Machining method for boring and rectifying inner hole of ultra-long part and bearing rotating and supporting device

Abstract

The invention relates to the field of part machining, in particular to a machining method for boring and rectifying an ultra-long part inner hole and a bearing rotary supporting device.The bearing rotary supporting device comprises a conical ring, an inner supporting ring, a shell and clamping rings located at the front end and the rear end, all of which are sequentially sleeved from inside to outside, and the conical ring is attached to the conical surface of the inner supporting ring; a pushing ring is arranged at the front end of the conical ring, a first screw penetrates through the clamping ring at the front end to be connected with the front end of the inner supporting ring through the pushing ring, and a second screw penetrates through the clamping ring at the rear end to be connected with the rear end of the inner supporting ring. A needle bearing is arranged between the inner supporting ring and the outer shell, thrust roller bearings are arranged at the two ends of the outer shell, at least three key grooves are evenly distributed in the outer shell in the radial direction, and supporting keys are installed in the key grooves. The invention further relates to a boring deviation rectifying method for machining the inner hole of the super-long part by using the bearing rotary supporting device. The method is simple in process, good in deviation correcting effect, low in machining difficulty, high in efficiency and convenient to operate.

Description

Technical Field

[0001] The invention relates to the field of parts processing, in particular to a processing method for boring and correcting the inner hole of an extra-long part and a bearing rotation support device. Background Art

[0002] The normalized process route for deep hole finishing is: drilling → rough boring → reduction → deviation correction → semi-finishing boring → arrangement → arrangement → finishing → grinding. Since there is little margin left in the hole diameter after semi-finishing boring, it is not easy to correct the deviation, and there may be a risk of product processing out-of-tolerance. The bottom hole must be corrected and straightened before semi-finishing boring (controlled by runout and wall thickness difference). Due to the particularity and limitations of deep hole processing conditions, the boring bar is overhanging too long, the rigidity is insufficient, the deflection is large, and the boring head sinks under great force during the boring process, resulting in eccentricity between the machining center and the product center. After exceeding a certain depth, the straightness of the hole deteriorates, and the hole is inevitably deflected during the processing. If the bottom hole needs to be corrected and straightened for each cut, it will not only waste a lot of time and cost, but also the phenomenon of boring deviation will still occur in the subsequent boring finishing. For the inner hole processing of ultra-long parts, the difficulty increases exponentially, and the above problems will be more serious, directly affecting the product qualification rate. Therefore, before the deep hole semi-finishing boring process, the straightness of the large hole bottom hole must be effectively controlled to avoid more risks and losses caused by repeated corrections.

[0003] Traditional deviation correction uses the method of rotating the workpiece and fixing the boring bar, and clamping and locking the support block at the keyway of the boring bar and boring head. Due to the long-term rotation and wear of the support block and the workpiece hole wall, the support gap increases, resulting in the increase of the straightness of the hole after the processing depth is increased, which poses a major quality hazard to the subsequent fine processing; the inner hole of the super-long part refers to the inner hole with a depth of more than 15m. At present, the first propeller shaft of a certain ship type in the country, the total length of the propeller shaft during deep hole processing is more than 21 meters, the depth of the large hole is more than 19 meters, the depth of the large hole accounts for 0.9 of the total shaft length, the straightness of the large hole is ≤φ1.0, and the coaxiality of the large and small holes is ≤φ1.25. During the processing process, the maximum wall thickness difference of the hole is still more than 5mm after multiple corrections by re-positioning the frame and conventional deviation correction processing methods. Therefore, it is extremely difficult to meet the final drawing requirements even if the wall thickness difference of the hole can be corrected by conventional methods.

[0004] CN117358967A discloses a boring bar intermediate support device for deep hole processing equipment, including a left connecting plate, a rotating support, an oil cylinder, a hydraulic control and a system operation program. The right end of the left connecting plate is connected to the rotating support by bolts, and the right end of the rotating support is connected to the oil cylinder by bolts. There is a thrust sleeve connection between the rotating support and the oil cylinder. The right end of the oil cylinder is provided with an oil inlet and oil return channel and is connected to the three-position four-way solenoid valve of the hydraulic control part through a hose, and then forms a closed loop with the oil tank. This scheme is to control the expansion and contraction of the rotating support by controlling the action of the oil cylinder through the program in the operating system to play a supporting role. It is necessary to increase the corresponding oil circuit and valve device, which is not only costly and inconvenient to control, but also has the problem of oil pipe interference; the processing aperture is limited. For processing small apertures and large and small step hole products, the installation space is insufficient. During the rotating processing, the oil pipe is easily broken, and iron filings accumulate and cut the hose. The oil cylinder does not move and cannot play a supporting role in time, causing hidden dangers to product quality. Summary of the invention

[0005] The purpose of the present invention is to solve the above technical problems and to provide a method for boring and correcting the inner hole of an overlong part with simple process, good correction effect, low processing difficulty, high efficiency and convenient operation.

[0006] Another object of the present invention is to provide a bearing rotation support device for the above method with a simple structure and good supporting stability.

[0007] The bearing rotation support device of the present invention comprises a conical ring, an inner support ring and an outer shell which are sequentially mounted from the inside to the outside, and a clamping ring located at the front and rear ends, wherein the conical ring is fitted with the conical surface of the inner support ring, a push ring is provided at the front end of the conical ring, a first screw passes through the clamping ring at the front end and is connected to the front end of the inner support ring via the push ring, and a second screw passes through the clamping ring at the rear end and is connected to the rear end of the inner support ring; the conical ring is composed of a plurality of arc-shaped metal springs evenly distributed along the circumference;

[0008] A needle bearing is arranged between the inner support ring and the outer shell, thrust roller bearings are arranged at both ends of the outer shell, and at least three key slots are evenly distributed along the radial direction on the outer shell, and support keys are arranged in the key slots.

[0009] Thrust rings are provided at both ends of the inner support ring and the outer shell. The first screw passes through the front end retaining ring, the top thrust ring, and the thrust ring in sequence to be connected to the front end of the inner support ring. The second screw passes through the rear end retaining ring and the thrust ring in sequence to be connected to the rear end of the inner support ring. A thrust roller bearing is provided between the thrust ring and the outer shell.

[0010] The housing has an outward protrusion at the keyway, and the maximum outer diameter of the clamping ring is smaller than the minimum outer diameter of the housing.

[0011] A Gly ring for bidirectional sealing is also provided between the thrust ring and the housing.

[0012] An adjusting gasket is arranged between the supporting key and the key slot.

[0013] A gasket is arranged between the thrust roller bearing and the housing, and a bearing retaining ring is arranged between the rear end of the needle roller bearing and the gasket.

[0014] A boring and deviation correction method for inner hole machining of an extra-long part comprises the following steps:

[0015] 1) Use a thickness gauge to measure the wall thickness of the inner hole of the part in different directions, record and calculate the wall thickness difference, and find out the bottom hole depth L with a wall thickness difference of ≤0.2mm and the wall thickness difference at the root of the hole, i.e., the correction amount α; measure the actual size d of the bottom hole, and calculate the diameter size d+α of the re-boring hole based on the actual size plus the correction amount α required for the hole.

[0016] 2) The boring head is equipped with a sharp knife, the part is controlled to rotate, and the hole is bored from the inner hole of the part to a depth that the boring head can support. According to the calculated diameter size d+α of the re-expanded hole, the sharp knife is used to lead the hole, and the depth of the sharp knife leading the hole is the length that the boring head can support; the sharp knife on the boring head is removed and replaced with a smooth knife. The smooth knife is close to the hole wall and the boring depth is reached. Then the boring head is equipped with a sharp knife and a smooth knife to expand the bottom hole d to (d+α+h) mm, where h=0.1-0.5 mm;

[0017] 3) Remove the sharp knife and the smooth knife from the boring head, replace them with the boring knife, and set and lock the bearing rotation support device at the connection between the two adjacent boring bars. The boring knife is retracted by 0.1-0.15mm to the hole wall, and the boring depth is reached to the hole leading depth of the sharp knife. At this time, all the bearing rotation support devices set between the two boring bars are located in the hole and are in a supporting state; the support key of the bearing rotation support device facing upward is controlled to have a gap of 0.2-0.5mm with the hole wall, and the support keys in other directions are close to the hole wall;

[0018] 4) Control the boring machine to rotate the boring bar, keep the part stationary, and perform the boring operation. During the boring process, the boring bar is supported in the hole by multiple bearing rotation support devices, and the overhanging boring head and boring bar are lifted up until the boring operation is completed.

[0019] In the step 2), after the sharp knife hole is completed, the bottom hole size after the sharp knife processing is measured, the smooth knife is close to the hole wall and the tool is aligned from the hole mouth with the bottom hole size d+(0.1-0.5mm), and the boring depth is to the sharp knife hole drawing depth.

[0020] In the step 3), before the boring tool enters the inner hole, the part is rotated to a position with the thickest wall facing upwards according to the recorded wall thickness difference, and then placed for clamping.

[0021] In the step 3), when a multi-section boring bar is supported by a plurality of support frames, all the bearing rotation support devices are first installed on the first section boring bar and the first screw and the second screw are loosened, and the bearing rotation support device does not hold the boring bar tightly; when the first section boring bar enters the hole and the connection between the first section boring bar and the second section boring bar is close to the hole mouth, the first bearing rotation support device is placed at the connection, and the first screw and the second screw of the bearing rotation support device are locked to hold the connection tightly; and so on, the other bearing rotation support devices are locked in turn at the connections between other adjacent boring bars.

[0022] In view of the problems existing in the background technology, the inventors have made the following improvements:

[0023] The bearing rotation support device of the present invention adopts a purely mechanical structure, without program control and the arrangement of hydraulic oil circuits, and has a simple structure and a long service life. The conical ring and the inner support ring are fitted with conical surfaces. When the bearing rotation support device is mounted on the connection between two adjacent boring bars, the push ring pushes the conical ring backward by tightening the first screw and the second screw, thereby completing the first locking. When the boring bar moves forward in the hole, the product hole wall and the support key rub against each other, and the friction force pushes the outer shell of the bearing rotation support device backward, pressing the conical ring and the inner support ring more and more tightly, and the conical ring is tightened. The conical ring and the inner support sleeve cooperate to lock the boring bar and complete the second locking; here, the conical ring is composed of multiple arc-shaped metal springs evenly distributed along the circumference. When subjected to the axial force from the top push ring, it can transmit the force and deform to a certain extent, generating a reaction force to hold the boring bar tightly; the metal clamping rings at both ends are used for limiting to prevent axial movement on the boring bar after installation; the thrust ring can prevent the thrust roller bearing from axial movement, and the Gley ring can play a bidirectional sealing role, driving the boring bar equipped with the support sleeve into the correction position to play a supporting role. The keyways are evenly distributed along the circumference of the outer shell, and the keyway parts are protruding, which is convenient for machining and cutting; an adjustment gasket is installed between the support key and the keyway. By replacing gaskets of different thicknesses, it is suitable for multiple hole correction support.

[0024] The present invention adopts a bearing rotating support device, and realizes synchronous positioning of the support block and the workpiece hole wall through the needle bearing radial force and rotational force. The support block only bears the support force, eliminates the rotational friction force, and avoids the boring deviation caused by the wear of the support block. The front end of the boring bar is connected to the correction boring head, and the deep hole drilling and boring machine is started to rotate the boring bar, and the boring head is driven into the inner boring hole for correction; during the boring, multiple sets of bearing rotating support devices are used for rotation support, and the overhanging boring head and boring bar are lifted to avoid the sinking of the boring head and the deflection bending of the boring bar caused by the rotation torque and radial cutting. A small gap is left between the support block and the hole wall, which can avoid the support axial movement locking caused by the wear of the tool and the shrinkage of the inner hole, so that the correction boring head can reach the root of the deep hole correction, and effectively control the straightness requirements of the deep hole. The present invention has a good correction effect. After the above correction, the large hole can be straightened, and the wall thickness difference at the root of the large hole is controlled within a very small range. Compared with the traditional multiple correction methods, it is more efficient and can eliminate the adverse effects of boring head sinking and boring bar overhang deflection bending on hole processing. The whole processing process is stably controlled with good surface quality. For the deep hole of propeller shaft with a length of up to 19 meters, the straightness of the large hole reaches φ0.7mm, and the coaxiality of the large and small holes is φ0.53mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the bearing rotation support device of the present invention.

[0026] Figure 2 This is a view of the bearing rotation support device of the present invention from another direction.

[0027] Figure 3 It is a schematic diagram of the structure of the conical ring.

[0028] Figure 4 This is a working state diagram of the bearing rotation support device of the present invention.

[0029] Figure 5 The present invention is a view from another direction showing the working state of the bearing rotation support device.

[0030] Among them, 1-conical ring, 1.1-metal spring, 2-inner support ring, 3-housing, 3.1-protrusion, 4-retaining ring, 5-thrust ring, 6-first screw, 7-second screw, 8-needle bearing, 9-thrust roller bearing, 10-keyway, 11-support key, 12-thrust ring, 13-Glay ring, 14-adjusting gasket, 15-gasket, 16-bearing retaining ring, 17-parts, 18-boring bar, 19-boring head, 20-bearing rotation support device. DETAILED DESCRIPTION

[0031] The device of the present invention is further explained below in conjunction with the accompanying drawings:

[0032] See also Figure 1-Figure 2The bearing rotation support device of the present invention comprises a tapered ring 1, an inner support ring 2 and an outer shell 3 which are sequentially mounted from the inside to the outside, and a snap ring 4 located at the front and rear ends, wherein the tapered ring 1 is fitted with the conical surface of the inner support ring 2, a top thrust ring 5 is provided at the front end of the tapered ring 1, and thrust rings 12 are provided at both ends of the inner support ring 2 and the outer shell 3 to prevent the thrust roller bearing 9 from axial movement, the first screw 6 sequentially passes through the front end snap ring 4, the top thrust ring 5, and the thrust ring 12 to connect with the front end of the inner support ring 2, and the second screw 7 sequentially passes through the rear end snap ring 4 and the thrust ring 5 to connect with the rear end of the inner support ring 2; see Figure 3 The conical ring 1 is composed of a plurality of arc-shaped metal spring pieces 1.1 evenly distributed along the circumference, which have high strength and good elasticity. The conical ring 1 can be axially pushed by the push ring 5 to press the conical surface of the inner support ring 2 tighter and tighter, thereby fixing the conical ring on the boring bar 18 without being moved on the boring bar 18 by the friction force.

[0033] A needle bearing 8 is provided between the inner support ring 2 and the outer shell 3, which mainly plays the role of rotation support. The radial force of the boring bar 18 during the processing is borne by the bearing; a thrust roller bearing 9 is provided between the thrust ring 12 and the outer shell 3, which mainly bears the axial thrust of the bearing rotation support device 20 moving inside the hole during processing. The two sets of bearings cooperate to avoid the problem of wear and burning of the mating surface caused by the end face friction of the inner and outer rings rotating against each other, which causes the inner and outer rings to fail to rotate normally.

[0034] At least three key slots 10 (three key slots 10 in this embodiment) are evenly distributed along the radial direction on the shell 3, and a support key 11 is installed in the key slot 10 (to achieve support in three directions on the circumference of the shell, and a gap of 0.2-0.5mm is left at the top support). An adjustment gasket 14 is installed between the support key 11 and the key slot 10. By replacing the adjustment gaskets 14 of different specifications to adjust the gap between the support key 11 and the hole wall, it is convenient for multiple hole correction support. The shell 3 has an outward protrusion 3.1 at the key slot 10, which is convenient for machining and cutting. The maximum outer diameter of the clamping ring 1 is smaller than the minimum outer diameter of the shell 3, ensuring that iron filings are not hooked and prevented from winding around the device.

[0035] A Gly ring 13 for bidirectional sealing is also provided between the thrust ring 12 and the housing 3 to effectively prevent impurities in the cutting fluid from entering the sealing surface and avoid the bearing from burning or jamming.

[0036] A gasket 15 is provided between the thrust roller bearing 9 and the housing 3 , and a bearing retaining ring 16 is provided between the rear end of the needle roller bearing 8 and the gasket 15 .

[0037] The inner support ring 2 can be made of alloy steel, the support key 11 can be made of bakelite or nylon, and the outer shell 3 can be made of aluminum alloy.

[0038] The working principle of the bearing rotation support device is:

[0039] First, loosen the first screw 6 and the second screw 7, and put the bearing rotation support device on the boring rod 18. Then, tighten the first screw 6 and the second screw 7 accordingly, and the push ring 5 pushes the tapered ring 1 backward to complete the first locking. When the boring rod 18 moves forward in the hole, the hole wall of the part 17 and the support key 11 rub against each other, and the friction force pushes the outer shell 3 of the bearing rotation support device backward, pressing the tapered ring 1 and the inner support ring 2 tighter and tighter, and the tapered ring and the inner support sleeve cooperate to lock the boring rod to complete the second locking.

[0040] An embodiment of a boring and deviation correction method for inner hole machining of an extra-long part:

[0041] 1) Use a thickness gauge to measure the wall thickness of the inner hole of the part in different directions, record and calculate the wall thickness difference, and find out the bottom hole depth L with a wall thickness difference ≤ 0.2mm and the wall thickness difference at the root of the hole, i.e., the correction amount α; measure the actual size d of the bottom hole, and calculate the diameter size d+α of the re-boring hole based on the actual size plus the correction amount α required for the hole;

[0042] 2) The boring head 19 (a common boring head may be used, preferably the one with patent number ZL201420597341.7 and invention name of deep hole processing boring head with front guide sleeve) is equipped with a sharp knife, the rotation of the part 17 is controlled, and the hole is bored from the inner hole of the part 17 to a depth that the boring head 19 can support. According to the calculated diameter size d+α of the re-expanded hole, the sharp knife is used to guide the hole, and the depth of the sharp knife is the length that the boring head can support;

[0043] Remove the sharp knife from the boring head 19, replace it with a smooth knife, measure the bottom hole size after the sharp knife is processed, and align the smooth knife with the hole wall. Align the smooth knife with the hole wall with the bottom hole size d+(0.1-0.5mm) from the hole mouth, and bore to the depth of the sharp knife leading hole. Then, install the sharp knife and the smooth knife on the boring head to expand the bottom hole d to (d+α+h)mm, where h=0.1-0.5mm;

[0044] 3) The boring head 19 removes the sharp knife and the smooth knife, and replaces the boring knife. Before the boring knife enters the inner hole of the part 17, according to the recorded wall thickness difference, the part 17 is rotated to a state where the thickest wall is facing upward, and then the part is clamped;

[0045] The bearing rotation support device is installed and locked at the connection between two adjacent boring bars 18. The specific method is as follows: when the multi-section boring bar 18 that has not yet entered the inner hole of the part is supported by multiple support frames, all the bearing rotation support devices are first installed on the first boring bar and the first screw 6 and the second screw 7 are loosened, and the bearing rotation support device does not hold the boring bar 18 tightly; when the first boring bar enters the hole and the connection between the first boring bar and the second boring bar is close to the hole mouth, the first bearing rotation support device is placed at the connection, and the first screw 6 and the second screw 7 of the bearing rotation support device are locked to hold the connection tightly; and so on, the other bearing rotation support devices are locked in turn at the connection between other adjacent boring bars.

[0046] The boring tool is retracted 0.1-0.15mm from the hole wall, and the boring depth is reached to the depth of the sharp tool leading the hole. At this time, all the bearing rotation support devices set between the two boring bars 18 are located in the hole and are in a supporting state; the support key 11 of the bearing rotation support device facing upward has a gap of 0.2-0.5mm with the hole wall, and the support keys 11 facing other directions are close to the hole wall;

[0047] 4) Record the processing starting point and the rear pointer of the deep hole drilling and boring machine at this time, make a record of the hole depth, control the boring machine to rotate the boring bar 18, keep the part 17 stationary, and perform the boring operation. During the boring process, the boring bar 18 is supported in the hole by multiple bearing rotation support devices, and the overhanging boring head 19 and boring bar 18 are lifted until the boring operation is completed.

[0048] The large hole can be straightened after the above correction, and the wall thickness difference at the root of the large hole can be controlled within a very small range. Compared with the traditional multiple correction methods, it is more efficient and can eliminate the adverse effects of boring head sinking and boring bar overhang deflection bending on hole processing. The whole processing process is stable, the bottom hole consistency and smoothness are high, the support block wear is small, and the straightness requirements of the full-length hole can be effectively controlled.

[0049] According to actual operation, the present invention is used to process a propeller shaft with a length of more than 21 meters. The depth of the large hole is 19 meters, accounting for 0.9 of the total shaft length. After one correction, the wall thickness difference at the root of the large hole is reduced from a deviation of 7mm to within 0.3mm. The straightness of the large hole is φ0.7mm, and the coaxiality of the large and small holes can reach φ0.53mm.

Claims

1. A bearing rotation support device, characterized in that: It includes a conical ring, an inner support ring and an outer shell which are sequentially mounted from the inside to the outside, and a clamping ring located at the front and rear ends, wherein the conical ring fits the conical surface of the inner support ring, a push ring is provided at the front end of the conical ring, a first screw passes through the clamping ring at the front end and is connected to the front end of the inner support ring via the push ring, and a second screw passes through the clamping ring at the rear end and is connected to the rear end of the inner support ring; the conical ring is composed of multiple arc-shaped metal springs evenly distributed along the circumference; A needle bearing is arranged between the inner support ring and the outer shell, thrust roller bearings are arranged at both ends of the outer shell, and at least three key slots are evenly distributed along the radial direction on the outer shell, and support keys are arranged in the key slots.

2. The bearing rotation support device according to claim 1, characterized in that: Thrust rings are provided at both ends of the inner support ring and the outer shell. The first screw passes through the front end retaining ring, the top thrust ring, and the thrust ring in sequence to be connected to the front end of the inner support ring. The second screw passes through the rear end retaining ring and the thrust ring in sequence to be connected to the rear end of the inner support ring. A thrust roller bearing is provided between the thrust ring and the outer shell.

3. The bearing rotation support device according to claim 1 or 2, characterized in that: The housing has an outward protrusion at the keyway, and the maximum outer diameter of the clamping ring is smaller than the minimum outer diameter of the housing.

4. The bearing rotation support device according to claim 2, characterized in that: A Gly ring for bidirectional sealing is also provided between the thrust ring and the housing.

5. The bearing rotation support device according to claim 2, characterized in that: An adjusting gasket is arranged between the supporting key and the key slot.

6. The bearing rotation support device according to claim 2, characterized in that: A gasket is arranged between the thrust roller bearing and the housing, and a bearing retaining ring is arranged between the rear end of the needle roller bearing and the gasket.

7. A boring and deviation correction method for inner hole machining of super-long parts, characterized in that: The following steps are involved: 1) Use a thickness gauge to measure the wall thickness of the inner hole of the part in different directions, record and calculate the wall thickness difference, and find out the bottom hole depth L with a wall thickness difference ≤ 0.2mm and the wall thickness difference at the root of the hole, i.e., the correction amount α; measure the actual size d of the bottom hole, and calculate the diameter size d+α of the re-boring hole based on the actual size plus the correction amount α required for the hole; 2) The boring head is equipped with a sharp knife, the part is controlled to rotate, and the hole is bored from the inner hole of the part to a depth that the boring head can support. According to the calculated diameter size d+α of the re-expanded hole, the sharp knife is used to lead the hole, and the depth of the sharp knife leading the hole is the length that the boring head can support; the sharp knife on the boring head is removed and replaced with a smooth knife. The smooth knife is close to the hole wall and the boring depth is reached. Then the boring head is equipped with a sharp knife and a smooth knife to expand the bottom hole d to (d+α+h) mm, where h=0.1-0.5 mm; 3) Remove the sharp knife and the smooth knife from the boring head, replace them with a boring knife, and set and lock the bearing rotation support device according to any one of claims 1 to 6 at the connection between two adjacent boring bars. The boring knife is retracted by 0.1 to 0.15 mm from the hole wall, and the boring depth is reached by the sharp knife leading the hole. At this time, all the bearing rotation support devices set between the two boring bars are located in the hole and are in a supporting state. The support key of the bearing rotation support device facing upward is controlled to have a gap of 0.2 to 0.5 mm with the hole wall, and the support keys in other directions are close to the hole wall. 4) Control the boring machine to rotate the boring bar, keep the part stationary, and perform the boring operation. During the boring process, the boring bar is supported in the hole by multiple bearing rotation support devices, and the overhanging boring head and boring bar are lifted up until the boring operation is completed.

8. The boring and deviation correction method for inner hole machining of an extra-long part according to claim 7, characterized in that: In the step 2), after the sharp knife hole is completed, the bottom hole size after the sharp knife processing is measured, the smooth knife is close to the hole wall and the tool is aligned from the hole mouth with the bottom hole size d+(0.1-0.5mm), and the boring depth is to the sharp knife hole drawing depth.

9. The boring and deviation correction method for inner hole machining of an extra-long part according to claim 7, characterized in that: In the step 3), before the boring tool enters the inner hole, the part is rotated to a position with the thickest wall facing upwards according to the recorded wall thickness difference, and then placed for clamping.

10. The boring and deviation correction method for inner hole machining of an extra-long part according to claim 7, characterized in that: In the step 3), when the multi-section boring bar is supported by multiple support frames, all the bearing rotation support devices are first installed on the first section boring bar and the first screw and the second screw are loosened, and the bearing rotation support device does not hold the boring bar tightly; when the first section boring bar enters the hole and the connection between the first section boring bar and the second section boring bar is close to the hole mouth, the first bearing rotation support device is placed at the connection, and the first screw and the second screw of the bearing rotation support device are locked to hold the connection tightly; By analogy, other bearing rotation support devices are correspondingly locked at the connection points between other adjacent boring bars.

Images