An irregular air duct internal holding tool and an irregular air duct holding method

Abstract

This invention discloses an internal fixing fixture and a method for fixing irregularly shaped air ducts. An air duct fixing base is set inside the irregularly shaped air duct. The positioning reference surface on the air duct fixing base supports and axially positions the irregularly shaped air duct. Simultaneously, several hydraulically jacking conformal components set on the air duct fixing base provide conformal support and fixing to the inner surface of the irregularly shaped air duct, replacing the external clamping method. This reduces the stress on the air duct, prevents deformation, and ensures the fixing accuracy of the air duct, effectively guaranteeing the wall thickness after fixing. The rotation of the air duct fixing base drives the rotation of the irregularly shaped air duct, facilitating the adjustment of the orientation of the processed surface of the air duct. This avoids the multiple clamping and hoisting operations required in traditional fixing methods, thus avoiding positioning errors caused by multiple positioning clamping and effectively controlling the fixing and positioning accuracy of the irregularly shaped air duct.

Description

Technical Field

[0001] This invention belongs to the technical field of irregular-shaped air duct processing, specifically relating to an internal fixing fixture for irregular-shaped air ducts and a fixing method for irregular-shaped air ducts. Background Technology

[0002] The aerodynamic requirements for duct components are extremely high, as are their strength requirements. This means the duct must strictly meet design requirements, with stringent demands on internal wall shape, surface quality, and wall thickness. Duct components not only have uneven thickness and significant deformation after demolding, but also exhibit low rigidity, resulting in substantial shape and positional deformation due to their own weight. Ensuring that the machined product simultaneously meets the internal wall shape and thickness requirements under these conditions presents a formidable challenge. Currently, the machining of these components employs an external duct clamping method. This involves prefabricating conformal fixtures based on the theoretical bottom shape of the duct. During clamping, pins are used for positioning, first fitting the bottom surface of the component to the conformal fixture, and then using clamping plates with adjustable supports to secure the sidewalls and top of the duct. For flipping, the same conformal fixture is used on the other side, and the clamping process is repeated. However, because the conformal fixtures are modeled based on the theoretical shape of the component, and the actual duct structure inevitably exhibits uneven wall thickness due to manufacturing characteristics, this clamping method has the following shortcomings:

[0003] 1. The shape of the part is not the theoretical shape. During clamping, different clamping stresses will be generated at the parts where the part and the tooling are in contact, which will aggravate the deformation of the part.

[0004] 2. Using a surface with low precision as the clamping and positioning surface of the part is not conducive to ensuring the machining accuracy of the part. After the part is flipped and machined, there will be a large tool-jointing step.

[0005] 3. The parts themselves are not rigid enough. When adjustable supports are used to hold them in place on the sides and top, the parts will undergo uncertain deformation depending on the magnitude and location of the force, which is not conducive to ensuring the thickness of the air duct wall.

[0006] 4. The flipping and secondary clamping operations are difficult and may cause uncertain stress deformation during the hoisting of the air duct.

[0007] In view of the above-mentioned defects of traditional external duct fixing structures, this invention discloses an internal fixing fixture for irregularly shaped ducts and a fixing method for irregularly shaped ducts. Summary of the Invention

[0008] The purpose of this invention is to provide a fixture for holding irregularly shaped air ducts and a method for holding irregularly shaped air ducts. This method supports and holds the interior of the irregularly shaped air ducts, reduces the holding stress on the air ducts, avoids air duct deformation, reduces the number of clamping and hoisting operations, thereby shortening the air duct manufacturing cycle and avoiding positioning errors caused by multiple clamping and hoisting operations, thus ensuring the holding accuracy of the air ducts.

[0009] This invention is achieved through the following technical solution:

[0010] A fixture for securing an irregularly shaped air duct includes a fixture base. An air duct holding base for axially fixing the irregularly shaped air duct is detachably and rotatably mounted inside the fixture base. The air duct holding base includes at least one positioning reference surface. Several spaced placement slots are provided on the positioning reference surface of the air duct holding base. A hydraulic jacking conforming component is disposed in each placement slot. When the jacking end of the hydraulic jacking conforming component extends out of the placement slot, it clamps and fixes the inner surface of the irregularly shaped air duct. When the jacking end of the hydraulic jacking conforming component retracts into the placement slot, it releases the fixation of the inner surface of the irregularly shaped air duct. A rotation drive device for driving the air duct holding base to rotate is provided on one side of the fixture base.

[0011] The irregularly shaped air duct is fitted onto the outside of the air duct holding base, and axially positioned by locating pins at both ends of the air duct holding base. Simultaneously, for the inner surface of the irregularly shaped air duct, hydraulic jacking conforming components in several axially arranged slots on the air duct holding base support and fix the inner surface of the air duct. After the irregularly shaped air duct is axially positioned by the air duct holding base, the hydraulic jacking conforming components extend from the slots, so that the jacking end of the hydraulic jacking conforming components fits against the inner surface of the irregularly shaped air duct, thereby supporting and fixing the inner surface of the air duct. Then, a rotation drive device can be used to drive the entire air duct holding base and the irregularly shaped air duct outside it to rotate circumferentially, thereby adjusting the position of the irregularly shaped air duct so that the machined surface of the air duct faces upwards in an easily machinable position, and then the fixed irregularly shaped air duct can be machined.

[0012] To better realize the present invention, the air duct holding base is further provided with a rotating shaft at both ends, and the tooling base is provided with a supporting plate at both ends. The supporting plate is provided with a U-shaped groove that is rotatably connected to the rotating shaft. An axial positioning plate is provided on the outer side of the rotating shaft, and a fixing cover plate is provided on the side wall of the supporting plate. The fixing cover plate and the side wall of the supporting plate form a space for rotatably engaging with the axial positioning plate. The end of the rotating shaft is connected to a rotation drive device.

[0013] To better realize the present invention, the two ends of the air duct holding base are further provided with positioning pin holes.

[0014] To better realize the present invention, the rotation drive device further includes a drive gear and a driven gear. The drive gear is rotatably mounted on the side wall of the support plate, and the driven gear is sleeved on the end of the rotating shaft. The driven gear and the drive gear mesh with each other.

[0015] To better realize the present invention, the hydraulic jacking conformal component further includes a hydraulic jacking cylinder and a conformal top block. The hydraulic jacking cylinder is disposed inside the air duct holding base. The conformal top block is installed at the end of the push rod of the hydraulic jacking cylinder. The conformal top block extends out of the placement groove or retracts into the placement groove along with the extension and retraction of the push rod of the hydraulic jacking cylinder. The end of the conformal top block near the inner surface of the irregular air duct is provided with a conformal jacking surface corresponding to the inner surface of the irregular air duct.

[0016] A method for securing irregularly shaped air ducts, based on the aforementioned fixture for securing irregularly shaped air ducts, includes the following steps:

[0017] Step 1: Divide the inner surface of the irregular-shaped air duct into axial segments. For each segment, set a conforming top block with a corresponding conforming pushing surface. Install the conforming top block into the placement groove of the air duct holding base according to the corresponding axial segment position, and connect the conforming top block to the hydraulic pushing cylinder.

[0018] Step 2: Erect the irregular-shaped air duct with the large end facing up and the small end facing down. Then, slowly hoist the air duct holding base with the built-in conformal top block and hydraulic jacking cylinder into the interior of the irregular-shaped air duct from the large end. Then, fix the air duct holding base axially inside the irregular-shaped air duct.

[0019] Step 3: Slowly lay the irregularly shaped air duct of the built-in air duct holding base horizontally, and then use the hydraulic jacking cylinder to push the conformal top block out of the placement slot, so that the conformal jacking surface of the conformal top block fits and contacts the inner surface of the irregularly shaped air duct.

[0020] Step 4: Flat-suspend the air duct holding base, so that the rotating shafts at both ends of the air duct holding base are rotated and clamped into the U-shaped grooves on the support plate. At the same time, the axial positioning plate on the rotating shaft is located between the fixed cover plate and the support plate. Then, the driven gear is installed at the end of the rotating shaft and meshed with the drive gear.

[0021] Step 5: Rotate the drive gear, which in turn drives the air duct holding base to rotate through the driven gear, so that the machined surface of the irregular air duct faces upward.

[0022] Step 6: Establish four reference surfaces at the four corners of the positioning reference surface of the air duct fixing base. Check the maximum flatness error between the four reference surfaces using a dial indicator. Adjust the position of the air duct fixing base according to the relationship between the maximum flatness error and the wall thickness tolerance of the irregular air duct until the maximum flatness error is less than or equal to one-third of the wall thickness tolerance of the irregular air duct.

[0023] Step 7: Tighten the axial positioning plate axially to fix the air duct holding base axially, and then process the machining surface of the irregular air duct.

[0024] To better realize the present invention, the end of the air duct holding base is provided with a square cavity. After the air duct holding base is axially fixed, the positional error between the actual positional degree and the standard positional degree of the square cavity is detected by a laser tracker. If the positional error is less than or equal to one-third of the wall thickness tolerance of the irregular air duct, the processing surface of the irregular air duct is directly processed. If the positional error is greater than one-third of the wall thickness tolerance of the irregular air duct, auxiliary supports are added in axial segments at the bottom of the irregular air duct, and then the processing surface of the irregular air duct is processed in axial segments.

[0025] To better realize the present invention, in step 3, the conformal top blocks are ejected from the placement groove in sequence from both ends toward the middle.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1) The present invention provides a duct holding base inside the irregular duct, and supports and axially positions the irregular duct by means of the positioning reference surface on the duct holding base. At the same time, for the inner surface of the irregular duct, the inner surface of the irregular duct is supported and held by means of several hydraulic push conformal components set on the duct holding base. This replaces the fixing method of clamping the duct from the outside, thereby reducing the stress on the duct, avoiding duct deformation, ensuring the accuracy of duct holding, and effectively ensuring the wall thickness of the duct after holding.

[0028] (2) The interior of the irregular air duct is supported and fixed by the air duct holding base. At the same time, the rotation of the air duct holding base drives the irregular air duct to rotate, thereby conveniently adjusting the orientation of the processing surface of the irregular air duct. This avoids the operation of clamping and hoisting the air duct multiple times in the traditional holding method, thereby avoiding the positioning error caused by multiple positioning clamping and effectively controlling the holding and positioning accuracy of the irregular air duct. Attached Figure Description

[0029] Figure 1 A schematic diagram of the structure of the fixture for holding irregularly shaped air ducts;

[0030] Figure 2 Schematic diagram of the structure of the air duct fixing base;

[0031] Figure 3 This is a schematic diagram of the tooling base.

[0032] Figure 4 This is a schematic diagram of the hydraulic jacking conformal assembly.

[0033] Figure 5 This is a schematic diagram of the fixing of an irregularly shaped air duct.

[0034] Wherein: 1-tooling base; 2-air duct holding base; 3-hydraulic jacking conformal component; 4-rotation drive device; 21-axial positioning plate; 22-fixed cover plate; 31-hydraulic jacking cylinder; 32-conformal top block; 41-drive gear; 42-driven gear. Detailed Implementation

[0035] Example 1:

[0036] A type of internal retaining fixture for irregularly shaped air ducts, such as Figures 1-4 As shown, the fixture includes a tooling base 1, inside which a duct holding base 2 for axially fixing an irregularly shaped air duct is detachably and rotatably installed. The duct holding base 2 includes at least one positioning reference surface, and a plurality of spaced placement slots are provided on the positioning reference surface of the duct holding base 2. A hydraulic jacking conforming component 3 is provided in the placement slot. When the jacking end of the hydraulic jacking conforming component 3 extends out of the placement slot, it clamps and fixes the inner surface of the irregularly shaped air duct. When the jacking end of the hydraulic jacking conforming component 3 retracts into the placement slot, it cancels the fixation of the inner surface of the irregularly shaped air duct. A rotation drive device 4 for driving the duct holding base 2 to rotate is provided on one side of the tooling base 1.

[0037] The air duct holding base 2 has a rotating shaft at both ends, and the tooling base 1 has a supporting plate at both ends. The supporting plate has a U-shaped groove that is rotatably connected to the rotating shaft. An axial positioning plate 21 is provided on the outer side of the rotating shaft, and a fixing cover plate 22 is provided on the side wall of the supporting plate. The fixing cover plate 22 and the side wall of the supporting plate form a space for rotatably engaging with the axial positioning plate 21. The end of the rotating shaft is connected to the rotation drive device 4. The air duct holding base 2 also has positioning pin holes at both ends.

[0038] The rotation drive device 4 includes a drive gear 41 and a driven gear 42. The drive gear 41 is rotatably mounted on the side wall of the support plate, and the driven gear 42 is sleeved on the end of the rotating shaft. The driven gear 42 meshes with the drive gear 41.

[0039] The air duct holding base 2 includes a hollow load-bearing frame. The load-bearing frame is designed as a hollow structure, firstly to reduce the weight of the entire air duct holding base 2, and secondly to facilitate the installation of the hydraulic jacking conformal component 3 inside the hollow air duct holding base 2. The tooling base 1 includes a positioning base plate. The bottom end face of the positioning base plate serves as the positioning surface. The bottom end face of the positioning base plate is connected to the worktable surface of the machine tool to achieve the positioning of the tooling base 1. Support plates are provided at both ends of the positioning base plate. The top of the support plates has an upward-opening U-shaped groove for rotatably mounting the end shaft of the air duct holding base 2. An L-shaped fixing cover plate 22 is provided on the side of the support plates near the air duct holding base 2. The fixing cover plate 22 and the side of the support plates form a space for the axial positioning plate 21 on the outside of the shaft to be rotated and locked. The axial positioning plate 21 is rotated and locked between the fixing cover plate 22 and the side of the support plates to limit the axial position of the air duct holding base 2 without affecting the rotation of the air duct holding base 2. By rotating the drive gear 41, the driven gear 42 at the end of the shaft is driven to rotate, thereby driving the air duct holding base 2 to rotate circumferentially to adjust the position of the machined surface of the irregular air duct.

[0040] After the irregular-shaped air duct is positioned, positioning holes are provided on the supporting plate, the fixed cover plate 22, and the axial positioning plate 21 to achieve circumferential fixation of the air duct holding base 2. Positioning pins or positioning screws are inserted into the aligned positioning holes to restrict the rotation of the axial positioning plate 21, thereby restricting the rotation of the air duct holding base 2. At the same time, a tightening bolt is provided on the end face of the supporting plate corresponding to the axial positioning plate 21. The axial positioning plate 21 is axially tightened by the tightening bolt, thereby achieving axial fixation of the air duct holding base 2.

[0041] Example 2:

[0042] This embodiment is an improvement on the above embodiment 1, such as... Figure 4 As shown, the hydraulic jacking conformal component 3 includes a hydraulic jacking cylinder 31 and a conformal jacking block 32. The hydraulic jacking cylinder 31 is disposed inside the air duct holding base 2. The conformal jacking block 32 is installed at the end of the push rod of the hydraulic jacking cylinder 31. The conformal jacking block 32 extends out of the placement groove or retracts into the placement groove along with the extension and retraction of the push rod of the hydraulic jacking cylinder 31. The end of the conformal jacking block 32 near the inner surface of the irregular air duct is provided with a conformal jacking surface corresponding to the inner surface of the irregular air duct.

[0043] The hydraulic jacking cylinder 31 is connected to an external oil pump via an oil pipe. The external oil pump controls the oil inlet and outlet of the piston chamber of the hydraulic jacking cylinder 31, thereby controlling the extension or retraction of the push rod. When the push rod retracts, the conformal top block 32 retracts completely into the placement groove, without affecting the installation and fixation of the irregular air duct outside the air duct holding base 2. When it is necessary to fix the inner surface of the irregular air duct, the push rod drives the conformal top block 32 to extend completely from the placement groove. The end of the conformal top block 32 is provided with a conformal jacking surface corresponding to the contour of the inner surface of the irregular air duct. Through the fit between the conformal jacking surface and the inner surface, and with the pressure maintained by the hydraulic jacking cylinder 31 providing a continuous jacking force, the inner surface of the irregular air duct is fixed.

[0044] The other parts of this embodiment are the same as those in Embodiment 1, so they will not be described again.

[0045] Example 3:

[0046] A method for securing irregularly shaped air ducts, implemented based on the irregularly shaped air duct securing fixture described in Embodiment 1 or 2, includes the following steps:

[0047] Step 1: Divide the inner surface of the irregular-shaped air duct into axial segments. For each segment, set a conforming top block 32 with a corresponding conforming pushing surface. Install the conforming top block 32 into the placement groove of the air duct holding base 2 according to the corresponding axial segment position, and connect the conforming top block 32 to the hydraulic pushing cylinder 31.

[0048] Step 2: Erect the irregular air duct with the large end facing up and the small end facing down. Then, slowly hoist the air duct holding base 2 with the built-in conformal top block 32 and hydraulic jacking cylinder 31 into the interior of the irregular air duct from the large end. Then, fix the air duct holding base 2 axially inside the irregular air duct.

[0049] Step 3: Slowly lay the irregularly shaped air duct of the built-in air duct holding base 2 horizontally, and then push the conformal top block 32 out of the placement groove through the hydraulic push cylinder 31 so that the conformal push surface of the conformal top block 32 fits and contacts the inner surface of the irregularly shaped air duct.

[0050] Step 4: Hang the air duct holding base 2 flat, so that the rotating shafts at both ends of the air duct holding base 2 are rotated and clamped into the U-shaped grooves on the support plate. At the same time, the axial positioning plate 21 on the rotating shaft is located between the fixed cover plate 22 and the support plate. Then, the driven gear 42 is installed at the end of the rotating shaft and the driven gear 42 is meshed with the drive gear 41.

[0051] Step 5: Rotate the drive gear 41, which in turn drives the air duct holding base 2 to rotate through the driven gear 42, so that the machined surface of the irregular air duct faces upward.

[0052] Step 6: Establish four reference surfaces at the four corners of the positioning reference surface of the air duct holding base 2. Check the maximum flatness error between the four reference surfaces using a dial indicator. Adjust the position of the air duct holding base 2 according to the relationship between the maximum flatness error and the wall thickness tolerance of the irregular air duct until the maximum flatness error is less than or equal to one-third of the wall thickness tolerance of the irregular air duct.

[0053] Step 7: Axially tighten the axial positioning plate 21, as follows. Figure 5 As shown, the axial fixation of the air duct holding base 2 is achieved, and then the machining surface of the irregular air duct is machined.

[0054] Furthermore, a square cavity is provided at the end of the air duct holding base 2. After the air duct holding base 2 is axially fixed, the positional error between the actual positional degree and the standard positional degree of the square cavity is detected by a laser tracker. If the positional error is less than or equal to one-third of the wall thickness tolerance of the irregular air duct, the machining surface of the irregular air duct is directly machined. If the positional error is greater than one-third of the wall thickness tolerance of the irregular air duct, auxiliary supports are added in axial segments at the bottom of the irregular air duct, and then the machining surface of the irregular air duct is machined in axial segments.

[0055] Furthermore, in step 3, the conformal top blocks 32 are ejected from the placement slots in sequence from both ends toward the middle.

[0056] The other parts of this embodiment are the same as those in Embodiment 1 above, so they will not be described again.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for holding a profiled air duct, based on a profiled air duct holding tool, characterized in that, The fixture includes a fixture base (1), and a duct holding base (2) for axially fixing the irregular air duct is detachably and rotatably installed inside the fixture base (1). The duct holding base (2) includes at least one positioning reference surface. Several spaced placement slots are provided on the positioning reference surface of the duct holding base (2). A hydraulic push conforming component (3) is provided in the placement slot. When the push end of the hydraulic push conforming component (3) extends out of the placement slot, it presses and fixes the inner surface of the irregular air duct. When the push end of the hydraulic push conforming component (3) retracts into the placement slot, it cancels the fixing of the inner surface of the irregular air duct. A rotation drive device (4) for driving the duct holding base (2) to rotate is provided on one side of the fixture base (1). The holding method includes the following steps: Step 1: The inner surface of the irregular air duct is axially segmented. For each segment, a conforming top block (32) with a corresponding conforming pushing surface is set. The conforming top block (32) is installed in the placement groove of the air duct holding base (2) according to the corresponding axial segment position, and the conforming top block (32) is connected to the hydraulic pushing cylinder (31). Step 2: Erect the irregular air duct with the large end facing up and the small end facing down. Then, slowly hoist the air duct holding base (2) with the built-in conformal top block (32) and hydraulic push cylinder (31) into the interior of the irregular air duct from the large end. Then, fix the air duct holding base (2) axially inside the irregular air duct. Step 3: Slowly lay the irregular air duct of the built-in air duct holding base (2) horizontally, and then push the conformal top block (32) out of the placement slot through the hydraulic push cylinder (31) so that the conformal push surface of the conformal top block (32) fits and contacts the inner surface of the irregular air duct. Step 4: Flat-suspend the air duct holding base (2) so that the rotating shafts at both ends of the air duct holding base (2) are rotated and clamped into the U-shaped grooves on the support plate. At the same time, the axial positioning plate (21) on the rotating shaft is located between the fixed cover plate (22) and the support plate. Then, the driven gear (42) is installed at the end of the rotating shaft and the driven gear (42) is meshed with the drive gear (41). Step 5: Rotate the drive gear (41), which in turn drives the air duct holding base (2) to rotate through the driven gear (42), so that the machined surface of the irregular air duct faces upward; Step 6: Establish four reference surfaces at the four corners of the positioning reference surface of the air duct holding base (2), check the maximum flatness error between the four reference surfaces with a dial indicator, and adjust the position of the air duct holding base (2) according to the relationship between the maximum flatness error and the wall thickness tolerance of the irregular air duct until the maximum flatness error is less than or equal to one-third of the wall thickness tolerance of the irregular air duct. Step 7: Axially tighten the axial positioning plate (21) to achieve axial fixation of the air duct holding base (2), and then process the machining surface of the irregular air duct.

2. The method of claim 1, wherein the method further comprises: The air duct holding base (2) is provided with a rotating shaft at both ends, and the tooling base (1) is provided with a supporting plate at both ends. The supporting plate is provided with a U-shaped groove that is rotatably connected to the rotating shaft. An axial positioning plate (21) is provided on the outside of the rotating shaft. A fixing cover plate (22) is provided on the side wall of the supporting plate. The fixing cover plate (22) and the side wall of the supporting plate form a space for rotatably engaging with the axial positioning plate (21). The end of the rotating shaft is connected to the rotation drive device (4).

3. The method of claim 2, wherein the method further comprises: The air duct holding base (2) is also provided with positioning pin holes at both ends.

4. The method of claim 3, wherein the step of holding the profiled air duct is performed by a plurality of holding members. The rotation drive device (4) includes a drive gear (41) and a driven gear (42). The drive gear (41) is rotatably mounted on the side wall of the support plate, and the driven gear (42) is sleeved on the end of the rotating shaft. The driven gear (42) meshes with the drive gear (41).

5. A method for securing an irregularly shaped air duct according to any one of claims 1-4, characterized in that, The hydraulic push conformal component (3) includes a hydraulic push cylinder (31) and a conformal push block (32). The hydraulic push cylinder (31) is located inside the air duct holding base (2). The push rod end of the hydraulic push cylinder (31) is equipped with a conformal push block (32). The conformal push block (32) extends out of the placement slot or retracts into the placement slot along with the extension and retraction of the push rod of the hydraulic push cylinder (31). The end of the conformal push block (32) near the inner surface of the irregular air duct is provided with a conformal push surface corresponding to the inner surface of the irregular air duct.

6. The method for securing an irregularly shaped air duct according to claim 5, characterized in that, The end of the air duct holding base (2) is provided with a square cavity. After the air duct holding base (2) is axially fixed, the positional error between the actual position of the square cavity and the standard positional error is detected by a laser tracker. If the positional error is less than or equal to one-third of the wall thickness tolerance of the irregular air duct, the processing surface of the irregular air duct is directly processed. If the positional error is greater than one-third of the wall thickness tolerance of the irregular air duct, auxiliary support is added in axial segment at the bottom of the irregular air duct, and then the processing surface of the irregular air duct is processed in axial segment.

7. The method for securing an irregularly shaped air duct according to claim 6, characterized in that, In step 3, the conformal top block (32) is ejected from the placement slot in sequence from both ends toward the middle.

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