An Unmanned Aerial Vehicle Engine Bracket Positioning Tooling and Precise Positioning Process

Abstract

The present invention relates to the field of unmanned aerial vehicle manufacturing, and particularly to a positioning tooling and precise positioning process for an engine bracket of an unmanned aerial vehicle. The bracket positioning tooling includes a tooling main body and a fixture. The fixture is detachably connected to the tooling main body. The fixture is used to position the spatial position of the bracket pipe in the bracket, and the tooling main body is used to position the position of the mounting sleeve in the bracket. The tooling main body includes a column, an upper positioning plate and a lower positioning plate. The two ends of the column are respectively connected to the upper positioning plate and the lower positioning plate. The upper positioning plate includes a column mounting hole and a first bracket positioning hole, and the lower positioning plate includes a column mounting hole and a second bracket positioning hole. The tooling main body is used to limit the overall spatial range of the bracket pipe. The positioning process configures the bracket pipe according to the spatial position structure of a specific digital model. The bracket pipe is welded under the constraint of the tooling fixture, and heat treatment is carried out together to eliminate the welding stress, so as to realize the positioning of the engine bracket.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) manufacturing, and particularly to a positioning tooling and precise positioning process for an engine bracket of a UAV. Background Art

[0002] In the field of UAV manufacturing, the installation bracket of the engine has high requirements for its internal space and positioning accuracy to avoid interference between the engine and its accessories during engine installation. For example Figure 1 , some engine brackets 3 are irregular three-dimensional space structures, composed of several bracket pipe fittings 31 and 8 mounting sleeves 32; the bracket pipe fittings 31 are inclined, and the end intersections converge at the mounting sleeves 32, having a stable structure; one end of the bracket 3 is to install an engine with high positional tolerance requirements, and the other end is to be connected and assembled with a prefabricated hole position on the fuselage.

[0003] Currently, for the bracket 3 with a supporting mechanical structure, most of the bracket pipe fittings 31 are made by manual assembly and welding during manufacturing. The welding ports of each bracket pipe fitting 31 are cut according to the shape of the bracket 3 and then manually butt-welded. The welding process has no restraint, is greatly affected by human factors, and after welding, a free annealing stress relief method is adopted. This method cannot achieve precise positioning of the main intersections of each bracket pipe fitting 31 inside the bracket 3 and the spatial positions of the bracket pipe fittings 31, and the welding stress will cause structural deformation. When heat treatment is performed on the bracket 3, after annealing stress relief, further deformation will occur, and since the bracket 3 has no restraint, it is difficult to find a reference during secondary processing, resulting in a large difference between the manufactured bracket 3 and the actual required structure, affecting its normal use.

[0004] The existing manual butt-welding process can meet the usage requirements for brackets 3 with a simple structure, low requirements for spatial positions, and weak interchangeability, but for brackets 3 with a complex spatial structure, high requirements for internal space, or high positioning accuracy, the existing manufacturing process cannot meet their performance requirements. Summary of the Invention

[0005] The purpose of the present invention is to: aiming at the problem that the bracket in the prior art adopts an unconstrained manual assembly and welding method, resulting in inaccurate positioning and large errors in the spatial position of the bracket, provide a positioning tooling and precise positioning process for an engine bracket of a UAV. Applying the bracket positioning tooling and positioning process to the field of UAV manufacturing enables precise positioning of the main intersections of the bracket and the spatial positions of the bracket pipe fittings, ensuring that the assembly accuracy of the engine bracket meets high-precision requirements.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] The present invention provides a positioning tooling for an unmanned aerial vehicle engine bracket, which includes a tooling main body and a fixture; the fixture is detachably connected to the tooling main body, the tooling main body is provided with a welding space adapted to the bracket, the bracket includes several bracket pipe fittings, the ends of the bracket pipe fittings are provided with mounting sleeves, the fixture is used to clamp and position the position of the bracket pipe fittings in the welding space, and the tooling main body is used to position the position of the mounting sleeves. Among them, the tooling main body includes an upper positioning plate, a lower positioning plate and a column; both ends of the column are respectively connected to the upper positioning plate and the lower positioning plate, the upper positioning plate includes a column mounting hole and a first bracket positioning hole, and the lower positioning plate includes a column mounting hole and a second bracket positioning hole. The column, the upper positioning plate and the lower positioning plate are used to limit the entire space range of the bracket; the first bracket positioning hole in the upper positioning plate and the second bracket positioning hole in the lower positioning plate are used as the positioning reference for the engine bracket mounting sleeve, and the column mounting hole is used as the alignment reference for the upper positioning plate and the lower positioning plate; the column plays a positioning and connecting role.

[0008] Further, the fixture is provided with a first positioning groove and a second positioning groove, the first positioning groove matches the bracket pipe fitting, and the second positioning groove matches the column, so as to position the space position of the bracket.

[0009] Further, the upper positioning plate and the lower positioning plate are oppositely arranged and have the same structure, which can be conveniently interchanged and used to save costs.

[0010] Further, the present invention also includes a pin sleeve, and the pin sleeve is fixed at the corresponding positions of the column mounting hole, the first bracket positioning hole and / or the second bracket positioning hole, which is beneficial to positioning and assembly.

[0011] Further, the column is a two-stage stepped shaft with a "larger middle and smaller ends", and both ends are provided with threads; during assembly, both ends of the column pass through the column mounting holes and are fixedly connected by nuts on the other side.

[0012] The present invention provides a precise positioning process for an unmanned aerial vehicle engine bracket. Based on the above-mentioned bracket positioning tooling, it includes the following steps:

[0013] Step 1, prepare the tooling main body and the fixture respectively according to the bracket structure, and combine them to form a bracket positioning tooling;

[0014] Step 2, fix the mounting sleeves at the first bracket positioning hole on the upper positioning plate and the second bracket positioning hole on the lower positioning plate respectively; the first bracket positioning hole and the second bracket positioning hole are used as the positioning references for both ends of the bracket pipe fitting;

[0015] Step 3, according to the structural position of the first positioning groove on the fixture, fix each bracket pipe fitting in the first positioning groove according to the digital model structure;

[0016] Step 4, weld the converging intersection points of each bracket pipe fitting to complete the construction and fixation of the bracket;

[0017] Step 5: Keep the constraint states of the tooling body, fixture and support pipe fittings, and perform heat treatment on the welded support.

[0018] When building the support, a tooling (including the tooling body and fixture) is used to position the key intersections and spatial orientations of the support pipe fittings, ensuring the precise positioning of the support's spatial position; when welding the support, welding is carried out under the fixation of the tooling, and the welding stress is enclosed within the entire tooling integration through the tooling body and fixture to form a balance; before the welding stress is eliminated, if the support is removed, the welding stress inside the support will be released from the constraint of the tooling and stress redistribution will occur, resulting in deformation, and in a more serious case, the weld may tear. Therefore, when annealing to eliminate stress after welding, the support and the tooling should be annealed together as a whole to further ensure the assembly accuracy of the support.

[0019] Preferably, the welding method is tungsten inert gas welding, the gas flow rate is controlled at 9 - 14 L / min, and a small current of 40 - 70 A is used.

[0020] Furthermore, the present invention further includes an auxiliary machining tooling plate, which includes a first support positioning hole and a second support positioning hole; after heat treatment, the support is taken out of the tooling and fixed on one side to the auxiliary machining tooling plate; the auxiliary machining tooling plate is installed on the machining center workbench; taking the first support positioning hole or the second support positioning hole on the auxiliary machining tooling plate as the coordinate definition origin, secondary machining is performed on the corresponding hole positions on the mounting sleeve on the other side of the support; the support is flipped, and secondary machining is performed on the corresponding hole positions on the remaining mounting sleeves.

[0021] Furthermore, after secondary machining, the qualified support is surface cleaned, and then a primer and a topcoat are sprayed, which is beneficial to improving the performance of the support and extending its service life.

[0022] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0023] 1. The present invention provides a positioning tooling for an unmanned aerial vehicle engine support, designs a tooling body and a fixture with a specific spatial structure, positions the key positions of the support pipe fittings, and then completes the construction and fixation of the support, capable of meeting high-precision requirements.

[0024] 2. The present invention designs the tooling as a split type. Each split component of the tooling can be assembled into a whole through the relevant positioning holes and slots and corresponding connecting parts during processing, and has arbitrary interchangeability. It is convenient for installation and disassembly, can be used multiple times, has a low input cost, and good economic benefits.

[0025] 3. Based on the tooling fixture with a specific structure, the present invention welds the support pipe fittings in a paired manner, which can accurately locate the main intersection points of the support pipe fittings and the spatial positions of each component of the support, and restrains the stress generated during welding. During heat treatment, the tooling main body, the fixture and the support are carried out simultaneously. After annealing and stress relieving, the deformation error can be kept within the constraint range of the tooling as a whole, which is convenient for subsequent secondary processing, ensures the installation accuracy of the support, and will not interfere with its accessories during the installation of the engine.

[0026] 4. The positioning tooling and positioning process design concept of the present invention provides a new idea for the construction of the support spatial structure with complex spatial structure, high internal space requirements and high positioning accuracy, which has practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic structural diagram of the support described in the present invention.

[0028] Figure 2 is an assembly schematic diagram of the positioning tooling for the unmanned aerial vehicle engine support in Embodiment 1.

[0029] Figure 3 is Figure 2 the bottom view of

[0030] Figure 4 is a schematic structural diagram of the tooling main body in Embodiment 1.

[0031] Figure 5 is a schematic structural diagram of the fixture in Embodiment 1.

[0032] Figure 6 is a schematic structural diagram of the auxiliary machining plate in Embodiment 2.

[0033] Figure 7 is a schematic structural diagram of the support during secondary processing.

[0034] ICON: 1 - Tooling main body; 11 - Column; 12 - Upper positioning plate; 13 - Lower positioning plate; 2 - Fixture; 21 - First positioning groove; 22 - Second positioning groove; 3 - Support; 31 - Support pipe fitting; 32 - Installation sleeve; 4 - Pressure cover; 5 - Pressing plate; 6 - Auxiliary machining plate; 7 - Column installation hole; 81 - First support positioning hole; 82 - Second support positioning hole; 9 - Bush. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention will be described in detail below with reference to the drawings.

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] Example 1

[0038] A positioning tooling for a drone engine bracket, as Figure 2-5 , includes a tooling main body 1 and a fixture 2; the fixture 2 is detachably connected to the tooling main body 1, the tooling main body 1 is provided with a welding space adapted to the bracket 3, the bracket 3 includes several bracket pipe fittings 31, the ends of the bracket pipe fittings 31 are provided with mounting sleeves 32, the fixture 2 is used to clamp and position the position of the bracket pipe fittings 31 in the welding space, and the tooling main body 1 is used to position the position of the mounting sleeve 32. Among them, the tooling main body 1 includes an upper positioning plate 12, a lower positioning plate 13 and a column 11; both ends of the column 11 are respectively connected to the upper positioning plate 12 and the lower positioning plate 13, the upper positioning plate 12 includes a column mounting hole 7 and a first bracket positioning hole 81, and the lower positioning plate 13 includes a column mounting hole 7 and a second bracket positioning hole 82. The column 11 and the upper positioning plate 12 and the lower positioning plate 13 are used to limit the entire space range of the bracket 3; the first bracket positioning hole 81 in the upper positioning plate 12 and the second bracket positioning hole 82 in the lower positioning plate 13 are used as the positioning reference for the main intersection mounting sleeve 32 of the bracket 3; the column 11 plays a positioning and connecting role.

[0039] Among them, the fixture 2 is made of 35CrMoA 40x4 square pipe, and a first positioning groove 21 matching the digital model state of the pipe material of the bracket pipe fitting 31 and a second positioning groove 22 matching the pipe material of the column 11 are machined on a machining center, as Figure 5 , when configuring the bracket pipe fitting 31, the corresponding bracket pipe fitting 31 has been ground with a bevel groove, and only need to install the corresponding bracket pipe fitting 31 into the prefabricated first positioning groove 21 to ensure the space position of the bracket 3; among them, there are four first positioning grooves 21, and connecting holes are provided on both sides of the two inner first positioning grooves 21, and the bracket pipe fitting 31 can be fixed by bolt connection with a pressing plate 5, and the two outer first positioning grooves 21 can be fixed by a G-clamp; at the second positioning groove 22, the fixture 2 and the column 11 can be bolt-connected through a gland 4, and the gland 4 is adapted to the column 11. The upper positioning plate 12 and the lower positioning plate 13 are welded by Q345 steel plates and are in a frame form, with good stability and convenient for installation and placement, as Figure 2 , 3 ; the upper positioning plate 12 further includes a second bracket positioning hole 82 with a relative position, the lower positioning plate 13 further includes a first bracket positioning hole 81 with a relative position, the first bracket positioning hole 81 and the second bracket positioning hole 82 on the upper positioning plate 12 respectively correspond to the first bracket positioning hole 81 and the second bracket positioning hole 82 on the lower positioning plate 13, that is, the upper positioning plate 12 and the lower positioning plate 13 have the same structure and are convenient for interchangeable use. The column 11 is a two-stage stepped shaft with a large middle and small ends, and threads are provided at both ends. Both ends of the column 11 pass through the column mounting hole 7 and are fixed by nut connection.

[0040] In addition, as Figure 2 ,4 , in order to avoid the repeated wear of the bracket 3 in the assembly positioning due to direct contact with the column 11, the upper positioning plate 12 or the lower positioning plate 13, pin bushings 9 are respectively arranged at the corresponding positions of the installation surfaces of the column installation holes 7, the first bracket positioning holes 81 and the second bracket positioning holes 82. The pin bushings 9 have the same cross-sectional diameter as the installation sleeve 32 and the column 11, which is easy to position; the pin bushings 9 are made of 35CrMoA with a strength slightly higher than 4130 and basically the same linear expansion coefficient.

[0041] Embodiment 2

[0042] A precise positioning process for a UAV engine bracket, based on the bracket positioning tooling in Embodiment 1, includes the following steps:

[0043] Step 1, according to the digital model structure, prepare the tooling main body 1 and the fixture 2 with a specific spatial structure, and combine and fix them;

[0044] Step 2, respectively fix the installation sleeves 32 for gathering the main intersection points of the bracket 3 at the first bracket positioning holes 81 on the upper positioning plate 12 and the second bracket positioning holes 82 on the lower positioning plate 13; there are also corresponding connection hole positions on the installation sleeves 32 and a secondary processing allowance for the applicable assembly holes is reserved; the installation sleeves 32 can be processed from hollow cylinders. The installation sleeves 32 serve as the reference for the end positioning of the bracket pipe fittings 31; among them, "upper" and "lower" only refer to the vertical placement state of the whole tooling. The installation sleeves 32 are detachably connected to both the upper positioning plate 12 and the lower positioning plate 13 and are respectively fixed on the upper positioning plate 12 and the lower positioning plate 13 through bolts.

[0045] Step 3, according to the digital model structure, fix each bracket pipe fitting 31 in the first positioning groove 21 by the structural position of the first positioning groove 21 on the fixture 2.

[0046] Step 4, weld the ends of each bracket pipe fitting 31 to complete the construction and fixation of the bracket 3; during welding, tungsten inert gas welding can be used, the gas flow rate is controlled at 9 - 14 L / min, and a small current of 40 - 70 A is used; under the clamping of the tooling main body 1 and the fixture 2, the bracket pipe fittings 31 are spot welded and assembled from top to bottom, and then full welding is carried out from inside to outside. After welding, all welds are inspected.

[0047] Step 5: Keep the restraint states of the tooling body 1, the fixture 2 and the support pipe fitting 31, and perform heat treatment on the welded support 3. During heat treatment, the method of full annealing in the furnace is adopted; load the furnace at room temperature, and after loading, heat up to 540°C at a heating rate of 160°C / h, hold at 540°C for 1.5 hours, then cool down to 380°C at a cooling rate of 180°C / h, and then take out of the furnace and air-cool; among them, the temperature difference in the furnace does not exceed ±20°C during the heating stage and does not exceed ±10°C during the holding stage. After the heat treatment is completed, remove the tooling, and measure and record the values of each part of the support 3 on the marking platform with measuring tools.

[0048] Further, after the heat treatment process is completed, in order to enable the processed support 3 to be directly installed on the UAV engine, secondary processing needs to be carried out according to the actual situation. The secondary processing tooling includes an auxiliary machining plate 6, as Figure 6 , and a support positioning hole one 81 and a support positioning hole two 82 are provided at the corresponding positions of the auxiliary machining plate 6. After the heat treatment is completed, take out the support 3 from the tooling, as Figure 7 , fix one side on the auxiliary machining plate 6; install the auxiliary machining plate 6 on the machining center workbench; define the origin of coordinates with the support positioning hole one 81 or the support positioning hole two 82 on the auxiliary machining plate 6, and perform secondary processing on the corresponding hole positions on the other side of the mounting sleeve 32 of the support 3; flip the support 3 and perform secondary processing on the corresponding hole positions on the remaining mounting sleeve 32.

[0049] Surface spraying is carried out after the completion and qualification of the previous processes. Before spraying, use a wire brush and a thousand-leaf disc to remove sundries such as rust on the surface of the support 3, and then use a cleaning agent to remove the oil stain on the surface of the support 3 and the coloring and developer left by flaw detection. After the surface cleaning is completed, spray a phosphating primer with extremely strong adhesion. After the primer solidifies and dries completely, spray the first topcoat, and after the first topcoat dries completely, spray the second topcoat.

[0050] The support pipe fittings 31 are assembled and welded under the fixed restraint of the tooling body 1 and the fixture 2. The welding stress is enclosed in the entire tooling integration through the tooling body 1 and the fixture 2 to form a balance, which can accurately position the main intersection point of the support pipe fittings 31 and the spatial position of the support 3, and restrain the stress generated during welding; during heat treatment, the support 3 can be kept within the restraint range of the tooling after annealing and stress relief, restraining the deformation error during the heat treatment stress relief process, facilitating subsequent secondary processing, ensuring the installation accuracy and structural accuracy of the support 3, and the installation accuracy can reach 0.1 mm, ensuring that there will be no interference with its accessories during engine installation.

[0051] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An unmanned aerial vehicle engine bracket positioning tooling, characterized in that It includes a tooling main body (1) and a fixture (2); the fixture (2) is detachably connected to the tooling main body (1), the tooling main body (1) is provided with a welding space adapted to a bracket (3), the bracket (3) includes a plurality of bracket pipe fittings (31), an installation sleeve (32) is arranged at the end of the bracket pipe fitting (31), the fixture (2) is used for clamping and positioning the position of the bracket pipe fitting (31) in the welding space, and the tooling main body (1) is used for positioning the position of the installation sleeve (32); The tooling main body (1) includes an upper positioning plate (12), a lower positioning plate (13) and a column (11), the two ends of the column (11) are respectively connected to the upper positioning plate (12) and the lower positioning plate (13), the upper positioning plate (12) is provided with a first bracket positioning hole (81), and the first bracket positioning hole (81) is used for bolt-fixing the installation sleeve (32); the lower positioning plate (13) is provided with a second bracket positioning hole (82), and the second bracket positioning hole (82) is used for bolt-fixing the installation sleeve (32); The fixture (2) is provided with a first positioning groove (21) and a second positioning groove (22), the first positioning groove (21) matches the bracket pipe fitting (31), the bracket pipe fitting (31) is used for being fixedly installed at the first positioning groove (21), the bracket pipe fitting (31) is bolt-connected to the connection holes on both sides of the first positioning groove (21) through a pressing plate, or is fixed to the first positioning groove (21) through a G-clamp; the second positioning groove (22) matches the column (11), and the fixture (2) is used for fixedly clamping the column (11) by bolt-connecting a gland (4); By maintaining the restraint states of the tooling main body (1), the fixture (2) and the bracket pipe fitting (31), it is used for heat-treating the welded bracket (3).

2. The positioning tooling for the drone engine bracket according to claim 1, characterized in that, Both the upper positioning plate (12) and the lower positioning plate (13) are provided with column installation holes (7).

3. The positioning tooling for an unmanned aerial vehicle engine bracket according to claim 2, characterized in that, The upper positioning plate (12) and the lower positioning plate (13) are arranged oppositely and have the same structure.

4. The positioning tooling for a drone engine bracket according to claim 3, characterized in that It further includes a pin sleeve (9), and the pin sleeve (9) is fixed at the corresponding positions of the column installation hole (7), the first bracket positioning hole (81) and / or the second bracket positioning hole (82).

5. The positioning tooling for an unmanned aerial vehicle engine bracket according to claim 4, wherein, The column (11) is a two-stage stepped shaft with a large middle and small ends, and threads are provided at both ends.

6. A precise positioning process for an unmanned aerial vehicle engine bracket, characterized in that, Based on the bracket positioning tooling according to any one of claims 2-5, it includes the following steps: Step 1, respectively prepare the tooling main body (1) and the fixture (2) according to the structure of the bracket (3), and combine them to form the bracket positioning tooling; Step 2, respectively fix the installation sleeve (32) at the first bracket positioning hole (81) on the upper positioning plate (12) and the second bracket positioning hole (82) on the lower positioning plate (13); Step 3, fix each bracket pipe fitting (31) in the first positioning groove (21) according to the structural position of the first positioning groove (21) on the fixture (2); Step 4, weld the converging intersections of the bracket pipe fittings (31) to complete the construction and fixation of the bracket (3); Step 5, while maintaining the restraint states of the tooling body (1), the fixture (2) and the support pipe fitting (31), perform heat treatment on the welded support (3).

7. The precise positioning process of a drone engine bracket according to claim 6, characterized in that, The welding in Step 4 is tungsten inert gas welding, with a gas flow rate of 9 - 14 L / min and a current of 40 - 70 A.

8. The precise positioning process of a drone engine bracket according to claim 6, characterized in that, It further includes an auxiliary machining mounting plate (6), and the auxiliary machining mounting plate (6) includes the first support positioning hole (81) and the second support positioning hole (82); after Step 5, take out the support (3) from the tooling, fix one side on the auxiliary machining mounting plate (6); the auxiliary machining mounting plate (6) is installed on the working table of the machining center; define the origin of coordinates with the first support positioning hole (81) or the second support positioning hole (82) on the auxiliary machining mounting plate (6), and perform secondary machining on the corresponding hole positions on the other side of the mounting sleeve (32) of the support (3); flip the support (3) and perform secondary machining on the corresponding hole positions on the remaining mounting sleeves (32).

9. The precise positioning process of a drone engine bracket according to claim 8, characterized in that, After the secondary machining, clean the surface of the qualified support (3), and then spray primer and topcoat.

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