Split type hub sealing structure for aviation aircraft wheel and design method of split type hub sealing structure

Abstract

According to the split type hub sealing structure for the aviation aircraft wheel and the design method of the split type hub sealing structure, the space of a closed containing cavity formed by the split type hub sealing structure is smaller than that of a rectangular structure, and an arc sealing face with the same radius as the section of a sealing ring is designed at the bottom of the cavity; the contact area of the sealing ring and the sealing surface of the sealing cavity is increased, and the sealing ring is not easy to fall off. According to the technical scheme, when the two half hubs are connected through bolts, the sealing structure can be used for sealing high-pressure gas in an aviation aircraft wheel tire, it is verified through tests that the sealing gas pressure can be increased to 13 MPa from original 8 MPa, and the sealing structure has guiding significance on aviation aircraft wheel hub sealing design.

Description

Technical Field

[0001] The invention relates to the technical field of aviation landing gears, in particular to a design method for a split hub sealing structure of an aircraft wheel. Background Art

[0002] Aircraft wheels are components of the aircraft landing gear system. The sealing of the wheel hub directly affects the airtightness of the wheel and plays an important role in the safety of aircraft takeoff and landing.

[0003] At present, in the automotive field at home and abroad, the wheel structure of the car is mainly composed of rims, spokes, bolts and hubs. The tire is directly installed on the rim, and the outer edge of the tire and the inner edge of the rim rely on the air pressure inside the tire to make the rims on both sides fit tightly, thereby achieving the seal between the tire and the wheel. There is no sealing structure that cooperates with the hub in the rim part, and the design method of the hub sealing structure in this part is not involved.

[0004] Most of the existing hub seal structures of aircraft wheels are rectangular groove type. In the engineering field, the seal ring is usually preliminarily selected based on the hub diameter size and design experience, and then the elongation and compression rate of the seal ring are checked, and finally the rectangular seal groove is designed based on engineering experience. This rectangular seal structure is usually suitable for wheels with low load-bearing capacity. For split aircraft wheels with high load-bearing capacity requirements, the rectangular seal structure cannot meet the requirements of high-pressure sealing. The hub seal design method based on engineering experience has no guiding significance for the design of hub seals for open aircraft wheel products. Summary of the invention

[0005] In order to overcome the problem in the prior art that the rectangular hub sealing structure cannot meet the high-pressure sealing performance of a split aircraft wheel with high load-bearing capacity, the present invention proposes a split hub sealing structure and a design method for an aircraft wheel hub.

[0006] The split hub sealing structure for aircraft wheels proposed in the present invention comprises an inner half hub, an outer half hub and a sealing ring; the sealing ring is located on the butt joint surface of the outer half hub and the inner half hub, and forms a closed cavity between the inner half hub, the outer half hub and the sealing ring and the tire, and the tire foot is tightly fitted with the wheel rims on both sides of the wheel by means of the air pressure inside the tire, thereby achieving sealing between the tire and the wheel.

[0007] Grooves for placing sealing rings are respectively arranged on the sealing surfaces of the inner half hubs; the radius of the grooves is the same as the cross-sectional radius of the sealing rings.

[0008] There is a fitting gap between the adjacent surfaces of the inner half hub 1 and the outer half hub 2, wherein the gap between the axial fitting surfaces of the inner half hub and the outer half hub is a radial gap δ1; the gap between the radial fitting surfaces of the inner half hub and the outer half hub is an axial gap δ2.

[0009] The design process of the split hub seal structure for aircraft wheels proposed by the present invention is as follows:

[0010] Step 1: Determine the structural parameters of the inner and outer half hubs:

[0011] The inner half hub diameter D N =282mm, inner half hub axial outer profile length L N =83mm;

[0012] The axial outer profile length L of the outer half hub W =92mm; outer half hub diameter D W =297mm.

[0013] Step 2: Preselect the seal:

[0014] Preselect the front wheel seal according to the seal cross-sectional diameter d and the seal nominal inner diameter D.

[0015] Determine the pre-selected front wheel seal according to the estimated calculation formulas (1) and (2) and refer to HB 7515 "O-ring dimensional tolerances".

[0016] D=D N -(9mm~10mm) (1)

[0017] d=(L W -L N ) / twenty two)

[0018] Where: D N is the diameter of the inner half of the hub; L W L is the axial outer profile length of the outer half hub; N It is the axial outer profile length of the inner half hub.

[0019] Determine the nominal inner diameter of the sealing ring Sealing ring cross section diameter

[0020] Step 3: Determine the seal groove depth A:

[0021] Preselected seal cross-section diameter The depth of the sealing groove is determined according to the estimated calculation formula (3) of the sealing groove depth.

[0022]

[0023] Where: D N is the inner half hub diameter.

[0024] The sealing groove depth A=0.6 mm was obtained.

[0025] Step 4: Check the stretching rate α:

[0026] Check the elongation rate α of the selected sealing ring, and the elongation rate must meet 1.02≤α≤1.04.

[0027] The stretch rate is checked by formula (4):

[0028]

[0029] Where: D1 is the distance from the lowest point of the sealing groove bottom to the center line of the front wheel; D is the nominal inner diameter of the sealing ring; d is the cross-sectional diameter of the sealing ring.

[0030] The D1 is obtained by formula (5).

[0031] D1=D N -A; (5)

[0032] Where: D N is the inner half hub diameter.

[0033] If the calculated elongation rate α≤1.01, increase the cross-sectional diameter d of the sealing ring or the nominal inner diameter D of the sealing ring so that the elongation rate meets the use requirements of 1.02 to 1.04. When increasing the cross-sectional inner diameter d of the sealing ring, the increased step length is 0.1mm; when increasing the nominal inner diameter D of the sealing ring, the increased step length is 1.0mm. Repeat steps 2 and 3 to obtain a new pre-selected front wheel sealing ring and a re-determined sealing groove depth; repeat step 4 to check the elongation rate and obtain a new elongation rate. If the new elongation rate still does not meet the use requirements of 1.02 to 1.04, repeat steps 1 to 4 again until the elongation rate meets the use requirements.

[0034] If the calculated elongation α≥1.05, repeat step 1 to reduce the inner diameter d of the sealing ring section or the nominal inner diameter D of the sealing ring, and repeat steps 2 and 3 to obtain a new pre-selected front wheel sealing ring and a re-determined sealing groove depth; repeat step 4 to check the elongation to obtain a new elongation. If the new elongation α≥1.05, repeat steps 1 to 4 again until the elongation meets the use requirements of 1.02 to 1.04.

[0035] The step size of reducing the cross-sectional diameter d of the sealing ring is 0.1 mm; the step size of reducing the nominal inner diameter D of the sealing ring is 1.0 mm.

[0036] Step 5: Determine the sealing groove structure angle X:

[0037] The sealing groove structure angle X is the angle between the outer half hub bevel and the inner half hub bevel in the closed cavity. X = 29.5° to 60.5°, and in this example X = 45°.

[0038] Step 6: Estimate the compression amount C:

[0039] The compression amount C is the amount of depression of the seal ring relative to the half hub. The compression amount C is determined by formulas (6) and (7).

[0040]

[0041] C=dh (7)

[0042] Where: h is the depth of the sealing groove; d is the cross-sectional diameter of the sealing ring.

[0043] Step 7: Compression ratio y b Verification:

[0044] The compression rate of the selected sealing ring is checked using formulas (8) and (9).

[0045]

[0046] Where: h is the depth of the sealing groove; b is the major axis of the cross section of the sealing ring that is deformed into an ellipse after being compressed; α is the elongation rate of the sealing ring; d is the cross-sectional diameter of the sealing ring.

[0047] If the calculated compression ratio y b ≤17%, reduce the compression amount C so that the compression rate meets the use requirement of 18% to 22%. When reducing the compression amount C, the reduction step is 0.1mm; repeat step 6 to obtain a new compression amount of the sealing ring; repeat step 7 to check the compression rate and obtain a new compression rate. If the new compression rate still does not meet the use requirement of 18% to 22%, repeat steps 6 to 7 again until the compression rate meets the use requirement.

[0048] If the calculated stretching rate y b ≥21%, repeat step 6 to increase the compression amount C, repeat step 7 to check the compression ratio, and obtain a new compression ratio. b ≥12%, repeat steps 6 and 7 again until the compression rate meets the usage requirement of 18% to 22%.

[0049] The step size of increasing the compression amount C is 0.1 mm.

[0050] At this point, the design of the split wheel hub sealing structure is completed.

[0051] The present invention proposes a split hub seal structure for aircraft wheels and a design method thereof. Compared with the prior art, the split hub seal structure and design method proposed by the present invention have the following beneficial effects:

[0052] 1. The closed cavity formed by the split wheel hub sealing structure proposed in the present invention has a smaller space than that of the rectangular structure, and the cavity bottom is designed with an arc sealing surface with the same radius as the cross-section of the sealing ring. After the sealing ring is installed in the sealing cavity, the contact area between the sealing ring and the sealing surface of the sealing cavity is increased, and the sealing ring is not easy to fall out.

[0053] 2. The split wheel hub sealing structure proposed in the present invention can seal the high-pressure gas in the aircraft wheel tire when the two halves of the wheel hub are connected by bolts. Tests have verified that the sealing air pressure can be increased from the original 8MPa to 13MPa.

[0054] 3. The design method of a split wheel hub seal structure proposed in the present invention has guiding significance for the design of aircraft wheel hub seals. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic diagram of the sealing structure of the split type wheel;

[0056] Figure 2 This is a diagram of the design elements of the split hub seal structure;

[0057] Figure 3 is a schematic diagram of known radial and axial dimensions of a hub of a front wheel of this embodiment;

[0058] Figure 4 It is a schematic diagram of the technical solution of the present invention.

[0059] Figure 5 It is a flow chart of the present invention.

[0060] In the figure: 1 inner half hub; 2 outer half hub; 3 sealing ring. DETAILED DESCRIPTION

[0061] This embodiment is a split hub seal structure of a certain type of aircraft wheel and a design method thereof.

[0062] like Figure 1 As shown, the split aircraft wheel structure is mainly composed of an inner half hub, an outer half hub, a sealing ring and bolts. The tire is installed on the two half hubs, and the outer half hub, the inner half hub, the tire and the sealing ring are connected by bolts to form a closed cavity. With the help of the air pressure inside the tire, the tire foot is tightly fitted with the rims on both sides of the wheel, thereby achieving the sealing between the tire and the wheel.

[0063] The present invention is to place a sealing ring at the butt joint of two half-hubs, and form a triangular closed cavity between the surfaces of the butt joint, and use the surface of the closed cavity as a sealing surface. The two half-hubs are an inner half-hub 1 and an outer half-hub 2. A groove for placing the sealing ring is provided on the sealing surface of the inner half-hub; the radius of the groove is the same as the cross-sectional radius of the sealing ring.

[0064] There is a fitting gap between the adjacent surfaces of the inner half hub 1 and the outer half hub 2, wherein the gap between the axial fitting surfaces of the inner half hub and the outer half hub is a radial gap δ1; the gap between the radial fitting surfaces of the inner half hub and the outer half hub is an axial gap δ2.

[0065] In this embodiment, δ1=0.50 mm, δ2=0.65 mm.

[0066] The split hub seal structure and design method determined by the present invention belong to the hub seal design module in the aircraft wheel structure design. The hub seal structure and design method are carried out under the premise that the basic radial dimensions and basic axial dimensions of the two existing half hubs are known conditions.

[0067] This embodiment takes a split hub seal structure and design method of a certain type of front wheel as an example. The radial dimensions and axial dimensions of the two half hubs of the front wheel are as follows: Figure 3 The design flow chart of this design method is shown in Figure 4 As shown, the specific steps include:

[0068] Step 1: Determine the structural parameters of the two half hubs:

[0069] The inner half hub diameter D N =282mm, inner half hub axial outer profile length L N =83mm; axial outer profile length of outer half hub L W =92mm; outer half hub diameter D W =297mm.

[0070] Step 2: Preselect the seal:

[0071] Preselect the front wheel seal according to the seal cross-sectional diameter d and the seal nominal inner diameter D.

[0072] Determine the pre-selected front wheel seal according to the estimated calculation formulas (1) and (2) and refer to HB 7515 "O-ring dimensional tolerances".

[0073] D=D N -(9mm~10mm) (1)

[0074] d=(L W -L N) / twenty two)

[0075] Where: D N is the diameter of the inner half of the hub; L W L is the axial outer profile length of the outer half hub; N It is the axial outer profile length of the inner half hub.

[0076] Determine the nominal inner diameter of the sealing ring Sealing ring cross section diameter

[0077] Step 3: Determine the seal groove depth A:

[0078] Preselected seal cross-section diameter The depth of the sealing groove is determined according to the estimated calculation formula (3) of the sealing groove depth.

[0079]

[0080] Where: D N is the inner half hub diameter.

[0081] The sealing groove depth A=0.6 mm was obtained.

[0082] Step 4: Check the stretching rate α:

[0083] Check the elongation rate α of the selected sealing ring, and the elongation rate must satisfy 1.02≤α≤1.04.

[0084] The stretch rate is checked by formula (4):

[0085]

[0086] Where: D1 is the distance from the lowest point of the sealing groove bottom to the center line of the front wheel; D is the nominal inner diameter of the sealing ring; d is the cross-sectional diameter of the sealing ring.

[0087] The D1 is obtained by formula (5).

[0088] D1=D N -A; (5)

[0089] Where: D N is the inner half hub diameter.

[0090] In this embodiment, the stretching ratio α=1.036, which meets the use requirement of 1.02-1.04.

[0091] If the calculated elongation rate α≤1.01, increase the cross-sectional diameter d of the sealing ring or the nominal inner diameter D of the sealing ring so that the elongation rate meets the use requirements of 1.02 to 1.04. When increasing the cross-sectional inner diameter d of the sealing ring, the increased step length is 0.1mm; when increasing the nominal inner diameter D of the sealing ring, the increased step length is 1.0mm. Repeat steps 2 and 3 to obtain a new pre-selected front wheel sealing ring and a re-determined sealing groove depth; repeat step 4 to check the elongation rate and obtain a new elongation rate. If the new elongation rate still does not meet the use requirements of 1.02 to 1.04, repeat steps 1 to 4 again until the elongation rate meets the use requirements.

[0092] If the calculated elongation α≥1.05, repeat step 1 to reduce the inner diameter d of the sealing ring section or the nominal inner diameter D of the sealing ring, and repeat steps 2 and 3 to obtain a new pre-selected front wheel sealing ring and a re-determined sealing groove depth; repeat step 4 to check the elongation to obtain a new elongation. If the new elongation α≥1.05, repeat steps 1 to 4 again until the elongation meets the use requirements of 1.02 to 1.04.

[0093] The step size of reducing the cross-sectional diameter d of the sealing ring is 0.1 mm; the step size of reducing the nominal inner diameter D of the sealing ring is 1.0 mm.

[0094] Step 5: Determine the sealing groove structure angle X:

[0095] The sealing groove structure angle X is the angle between the outer half hub bevel and the inner half hub bevel in the closed cavity. X = 29.5° to 60.5°, and in this example X = 45°.

[0096] Step 6: Estimate the compression amount C:

[0097] The compression amount C is the amount of depression of the seal ring relative to the half hub. The compression amount C is determined by estimating formulas (6) and (7).

[0098]

[0099] C=dh (7)

[0100] Where: h is the depth of the sealing groove; d is the cross-sectional diameter of the sealing ring.

[0101] In this embodiment, the estimated compression amount C=1.20 mm.

[0102] Step 7: Compression ratio y b Verification:

[0103] The compression rate of the selected sealing ring is checked using formulas (8) and (9).

[0104]

[0105] Where: h is the depth of the sealing groove; b is the major axis of the cross section of the sealing ring that is deformed into an ellipse after being compressed; α is the elongation rate of the sealing ring; d is the cross-sectional diameter of the sealing ring.

[0106] In this embodiment, the compression rate y b =20.76%, meeting the usage requirements of 18% to 22%.

[0107] If the calculated compression ratio y b ≤17%, reduce the compression amount C so that the compression rate meets the use requirement of 18% to 22%. When reducing the compression amount C, the reduction step is 0.1mm; repeat step 6 to obtain a new compression amount of the sealing ring; repeat step 7 to check the compression rate and obtain a new compression rate. If the new compression rate still does not meet the use requirement of 18% to 22%, repeat steps 6 to 7 again until the compression rate meets the use requirement.

[0108] If the calculated stretching rate y b ≥21%, repeat step 6 to increase the compression amount C, repeat step 7 to check the compression ratio, and obtain a new compression ratio. b ≥12%, repeat steps 6 and 7 again until the compression rate meets the usage requirement of 18% to 22%.

[0109] The step size of increasing the compression amount C is 0.1 mm.

[0110] At this point, the design of the split wheel hub sealing structure is completed.

Claims

1. A split hub seal structure for an aircraft wheel, characterized in that: It includes an inner half hub, an outer half hub and a sealing ring; the sealing ring is located on the butt joint surface of the outer half hub and the inner half hub, and forms a closed cavity between the inner half hub, the outer half hub and the sealing ring and the tire, and the tire foot is tightly fitted with the wheel rims on both sides of the wheel by means of the air pressure inside the tire, thereby achieving sealing between the tire and the wheel.

2. The split hub seal structure for an aircraft wheel according to claim 1, characterized in that: Grooves for placing sealing rings are respectively arranged on the sealing surfaces of the inner half hubs; the radius of the grooves is the same as the cross-sectional radius of the sealing rings.

3. The split hub seal structure for an aircraft wheel according to claim 1, characterized in that: There is a fitting gap between the adjacent surfaces of the inner half hub 1 and the outer half hub 2, wherein the gap between the axial fitting surfaces of the inner half hub and the outer half hub is a radial gap δ1; the gap between the radial fitting surfaces of the inner half hub and the outer half hub is an axial gap δ2.

4. A design method for a split hub seal structure for an aircraft wheel according to claim 1, characterized in that: The specific process is: Step 1: Determine the structural parameters of the inner and outer half hubs: The inner half hub diameter D N =282mm, inner half hub axial outer profile length L N =83mm; The axial outer profile length L of the outer half hub W =92mm; outer half hub diameter D W =297mm; Step 2: Preselect the seal: Pre-select the front wheel seal ring according to the seal ring cross-sectional diameter d and the seal ring nominal inner diameter D; Determine the pre-selected front wheel seal ring according to the estimated calculation formulas (1) and (2) and refer to HB 7515 "O-type rubber seal ring size tolerance"; D=D N -(9mm~10mm) (1) d=(L W -L N ) / 2 (2) Where: D N is the diameter of the inner half of the hub; L W L is the axial outer profile length of the outer half hub; N is the axial outer profile length of the inner half hub; Determine the nominal inner diameter of the sealing ring Diameter of sealing ring Step 3: Determine the seal groove depth A: Preselected seal cross-section diameter Determine the depth of the sealing groove according to the estimated calculation formula (3) of the sealing groove depth; Where: D N is the inner half hub diameter; The sealing groove depth A is obtained as 0.6 mm; Step 4: Check the stretching rate α: Check the elongation rate α of the selected sealing ring, and the elongation rate must meet 1.02≤α≤1.04; The stretch rate is checked by formula (4): Where: D1 is the distance from the lowest point of the sealing groove bottom to the centerline of the front wheel; D is the nominal inner diameter of the sealing ring; d is the cross-sectional diameter of the sealing ring; The D1 is obtained by formula (5); D1=D N -A; (5) Where: D N is the inner half hub diameter; Step 5: Determine the sealing groove structure angle X: The sealing groove structure angle X is the angle between the outer half hub bevel and the inner half hub bevel in the closed cavity; X = 29.5° to 60.5°, and in this example X = 45°; Step 6: Estimate the compression amount C: The compression amount C is the amount of depression of the sealing ring relative to the half hub; the compression amount C is estimated by formulas (6) and (7); C=dh (7) Where: h is the depth of the sealing groove; d is the cross-sectional diameter of the sealing ring; Step 7: Compression ratio y b Verification: The compression rate of the selected sealing ring is checked by formulas (8) and (9); Where: h is the depth of the sealing groove; b is the major axis of the cross section of the sealing ring after being compressed and deformed into an elliptical shape; α is the elongation rate of the sealing ring; d is the cross-sectional diameter of the sealing ring; If the calculated compression ratio y b ≤17%, reduce the compression amount C so that the compression rate meets the use requirement of 18% to 22%; when reducing the compression amount C, the reduction step is 0.1mm; repeat step 6 to obtain a new compression amount of the sealing ring; repeat step 7 to check the compression rate and obtain a new compression rate; if the new compression rate still does not meet the use requirement of 18% to 22%, repeat steps 6 to 7 again until the compression rate meets the use requirement; If the calculated stretching rate y b ≥21%, repeat step 6 to increase the compression amount C, repeat step 7 to check the compression ratio, and obtain a new compression ratio; if the new compression ratio y b ≥12%, repeat steps 6 and 7 again until the compression rate meets the usage requirement of 18% to 22%; The step size of increasing the compression amount C is 0.1 mm; At this point, the design of the split wheel hub sealing structure is completed.

5. The design method of the split hub seal structure for aircraft wheels according to claim 4, characterized in that: If the calculated stretching rate α≤1.01, increase the cross-sectional diameter d of the sealing ring or the nominal inner diameter D of the sealing ring so that the stretching rate meets the use requirement of 1.02-1.04; when increasing the cross-sectional inner diameter d of the sealing ring, the increased step length is 0.1 mm; when increasing the nominal inner diameter D of the sealing ring, the increased step length is 1.0 mm; repeat steps 2 and 3 to obtain a new pre-selected front wheel sealing ring and a re-determined sealing groove depth; repeat step 4 to check the stretching rate and obtain a new stretching rate; if the obtained new stretching rate still does not meet the use requirement of 1.02-1.04, repeat steps 1 to 4 again until the stretching rate meets the use requirement; If the calculated stretching rate α is ≥ 1.05, repeat step 1 to reduce the sealing ring cross-sectional inner diameter d or the sealing ring nominal inner diameter D, and repeat steps 2 and 3 to obtain a new pre-selected front wheel sealing ring and a re-determined sealing groove depth; Repeat step 4 to check the stretch rate and obtain a new stretch rate; if the new stretch rate α obtained is ≥1.05, repeat steps 1 to 4 again until the stretch rate meets the use requirement of 1.02 to 1.

04.

6. The design method of the split hub seal structure for an aircraft wheel as claimed in claim 4, characterized in that: The step size of reducing the cross-sectional diameter d of the sealing ring is 0.1 mm; the step size of reducing the nominal inner diameter D of the sealing ring is 1.0 mm.

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