A twin-tube unmanned aerial vehicle landing gear damper

Abstract

The application discloses a double-cylinder unmanned aerial vehicle landing gear buffer, which is characterized by comprising an inner cylinder and an outer cylinder which are separated in a radial direction, a side chamber arranged between the outer cylinder and the inner cylinder, a piston arranged in the inner cylinder and capable of moving reciprocally along an axial direction of the piston and dividing the inner cylinder into an upper chamber and a lower chamber, and a bottom valve and a holding mechanism arranged at an end of the inner cylinder and being in communication with the side chamber, wherein a pressure accumulation mechanism is coaxially arranged on a side of the holding mechanism and in communication with the bottom valve and the holding mechanism, and the pressure accumulation mechanism is provided with a pressure accumulation cavity which is capable of expanding or shrinking along with movement of the piston for accumulating or releasing damping oil. In one aspect, a throttle hole is arranged on a wall of the inner cylinder to cooperate with a guide mechanism and the bottom valve to construct an oil return path, and in another aspect, the floating piston, the bottom valve and the guide mechanism are coaxially arranged to make the buffer compact in structure and improve durability of the buffer.

Description

Technical Field

[0001] This invention relates to the field of landing gear for small aircraft, and particularly to a twin-tube unmanned aerial vehicle landing gear buffer. Background Technology

[0002] Chinese invention patent publication number CN114110081B discloses a helicopter landing gear damper that integrates a high-pressure oil-gas working chamber inside the piston rod, increasing energy absorption efficiency by increasing the compressible volume of the working chamber. Simultaneously, a burst diaphragm at the end releases the energy accumulated during long-stroke compression to increase maximum load. However, the hollow piston rod has reduced stiffness, and the oil-gas hybrid structure has higher after-sales maintenance costs. Summary of the Invention

[0003] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0004] A twin-tube unmanned aerial vehicle (UAV) landing gear damper includes an inner tube and an outer tube that are radially spaced apart. A side chamber is provided between the outer tube and the inner tube. A piston is provided in the inner tube, which reciprocates along its axial direction and divides the inner tube into an upper chamber and a lower chamber. The inner tube communicates with the side chamber through a bottom valve and a retaining mechanism provided at its end. A pressure accumulator mechanism is also provided on the side of the retaining mechanism and is arranged coaxially with the bottom valve and the retaining mechanism. The pressure accumulator mechanism has a pressure accumulator chamber that expands or contracts with the movement of the piston to accumulate or release damping oil.

[0005] Furthermore, the inner cylinder is also provided with at least one throttling orifice that forms a circuit with the bottom valve, the retaining mechanism and the side chamber.

[0006] Furthermore, the bottom valve and the retaining mechanism are one-way valves for controlling the entry of damping oil into the inner cylinder.

[0007] Furthermore, the pressure accumulator mechanism includes a floating piston that also reciprocates axially, and the expansion or contraction of the pressure accumulator chamber is achieved by the movement of the floating piston.

[0008] Furthermore, the retaining mechanism is provided with a plurality of second side cavity flow channels connecting the side cavity and the accumulator mechanism, and a plurality of upper return oil channels connecting the accumulator mechanism and the upper cavity, wherein the upper return oil channels are unidirectional return oil channels.

[0009] Furthermore, the second side cavity flow channel and the upper return oil channel are equally divided radially in the retaining mechanism.

[0010] Furthermore, the retaining mechanism has radially unequal stepped portions, and the retaining mechanism is fixed to the inner cylinder and the pressure accumulator mechanism respectively through the stepped portions.

[0011] Furthermore, the bottom valve includes a valve body for controlling the flow of damping oil. The valve body is disposed within the bottom valve seat and forms a collecting cavity between the two. At least one first side cavity flow channel communicating with the collecting cavity and the side cavity is provided on the side wall of the bottom valve seat.

[0012] Furthermore, an annular boss is provided on the bottom valve seat, and an annular boss is provided on the outer periphery of the valve body. The inner cylinder is inserted between the bottom valve seat and the valve body and connects with the annular boss to fix the bottom valve.

[0013] Furthermore, the collection cavity is circular.

[0014] Furthermore, the valve body has a lower return oil passage in the center that connects the collecting chamber and the lower chamber, and the lower return oil passage is a one-way return oil passage.

[0015] Furthermore, the one-way return oil passage is achieved through a stop body and a return spring located on the rear side of the stop body. The return spring provides pre-pressure to the stop body so that the stop body can only move and open in one direction.

[0016] Furthermore, the throttling orifices are arranged along the axial direction of the inner cylinder.

[0017] Furthermore, the pressure accumulator mechanism also includes an elastic element connected to the floating piston, which absorbs energy when the pressure accumulator chamber expands.

[0018] Furthermore, the elastic element is a helical spring.

[0019] Furthermore, an oil-filled component is coaxially disposed on the bottom valve seat, connecting the collecting cavity to the outside.

[0020] The beneficial effects of this invention are as follows:

[0021] The present invention provides a dual-cylinder UAV landing gear buffer. On the one hand, the throttle orifice is set on the inner cylinder wall to form a return oil circuit in conjunction with the guide mechanism and the bottom valve. On the other hand, the floating piston, the bottom valve and the guide mechanism are arranged coaxially to make the buffer structure compact, thereby improving the durability of the buffer. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0023] Figure 1 This is a cross-sectional view of the present invention.

[0024] Figure 2 This is a diagram of the inner cylinder. Figure 1 .

[0025] Figure 3 yes Figure 2 The lower sectional view.

[0026] Figure 4 This is a cross-sectional view of the foot valve.

[0027] Figure 5 It is a schematic diagram of the organization. Figure 1 .

[0028] Figure 6 It is a schematic diagram of the organization. Figure 2 .

[0029] Figure 7 This is a simplified diagram of the present invention.

[0030] Figure 8 This is a stretching diagram of the present invention. Detailed Implementation

[0031] In the description of this invention, it should be noted that the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. The above description is for the purpose of simplifying the description of this invention and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0032] Unless otherwise specified, the singular forms “a,” “the,” and “the” used in this specification include the plural forms. The terms “comprising,” “including,” and “containing” used in this specification indicate the presence of the claimed feature, but do not exclude the presence of one or more other features.

[0033] In the specification, when an element is described as being "on," "fixed" to, "connected" to, or "joined" to another element, the element may be directly located on, fixed to, connected to, joined to, or in contact with the other element, or there may be an intermediate element present. In the specification, the description of a feature being arranged "adjacent" to another feature may refer to a feature having a portion that overlaps with the adjacent feature or a portion located above or below the adjacent feature.

[0034] It is understood that although the terms "first," "second," etc., may be used herein to describe different elements, these elements should not be limited by these terms. These terms are merely used to distinguish one element from another. Therefore, a first element may be referred to as a second element without departing from the teachings of this application.

[0035] Exemplary embodiments of this application will now be described with reference to the accompanying drawings. However, it should be understood that this application can be presented in many different ways and is not limited to the embodiments described below. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide further additional embodiments. Throughout the drawings, the same reference numerals denote the same or functionally identical elements.

[0036] refer to Figure 1 The overall structure is as follows: the inner cylinder 50 and the accumulator cylinder 22 are arranged adjacently within the outer cylinder 60. The piston component 11, along with the piston rod 10, is inserted into the inner cylinder 50 from one end, dividing the inner cylinder 50 into a lower chamber 52 and an upper chamber 53. The retaining mechanism 40 is bridged between the accumulator cylinder 22 and the inner cylinder 50. One side of the retaining mechanism 40, in conjunction with the bottom valve 30 located at the other end of the inner cylinder 50, seals both ends of the inner cylinder 50. The other side of the retaining mechanism 40, together with the accumulator cylinder 22, forms an accumulator chamber 23. A throttling orifice 51 is provided on the wall of the inner cylinder 50. When the shock absorber performs compression / tension movements, the piston component 11 moves within the inner cylinder 50 along with the piston rod 10. A pressure difference is created between the upper chamber 53 and the lower chamber 52, causing the shock absorber oil to flow through the throttling orifice 51 between the inner cylinder 50, the outer cylinder 60, and the accumulator cylinder 22, thereby generating a damping force.

[0037] refer to Figure 2 and Figure 3 The inner cylinder structure shown has several throttling orifices 51 arranged circumferentially along the inner cylinder 50. The damping force (i.e., piston damping) experienced by the piston assembly 11 at different stroke positions can be adjusted by changing the orifice diameter of the throttling orifice 51 and the spacing between each adjacent throttling orifice 51.

[0038] In one embodiment (not shown), the spacing of the throttling orifices 51 in the compression direction 1 gradually increases from the first orifice, causing the damping force of the damper to rise sharply during compression. At a certain speed, the force-stroke curve is steep with a large slope; while during extension, the damping force rises gently, and the force-stroke curve is gentle with a relatively smaller slope compared to extension.

[0039] In one embodiment (not shown), the spacing of the throttling orifices 51 in the compression direction 1 gradually decreases starting from the first orifice, resulting in a gradual increase in the damping force of the damper during compression. At a certain speed, the force-stroke curve is gentle with a small slope; while during tension, the damping force increases sharply, and the force-stroke curve is steep with a relatively larger slope compared to tension.

[0040] In one embodiment not shown, the spacing of the throttling orifices 51 in the compression direction 1 gradually decreases from the middle to both sides, or gradually increases from the middle orifice to both sides, or increases on one side and decreases on the other side from the middle orifice, or different orifice diameters combined with different orifice spacings achieve different curve characteristics.

[0041] refer to Figure 4 The bottom valve structure shown has an annular boss 34 on the bottom valve seat 31. The valve body 35 is positioned on the upper part of the annular boss 34 by abutting against the annular boss 34 through an annular lug 37 on its outer periphery. The end of the inner cylinder 60 is inserted into the bottom valve 30 and finally abuts against the upper part of the annular lug 34. A circular chamber 33 is formed between the valve body 35 and the bottom valve seat 31. At least one pair of first side chamber flow channels 32 connected to the side chamber 61 are also provided on the side wall of the bottom valve seat 31, allowing the damper oil in the side chamber 61 to flow freely into the circular chamber 33. A lower return oil channel 36a is provided in the center of the valve body 35 to connect the circular chamber 33 and the lower chamber 52. A valve core 36 is provided in the lower return oil channel 36a to prevent liquid from flowing from the lower chamber 52 to the circular chamber 33 in the reverse direction. The function of the valve core 36 is mainly achieved by a movable stop body 36b that blocks the lower return oil passage 36a. A return spring 36c is provided on the side of the stop body 36b near the lower chamber 52. Therefore, the stop body 36b will only open when the pressure on the circular chamber 33 side is greater than the preload provided by the lower chamber 52 and the return spring 36c. Specifically, the return spring 36c is fixed by a retaining ring 36d that snaps into the lower return oil passage 36a as a base.

[0042] In addition, an oil filling component 38 coaxial with the lower return oil passage 36a is provided on the bottom valve seat 31. The oil filling component 38 has an oil injection channel 38a that connects to the outside and the circular chamber 33. After high-pressure damper oil is injected into the buffer through the oil injection channel 38a, a sealing element 38b is inserted into the oil injection channel 38a and a fastener 38c is screwed in to seal it.

[0043] Reference Figure 5 and Figure 6The exhibited retaining mechanism 40 consists of a second stepped portion 43 and a first stepped portion 42 and a third stepped portion 45 respectively disposed on its two sides. The radial dimensions of the first stepped portion 42, the second stepped portion 43, and the third stepped portion 45 are different, giving it a stepped structure in cross-sectional view. Specifically, the outer periphery of the second stepped portion 43 is tightly fitted to the inner wall of the outer cylinder 60, the lower end face 40b of the first stepped portion 42 is inserted into the inner cylinder 50 to seal its end, and the upper end face 40a of the third stepped portion 34 is inserted into the accumulator 22. The retaining mechanism 40 has several second side cavity flow channels 44 connecting the side chamber 61 and the accumulator 23, and several upper return oil channels 46 connecting the upper chamber 53 and the accumulator 23. Since pressure chambers are provided on both sides of the retaining mechanism 40, the multiple openings formed by the upper return oil channels 46 and the second side cavity flow channels 44 on one side of the retaining mechanism 40 are equally divided radially, thereby ensuring that the retaining mechanism 40 is subjected to balanced force. A check valve core consisting of a stop body 36b, a return spring 36c, and a retaining ring 36d is also provided in the upper return oil passage 46 to prevent damping oil from entering the accumulator chamber 23 from the upper chamber 53. The piston rod 10 passes through the through hole 41 in the center of the retaining mechanism 40 and maintains the stability of its reciprocating motion through the retaining mechanism 40.

[0044] In addition, a floating piston 21 is installed inside the accumulator 22. When the shock absorber is compressed, the piston rod 10 continues to insert into the inner cylinder 60, the volume of the lower chamber 52 decreases, and the shock absorber oil flows into the accumulator 23, pushing the floating piston 21 to move in the opposite direction. An elastic element 24 is provided on the upper part of the floating piston 21. The elastic element 24 provides a restoring force to the floating piston 21, that is, when the shock absorber is stretched, it pushes the floating piston 21 to move in the opposite direction, discharging the shock absorber oil from the accumulator 23.

[0045] refer to Figure 7 and Figure 8The demonstrated operating mechanism is as follows: When the damper is compressed, the piston assembly 11 moves downwards towards the lower chamber 52 along with the piston rod 10. The bottom valve 30 locks, increasing the pressure in the lower chamber 52. Damper oil is discharged from the throttle orifice 51 on the side of the lower chamber 52, enters the accumulator chamber 23 along the side chamber 61, and then enters the upper chamber 53 along the upper return oil passage 46. Because the synchronous increase in volume of the upper chamber 53 is less than the decrease in volume of the lower chamber 52, the damper oil pushes the floating piston 21 upwards, causing the accumulator chamber 23 to increase in volume as compensation. Furthermore, as the total diameter of the throttle orifice 51 on the side of the lower chamber 52 decreases, the piston damping continuously increases. When the shock absorber is stretched, the piston assembly 11 moves towards the upper chamber 53 along with the piston rod 10, locking the upper return oil passage 46. The pressure in the upper chamber 53 increases, and the shock absorber oil is discharged from the throttle orifice 51 on the side of the upper chamber 53. It then flows along the side chamber 61 and the circular chamber 33, pushing the bottom valve 30 open before entering the lower chamber 52. Simultaneously, the floating piston 21 resets under the push of the elastic element 24, reducing the volume of the accumulator chamber. Similarly, as the total diameter of the throttle orifice 51 on the side of the upper chamber 53 decreases, the piston damping continuously increases.

[0046] In one embodiment not shown, the elastic element 24 is preferably a helical spring. Compared to compressed gas, it has the advantages of a longer service life and lower maintenance frequency.

Claims

1. A twin-tube unmanned aerial vehicle (UAV) landing gear buffer, characterized in that, The device includes an inner cylinder and an outer cylinder separated radially. A side chamber is provided between the outer cylinder and the inner cylinder. A piston is provided in the inner cylinder, which reciprocates along its axial direction and divides the inner cylinder into an upper chamber and a lower chamber. The inner cylinder communicates with the side chamber through a bottom valve and a retaining mechanism provided at its end. A pressure accumulator mechanism is also provided on the side of the retaining mechanism and is arranged coaxially with the bottom valve and the retaining mechanism. The pressure accumulator mechanism has a pressure accumulator chamber that expands or contracts with the movement of the piston to accumulate or release damping oil. The inner cylinder is also provided with at least one throttling orifice that forms a circuit with the bottom valve, the retaining mechanism, and the side chamber; The bottom valve and the retaining mechanism are one-way valves that control the entry of damping oil into the inner cylinder.

2. The dual-tube UAV landing gear buffer as described in claim 1, characterized in that, The pressure accumulator mechanism includes a floating piston that also reciprocates axially, and the expansion or contraction of the pressure accumulator chamber is achieved by the movement of the floating piston.

3. A twin-tube UAV landing gear buffer as described in claim 2, characterized in that, The retaining mechanism has several second side cavity flow channels connecting the side cavity and the accumulator mechanism, and several upper return oil channels connecting the accumulator mechanism and the upper cavity. The upper return oil channels are unidirectional return oil channels.

4. A twin-tube UAV landing gear buffer as described in claim 3, characterized in that, The second side cavity flow channel and the upper return oil channel are equally divided radially in the retaining mechanism.

5. A twin-tube UAV landing gear buffer as described in claim 4, characterized in that, The retaining mechanism has radially unequal stepped portions, and the retaining mechanism is fixed to the inner cylinder and the pressure accumulator mechanism respectively through the stepped portions.

6. A twin-tube UAV landing gear buffer as described in claim 2 or 3, characterized in that, The bottom valve includes a valve body for controlling the flow of damping oil. The valve body is disposed in the bottom valve seat and forms a collecting cavity between the two. At least one first side cavity flow channel communicating with the collecting cavity and the side cavity is provided on the side wall of the bottom valve seat.

7. A twin-tube UAV landing gear buffer as described in claim 6, characterized in that, An annular boss is provided on the bottom valve seat, and an annular boss is provided on the outer periphery of the valve body. The inner cylinder is inserted between the bottom valve seat and the valve body and connects with the annular boss to fix the bottom valve.

8. A twin-tube UAV landing gear buffer as described in claim 6, characterized in that, The collection cavity is circular.

9. A twin-tube UAV landing gear buffer as described in claim 6, characterized in that, The valve body has a lower return oil passage in the center that connects the collecting chamber and the lower chamber. The lower return oil passage is a one-way return oil passage.

10. A twin-tube UAV landing gear buffer as described in claim 9, characterized in that, The one-way return oil passage is achieved by a stop body and a return spring located on the rear side of the stop body. The return spring provides pre-pressure to the stop body so that the stop body can only move in one direction to open.

11. A twin-tube UAV landing gear buffer as described in claim 2 or 3, characterized in that, The throttling orifices are arranged along the axial direction of the inner cylinder.

12. A twin-tube UAV landing gear buffer as described in claim 11, characterized in that, The accumulator mechanism also includes an elastic element connected to the floating piston, which absorbs energy when the accumulator chamber expands.

13. A twin-tube UAV landing gear buffer as described in claim 12, characterized in that, The elastic element is a helical spring.

14. A twin-tube UAV landing gear buffer as described in claim 9, characterized in that, The bottom valve seat is also coaxially provided with an oil-filled component that connects the collecting cavity to the outside.

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