle valve also includes: The first ejector pin is disposed within the ejector pin hole; A secondary hole cover is disposed at the secondary oil hole; wherein, one end of the first ejector pin abuts against the secondary hole cover; A secondary hole retaining ring is disposed below the secondary hole cover; wherein, the secondary hole retaining ring is used to limit the travel of the secondary hole cover; A secondary hole spring, one end of which contacts the secondary hole cover, and the other end of which contacts the secondary hole retaining ring; The three-stage throttle valve also includes: The second ejector pin is disposed inside the ejector pin hole; A third-stage orifice cover is disposed at the third-stage oil hole; wherein, one end of the second ejector pin abuts against the third-stage orifice cover; A three-stage hole retaining ring is disposed below the three-stage hole cover; A three-stage hole spring, one end of which contacts the three-stage hole cover, and the other end of which contacts the three-stage hole retaining ring.

2. The three-stage throttle valve for crash-resistant landing gear according to claim 1, characterized in that, The three-stage throttle valve also includes: A hole cover baffle is disposed between the third-level hole cover and the third-level hole retaining ring; wherein the hole cover baffle is used to limit the travel of the third-level hole cover.

3. The three-stage throttle valve for crash-resistant landing gear according to claim 2, characterized in that, The secondary and tertiary orifice covers are provided with oil passages.

4. The three-stage throttle valve for crash-resistant landing gear according to claim 3, characterized in that, The valve body also includes: First inner cavity; The second inner cavity is connected to the first inner cavity; wherein the primary oil hole is connected to the first inner cavity; and the secondary oil hole and the tertiary oil hole are connected to the second inner cavity.

5. The three-stage throttle valve for crash-resistant landing gear according to claim 4, characterized in that, The secondary hole cover, secondary hole retaining ring, secondary hole spring, tertiary hole cover, tertiary hole retaining ring, tertiary hole spring, and hole cover baffle are all disposed in the second inner cavity.

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