A precision machining method for high-precision coaxial hole parts with weak rigidity connection

Abstract

The application discloses a precision machining method for weak-rigidity connection high-precision coaxial hole parts, and adopts a method of "finding the far end to machine the near end" in the turning process, avoids the weak-rigidity part which rigidity cannot meet the machining requirement, and makes the machining process basically without elastic avoidance and cutting vibration, so that the coaxial precision of the two outer circles of the two ends of the weak-rigidity connection can be ensured; the auxiliary features with high coaxial precision are established on the tooling to ensure the high coaxial precision of the positioning hole of the tooling and the two outer circles of the two ends of the part, so that the coaxiality requirement of the weak-rigidity connection hole is indirectly ensured; the clamping force and the cutting force are avoided from the weak-rigidity part by adopting the natural suspension clamping mode, so that the clamping and cutting process will not produce compression or distortion, and the influence of the weak rigidity on the clamping and machining precision is avoided. The weak-rigidity connection high-precision coaxial holes at two ends are bored on the vertical coordinate boring machine by adopting the method, and the coaxial precision can be stably controlled within 0.006 mm.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical manufacturing, and can be specifically applied to the precision machining of high-precision coaxial hole parts with weak rigidity connections. Background Art

[0002] To improve the thrust-to-weight ratio of aircraft, industries such as aerospace strive to minimize component weight while ensuring safe use, often designing parts with thin-walled or hollow structures. Parts with high-precision coaxial holes with weak rigidity connections are typically hollowed out. High-precision coaxial holes on both sides are typically weakly rigidly connected and have a long span. In addition to the high dimensional accuracy requirements of the holes themselves, the coaxial accuracy of the two holes is typically less than 0.01mm. The main process difficulties for these parts are reflected in the following aspects:

[0003] First, elastic avoidance is likely to occur during the cutting process, resulting in inconsistency between the processed size and the theoretical processing size, making it difficult to ensure dimensional accuracy and coaxiality.

[0004] Second, the cutting vibration is serious, which forms vibration marks on the surface of the part, resulting in the surface roughness of the part not meeting the requirements.

[0005] Third, parts are prone to deformation when clamped, and improper clamping can easily cause compression or distortion, thus affecting machining accuracy. Summary of the Invention

[0006] Based on the above difficulties, in the method of the present invention, the method of "aligning the distal end and processing the proximal end" is adopted during the turning process, avoiding the weak rigidity parts whose rigidity cannot meet the processing requirements, so that there is basically no elastic avoidance and cutting tremor during the processing; and by establishing auxiliary features with high coaxial precision on the tooling, the high coaxiality requirements of the weak rigidity connecting holes are indirectly guaranteed; and the natural suspension clamping method is adopted to avoid the influence of weak rigidity on the clamping and processing accuracy.

[0007] The technical problem to be solved by the present invention is to solve the problem of precision machining of high-precision coaxial hole parts with weak rigidity connection, ensure high coaxial precision and improve product qualification rate.

[0008] To achieve the above object, the present invention is implemented through the following technical solutions:

[0009] A precision machining method for a weak rigid connection high-precision coaxial hole part, wherein the connection between the two end holes of the weak rigid connection high-precision coaxial hole part (3) is weak rigidity, and the two end holes are respectively the first inner hole Second inner hole And part 3 includes the following shape and position accuracy: the first inner hole With the second inner hole Coaxiality, first inner hole With the first inner hole Second inner hole coaxiality of the common axis, the second inner hole with the first inner hole the second inner hole coaxiality of the common axis, comprising the following processing steps:

[0010] Step 1), establish a first outer circle 31 and a second outer circle 32 on the part 3, the first outer circle 31 and the second outer circle 32 have high coaxial accuracy;

[0011] Step 2), design a first auxiliary tool 1, the first auxiliary tool 1 has an inner hole 11, an upper end face 12 and a lower end face 13;

[0012] Step 3), design a second auxiliary tool 2, the second auxiliary tool 2 has an upper inner hole 21, a lower inner hole 22 and a reference surface 23;

[0013] Step 4), the first outer circle 31 of the part 3 is fitted into the lower inner hole 22 of the second auxiliary tool 2, and is clamped;

[0014] Step 5), the first auxiliary tool 1 is fixed on the machine tool workbench or the lathe spindle, and the lower end face 13 is the mounting surface;

[0015] Step 6), the second auxiliary tool 2 is connected to the first auxiliary tool 1, the upper end face 12 is in contact with the reference surface 23 of the second auxiliary tool 2, and the part 3 is suspended;

[0016] Step 7), align the upper inner hole 21 on the second auxiliary tool 2, the alignment accuracy is within 0.001-0.002mm;

[0017] Step 8), precisely process the first inner hole to the size requirement;

[0018] Step 9), disassemble the second auxiliary tool 2 and the part 3;

[0019] Step 10), the second outer circle 32 of the part 3 is fitted into the lower inner hole 22 of the second auxiliary tool 2, and is clamped;

[0020] Step 11), repeat steps 6) and 7);

[0021] Step 12), precisely process the second inner hole to the size requirement.

[0022] Among them, the coaxiality of the weak rigid connection high-precision coaxial hole is less than 0.01mm.

[0023] Among them, the coaxial accuracy of the weak rigid connection high-precision coaxial hole is indirectly ensured by ensuring the coaxial accuracy of the two outer circles at both ends of the part and the two inner holes on the second auxiliary tool.

[0024] Wherein, the two coaxial first outer circle 31 and second outer circle 32 on the part 3 in the step 1) can be the outer circle that the part 3 has itself, or can be the outer circle that is added.

[0025] Wherein, the two coaxial first outer circle 31 and second outer circle 32 on the part 3 in the step 1) should be as close as possible to the first inner hole Second inner hole The coaxiality of the first outer circle 31 and the second outer circle 32 is at least less than 0.5 times of the coaxiality of the first inner hole With the second inner hole The coaxiality of the first outer circle 31 and the second outer circle 32 is at least less than 0.5 times of the coaxiality of the first inner hole

[0026] Wherein, the two coaxial first outer circle 31 and second outer circle 32 on the part 3 in the step 1) can be the outer circle that the part 3 has itself, or can be the outer circle that is added.

[0027] Wherein, the upper inner hole 21 and the lower inner hole 22 on the second auxiliary tool 2 and the reference surface 23 in the step 3) are machined by one-time clamping, and the coaxiality of the upper inner hole 21 and the lower inner hole 22 and the perpendicularity of the upper inner hole 21, the lower inner hole 22 and the reference surface 23 are all less than 0.002mm.

[0028] Wherein, the lower inner hole 22 on the second auxiliary tool 2 and the first outer circle 31 and the second outer circle 32 on the part 3 in the step 3) have a fit precision requirement, which is a small gap fit.

[0029] Wherein, the upper end surface 12 and the lower end surface 13 on the first auxiliary tool 1 in the step 2) have a parallelism precision requirement.

[0030] Wherein, the clamping mode in the steps 4) and 10) is screw 4 tightening, pressing plate pressing, outer circle clamping or interference locking.

[0031] Wherein, the precision machining mode in the steps 8) and 12) is precision boring or precision turning.

[0032] Wherein, the machining method of the weak rigid connection high-precision coaxial hole is also applicable to the precision machining of coaxial holes of other types, such as intermediate small and two-end large coaxial holes.

[0033] The present application has the following advantages:

[0034] First, by establishing high coaxial precision auxiliary features, the coaxiality of the required features is indirectly ensured.

[0035] Second, there is basically no elastic avoidance and cutting vibration in the machining process, and there is no compression or distortion in clamping.

[0036] Third, the clamping and cutting processes can avoid the influence of weak rigidity on the clamping and processing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a schematic diagram of a method for machining a high-precision coaxial hole with weak rigidity connection according to the present invention;

[0038] Figure 2 yes Figure 1 A partial enlarged view of

[0039] Figure 3 It is a schematic diagram of the weak rigidity connection of high-precision coaxial hole parts of the present invention;

[0040] Figure 4 is a cross-sectional view of the second auxiliary tooling, i.e., the positioning tooling, of the present invention;

[0041] Figure 5 is a cross-sectional view of the first auxiliary tooling of the present invention;

[0042] The numbers in the figure represent:

[0043] 1. First auxiliary tooling; 11. Inner hole; 12. Upper end surface, i.e., mounting surface for positioning tooling; 13. Lower end surface, i.e., mounting surface for machine tool;

[0044] 2. The second auxiliary tooling is the positioning tooling; 21. The upper inner hole is the positioning and alignment hole; 22. The lower inner hole is the hole for the clearance fit with the part; 23. The reference surface is the installation surface of the first auxiliary tooling;

[0045] 3. Part; 31. First outer circle; 32. Second outer circle; 33. First inner hole 34. Second inner hole

[0046] 4. Screws. DETAILED DESCRIPTION

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0048] refer to Figures 1 to 5 A precision machining method for high-precision coaxial hole parts with weak rigidity connection includes the following machining steps:

[0049] Step 1) Create two high coaxial precision first outer circles 31 and second outer circles 32 on the part 3;

[0050] Step 2) designing a first auxiliary tooling 1, including features of an inner hole 11, an upper end surface 12 and a lower end surface 13;

[0051] Step 3) Design the second auxiliary tooling 2, including features of an upper inner hole 21, a lower inner hole 22 and a reference surface 23;

[0052] Step 4), the first outer circle 31 of the part 3 is installed into the lower inner hole 22 of the second auxiliary tool 2, and clamped;

[0053] Step 5), the first auxiliary tool 1 is fixed on the boring machine workbench, and the lower end surface 13 is the installation surface;

[0054] Step 6), the second auxiliary tool 2 is connected to the first auxiliary tool 1, so that the upper end surface 12 is attached to the reference surface 23, and the part 3 is suspended;

[0055] Step 7), the upper inner hole 21 on the second auxiliary tool 2 is aligned, and the alignment accuracy is within 0.001-0.002 mm;

[0056] Step 8), the first inner hole on the part 3 is bored by using a precision vertical boring machine to meet the size requirements;

[0057] Step 9), the second auxiliary tool 2 and the part 3 are disassembled;

[0058] Step 10), the second outer circle 32 of the part 3 is installed into the lower inner hole 22 of the second auxiliary tool 2, and clamped;

[0059] Step 11), steps 6) and 7) are repeated;

[0060] Step 12), the second inner hole on the part 3 is bored by using a precision vertical boring machine to meet the size requirements;

[0061] In the step 1), the two coaxial first outer circle 31 and second outer circle 32 on the part 3 can be the outer circles that the part 3 itself has, or can be the outer circles that are added;

[0062] In the step 1), the two coaxial first outer circle 31 and second outer circle 32 on the part 3 should be as close as possible to the first inner hole and the second inner hole respectively, and the coaxiality of the first outer circle 31 and the second outer circle 32 is at least 0.5 times the coaxiality of the first inner hole and the second inner hole ;

[0063] In the step 1), the processing of the two coaxial first outer circle 31 and second outer circle 32 on the part 3 can adopt the process method of "aligning the far end to process the near end", so that the processing position is always close to the clamping positioning surface, avoiding the influence of the weak rigidity of the part 3 on the processing accuracy;

[0064] Wherein, in said step 2), the upper inner hole 21, the lower inner hole 22 and the reference surface 23 on the second auxiliary tooling 2 are clamped and processed in one step, and the coaxiality of the upper inner hole 21 and the lower inner hole 22, and the perpendicularity of the upper inner hole 21, the lower inner hole 22 and the reference surface 23 are all less than 0.002 mm;

[0065] In the step 2), the lower inner hole 22 on the second auxiliary tooling 2 and the first outer circle 31 and the second outer circle 32 on the part 3 respectively meet the matching accuracy requirements and are small clearance fits;

[0066] Wherein, in step 3), the upper end surface 12 and the lower end surface 13 on the first auxiliary tooling 1 have parallel accuracy requirements;

[0067] The clamping methods in step 4) and step 10) are tightening the screw 4, pressing the pressure plate, hugging the outer circle or interference locking.

[0068] The method of the invention is used to bore high-precision coaxial holes with weak rigidity connections at both ends on a vertical coordinate boring machine, and the coaxial accuracy reaches within 0.006mm.

[0069] In the method of the present invention, the method of "aligning the distal end and processing the proximal end" is adopted during the turning process, avoiding the weak rigidity parts whose rigidity cannot meet the processing requirements, so that there is basically no elastic avoidance and cutting tremor during the processing, which can ensure the coaxial accuracy of the outer circles at both ends of the weak rigid connection; by establishing auxiliary features with high coaxial accuracy on the tooling, the high coaxial accuracy of the tooling positioning hole and the outer circles at both ends of the part is guaranteed, thereby indirectly ensuring the coaxiality requirements of the weak rigid connection hole; using a natural hanging clamping method, the clamping and cutting process will not produce compression or distortion, avoiding the influence of weak rigidity on the clamping and processing accuracy. In addition, the method of the present invention can also be applied to the precision machining problems of non-through coaxial holes and coaxial holes with a small middle and large ends.

[0070] Parts not described in detail in the present invention belong to the well-known technology in the field.

[0071] The above description is only part of the specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the art within the technical scope disclosed in the present invention should be covered by the protection scope of the present invention.

Claims

1. A precision machining method for a weak rigid connection high precision coaxial hole part, wherein the connection between the two end holes of the weak rigid connection high precision coaxial hole part (3) is weak rigidity, and the two end holes are respectively the first inner hole φ (33), the second inner hole φ (34), and the part (3) includes the following shape and position accuracy: the first inner hole φ (33) and the second inner hole φ (34) coaxiality, the first inner hole φ (33) and the first inner hole φ (33), the second inner hole φ (34) Coaxiality of the common axis, second inner hole φ (34) and the first inner hole φ (33), the second inner hole φ (34) Coaxiality of the common axis, characterized in that: The processing steps include: Step 1) establishing a first outer circle (31) and a second outer circle (32) on the part (3), wherein the first outer circle (31) and the second outer circle (32) are coaxial; Step 2) designing a first auxiliary tooling (1), wherein the first auxiliary tooling (1) has an inner hole (11), an upper end surface (12) and a lower end surface (13); Step 3) designing a second auxiliary tooling (2), wherein the second auxiliary tooling (2) has an upper inner hole (21), a lower inner hole (22) and a reference surface (23); Step 4), insert the first outer circle (31) of the part (3) into the lower inner hole (22) of the second auxiliary tooling (2) and clamp it; Step 5), fix the first auxiliary tooling (1) on the machine tool workbench or lathe spindle, with the lower end surface (13) serving as the mounting surface; Step 6) Connect the second auxiliary tooling (2) to the first auxiliary tooling (1) so that the upper end surface (12) fits with the reference surface (23) of the second auxiliary tooling (2), and the part (3) is suspended in the air; Step 7) Aligning the upper inner hole (21) on the second auxiliary tooling (2) with an alignment accuracy within 0.001-0.002 mm; Step 8), the first inner hole φ on the precision machined part (3) (33) Meet size requirements; Step 9), disassemble the second auxiliary tooling (2) and the parts (3); Step 10), insert the second outer circle (32) of the part (3) into the lower inner hole (22) of the second auxiliary tooling (2) and clamp it; Step 11), repeat steps 6) and 7); Step 12), the second inner hole φ on the precision machined part (3) (34) Meet size requirements.

2. The processing method according to claim 1, characterized in that: The coaxiality of the weak rigidity connection high-precision coaxial hole parts is less than 0.01 mm.

3. The processing method according to claim 1, characterized in that: The coaxial accuracy of the weak rigidity connection high-precision coaxial hole parts is indirectly guaranteed by ensuring the coaxial accuracy of the two outer circles at both ends of the parts and the two inner holes on the second auxiliary tooling.

4. The processing method according to claim 1, characterized in that: In the step 1), the two coaxial first outer circles (31) and the second outer circle (32) on the part (3) are the outer circles inherent in the part (3) or are auxiliary outer circles.

5. The processing method according to claim 1, characterized in that: In the step 1), the two coaxial first outer circles (31) and the second outer circle (32) on the part (3) are respectively close to the first inner hole φ (33), the second inner hole φ (34), the coaxiality of the first outer circle (31) and the second outer circle (32) is less than the first inner hole φ (33), the second inner hole φ (34) 0.5 times the coaxiality.

6. The method according to claim 1, characterized in that: In the step 1), the processing of the two coaxial first outer circles (31) and the second outer circle (32) on the part (3) can align the portion away from the clamping positioning surface, and process the portion close to the clamping positioning surface, that is, adopting the process method of "aligning the far end and processing the near end", thereby avoiding the influence of the weak rigidity of the part (3) on the processing accuracy.

7. The processing method according to claim 1, characterized in that: In the step 3), the upper inner hole (21), the lower inner hole (22) and the reference surface (23) on the second auxiliary tooling (2) are clamped and processed in one step, and the coaxiality of the upper inner hole (21) and the lower inner hole (22), and the perpendicularity of the upper inner hole (21), the lower inner hole (22) and the reference surface (23) are all less than 0.002 mm.

8. The processing method according to claim 1, characterized in that: In the step 3), the lower inner hole (22) on the second auxiliary tooling (2) and the first outer circle (31) and the second outer circle (32) on the part (3) respectively have matching accuracy requirements, which are clearance fit.

9. The processing method according to claim 1, characterized in that: In the step 2), the upper end surface (12) and the lower end surface (13) on the first auxiliary tooling (1) have parallel accuracy requirements.

10. The processing method according to claim 1, characterized in that: The clamping methods in step 4) and step 10) are tightening the screw (4), pressing the pressure plate, hugging the outer circle or interference locking.

11. The processing method according to claim 1, characterized in that: The precision machining method in step 8) and step 12) is precision boring or precision turning.

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