A Coaxial Alignment Method for the Return Air Device of a Centrifugal Fan

Abstract

The present invention belongs to the field of the processing of the return device of a centrifugal fan, and particularly relates to a coaxial alignment method for the return device of a centrifugal fan, comprising the following steps: Step 1: Make the middle plane of the coaxial positioning table closely abut against the vertical workbench of the radial drilling machine; Step 2: Make the middle planes of the upper disc semi-circle and the lower disc semi-circle also closely abut against the vertical workbench and stack them up and down; Step 3: Position the upper processing surface and the lower processing surface by using the coaxial positioning table; Step 4: At the bottom edge of the lower disc semi-circle, fix it with a pressing plate, a fastening pad and a fastener; Step 5: Use the radial drilling machine to process fixing holes at the designated positions on the upper disc semi-circle, penetrate the fixing holes through the upper disc semi-circle and the lower disc semi-circle, and fix them with a bolt group; Step 6: Then repeat Steps 1 to 5 to also fix the other half of the upper disc semi-circle and the lower disc semi-circle with a bolt group; Step 7: Fix and clamp the two groups of upper and lower disc semi-circles on a lathe, and machine the upper processing surface and the lower processing surface on the lathe.

Description

Technical Field

[0001] The present invention belongs to the field of processing of centrifugal fan return ducts, and particularly relates to a method for coaxial alignment of a centrifugal fan return duct. Background Art

[0002] Centrifugal fans are widely used for ventilation, dust removal, and cooling in factories, mines, tunnels, cooling towers, vehicles, ships, and buildings. Their return ducts are consumable parts that need to be replaced in a timely manner. Existing return ducts are all integrally designed. Once replaced, they need to be replaced as a whole, resulting in a high cost. Therefore, in order to save expenses, the return duct is designed as an upper disc and a lower disc, and both the upper and lower discs are split into two halves from the symmetry plane. Among them, the lower disc is replaced according to the needs of design parameters to use different unit performances, so as to save the material cost of the upper disc. However, although such a design saves expenses, new problems have emerged, that is, the coaxiality requirement between the upper machining surface of the upper disc and the lower machining surface of the lower disc is ≤0.1, and the upper machining surface and the lower machining surface also need to be symmetric about the middle parting plane, with a symmetry of ≤0.1. How to ensure these geometric tolerances and alignment is the difficulty in machining such workpieces. Summary of the Invention

[0003] In view of the problems mentioned above, the present invention specifically designs a method for coaxial alignment of a centrifugal fan return duct, which can conveniently and simply complete the machining of such workpieces and ensure the requirements of geometric tolerances.

[0004] To achieve the above object, the present invention provides a method for coaxial alignment of a centrifugal fan return duct, including the following steps:

[0005] Step 1: Make the middle parting plane of the coaxial positioning table closely abut against the vertical workbench of the radial drill press.

[0006] Step 2: Make the middle parting planes of the upper semi-disc and the lower semi-disc of the return duct also closely abut against the vertical workbench and stack them vertically. Thus, it is ensured that the middle parting planes of the upper semi-disc and the lower semi-disc are coplanar.

[0007] Step 3: Position the upper machining surface of the upper semi-disc and the lower machining surface of the lower semi-disc using the coaxial positioning table. Thus, the coaxiality between the upper machining surface and the lower machining surface is ensured.

[0008] Step 4: After positioning in the manner described in Step 3, at the bottom edge of the lower semi-disc, fix it with a pressing plate, a fastening pad, and a fastener.

[0009] Step 5: Use the radial drill press to machine fixing holes at the designated positions on the upper semi-disc, penetrate the fixing holes through the upper semi-disc and the lower semi-disc, and use a bolt group to penetrate the fixing holes to fix the upper semi-disc and the lower semi-disc.

[0010] Step 6 Then repeat Steps 1 to 5 to also fix the other half of the upper disc semi-circle and the lower disc semi-circle with the bolt group;

[0011] Step 7 Fix and clamp the two groups of upper and lower disc semi-circles on the lathe, and machine the upper machining surface and the lower machining surface.

[0012] Furthermore, the coaxial positioning table includes an upper ring and a lower ring; the upper ring and the lower ring are connected by a steel plate to form a frustum shape, and the coaxiality requirement of the outer circles of the upper ring and the lower ring is the same as that of the upper machining surface and the lower machining surface.

[0013] Furthermore, a positioning table spacer block is also provided below the coaxial positioning table in Step 1, which is used to adjust the relative positions of the coaxial positioning table and the upper disc semi-circle and the lower disc semi-circle, so that the upper machining surface is tightly attached to the outer circle of the upper ring, and the lower machining surface is tightly attached to the outer circle of the lower ring.

[0014] Preferably, when machining the fixing holes in Step 5, one far-center fixing hole and one near-center fixing hole of the upper disc semi-circle should be machined simultaneously to ensure the fixing accuracy; when a group of far and near fixing holes are machined simultaneously, they should be promptly fixed through with the bolt group to avoid the offset of the hole positions when machining other fixing holes.

[0015] In summary, a coaxial alignment method for a centrifugal fan return device of the present invention has the following advantages and beneficial technical effects:

[0016] This method solves the problem that it is difficult to machine and align the position tolerances of the upper disc semi-circle and the lower disc semi-circle of the return device due to the new design for cost savings, enabling the product to be installed in a mode of combining four semi-circles together, thus saving costs.

[0017] This method utilizes the positioning function of the vertical workbench of the radial drill press and the coaxial alignment function of the outer circles of the upper and lower rings of the coaxial positioning table to relatively accurately fix the semi-circles of the upper and lower discs together, and then complete the machining of the upper and lower machining surfaces, ensuring the requirements of coaxiality and symmetry, and saving machining costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where:

[0019] Figure 1 is a schematic diagram of the alignment structure of a group of upper disc semi-circle and lower disc semi-circle of the return device;

[0020] Figure 2 is a schematic diagram after the alignment and fixation of two groups of return devices;

[0021] Figure 3 is Figure 2 the schematic view in the A direction of

[0022] The reference numerals in the drawings are as follows:

[0023] 1 - Bed body workbench; 2 - Vertical workbench; 3 - Coaxial positioning table; 31 - Upper ring; 32 - Lower ring; 4 - Upper machining surface; 5 - Lower machining surface; 6 - Upper disc semi - circle; 7 - Lower disc semi - circle; 8 - Pressure plate; 9 - Fastening cushion block; 10 - Fastener; 11 - Positioning table cushion block; 12 - Fixing hole; 13 - Bolt group. Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the implementation of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions; the described embodiments are some but not all of the embodiments of the present invention; the embodiments described below with reference to the drawings and directional terms are all exemplary and are intended to explain the present invention and should not be construed as limiting the present invention; all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. The embodiments of the present invention will be described in detail below with reference to the drawings:

[0025]

Embodiment 1

[0026] As shown in Figure 1 , Figure 2 and Figure 3 , a coaxial alignment method for the centrifugal fan return duct specifically includes the following steps:

[0027] Step 1: Weld the upper ring 31 and the lower ring 32 into a frustum shape by using a steel plate, and at the same time ensure that the coaxiality of the outer circles of the upper ring 31 and the lower ring 32 is less than 0.1. Make the middle - dividing plane of the coaxial positioning table 3 closely abut against the vertical workbench 2 of the radial drill press. Select the positioning table cushion block 11 under the coaxial positioning table 3 according to the height of the upper machining surface 4 and the lower machining surface 5 of the return duct from the bed body workbench 1;

[0028] Step 2: Make the middle - dividing planes of the upper disc semi - circle 6 and the lower disc semi - circle 7 of the return duct also closely abut against the vertical workbench 2, and stack them up and down. Thus, ensure that the middle - dividing planes of the upper disc semi - circle 6 and the lower disc semi - circle 7 are coplanar;

[0029] Step 3: Position the upper machining surface 4 of the upper disc semi - circle 6 and the lower machining surface 5 of the lower disc semi - circle 7 by using the coaxial positioning table 3. Thus, ensure the coaxiality of the upper machining surface 4 and the lower machining surface 5;

[0030] Step 4 After positioning according to the method in Step 3, fix it at the bottom edge of the lower semi-circle 7 with a pressing plate 8, a fastening spacer 9 and a fastener 10;

[0031] Step 5 Use a radial drill press to machine a fixing hole 12 at the designated position on the upper semi-circle 6. Pass the fixing hole 12 through the upper semi-circle 6 and the lower semi-circle 7, and penetrate the fixing hole 12 with a bolt group 13 to fix the upper semi-circle 6 and the lower semi-circle 7; when machining the fixing hole 12, one far-center fixing hole and one near-center fixing hole of the upper semi-circle 6 should be machined simultaneously to ensure the fixing accuracy; when a group of far and near fixing holes are machined simultaneously, they should be promptly penetrated and fixed with a bolt group 13 to avoid the offset of the hole position when machining other fixing holes 13;

[0032] Step 6 Then repeat Steps 1 to 5 to also fix the other half of the upper semi-circle 6 and the lower semi-circle 7 with a bolt group 13;

[0033] Step 7 Clamp the two sets of upper and lower semi-circles on a lathe and machine the upper machining surface 4 and the lower machining surface 5.

[0034] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coaxial alignment method for the return air duct of a centrifugal fan, characterized in that, It includes the following steps: In Step 1, the middle dividing plane of the coaxial positioning table is closely attached to the vertical workbench of the radial drill press; In Step 2, the middle dividing planes of the upper disc semi-circle and the lower disc semi-circle of the refluxer are also closely attached to the vertical workbench and stacked vertically. Thus, it is ensured that the middle dividing planes of the upper disc semi-circle and the lower disc semi-circle are coplanar; In Step 3, the upper machining surface of the upper disc semi-circle and the lower machining surface of the lower disc semi-circle are positioned by the coaxial positioning table. Thus, the coaxiality of the upper machining surface and the lower machining surface is ensured; After positioning in the manner described in Step 3, at the bottom edge of the lower disc semi-circle, it is fixed with a pressing plate, a fastening cushion block and a fastener; In Step 5, a fixed hole is machined at the designated position on the upper disc semi-circle with a radial drill press. The fixed hole penetrates through the upper disc semi-circle and the lower disc semi-circle. A bolt group penetrates through the fixed hole to fix the upper disc semi-circle and the lower disc semi-circle; In Step 6, then Steps 1 to 5 are repeated to also fix the other half of the upper disc semi-circle and the lower disc semi-circle with a bolt group; In Step 7, the two groups of upper and lower disc semi-circles are fixedly clamped on a lathe, and the upper machining surface and the lower machining surface are machined on the lathe; The coaxial positioning table includes an upper ring and a lower ring; the upper ring and the lower ring are connected by a steel plate to form a frustum shape. The coaxiality requirement of the outer circles of the upper ring and the lower ring is the same as the coaxiality of the upper machining surface and the lower machining surface; Below the coaxial positioning table described in Step 1, there is also a positioning table cushion block for adjusting the relative positions of the coaxial positioning table and the upper disc semi-circle and the lower disc semi-circle, so that the upper machining surface is closely attached to the outer circle of the upper ring, and the lower machining surface is closely attached to the outer circle of the lower ring; When machining the fixed hole in Step 5, one far-center fixed hole and one near-center fixed hole of the upper disc semi-circle should be machined simultaneously to ensure the fixing precision; when a group of far and near fixed holes are machined simultaneously, they should be promptly penetrated and fixed with a bolt group to avoid the offset of the hole positions when machining other fixed holes.

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