A method for processing an inner hole key groove of a rotary part

Abstract

A kind of inner hole keyway processing method of rotary type parts, the inner hole keyway processing method includes: first, rotary type parts are placed in the insertion bench workbench with the attitude of blind hole opening end upwards, after pre-fixing, fine adjustment part is consistent with the center of main shaft and is locked to its rotation center;Second step, install tool bar on insertion bench main shaft, and adjust the position of tool bar so that the generatrix runout of tool bar meets the processing requirements, then lock and recheck;Third step, install rough machining tool at the lower end of tool bar, insert and cut one side to form first keyway, after the insertion bench workbench is rotated 180 °, symmetric second keyway is processed;Fourth step, install finishing tool at the lower end of tool bar, repeat symmetric insert and cut to first keyway and second keyway meet the requirements;Fifth step, remove the part, detect and grind keyway to the clearance of cooperation is qualified.Therefore, the design can process inner hole keyway with good precision and symmetry in small size blind hole.

Description

Technical Field

[0001] This invention relates to a method for machining internal keyways, belonging to the field of machining, and particularly to a method for machining internal keyways of rotating parts. Background Technology

[0002] In mechanical transmission, the keyway in the inner hole of rotating parts is a key structure for achieving circumferential fixation and transmitting torque. The machining accuracy of the inner hole keyway directly affects the stability of power transmission. For example, the inner hole keyway of the rudder shaft works by forming a tight fit with the key on the matching shaft. A high-precision inner hole keyway can ensure stable force transmission without loosening and avoid impact vibration or power loss. Currently, the machining of keyways in the inner holes of rotary parts typically employs methods such as milling, lathe machining, and wire EDM. When machining small blind holes with diameters of 20-200mm, milling is problematic because the radial space of the blind hole is narrow, the milling cutter diameter is limited, and the rigidity is insufficient, leading to easy cutting wobble and resulting in symmetry deviation. Lathe machining is limited by the closed structure of the blind hole, and radial feed can easily deform the hole wall. Furthermore, the tool guidance in deep holes is poor, making it difficult to guarantee symmetry accuracy. Wire EDM requires a complete discharge circuit, making wire threading and positioning difficult in small blind holes. Uneven electrode wire wear causes accuracy fluctuations, and secondary clamping can also generate cumulative errors. Consequently, it is impossible to machine inner keyways with both good accuracy and symmetry in small blind holes.

[0003] Chinese patent application No. 201711048164.1, filed on October 31, 2017, discloses a method for machining internal keyways. This method involves providing a workpiece with preset values ​​for internal hole accuracy, end face flatness, and parallelism. The keyway length is milled in two stages by adjusting the surface. Before each milling stage, the position of the workpiece is adjusted based on the internal hole and end face to ensure the internal hole axis is parallel to the boring machine spindle. This improves the coaxiality between the internal hole axis and the boring machine spindle, thereby increasing the machining accuracy of the internal keyway. It also reduces the amount of fitting work and improves machining efficiency. Although this patent produces symmetrical internal keyways using a boring machine, it still has the following drawbacks: This design can only process symmetrically distributed through-hole keyways, but it cannot process internal keyways with good accuracy and symmetry in small-sized blind holes.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this patent application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects and problems in the prior art that it is impossible to machine internal keyways with good accuracy and symmetry in small blind holes, and to provide a method for machining internal keyways of rotating parts that can machine internal keyways with good accuracy and symmetry in small blind holes.

[0006] To achieve the above objectives, the technical solution of the present invention is: a method for machining the internal keyway of a rotating part, the method comprising the following steps: Step 1: Place the rotary part to be processed on the slotting machine table with the blind hole opening end facing upwards, pre-fix the end away from the blind hole opening end, and finely adjust the position of the rotary part to make the rotation center of the rotary part consistent with the center of the slotting machine spindle. Then lock and fix the slotting machine table and the rotary part. Step 2: After the above-mentioned rotary parts are fixed, first install the tool holder on the spindle of the slotting machine, then adjust the position of the tool holder so that the generatrix runout of the tool holder meets the machining requirements, then lock and fix the spindle of the slotting machine to the tool holder, and re-inspect the generatrix runout of the tool holder; Step 3: First, install the roughing tool at the lower end of the tool holder and perform positioning and calibration. Control the slotting machine spindle to drive the roughing tool to perform roughing on one side of the inner wall of the blind hole until the first keyway that meets the preset roughing value is formed. Then, completely remove the roughing tool from the blind hole. Then, rotate the slotting machine table 180° and control the slotting machine spindle to drive the roughing tool to perform roughing on the symmetrical side of the first keyway to machine a second keyway that is consistent with and symmetrical to the first keyway. Then, completely remove the roughing tool from the blind hole. Step 4: Remove the roughing tool, install the finishing tool at the lower end of the tool holder and perform positioning and calibration. Control the slotting machine spindle to drive the finishing tool to perform finishing cut on the first keyway until the first keyway meets the finishing preset value. Then, completely remove the finishing tool from the blind hole. After rotating the slotting machine table 180°, control the slotting machine spindle to drive the finishing tool to perform finishing cut on the second keyway until the second keyway meets the finishing preset value. Then, completely remove the finishing tool from the blind hole and remove the finishing tool. Step 5: Remove the rotary part from the slotting machine table, and test the fit clearance between the first keyway, the second keyway and the part to be assembled by brushing. Grind the surfaces of the first keyway and the second keyway according to the fit clearance until the fit clearance meets the requirements, and complete the machining of the inner hole keyway.

[0007] The rotating parts include shaft parts and disc parts.

[0008] In the first step, the pre-fixing of the end away from the blind hole opening means: first, insert the locking screw into the slot of the slotting machine worktable, while keeping the rotating parts vertical; then, place a height equalizer under the pressure plate; by adjusting the height of the height equalizer, the pressure plate presses down on the end of the rotating parts away from the blind hole opening; then, rotate the locking nut to perform initial tightening, so that the rotating parts do not wobble but leave room for adjustment. In the first step, the step of finely adjusting the position of the rotary parts to make the rotation center of the rotary parts consistent with the center of the slotting machine spindle means: measuring the runout between the blind hole of the rotary parts and the slotting machine spindle, and adjusting the position of the rotary parts until the runout between the blind hole of the rotary parts and the slotting machine spindle is less than or equal to 0.02mm. At this time, the rotation center of the rotary parts is consistent with the center of the slotting machine spindle. In the first step, locking and fixing the slotting machine table and the rotating parts means: tightening the locking nut so that the pressure plate applies a stable clamping force to the rotating parts through the high-speed rail, ensuring that the rotating parts cannot move along the slotting machine table.

[0009] In the second step, the tool holder includes a large end and a small end; The large end of the tool holder is connected to the small end of the tool holder. The upper end face of the large end of the tool holder is provided with a threaded lifting hole. The lower part of the small end of the tool holder is provided with a radially penetrating blade mounting hole. The lower end face of the small end of the tool holder is provided with a threaded fixing hole, which communicates with the blade mounting hole. The outer diameter of the small end of the tool holder is smaller than the inner diameter of the blind hole, and the length of the small end of the tool holder is greater than the height of the blind hole.

[0010] In the second step, installing the tool holder on the slotting machine spindle means: installing a lifting eye screw at the threaded lifting hole, lifting the tool holder vertically into the tool holder mounting bracket of the slotting machine spindle with the lifting eye screw, adjusting the installation height of the tool holder, and then pre-fixing the large end of the tool holder to the tool holder mounting bracket with the locking screw; In the second step, adjusting the position of the tool holder to ensure that its generatric runout meets the machining requirements, then locking the slotting spindle to the tool holder and rechecking the generatric runout of the tool holder means: first, measuring the generatric runout of the tool holder; if the generatric runout is greater than 0.02mm, adjusting the position of the tool holder until the generatric runout is less than or equal to 0.02mm; then, using locking screws to lock the large end of the tool holder to the tool holder mounting bracket; and finally, rechecking the generatric runout of the tool holder to ensure that the generatric runout of the tool holder after locking is less than or equal to 0.02mm.

[0011] In the third step, the roughing tool includes a roughing tool body and a roughing tool holder; the roughing tool holder is adapted to the insert mounting hole; The roughing tool body includes an upper end face, a lower end face, a front end face, a rear end face, a left end face, and a right end face; one side of the upper end face is connected to the top edge of the rear end face, the bottom edge of the rear end face is connected to one side of the lower end face, the other side of the lower end face is connected to the bottom edge of the front end face, and the top edge of the front end face is connected to the other side of the upper end face; the left end face and the right end face are respectively connected to the two side edges of the upper end face, the lower end face, the front end face, and the rear end face, forming a closed hexahedral structure; The width and length of the upper end face are smaller than the width and length of the lower end face, respectively. The lower end face is an isosceles trapezoid with the base of the lower end face as the main cutting edge. The front end face and the rear end face are symmetrical right-angled trapezoids, and the intersection lines of the front end face and the rear end face with the lower end face form side cutting edges. The left end face is an inclined plane and is an isosceles trapezoid. The right end face is fixedly connected to the end face of the roughing tool holder.

[0012] In the third step, installing the roughing tool at the lower end of the tool holder and performing positioning calibration means: inserting the roughing tool holder into the blade mounting hole at the small end of the tool holder, adjusting the position, and then using a screw to press and fix the roughing tool holder through the threaded fixing hole. After pressing, the distance from the lower end face of the roughing tool to the lower end face of the screw is less than the length of the tool relief groove of the first keyway and the second keyway. Then, positioning calibration is performed through tool setting operation. In the third step, controlling the slotting spindle to drive the roughing tool to perform roughing on one side of the blind hole's inner wall until a first keyway that meets the preset roughing value means: setting the radial feed of the slotting spindle as the roughing feed, the main cutting edge of the roughing tool body cutting radially into the blind hole, and the side cutting edge controlling the keyway width; measuring the depth and width of the keyway after each slotting operation until the depth and width of the keyway reach the preset roughing allowance, thus forming the first keyway; In the third step, rotating the slotting machine table by 180° and controlling the slotting machine spindle to drive the roughing tool to perform rough slotting on the symmetrical side of the first keyway to produce a second keyway that is consistent with and symmetrical to the first keyway means: keeping the slotting machine parameters unchanged, rotating the slotting machine table by 180° so that the roughing tool is aligned with the symmetrical position of the first keyway, repeating the above slotting process to produce a second keyway that is consistent with the first keyway; In the third step, the step of completely removing the roughing tool from the blind hole means that after the roughing is completed, the spindle of the slotting machine is controlled to drive the roughing tool to rise axially until the roughing tool body is completely removed from the opening end of the blind hole.

[0013] In the fourth step, the finishing tool includes a finishing tool body and a finishing tool holder; the finishing tool holder is adapted to the insert mounting hole; The finishing cutter body is connected to the finishing cutter shank. The finishing cutter body includes a main cutting edge and a side cutting edge. The surface of the main cutting edge is provided with an arc-shaped groove that is recessed into the cutter body. The side cutting edges are symmetrically distributed on both sides of the main cutting edge and connected vertically.

[0014] In the fourth step, installing the finishing tool at the lower end of the tool holder and performing positioning calibration means: inserting the finishing tool holder into the blade mounting hole at the small end of the tool holder, adjusting the position, and then using a screw to press and fix the finishing tool holder through the threaded fixing hole. After pressing, the distance from the lower end of the finishing tool to the lower end face of the screw is less than the length of the relief groove of the first keyway and the second keyway. Then, positioning calibration is performed through the tool setting operation. In the fourth step, controlling the slotting machine spindle to drive the finishing tool to perform fine slotting on the first keyway until the first keyway meets the preset finishing value means: setting the radial feed of the slotting machine spindle to 1 / 5-1 / 10 of the roughing feed, finishing the bottom and depth direction of the first keyway with the main cutting edge, controlling the width of the first keyway with the side cutting edge, measuring the depth and width of the first keyway after each slotting, until the depth and width of the first keyway reach the preset finishing allowance; In the fourth step, after rotating the slotting machine table by 180°, controlling the slotting machine spindle to drive the finishing tool to perform fine slotting on the second keyway until the second keyway meets the preset finishing value means: keeping the slotting machine parameters unchanged, rotating the slotting machine table by 180°, aligning the finishing tool with the position of the second keyway, and repeating the above fine slotting process to ensure that the second keyway is consistent with the first keyway. In the fourth step, the step of completely removing the finishing tool from the blind hole means that after the finishing cut is completed, the spindle of the slotting machine is controlled to drive the finishing tool to rise axially until the finishing tool body is completely removed from the opening end of the blind hole.

[0015] In the fifth step, the step of testing the fit clearance between the first keyway, the second keyway and the part to be assembled by means of: first, test fitting the key of the part to be assembled with the first keyway and the second keyway, and then measuring the fit clearance with a feeler gauge. In the fifth step, grinding the surfaces of the first keyway and the second keyway according to the fit clearance until the fit clearance meets the requirements means: using a file or scraper to grind the surfaces of the first keyway and the second keyway until a 0.02mm feeler gauge cannot be inserted, and the fit clearance meets the assembly and use requirements.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention discloses a method for machining the keyway in the inner hole of a rotary part, comprising: First, placing the part with the blind hole facing upwards on a slotting machine, pre-fixing it, adjusting it so that its rotation center is aligned with the spindle center, and locking it; Second, installing a tool holder and ensuring its generatrice runout is within acceptable limits, then locking and re-inspecting; Third, installing a roughing tool at the lower end of the tool holder, slotting one side to form a first keyway, and rotating the slotting machine 180° to machine a symmetrical second keyway; Fourth, installing a finishing tool at the lower end of the tool holder, repeating the symmetrical slotting until the target is met; Fifth, removing the part, inspecting the fit, and grinding the keyway until the fit clearance is acceptable. In application, the rotary part is first placed on the slotting machine table with the blind hole facing upwards, and the end of the part furthest from the blind hole opening is pre-fixed. Fine-tune the part position to align the part's rotation center with the spindle center before locking the part, establishing a precise reference for machining. Next, install the tool holder, adjust its position to ensure its generatric runout meets requirements, and then lock the tool holder. Recheck the generatric runout to ensure the tool holder is stable and free of wobble. After installing and calibrating the roughing tool, rough-cut the first keyway. Rotate the slotting machine table 180° to machine a symmetrical second keyway, initially ensuring symmetry. Then, install the finishing tool at the lower end of the tool holder and repeat the symmetrical slotting to improve accuracy. Finally, remove the part, inspect the fit, and grind it until the clearance is acceptable. This allows for the machining of internal keyways in small blind holes with diameters of 20-200mm. The advantages of this invention also include: Firstly, the internal space of small blind holes is narrow, limiting the tool range. Small dimensional deviations are easily magnified. However, the slotting machine uses axial feed and cuts along the depth direction of the blind hole, which can avoid the interference risk of radial movement. With the addition of tool holder generatrix runout rechecking and tool clamping and fixing, the tool wobbling in the narrow space can be controlled within a small range, ensuring stable cutting without wobbling. This allows for the machining of high-precision internal keyways in small blind holes. Secondly, small blind holes are more sensitive to datum deviation. Even a slight positioning error can amplify the symmetry deviation. By pre-fixing the parts and fine-tuning them until their rotation center is consistent with the center of the slotting machine spindle, a unified datum is established, reducing errors from the source, ensuring the symmetry of the keyway, and reducing errors caused by datum deviation. Thirdly: After rough machining one side of the keyway, rotate the worktable 180° to machine the symmetrical side, and repeat the same symmetrical machining process for finishing. By using the rotational accuracy of the slotting machine, the dimensions of the keyways on both sides are consistent, improving the symmetry, and avoiding the accumulation of errors caused by secondary tool setting. Fourthly, regarding the difficulty in controlling the precision of small blind holes, the slotting machine's machining area is relatively open, making it easy to observe and adjust in a timely manner. Combined with the roughing allowance and the small feed rate for finishing, the cutting amount can be precisely controlled in a confined space. Furthermore, by combining the mating inspection and grinding, the keyway precision and mating clearance can be ensured to meet the standards. Therefore, the present invention can not only process internal keyways, but also process internal keyways with good precision and symmetry in small blind holes.

[0017] 2. In the method for machining the keyway of an internal hole of a rotary part according to the present invention, in the third step, the roughing tool includes a roughing tool body and a roughing tool holder, and the roughing tool holder is adapted to the insert mounting hole; in the fourth step, the finishing tool includes a finishing tool body and a finishing tool holder; the finishing tool holder is adapted to the insert mounting hole; in application, both the roughing tool holder and the finishing tool holder can be adapted to the insert mounting hole at the small end of the tool holder, and can be quickly inserted into the hole for initial positioning during installation. After adjusting the position, a screw is passed through the threaded fixing hole of the tool holder to fix it. The roughing and finishing tool holders are clamped and fixed separately to ensure a tight fit between the tool holder and the tool shank without any looseness or gaps. This clamping method can resist the impact of large cutting forces during roughing, preventing the roughing tool holder from wobbling within the tool shank. During finishing, it can reduce machining deviations caused by slight tool displacement, ensuring that the tool maintains a stable posture throughout the cutting process. This provides stable support for the accuracy and symmetry of keyway machining. Furthermore, fixing the tool holder with screws facilitates quick replacement of the roughing and finishing tool holders during machining. Therefore, this invention not only enables the machining of internal keyways with good accuracy and symmetry in small blind holes but also improves machining stability.

[0018] 3. In the fifth step of the present invention, a method for machining the inner keyway of a rotating part, the surfaces of the first and second keyways are ground with a file or scraper until a 0.02mm feeler gauge cannot be inserted, ensuring the fit clearance meets assembly and usage requirements. In application, the key of the part to be assembled is first trial-fitted with the first and second keyways. Then, a 0.02mm feeler gauge is used to measure the fit clearance. If the fit clearance is greater than 0.02mm, the keyway surface is finely ground with a file or scraper. The file can remove burrs and small protrusions on the keyway edge, while the scraper can precisely handle local high points. During the grinding process, repeated trial fitting and measurement are performed until the feeler gauge cannot be inserted into the mating surface of the keyway and key, ensuring the clearance is controlled within the allowable assembly range. This method flexibly corrects machining errors, improves assembly fit, and ensures power transmission stability. Therefore, the present invention not only improves machining stability but also flexibly corrects machining errors and improves assembly fit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure in this invention.

[0020] Figure 2 This is a schematic diagram of the rudder shaft in this invention.

[0021] Figure 3 This is a schematic diagram of the structure of the keyway in the inner hole of a rotary part in this invention.

[0022] Figure 4 In this invention Figure 2 A schematic diagram of direction C.

[0023] Figure 5 This is a top view of the tool holder cooperating with the slotting machine spindle in this invention.

[0024] Figure 6 This is a schematic diagram of the structure of the tool holder and the slotting machine spindle in this invention.

[0025] Figure 7 This is a schematic diagram of the tool holder structure in this invention.

[0026] Figure 8 This is a top view of the tool holder in this invention.

[0027] Figure 9 This is a top view of the roughing tool in this invention.

[0028] Figure 10 This is a front view of the roughing tool in this invention.

[0029] Figure 11 This is a front view of the finishing tool in this invention.

[0030] Figure 12 This is a top view of the finishing tool in this invention.

[0031] In the diagram: Rotary parts 1, blind hole 2, first keyway 21, second keyway 22, slotting machine table 31, slotting machine spindle 32, tool holder mounting bracket 321, locking screw 322, locking screw 33, pressure plate 34, high-speed rail 35, locking nut 36, tool holder 41, tool holder large end 411, tool holder small end 412, threaded lifting hole 413, blade mounting hole 414, threaded fixing hole 415, roughing tool 42, roughing tool body 421, roughing tool holder 422, upper end face 423, lower end face 424, front end face 425, rear end face 426, left end face 427, right end face 428, finishing tool 43, finishing tool body 431, finishing tool holder 432, main cutting edge 433, side cutting edge 434, arc-shaped groove 435, rudder shaft 5, flange 51, protruding fan-shaped 52. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] See Figure 1 — Figure 12 A method for machining the internal keyway of a rotating part, the method comprising the following steps: Step 1: Place the rotary part 1 to be processed on the slotting machine table 31 with the blind hole 2 opening end facing upwards, pre-fix the end away from the blind hole 2 opening end, and finely adjust the position of the rotary part 1 so that the rotation center of the rotary part 1 is consistent with the center of the slotting machine spindle 32. Then lock and fix the slotting machine table 31 and the rotary part 1. Step 2: After the above-mentioned rotary part 1 is fixed, first install the tool holder 41 on the spindle 32 of the slotting machine, then adjust the position of the tool holder 41 so that the generatrix runout of the tool holder 41 meets the processing requirements, then lock and fix the spindle 32 of the slotting machine and the tool holder 41, and re-inspect the generatrix runout of the tool holder 41. Step 3: First, install the roughing tool 42 at the lower end of the tool holder 41 and perform positioning and calibration. Control the slotting machine spindle 32 to drive the roughing tool 42 to perform roughing on one side of the inner wall of the blind hole 2 until the first keyway 21 that meets the preset roughing value is formed. Then, completely remove the roughing tool 42 from the blind hole 2. Then, rotate the slotting machine table 31 180° and control the slotting machine spindle 32 to drive the roughing tool 42 to perform roughing on the symmetrical side of the first keyway 21 to produce a second keyway 22 that is consistent with and symmetrical to the first keyway 21. Then, completely remove the roughing tool 42 from the blind hole 2. Step 4: Remove the roughing tool 42, install the finishing tool 43 at the lower end of the tool holder 41 and perform positioning and calibration, control the slotting machine spindle 32 to drive the finishing tool 43 to perform finishing cut on the first keyway 21 until the first keyway 21 meets the finishing preset value, then completely remove the finishing tool 43 from the blind hole 2, rotate the slotting machine table 31 180°, control the slotting machine spindle 32 to drive the finishing tool 43 to perform finishing cut on the second keyway 22 until the second keyway 22 meets the finishing preset value, then completely remove the finishing tool 43 from the blind hole 2, and then remove the finishing tool 43. Step 5: Remove the rotary part 1 from the slotting machine worktable 31, and check the fit clearance between the first keyway 21, the second keyway 22 and the part to be assembled by the mating test. Grind the surfaces of the first keyway 21 and the second keyway 22 according to the fit clearance until the fit clearance meets the requirements, and complete the machining of the inner hole keyway.

[0034] The rotary parts 1 include shaft parts and disc parts.

[0035] In the first step, the pre-fixing of the end away from the opening of the blind hole 2 means: first, inserting the locking screw 33 into the slot of the slotting machine worktable 31, while keeping the rotating part 1 in a vertical state; then, placing the equalizing iron 35 under the pressure plate 34; by adjusting the height of the equalizing iron 35, pressing the pressure plate 34 against the end of the rotating part 1 away from the opening of the blind hole 2; then rotating the locking nut 36 to perform preliminary tightening, so that the rotating part 1 does not shake but leaves room for adjustment. In the first step, the step of finely adjusting the position of the rotary part 1 so that the rotation center of the rotary part 1 is consistent with the center of the slotting machine spindle 32 means: measuring the runout between the blind hole 2 of the rotary part 1 and the slotting machine spindle 32, and adjusting the position of the rotary part 1 until the runout between the blind hole 2 of the rotary part 1 and the slotting machine spindle 32 is less than or equal to 0.02mm. At this time, the rotation center of the rotary part 1 is consistent with the center of the slotting machine spindle 32. In the first step, locking the slotting machine table 31 to the rotary part 1 means: tightening the locking nut 36 so that the pressure plate 34 applies a stable clamping force to the rotary part 1 through the high-speed rail 35, ensuring that the rotary part 1 cannot move along the slotting machine table 31.

[0036] In the second step, the tool holder 41 includes a large end 411 and a small end 412. The large end 411 of the tool holder is connected to the small end 412 of the tool holder. The upper end face of the large end 411 of the tool holder is provided with a threaded lifting hole 413. The lower part of the small end 412 of the tool holder is provided with a radially penetrating blade mounting hole 414. The lower end face of the small end 412 of the tool holder is provided with a threaded fixing hole 415, which communicates with the blade mounting hole 414. The outer diameter of the small end 412 of the tool holder is smaller than the inner diameter of the blind hole 2, and the length of the small end 412 of the tool holder is greater than the height of the blind hole 2.

[0037] In the second step, installing the tool holder 41 on the slotting machine spindle 32 means: installing a lifting eye screw at the threaded lifting hole 413, lifting the tool holder 41 vertically into the tool holder mounting bracket 321 of the slotting machine spindle 32 by the lifting eye screw, adjusting the installation height of the tool holder 41, and pre-fixing the large end 411 of the tool holder to the tool holder mounting bracket 321 by the locking screw 322; In the second step, adjusting the position of the tool holder 41 to ensure that its generatric runout meets the machining requirements, then locking the slotting spindle 32 to the tool holder 41 and rechecking the generatric runout of the tool holder 41 means: first, measuring the generatric runout of the tool holder 41; if the generatric runout of the tool holder 41 is greater than 0.02mm, then adjusting the position of the tool holder 41 until the generatric runout of the tool holder 41 is less than or equal to 0.02mm; then, using locking screws 322 to lock the large end 411 of the tool holder to the tool holder mounting bracket 321; and then rechecking the generatric runout of the tool holder 41 to ensure that the generatric runout of the tool holder 41 after locking is less than or equal to 0.02mm.

[0038] In the third step, the roughing tool 42 includes a roughing tool body 421 and a roughing tool holder 422; the roughing tool holder 422 is adapted to the insert mounting hole 414. The roughing tool body 421 includes an upper end face 423, a lower end face 424, a front end face 425, a rear end face 426, a left end face 427, and a right end face 428. One side of the upper end face 423 is connected to the top edge of the rear end face 426, the bottom edge of the rear end face 426 is connected to one side of the lower end face 424, the other side of the lower end face 424 is connected to the bottom edge of the front end face 425, and the top edge of the front end face 425 is connected to the other side of the upper end face 423. The left end face 427 and the right end face 428 are respectively connected to the two side edges of the upper end face 423, the lower end face 424, the front end face 425, and the rear end face 426, forming a closed hexahedral structure. The width and length of the upper end face 423 are smaller than the width and length of the lower end face 424, respectively. The lower end face 424 is an isosceles trapezoid, and the base of the lower end face 424 is the main cutting edge. The front end face 425 and the rear end face 426 are symmetrical right trapezoids. The intersection lines of the front end face 425 and the rear end face 426 with the lower end face 424 respectively form side cutting edges. The left end face 427 is an inclined plane and is an isosceles trapezoid. The right end face 428 is fixedly connected to the end face of the roughing tool holder 422.

[0039] In the third step, installing the roughing tool 42 at the lower end of the tool holder 41 and performing positioning calibration means: inserting the roughing tool holder 422 into the blade mounting hole 414 of the small end 412 of the tool holder, adjusting the position, and then using a screw to press and fix the roughing tool holder 422 through the threaded fixing hole 415. After pressing, the distance from the lower end face 424 of the roughing tool 42 to the lower end face of the screw is less than the length of the tool relief groove of the first keyway 21 and the second keyway 22. Then, positioning calibration is performed through tool setting operation. In the third step, controlling the slotting spindle 32 to drive the roughing tool 42 to perform roughing on one side of the inner wall of the blind hole 2 until the first keyway 21 that meets the preset roughing value means: setting the radial feed of the slotting spindle 32 as the roughing feed, the main cutting edge of the roughing tool body 421 cutting radially into the blind hole 2, and the side cutting edge controlling the width of the keyway; measuring the depth and width of the keyway after each slotting operation until the depth and width of the keyway reach the preset roughing allowance, thus forming the first keyway 21; In the third step, rotating the slotting table 31 by 180° and controlling the slotting spindle 32 to drive the roughing tool 42 to perform rough slotting on the symmetrical side of the first keyway 21 to produce a second keyway 22 that is consistent with and symmetrical to the first keyway 21 means: keeping the slotting parameters unchanged, rotating the slotting table 31 by 180° so that the roughing tool 42 is aligned with the symmetrical position of the first keyway 21, repeating the above slotting process to produce a second keyway 22 that is consistent with the first keyway 21; In the third step, the step of completely disengaging the roughing tool 42 from the blind hole 2 means that after the roughing is completed, the spindle 32 of the slotting machine is controlled to drive the roughing tool 42 to rise axially until the roughing tool body 421 is completely withdrawn from the opening end of the blind hole 2.

[0040] In the fourth step, the finishing tool 43 includes a finishing tool body 431 and a finishing tool holder 432; the finishing tool holder 432 is adapted to the cutting tool mounting hole 414; The finishing cutter body 431 is connected to the finishing cutter handle 432. The finishing cutter body 431 includes a main cutting edge 433 and a side cutting edge 434. The surface of the main cutting edge 433 is provided with an arc-shaped groove 435 that is recessed into the cutter body. The side cutting edges 434 are symmetrically distributed on both sides of the main cutting edge 433 and connected vertically.

[0041] In the fourth step, installing the finishing tool 43 at the lower end of the tool holder 41 and performing positioning calibration means: inserting the finishing tool holder 432 into the blade mounting hole 414 of the small end 412 of the tool holder, adjusting the position, and then using a screw to press and fix the finishing tool holder 432 through the threaded fixing hole 415. After pressing, the distance from the lower end of the finishing tool 43 to the lower end face of the screw is less than the length of the tool relief groove of the first keyway 21 and the second keyway 22. Then, positioning calibration is performed through tool setting operation. In the fourth step, controlling the slotting spindle 32 to drive the finishing tool 43 to perform fine slotting on the first keyway 21 until the first keyway 21 meets the preset finishing value means: setting the radial feed of the slotting spindle 32 to 1 / 5-1 / 10 of the roughing feed, finishing the bottom and depth direction of the first keyway 21 through the main cutting edge 433, controlling the width of the first keyway 21 through the side cutting edge 434, measuring the depth and width of the first keyway 21 after each slotting, until the depth and width of the first keyway 21 reach the preset finishing allowance; In the fourth step, after rotating the slotting table 31 by 180°, controlling the slotting spindle 32 to drive the finishing tool 43 to perform fine slotting on the second keyway 22 until the second keyway 22 meets the preset finishing value means: keeping the slotting parameters unchanged, rotating the slotting table 31 by 180°, aligning the finishing tool 43 with the position of the second keyway 22, and repeating the above fine slotting process to ensure that the second keyway 22 is consistent with the first keyway 21; In the fourth step, the step of completely disengaging the finishing tool 43 from the blind hole 2 means that after the finishing cut is completed, the spindle 32 of the cutting machine is controlled to drive the finishing tool 43 to rise axially until the finishing tool body 431 is completely removed from the opening end of the blind hole 2.

[0042] In the fifth step, the step of testing the fit clearance between the first keyway 21, the second keyway 22 and the part to be assembled by means of: first, test fitting the key of the part to be assembled with the first keyway 21 and the second keyway 22, and then measuring the fit clearance with a feeler gauge. In the fifth step, grinding the surfaces of the first keyway 21 and the second keyway 22 according to the fit clearance until the fit clearance meets the requirements means: using a file or scraper to grind the surfaces of the first keyway 21 and the second keyway 22 until a 0.02mm feeler gauge cannot be inserted, and the fit clearance meets the assembly and use requirements.

[0043] The following are supplementary descriptions of the present invention: Preferably, the large end 411 of the tool holder is a square column structure. The size of the large end 411 of the tool holder is adapted to the tool holder mounting bracket 321 of the slotting machine, so that the tool holder 41 can be firmly fixed on the slotting machine spindle 32 by multiple locking screws 322, providing sufficient rigid support for the tool holder 41 as a whole, and avoiding the impact of the tool holder 41 shaking on the keyway machining accuracy during slotting.

[0044] Preferably, the small end 412 of the tool holder is a slender cylinder, and the outer diameter of the small end 412 is smaller than the inner diameter of the blind hole 2 (to meet the processing requirements of the inner hole size Φ20-Φ200), so as to ensure that the small end 412 of the tool holder can be smoothly inserted into the blind hole 2 without interfering with the hole wall of the blind hole 2.

[0045] Preferably, the length of the small end 412 of the tool holder is greater than the height of the blind hole 2, so as to ensure that the tool in the tool mounting hole 414 can penetrate deep into the bottom of the blind hole 2 and meet the machining requirements of 160-200mm axial depth of the keyway.

[0046] The present invention preferably specifies that the height of the rotary part 1 does not exceed 1200mm and the weight does not exceed 5 tons. The height does not exceed 1200mm because the spindle travel of the slotting machine is limited; the weight does not exceed 5 tons because the load-bearing capacity of the machine tool is limited.

[0047] Example 1: See Figure 1 — Figure 12 A method for machining the internal keyway of a rotating part, the method comprising the following steps: Step 1: Place the rotary part 1 to be processed on the slotting machine table 31 with the blind hole 2 opening end facing upwards, pre-fix the end away from the blind hole 2 opening end, and finely adjust the position of the rotary part 1 so that the rotation center of the rotary part 1 is consistent with the center of the slotting machine spindle 32. Then lock and fix the slotting machine table 31 and the rotary part 1. Step 2: After the above-mentioned rotary part 1 is fixed, first install the tool holder 41 on the spindle 32 of the slotting machine, then adjust the position of the tool holder 41 so that the generatrix runout of the tool holder 41 meets the processing requirements, then lock and fix the spindle 32 of the slotting machine and the tool holder 41, and re-inspect the generatrix runout of the tool holder 41. Step 3: First, install the roughing tool 42 at the lower end of the tool holder 41 and perform positioning and calibration. Control the slotting machine spindle 32 to drive the roughing tool 42 to perform roughing on one side of the inner wall of the blind hole 2 until the first keyway 21 that meets the preset roughing value is formed. Then, completely remove the roughing tool 42 from the blind hole 2. Then, rotate the slotting machine table 31 180° and control the slotting machine spindle 32 to drive the roughing tool 42 to perform roughing on the symmetrical side of the first keyway 21 to produce a second keyway 22 that is consistent with and symmetrical to the first keyway 21. Then, completely remove the roughing tool 42 from the blind hole 2. Step 4: Remove the roughing tool 42, install the finishing tool 43 at the lower end of the tool holder 41 and perform positioning and calibration, control the slotting machine spindle 32 to drive the finishing tool 43 to perform finishing cut on the first keyway 21 until the first keyway 21 meets the finishing preset value, then completely remove the finishing tool 43 from the blind hole 2, rotate the slotting machine table 31 180°, control the slotting machine spindle 32 to drive the finishing tool 43 to perform finishing cut on the second keyway 22 until the second keyway 22 meets the finishing preset value, then completely remove the finishing tool 43 from the blind hole 2, and then remove the finishing tool 43. Step 5: Remove the rotary part 1 from the slotting machine worktable 31, and check the fit clearance between the first keyway 21, the second keyway 22 and the part to be assembled by the mating test. Grind the surfaces of the first keyway 21 and the second keyway 22 according to the fit clearance until the fit clearance meets the requirements, and complete the machining of the inner hole keyway.

[0048] Example 2: The basic content is the same as in Embodiment 1, except that the rotary parts 1 include shaft parts and disc parts.

[0049] In applications, shafts are core components in mechanical transmission systems that transmit torque and support rotating parts. They transmit power through rotational motion and bear radial or axial loads. Taking the rudder shaft as an example, as a key shaft component in a ship's steering gear, it transmits steering torque to the rudder blade to control the course through the cooperation of its internal keyway and matching key. The performance of the internal keyway directly affects the ship's maneuverability. Common shaft components also include motor shafts, gear shafts, and drive shafts, which are widely used in machine tools, automobiles, and other fields. Disc-shaped parts are rotating parts with a large radial dimension and a small axial thickness. They mainly serve the functions of axial positioning, sealing, transmission, or support. Common disc-shaped parts include flanges, gear discs, pulleys, brake discs, end caps, etc., which are used in mechanical equipment to realize functions such as power distribution, motion conversion, or structural support.

[0050] Example 3: The basic content is the same as in Embodiment 1, except that: in the first step, the pre-fixing of the end away from the opening of the blind hole 2 refers to: first, inserting the locking screw 33 into the slot of the slotting machine worktable 31, while keeping the rotating part 1 vertical; then, placing a height equalizer 35 under the pressure plate 34; by adjusting the height of the height equalizer 35, making the pressure plate 34 press down on the end of the rotating part 1 away from the opening of the blind hole 2; then, rotating the locking nut 36 for initial tightening, so that the rotating part 1 does not wobble but leaves room for adjustment; in the first step, by finely adjusting the position of the rotating part 1, so that the rotating part 1... The alignment of the rotation center with the center of the slotting machine spindle 32 means: measuring the runout of the blind hole 2 of the rotary part 1 and the slotting machine spindle 32, and adjusting the position of the rotary part 1 until the runout of the blind hole 2 of the rotary part 1 and the slotting machine spindle 32 is less than or equal to 0.02mm. At this time, the rotation center of the rotary part 1 is aligned with the center of the slotting machine spindle 32. In the first step, locking and fixing the slotting machine table 31 and the rotary part 1 means: tightening the locking nut 36 so that the pressure plate 34 applies a stable clamping force to the rotary part 1 through the high-speed rail 35, ensuring that the rotary part 1 cannot move along the slotting machine table 31.

[0051] In application, for blind hole parts such as rudder shafts with small inner diameters (specifically Φ75mm) and deep keyways (specifically axial depth 160-200mm), this pre-fixing and fine-tuning method can precisely adapt to their structural characteristics: The rudder shaft 5 is placed vertically on the slotting machine table 31 with one end of the flange 51 facing downwards. Stable support is formed by the back of the flange 51 and the protruding fan-shaped 52. The pressure of the pressure plate 34 is adjusted using the equalizer 35 (the height of which can be adjusted by adding shims) to avoid... Long shaft parts undergo bending deformation due to their own weight; by measuring the runout of the blind hole 2 and the slotting machine spindle 32 and controlling it to ≤0.02mm, it is ensured that the rotation center of the rudder shaft 5 is coaxial with the slotting machine spindle 32, laying a benchmark for the machining of symmetrical keyways, which can effectively avoid uneven force on the keyways on both sides due to center deviation; when locking, the pressure plate 34, through the stable clamping force applied by the equal high-speed rail 35, can resist the radial impact force of the tool on the inner wall of the blind hole during the slotting process, preventing the rudder shaft 5 from undergoing slight displacement during the machining process; When measuring the runout of the blind hole 2 of the rotary part 1 and the slotting machine spindle 32, fix the magnetic base of the dial indicator to the slotting machine spindle 32, and insert the dial indicator probe into the blind hole 2, perpendicularly against the inner wall of the blind hole 2 (select a suitable measurement position to ensure stable contact between the probe and the hole wall); manually and slowly rotate the slotting machine table 31 to drive the rotary part 1 to rotate synchronously, observe the swing of the dial indicator pointer, and record the maximum and minimum readings of the pointer. The difference between the two is the runout of the blind hole 2 and the slotting machine spindle 32; if the runout is greater than 0.02mm, loosen the pre-fixing device of the rotary part 1, slightly adjust its position on the table, and repeat the above measurement process until the runout shown by the dial indicator is less than or equal to 0.02mm. At this time, it can be determined that the rotation center of the rotary part 1 is consistent with the center of the slotting machine spindle 32.

[0052] Example 4: The basic content is the same as in Embodiment 1, except that: in the second step, the tool holder 41 includes a large end 411 and a small end 412; the large end 411 is connected to the small end 412, the upper end face of the large end 411 is provided with a threaded lifting hole 413, the lower part of the small end 412 is provided with a radially penetrating blade mounting hole 414, the lower end face of the small end 412 is provided with a threaded fixing hole 415, and the threaded fixing hole 415 communicates with the blade mounting hole 414; the outer diameter of the small end 412 is smaller than the inner diameter of the blind hole 2, and the length of the small end 412 is greater than the height of the blind hole 2.

[0053] In application, the large end 411 of the tool holder is fitted with the tool holder mounting bracket 321, and multi-point fixation is achieved through locking screws 322 (specifically 9 screws), which can effectively resist the impact force during planing machining and prevent the tool holder 41 from shaking and affecting machining accuracy. The threaded lifting hole 413 of the large end 411 of the tool holder can be fitted with eye bolts, which facilitates the stable installation of the tool holder 41 onto the spindle 32 of the planing machine with the help of lifting equipment (especially suitable for tool holders weighing more than 15Kg, which saves manpower and avoids the tool holder 41 from bumping and damaging the inner wall of the blind hole 2 during installation). The outer diameter of the small end 412 of the tool holder is smaller than the inner diameter of the blind hole 2 (suitable for Φ20-Φ200 inner holes), and the length is greater than the height of the blind hole 2, which ensures that the tool holder 41 can penetrate deep into the bottom of the blind hole 2 for machining (meeting 160-200mm). The keyway requires a certain axial depth (m), while avoiding interference with the hole wall; the radially penetrating insert mounting hole 414 and the threaded fixing hole 415 are connected, and the insert can be tightened from the end face by screws to ensure that the insert is firmly clamped and prevent the insert from loosening during broaching; the gap between the insert shank and the insert mounting hole 414 is the installation gap. The installation gap is set to be less than or equal to 1mm because: if the installation gap is too small (such as close to zero), it will be difficult to insert the insert shank into the mounting hole, increasing the difficulty of clamping; if the installation gap is too large (more than 1mm), the stability of the insert clamping cannot be guaranteed. During broaching, the insert is prone to shaking due to radial cutting force, resulting in keyway size deviation, excessive surface roughness, and may even cause problems such as insert loosening and tool damage.

[0054] Example 5: The basic content is the same as in Embodiment 1, except that: in the second step, installing the tool holder 41 on the slotting spindle 32 means: installing a lifting eye screw at the threaded lifting hole 413, lifting the tool holder 41 vertically into the tool holder mounting bracket 321 of the slotting spindle 32 using the lifting eye screw, adjusting the installation height of the tool holder 41, and then pre-fixing the large end 411 of the tool holder to the tool holder mounting bracket 321 using the locking screw 322; in the second step, adjusting the position of the tool holder 41 so that the generatrix runout of the tool holder 41 meets the machining requirements, then... Then, lock and fix the slotting machine spindle 32 and the tool holder 41, and recheck the generatrix runout of the tool holder 41. This means: first, measure the generatrix runout of the tool holder 41. If the generatrix runout of the tool holder 41 is greater than 0.02mm, adjust the position of the tool holder 41 until the generatrix runout of the tool holder 41 is less than or equal to 0.02mm. Then, use the locking screw 322 to lock and fix the large end 411 of the tool holder to the tool holder mounting bracket 321. Then, recheck the generatrix runout of the tool holder 41 to ensure that the generatrix runout of the tool holder 41 after locking and fixing is less than or equal to 0.02mm.

[0055] In application, measure the runout of the generatrix of the tool holder 41. Fix the magnetic dial indicator base to the bed or worktable 31 of the slotting machine, and place the dial indicator probe perpendicularly against the generatrix (i.e., the axial contour line) of the tool holder 41. Manually or start the slotting machine spindle 32 to drive the tool holder 41 to reciprocate up and down, and observe the swing range of the dial indicator pointer to determine the runout of the generatrix of the tool holder 41. If the runout is greater than 0.02mm, loosen the pre-fixed locking screws 322 and fine-tune the angular position of the tool holder 41 in the mounting bracket to eliminate the deviation caused by the installation tilt of the tool holder 41. When the runout is ≤0.02mm, tighten all locking screws 322. 22. Rigid fixation is achieved by the tight fit between the large end 411 of the tool holder and the tool holder mounting bracket 321. The runout is checked after fixation because the tool holder 41 may have slight positional changes due to uneven force during the locking process. The check ensures that the runout is maintained within the range of ≤0.02mm, which effectively avoids uneven force on the cutting edge during the roughing stage and deviation of the main cutting edge and side cutting edge trimming allowance during the finishing stage due to the sway of the generatrix of the tool holder 41 during broaching. This ensures that the symmetry and dimensional accuracy of the keyway meet the design requirements, and is especially suitable for the machining needs of shaft and disc parts with inner holes of Φ20-Φ200 and keyway depths of 160-200mm.

[0056] Example 6: The basic content is the same as in Embodiment 1, except that: in the third step, the roughing tool 42 includes a roughing tool body 421 and a roughing tool holder 422; the roughing tool holder 422 is adapted to the insert mounting hole 414; the roughing tool body 421 includes an upper end face 423, a lower end face 424, a front end face 425, a rear end face 426, a left end face 427, and a right end face 428; one side of the upper end face 423 is connected to the top edge of the rear end face 426, the bottom edge of the rear end face 426 is connected to one side of the lower end face 424, the other side of the lower end face 424 is connected to the bottom edge of the front end face 425, and the top edge of the front end face 425 is connected to the other side of the upper end face 423. The left end face 427 and the right end face 428 are respectively connected to the two sides of the upper end face 423, the lower end face 424, the front end face 425, and the rear end face 426, forming a closed hexahedral structure. The width and length of the upper end face 423 are smaller than the width and length of the lower end face 424, and the lower end face 424 is an isosceles trapezoid with the base of the lower end face 424 as the main cutting edge. The front end face 425 and the rear end face 426 are symmetrical right trapezoids, and the intersection lines of the front end face 425 and the rear end face 426 with the lower end face 424 form side cutting edges. The left end face 427 is an inclined plane and an isosceles trapezoid. The right end face 428 is fixedly connected to the end face of the roughing tool holder 422.

[0057] In application, the roughing tool 42 is made entirely of high-speed steel (specifically, white steel strip), possessing excellent strength and wear resistance. The hexahedral structure of the roughing tool 42 achieves precise cutting through the specific shapes of each end face. The isosceles trapezoidal base of the lower end face 424 serves as the main cutting edge, undertaking the main cutting task in the radial depth direction. Combined with the side cutting edge formed by the intersection of the front end face 425, the rear end face 426, and the lower end face 424, the keyway width can be controlled simultaneously. The width and length of the upper end face 423 are smaller than those of the lower end face 424, respectively. Combined with the inclined structure of the left end face 427, the chip removal space can be effectively optimized, preventing chips from accumulating in the blind hole 2. The symmetrical right-angled trapezoidal structure of the front end face 425 and the rear end face 426 can make the cutting force uniform on both sides of the keyway, reducing machining vibration. Combined with the clamping and fixing of the screw from the threaded fixing hole 415, it ensures that the tool does not loosen during the planing process. The axial length of the roughing tool body 421 is greater than the designed radial depth of the first keyway 21 and the second keyway 22, so as to ensure that the radial depth of the keyway machining is covered; the width (base of the isosceles trapezoid) of the lower end face 424 is less than the designed width of the first keyway 21 and the second keyway 22, so as to meet the allowance requirements during roughing.

[0058] Example 7: The basic content is the same as in Embodiment 1, except that: in the third step, installing the roughing tool 42 at the lower end of the tool holder 41 and performing positioning calibration means: inserting the roughing tool holder 422 into the blade mounting hole 414 of the small end 412 of the tool holder, adjusting the position, and then using a screw to pass through the threaded fixing hole 415 to press and fix the roughing tool holder 422. After pressing, the distance from the lower end face 424 of the roughing tool 42 to the lower end face of the screw is less than the length of the retraction groove of the first keyway 21 and the second keyway 22. Then, positioning calibration is performed through tool setting operation. In the third step, controlling the slotting machine spindle 32 to drive the roughing tool 42 to perform roughing on one side of the inner wall of the blind hole 2 until the first keyway 21 that meets the roughing preset value means: setting the radial feed of the slotting machine spindle 32 as the roughing feed, and the main cutting edge of the roughing tool body 421 cutting radially into the blind hole 2. The side cutting edge controls the keyway width; after each cutting, the depth and width of the keyway are measured until the depth and width of the keyway reach the preset roughing allowance, forming the first keyway 21; in the third step, rotating the slotting machine table 31 by 180° and controlling the slotting machine spindle 32 to drive the roughing tool 42 to perform rough cutting on the symmetrical side of the first keyway 21 to produce a second keyway 22 that is consistent with and symmetrical to the first keyway 21 means: keeping the slotting machine parameters unchanged, rotating the slotting machine table 31 by 180° so that the roughing tool 42 is aligned with the symmetrical position of the first keyway 21, repeating the above cutting process to produce a second keyway 22 that is consistent with the first keyway 21; in the third step, completely removing the roughing tool 42 from the blind hole 2 means: after the rough cutting is completed, controlling the slotting machine spindle 32 to drive the roughing tool 42 to rise axially until the roughing tool body 421 completely exits the opening end of the blind hole 2.

[0059] In application, the clearance between the roughing tool holder 422 and the insert mounting hole 414 is controlled within 1mm. It is secured by screws from the threaded fixing hole 415 to ensure the tool is firmly clamped. After clamping, the distance from the lower end face 424 of the roughing tool 42 to the lower end face of the screw is less than the length of the relief groove of the first keyway 21 and the second keyway 22. This is to avoid the tool interfering with the relief groove of the blind hole 2 when it is cutting to the bottom of the keyway, ensuring that the keyway length is machined to the correct position, and preventing damage to the parts, tools and machine tools. During tool setting, the roughing tool 42 is moved to the upper end face of the blind hole 2, so that the small end 412 of the tool holder and the tip of the roughing tool body 421 extend into the blind hole 2, ensuring that the tip is close to the inner wall of the blind hole 2 but does not contact it. Then, a feeler gauge (specifically 0.1mm or 0.05mm) is inserted between the tip of the roughing tool body 421 and the inner wall of the blind hole 2 to check and record the gap value. The roughing tool 42 is then slowly moved so that the tip gradually approaches the inner wall of the blind hole 2 until the feeler gauge cannot be inserted (i.e., the tip contacts the workpiece blank). This position is the machining reference point. Using this reference point as a reference, combined with the preset roughing allowance (such as reserving a 1mm depth allowance) and roughing feed rate, the initial cutting position of the tool is determined to ensure that the main cutting edge can accurately cut into the blind hole 2 radially during subsequent planing, providing an initial reference for the control of the keyway depth and width, and avoiding keyway size deviation due to the initial position deviation of the tool. During planing, a roughing feed rate of 0.5-1mm (i.e., radial feed rate, 5-10 times that of finishing feed rate) is used to balance machining efficiency and quality. If the feed rate is too small (less than 0.5mm), machining efficiency will be significantly reduced; if the feed rate is too large (greater than 1mm), it will easily lead to accelerated tool wear and increased impact force between the tool and the workpiece, which will not only affect the stability of machining quality but may also damage the tool and machine tool. During the machining process, the first cut is made through the front end face 425, the rear end face 426, the lower end face 424, and the left end face 427. Subsequent cuts are made using... The cutting efficiency is ensured by trimming the intersection line of the front end face 425 and the lower end face 424. After machining the first keyway 21, the worktable is rotated 180° to directly machine the symmetrical positions. The symmetry of the keyways on both sides is ensured by the machine tool's own precision, eliminating the need for secondary tool setting. This effectively shortens the machining cycle and avoids the accumulation of errors caused by repeated tool setting, ensuring that the depth and width of the second keyway 22 are consistent with those of the first keyway 21. The rough machining preset depth allowance is 1mm and the width allowance is 1mm on each side, which provides sufficient trimming space for subsequent finishing.

[0060] Example 8: The basic content is the same as in Embodiment 1, except that in the fourth step, the finishing tool 43 includes a finishing tool body 431 and a finishing tool holder 432; the finishing tool holder 432 is adapted to the blade mounting hole 414; the finishing tool body 431 is connected to the finishing tool holder 432, the finishing tool body 431 includes a main cutting edge 433 and a side cutting edge 434, the surface of the main cutting edge 433 is provided with an arc-shaped groove 435 that is recessed into the tool body, and the side cutting edges 434 are symmetrically distributed on both sides of the main cutting edge 433 and vertically connected.

[0061] In application, the finishing tool 43 is made of cemented carbide, which, with its high hardness and wear resistance, can meet the surface roughness requirements of finishing; the vertical distribution of the main cutting edge 433 and the side cutting edge 434 precisely matches the machining requirements of the bottom and two sides of the keyway. The width of the main cutting edge 433 is less than the designed width of the first keyway 21, allowing for one-time trimming of the 1mm width allowance reserved on one side during rough machining. The side cutting edge 434 ensures the parallelism of the two sides of the keyway through symmetrical cutting. The arc-shaped groove 435 on the surface of the main cutting edge 433 guides the chips to be discharged upward along the arc surface, avoiding accumulation in the blind hole 2 and scratching the machined surface, thus improving the surface finish and meeting the roughness requirements for the bottom of the keyway. The axial length of the finishing tool body 431 is greater than the designed radial depth of the first keyway 21, ensuring that the main cutting edge 433 can completely cover the depth range of the keyway. Combined with the radial feed, it can achieve micro-cutting, improve the flatness of the bottom and sides of the keyway, and is suitable for machining parts such as rudder shafts that have extremely high requirements for keyway assembly accuracy.

[0062] Example 9: The basic content is the same as in Embodiment 1, except that: in the fourth step, installing the finishing tool 43 at the lower end of the tool holder 41 and performing positioning calibration means: inserting the finishing tool holder 432 into the blade mounting hole 414 of the small end 412 of the tool holder, adjusting the position, and then using a screw to pass through the threaded fixing hole 415 to press and fix the finishing tool holder 432. After pressing, the distance from the lower end of the finishing tool 43 to the lower end face of the screw is less than the length of the relief groove of the first keyway 21 and the second keyway 22. Then, positioning calibration is performed through tool setting operation; in the fourth step, controlling the slotting machine spindle 32 to drive the finishing tool 43 to perform finishing slotting on the first keyway 21 until the first keyway 21 meets the finishing preset value means: setting the radial feed of the slotting machine spindle 32 to 1 / 5-1 / 10 of the roughing feed, and finishing the bottom of the first keyway 21 and the main cutting edge 433. In the depth direction, the side cutting edge 434 controls the width of the first keyway 21. After each cutting, the depth and width of the first keyway 21 are measured until the depth and width of the first keyway 21 reach the preset finishing allowance. In the fourth step, after rotating the cutting table 31 by 180°, the cutting spindle 32 is controlled to drive the finishing tool 43 to perform finishing cutting on the second keyway 22 until the second keyway 22 meets the preset finishing value. This means: keeping the cutting parameters unchanged, rotating the cutting table 31 by 180°, aligning the finishing tool 43 with the position of the second keyway 22, and repeating the above finishing cutting process to ensure that the second keyway 22 is consistent with the first keyway 21. In the fourth step, the finishing tool 43 is completely removed from the blind hole 2. This means: after the finishing cutting is completed, the cutting spindle 32 is controlled to drive the finishing tool 43 to rise axially until the finishing tool body 431 is completely removed from the opening end of the blind hole 2.

[0063] During application, in the installation stage of the finishing tool 43, the clearance between the finishing tool holder 432 and the insert mounting hole 414 is controlled within 1mm. The screw is axially pressed from the threaded fixing hole 415 to ensure that the tool does not loosen during high-frequency micro-cutting and to avoid keyway size fluctuations caused by tool holder movement. The distance from the lower end of the finishing tool 43 to the lower end face of the screw is less than the length of the relief groove of the first keyway 21 and the second keyway 22, which can prevent the tool from interfering with the relief groove at the bottom of the blind hole 2 during precision insertion and ensure a complete transition between the bottom of the keyway and the relief groove. Positioning and calibration are performed by tool setting: the finishing tool 43 is moved to the upper end face of the blind hole 2, so that the tip of the finishing tool 43 extends into the hole and approaches the surface of the rough-machined keyway. The initial gap between the tool tip and the side wall of the keyway is calibrated by a 0.05mm or 0.1mm feeler gauge. The tool is slowly moved until the feeler gauge cannot be inserted (i.e. the tool tip is in contact with the rough-machined surface). The feed rate is set based on this to ensure machining accuracy. During fine planing, the radial feed rate is 1 / 5 to 1 / 10 of the roughing feed rate (specifically 0.1 to 0.2 mm, processed in multiple passes). This is combined with the main cutting edge 433 for fine finishing of the bottom and depth of the keyway, and the side cutting edge 434 for precise control of the width. The depth and width are measured after each planing pass until the preset finishing allowance is reached. The preset finishing allowance is: depth machined to the design value, and width 0.1 mm on each side. The parameters remain unchanged after the worktable is rotated 180°. The symmetry of the keyway is ensured by the rotation of the machine tool. This eliminates the need for secondary tool setting, shortens the machining time, and avoids the accumulation of errors from repeated calibration. Finally, the tool is completely withdrawn from the blind hole 2 to prevent the cutting edge from scratching the machined surface.

[0064] Example 10: The basic content is the same as in Example 1, except that: in the fifth step, the step of testing the fit clearance between the first keyway 21, the second keyway 22 and the part to be assembled by means of: first, test fitting the key of the part to be assembled with the first keyway 21 and the second keyway 22, and then measure the fit clearance with a feeler gauge; in the fifth step, the step of grinding the surface of the first keyway 21 and the second keyway 22 according to the fit clearance until the fit clearance meets the requirements means: use a file or scraper to grind the surface of the first keyway 21 and the second keyway 22 until a 0.02mm feeler gauge cannot be inserted, and the fit clearance meets the assembly and use requirements.

[0065] In application, the key of the part to be assembled is initially fitted with the first keyway 21 and the second keyway 22. A feeler gauge is used to check the gap point by point, accurately locating the areas on the keyway surface that need grinding (such as localized protrusions on the sides of the keyway or tiny burrs on the bottom). Grinding is done manually with a file or scraper, using the sharp edge of the tool to finely adjust the 0.1mm single-sided allowance. This removes tool marks left from roughing and finishing, and allows for minor adjustments to the keyway dimensions, ultimately ensuring that a 0.02mm feeler gauge cannot be inserted into the fit gap, guaranteeing a tight fit between the key and the keyway. This process fully utilizes… By leveraging the flexibility of manual operation by fitters, minor errors that may exist in machining can be compensated for: for deep cavity structures such as blind holes, inner holes, and keyways that are difficult for cutting tools to fully reach, machining can easily leave machining marks near the relief groove or at the corners of the keyway, while manual grinding can specifically address these details and ensure that the surface roughness of the keyway meets the requirements; at the same time, the fit clearance is controlled within 0.02mm, which can avoid impact vibration caused by excessive clearance when the rudder shaft transmits torque, or assembly difficulties caused by interference fit, ultimately meeting the power transmission stability requirements of the rudder shaft and coupling during long-term operation.

[0066] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A method for machining the keyway in the inner hole of a rotating part, characterized in that: The method for machining the internal keyway includes the following steps: Step 1: Place the rotary part (1) to be processed on the slotting machine table (31) with the blind hole (2) opening end facing upwards. Pre-fix one end away from the blind hole (2) opening end. By finely adjusting the position of the rotary part (1), make the rotation center of the rotary part (1) consistent with the center of the slotting machine spindle (32). Then lock and fix the slotting machine table (31) and the rotary part (1). Step 2: After the above-mentioned rotary parts (1) are fixed, first install the tool holder (41) on the spindle (32) of the slotting machine, then adjust the position of the tool holder (41) so that the generatrix runout of the tool holder (41) meets the processing requirements, then lock the spindle (32) of the slotting machine and the tool holder (41) and recheck the generatrix runout of the tool holder (41); Step 3: First, install the roughing tool (42) at the lower end of the tool holder (41) and perform positioning calibration. Control the slotting machine spindle (32) to drive the roughing tool (42) to perform roughing on one side of the inner wall of the blind hole (2) until the first keyway (21) that meets the preset roughing value is formed. Then, completely remove the roughing tool (42) from the blind hole (2). Then, rotate the slotting machine table (31) 180° and control the slotting machine spindle (32) to drive the roughing tool (42) to perform roughing on the symmetrical side of the first keyway (21) to produce a second keyway (22) that is consistent with and symmetrical to the first keyway (21). Then, completely remove the roughing tool (42) from the blind hole (2). Step 4: Remove the roughing tool (42), install the finishing tool (43) at the lower end of the tool holder (41) and perform positioning calibration. Control the slotting machine spindle (32) to drive the finishing tool (43) to perform fine slotting on the first keyway (21) until the first keyway (21) meets the preset value for finishing. Then, completely remove the finishing tool (43) from the blind hole (2). After rotating the slotting machine table (31) 180°, control the slotting machine spindle (32) to drive the finishing tool (43) to perform fine slotting on the second keyway (22) until the second keyway (22) meets the preset value for finishing. Then, completely remove the finishing tool (43) from the blind hole (2) and remove the finishing tool (43). Step 5: Remove the rotary part (1) from the slotting machine worktable (31), check the fit clearance between the first keyway (21), the second keyway (22) and the part to be assembled by the mating test, grind the surface of the first keyway (21) and the second keyway (22) according to the fit clearance until the fit clearance meets the requirements, and complete the machining of the inner hole keyway.

2. The method for machining the keyway in the inner hole of a rotary part according to claim 1, characterized in that: The rotating parts (1) include shaft parts and disc parts.

3. A method for machining the keyway in the inner hole of a rotary part according to claim 1 or 2, characterized in that: In the first step, the pre-fixing of the end away from the opening of the blind hole (2) means: first, insert the locking screw (33) into the slot of the slotting machine worktable (31), while keeping the rotary part (1) vertical, then place the equal height iron (35) under the pressure plate (34), and by adjusting the height of the equal height iron (35), press the pressure plate (34) against the end of the rotary part (1) away from the opening of the blind hole (2), and then rotate the locking nut (36) to perform preliminary tightening, so that the rotary part (1) does not shake but leaves room for adjustment; In the first step, the step of finely adjusting the position of the rotary part (1) so that the rotation center of the rotary part (1) is consistent with the center of the slotting machine spindle (32) means: measuring the runout between the blind hole (2) of the rotary part (1) and the slotting machine spindle (32), and adjusting the position of the rotary part (1) until the runout between the blind hole (2) of the rotary part (1) and the slotting machine spindle (32) is less than or equal to 0.02 mm. At this time, the rotation center of the rotary part (1) is consistent with the center of the slotting machine spindle (32). In the first step, locking the slotting machine table (31) and the rotary part (1) means: tightening the locking nut (36) so that the pressure plate (34) applies a stable clamping force to the rotary part (1) through the high-speed rail (35) to ensure that the rotary part (1) cannot move along the slotting machine table (31).

4. A method for machining the keyway in the inner hole of a rotary part according to claim 1 or 2, characterized in that: In the second step, the tool holder (41) includes a large end (411) and a small end (412). The large end (411) of the tool holder is connected to the small end (412). The upper end face of the large end (411) of the tool holder is provided with a threaded hoisting hole (413). The lower part of the small end (412) of the tool holder is provided with a radially penetrating blade mounting hole (414). The lower end face of the small end (412) of the tool holder is provided with a threaded fixing hole (415). The threaded fixing hole (415) is connected to the blade mounting hole (414). The outer diameter of the small end (412) of the tool holder is smaller than the inner diameter of the blind hole (2). The length of the small end (412) of the tool holder is greater than the height of the blind hole (2).

5. A method for machining the keyway in the inner hole of a rotating part according to claim 4, characterized in that: In the second step, the installation of the tool holder (41) on the slotting spindle (32) refers to: installing a lifting eye screw at the threaded lifting hole (413), lifting the tool holder (41) vertically into the tool holder mounting bracket (321) of the slotting spindle (32) by the lifting eye screw, adjusting the installation height of the tool holder (41), and pre-fixing the large end (411) of the tool holder to the tool holder mounting bracket (321) by the locking screw (322); In the second step, adjusting the position of the tool bar (41) to ensure that the generatrix runout of the tool bar (41) meets the machining requirements, then locking the spindle (32) of the slotting machine to the tool bar (41) and rechecking the generatrix runout of the tool bar (41) means: first measuring the generatrix runout of the tool bar (41), if the generatrix runout of the tool bar (41) is greater than 0.02mm, then adjusting the position of the tool bar (41) until the generatrix runout of the tool bar (41) is less than or equal to 0.02mm, then using the locking screw (322) to lock the large end (411) of the tool bar to the tool bar mounting bracket (321), and then rechecking the generatrix runout of the tool bar (41) to ensure that the generatrix runout of the tool bar (41) after locking is less than or equal to 0.02mm.

6. A method for machining the keyway in the inner hole of a rotary part according to claim 4, characterized in that: In the third step, the roughing tool (42) includes a roughing tool body (421) and a roughing tool holder (422); the roughing tool holder (422) is adapted to the insert mounting hole (414); The roughing tool body (421) includes an upper end face (423), a lower end face (424), a front end face (425), a rear end face (426), a left end face (427), and a right end face (428); one side of the upper end face (423) is connected to the top edge of the rear end face (426), the bottom edge of the rear end face (426) is connected to one side of the lower end face (424), the other side of the lower end face (424) is connected to the bottom edge of the front end face (425), and the top edge of the front end face (425) is connected to the other side of the upper end face (423); the left end face (427) and the right end face (428) are respectively connected to the two side edges of the upper end face (423), the lower end face (424), the front end face (425), and the rear end face (426), forming a closed hexahedral structure; The width and length of the upper end face (423) are smaller than the width and length of the lower end face (424), respectively. The lower end face (424) is an isosceles trapezoid, and the base of the lower end face (424) is the main cutting edge. The front end face (425) and the rear end face (426) are symmetrical right trapezoids. The intersection lines of the front end face (425) and the rear end face (426) with the lower end face (424) respectively form the side cutting edge. The left end face (427) is an inclined plane and is an isosceles trapezoid. The right end face (428) is fixedly connected to the end face of the roughing tool holder (422).

7. A method for machining the keyway in the inner hole of a rotary part according to claim 6, characterized in that: In the third step, installing the roughing tool (42) at the lower end of the tool holder (41) and performing positioning calibration means: inserting the roughing tool holder (422) into the blade mounting hole (414) of the small end (412) of the tool holder, adjusting the position, and then using a screw to press and fix the roughing tool holder (422) through the threaded fixing hole (415). After pressing, the distance from the lower end face (424) of the roughing tool (42) to the lower end face of the screw is less than the length of the tool relief groove of the first keyway (21) and the second keyway (22). Then, positioning calibration is performed through the tool setting operation. In the third step, the control of the slotting spindle (32) to drive the roughing tool (42) to perform roughing on one side of the inner wall of the blind hole (2) until the first keyway (21) that meets the preset roughing value is formed means: setting the radial feed of the slotting spindle (32) as the roughing feed, the main cutting edge of the roughing tool body (421) cuts into the blind hole (2) radially, and the side cutting edge controls the width of the keyway; after each slotting, the depth and width of the keyway are measured until the depth and width of the keyway reach the preset roughing allowance, thus forming the first keyway (21). In the third step, rotating the slotting table (31) by 180° and controlling the slotting spindle (32) to drive the roughing tool (42) to perform roughing on the symmetrical side of the first keyway (21) to produce a second keyway (22) that is consistent with and symmetrical to the first keyway (21) means: keeping the slotting parameters unchanged, rotating the slotting table (31) by 180°, aligning the roughing tool (42) with the symmetrical position of the first keyway (21), repeating the above slotting process, and producing a second keyway (22) that is consistent with the first keyway (21). In the third step, the step of completely removing the roughing tool (42) from the blind hole (2) means that after the roughing is completed, the spindle (32) of the slotting machine is controlled to drive the roughing tool (42) to rise axially until the roughing tool body (421) completely exits the opening end of the blind hole (2).

8. A method for machining the keyway in the inner hole of a rotary part according to claim 4, characterized in that: In the fourth step, the finishing tool (43) includes a finishing tool body (431) and a finishing tool holder (432); the finishing tool holder (432) is adapted to the cutting tool mounting hole (414); The finishing cutter body (431) is connected to the finishing cutter shank (432). The finishing cutter body (431) includes a main cutting edge (433) and a side cutting edge (434). The surface of the main cutting edge (433) is provided with an arc-shaped groove (435) that is recessed into the inside of the cutter body. The side cutting edges (434) are symmetrically distributed on both sides of the main cutting edge (433) and connected vertically.

9. A method for machining the keyway in the inner hole of a rotary part according to claim 8, characterized in that: In the fourth step, installing the finishing tool (43) at the lower end of the tool holder (41) and performing positioning calibration means: inserting the finishing tool holder (432) into the blade mounting hole (414) of the small end (412) of the tool holder, adjusting the position, and then using a screw to press and fix the finishing tool holder (432) through the threaded fixing hole (415). After pressing, the distance from the lower end of the finishing tool (43) to the lower end face of the screw is less than the length of the unloading groove of the first keyway (21) and the second keyway (22). Then, positioning calibration is performed through the tool setting operation. In the fourth step, the control of the slotting spindle (32) to drive the finishing tool (43) to perform fine slotting on the first keyway (21) until the first keyway (21) meets the preset finishing value means: setting the radial feed of the slotting spindle (32) to 1 / 5-1 / 10 of the roughing feed, finishing the bottom and depth direction of the first keyway (21) through the main cutting edge (433), controlling the width of the first keyway (21) with the side cutting edge (434), measuring the depth and width of the first keyway (21) after each slotting, until the depth and width of the first keyway (21) reach the preset finishing allowance; In the fourth step, after rotating the slotting table (31) by 180°, controlling the slotting spindle (32) to drive the finishing tool (43) to perform fine slotting on the second keyway (22) until the second keyway (22) meets the preset value of fine machining means: keeping the slotting parameters unchanged, rotating the slotting table (31) by 180°, aligning the finishing tool (43) with the position of the second keyway (22), repeating the above fine slotting process to ensure that the second keyway (22) is consistent with the first keyway (21); In the fourth step, the complete removal of the finishing tool (43) from the blind hole (2) means that after the finishing cut is completed, the spindle (32) of the cutting machine is controlled to drive the finishing tool (43) to rise axially until the finishing tool body (431) completely exits the opening end of the blind hole (2).

10. A method for machining the keyway in the inner hole of a rotary part according to claim 1 or 2, characterized in that: In the fifth step, the step of testing the fit clearance between the first keyway (21), the second keyway (22) and the part to be assembled by means of: first, test fit the key of the part to be assembled with the first keyway (21) and the second keyway (22), and then measure the fit clearance with a feeler gauge; In the fifth step, grinding the surfaces of the first keyway (21) and the second keyway (22) according to the fit clearance until the fit clearance meets the requirements means: grinding the surfaces of the first keyway (21) and the second keyway (22) with a file or scraper until a 0.02mm feeler gauge cannot be inserted, and the fit clearance meets the assembly and use requirements.

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