Long axis symmetrical keyway milling tooling
Patent Information
- Application Number
- CN202522299772.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-30
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-10-30
AI Technical Summary
Existing technologies struggle to efficiently and accurately machine symmetrical keyways on long shafts, especially when the shaft lacks sufficient rigidity. This results in low machining efficiency, poor precision, and complex operation, making it difficult to meet the demands of mass production.
The tooling structure includes three sets of clamping components and two sets of positioning components. The combination of T-screws and V-groove positioning blocks for clamping, along with connecting guide posts and anti-rotation waist-shaped heads, ensures the stable positioning and rotation of the long shaft on the milling machine table, enabling efficient machining of symmetrical keyways.
It significantly improves the machining accuracy and efficiency of long axis symmetrical keyways, reduces the difficulty of operation, reduces cumulative errors, and is suitable for mass production.
Smart Images
Figure CN224927467U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a special tooling for milling keyways of shaft parts, and particularly to a special tooling for milling symmetrical keyways of long shafts (shaft parts with a length-to-diameter ratio greater than 18), belonging to the field of milling tooling technology. Background Technology
[0002] The challenge in milling long-axis symmetrical keyways on a milling machine lies in ensuring the symmetry of the two keyways. For short shafts (shaft parts with a length-to-diameter ratio of less than 8), a dividing head and centers are generally used for positioning and clamping. One end of the short shaft is held in place by a center, and the other end is clamped by the three-jaw chuck of the dividing head—a clamping and holding method. Rotating the dividing head handle causes the three-jaw chuck to precisely rotate the short shaft 180°, thus ensuring the symmetry of the keyways on both sides of the machined short shaft.
[0003] When machining a long shaft whose length exceeds the length of the milling machine's worktable, the long shaft, due to its poor rigidity, is prone to instability and deformation under axial forces. Using a general-purpose tooling with a short shaft clamp and a center is insufficient to guarantee the rigidity of the long shaft, and there is also a lack of mounting positions for the center and indexing head. Currently, the machining of symmetrical keyways on long shafts generally employs a scribing alignment process. This involves scribing longitudinal reference lines on both sides of the long shaft's outer diameter at the center, ensuring the two reference lines are at the same height, allowing machining of the keyway on one side of the long shaft. Then, the long shaft is rotated 180° around its axis, again ensuring the two reference lines are at the same height, before machining the keyway on the other side. This machining process is inefficient, inaccurate, and the symmetry tolerance of the keyways on both sides of the milled long shaft is difficult to meet requirements. Furthermore, it requires a relatively high level of operator skill. Additionally, if the milling machine's machining stroke is insufficient, the long shaft needs to be moved axially, resulting in even greater cumulative errors, which is detrimental to mass production. Utility Model Content
[0004] The purpose of this invention is to provide a long axis symmetrical keyway milling fixture that is simple in structure, easy to clamp, and has high machining accuracy.
[0005] This utility model is achieved through the following technical solution:
[0006] A long-axis symmetrical keyway milling fixture includes three sets of clamping assemblies and at least two sets of positioning assemblies. The three sets of clamping assemblies, arranged at intervals, respectively clamp the long shaft at both ends and the middle. Each clamping assembly includes an upper pressure plate and two T-screws. The V-grooves in the middle of the upper pressure plate are located at the upper part of the corresponding positions on the outer circle of the long shaft. The lower ends of the T-screws are respectively embedded in the corresponding T-grooves of the milling machine worktable, and the upper ends of the T-screws respectively pass through both ends of the upper pressure plate. By screwing nuts onto the upper ends of the T-screws, the V-grooves in the middle of the upper pressure plate clamp the two ends of the long shaft. The positioning assemblies include upper and lower pairs. The machine consists of V-groove positioning blocks and two connecting guide pillars. The lower V-groove positioning blocks are spaced apart on the milling machine worktable, with the lower part of the lower V-groove positioning blocks positioned in the corresponding T-groove of the milling machine worktable. The middle part of the long shaft is supported on the lower V-groove positioning blocks, and the upper V-groove positioning blocks press on the middle part of the long shaft, with the upper and lower V-groove positioning blocks corresponding to each other. The connecting guide pillars pass through the guide holes at both ends of the upper and lower V-groove positioning blocks from bottom to top, and by tightening the nuts on the upper end of the connecting guide pillars, the middle part of the long shaft is positioned in the upper and lower V-groove positioning blocks.
[0007] The objective of this utility model can also be further achieved through the following technical measures.
[0008] Furthermore, a positioning key extends outward from the center of the V-groove plane away from the V-groove, and the two sides of the positioning key are clearance-fitted with the upper opening of the T-groove of the milling machine table. The clearance between the two sides of the positioning key and the upper opening of the T-groove of the milling machine table is 0.05 to 0.10 mm.
[0009] Furthermore, each end of the V-groove positioning block is provided with a guide hole. The connecting guide post passes through the guide holes at both ends of the upper and lower V-groove positioning blocks and is clearance-fitted with the corresponding guide hole. The clearance between the connecting guide post and the guide hole is 0.08 to 0.12 mm. Tighten the nuts on the upper screw of the connecting guide post to position the middle part of the long shaft in the two sets of V-groove positioning blocks arranged in pairs.
[0010] Furthermore, an anti-rotation waist-shaped head extends laterally from the lower end of the connecting guide post, and the anti-rotation waist-shaped head is embedded in the elongated countersunk hole at the lower end of the guide hole.
[0011] This invention features a simple and secure clamping mechanism. It minimizes cumulative errors during workpiece movement. It requires relatively low operator skill levels. It effectively improves processing efficiency and accuracy while saving time.
[0012] This invention employs a structure where locating keys are provided on both sides of the V-groove locating block away from the center of the plane opposite to the V-groove. It also features a structure where the guide holes at both ends of the upper and lower V-groove locating blocks, which clamp the middle of the long shaft, are fixedly connected as a single unit via clearance-fitted connecting guide posts. By simultaneously tightening the nuts on both sets of upper and lower V-groove locating blocks, the upper and lower surfaces of the tightened blocks become parallel. Furthermore, the clearance fit between the locating key on the lower side of the V-groove locating block and the upper opening of the T-slot on the milling machine table significantly reduces the straightness error when machining keyways arranged longitudinally on the long shaft. When machining several keyways on one side of the long shaft, if the working stroke of the keyway milling cutter is insufficient, the V-groove locating blocks can be moved along the T-slot on the milling machine table without affecting the machining accuracy of the keyways. When machining several keyways on the other side of a long shaft, simply move the two sets of upper and lower V-groove locating blocks, clamped and positioned in the middle of the long shaft, vertically upwards. This disengages the locating key on the lower side of the V-groove locating blocks from the T-slot of the milling machine table. Then, rotate the two sets of upper and lower V-groove locating blocks and the long shaft 180° along its axis. This causes the locating key, originally facing upwards, to face downwards and embed into the upper slot of the T-slot on the milling machine table. This allows for the sequential machining of several keyways on the other side of the long shaft. This invention features simple and secure clamping. It minimizes cumulative errors during workpiece movement. It requires a low level of operator skill. It effectively improves the machining efficiency and accuracy of symmetrical keyways, thereby significantly reducing the symmetry deviation of the machined keyways on both sides of the long shaft.
[0013] The advantages and features of this utility model will be illustrated and explained through the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description
[0014] Figure 1 It is a structural diagram of the long axis with symmetrical keyways;
[0015] Figure 2 A schematic diagram illustrating how the long axis of the symmetrical keyway to be machined is positioned and fixed on the milling machine worktable using this utility model;
[0016] Figure 3 yes Figure 2 DD enlarged sectional view;
[0017] Figure 4 yes Figure 2 Enlarged sectional view of EE;
[0018] Figure 5 yes Figure 4 The enlarged view from direction F. Detailed Implementation
[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0020] like Figure 1As shown, three pairs of symmetrical keyways 101 are arranged in a straight line along the axial direction of the major axis 10.
[0021] like Figures 2-4 As shown, this embodiment includes three sets of clamping components 1 and two sets of positioning components 2. The three sets of clamping components 1, arranged at intervals, are respectively pressed against the two ends and the middle of the long shaft 10. The clamping component 1 includes an upper pressure plate 11 and two T-shaped screws 12. The V-shaped groove 111 in the middle of the upper pressure plate 11 is located at the upper part of the corresponding position on the outer circle of the long shaft 10. The lower ends of the T-shaped screws 12 are respectively embedded in the corresponding T-shaped grooves 201 of the milling machine worktable 20. The upper ends of the T-shaped screws 12 pass through the two ends of the upper pressure plate 11. By screwing the nuts 13 on the upper ends of the T-shaped screws 12, the V-shaped groove 111 in the middle of the upper pressure plate 11 is pressed against the middle and two ends of the long shaft 10.
[0022] The positioning assembly 2 includes a pair of V-groove positioning blocks 21 and two connecting guide posts 22. The lower V-groove positioning blocks 21 are spaced apart on the milling machine table 20, and the lower part of the lower V-groove positioning blocks 21 is positioned in the corresponding T-groove 201 of the milling machine table 20. The middle part of the long shaft 10 is supported on the lower V-groove positioning blocks 21, and the upper V-groove positioning blocks 21 are pressed on the middle part of the long shaft 10, with the upper and lower V-groove positioning blocks 21 corresponding to each other. The connecting guide posts 22 pass through the guide holes 211 at both ends of the upper and lower V-groove positioning blocks 21 from bottom to top. By tightening the nuts 13 on the upper end of the connecting guide posts 22, the middle part of the long shaft 10 is positioned in the upper and lower V-groove positioning blocks 21.
[0023] The V-groove positioning block 21 extends outward from the center of the plane opposite to the V-groove 212 to form a positioning key 213. The two sides of the positioning key 213 are in clearance fit with the upper opening of the T-groove 201 of the milling machine worktable 20. The clearance between the two sides of the positioning key 213 and the upper opening of the T-groove 201 of the milling machine worktable 20 is 0.08mm.
[0024] The V-groove positioning block 21 has guide holes 213 at both ends. The connecting guide post 22 passes through the guide holes 211 at both ends of the upper and lower V-groove positioning blocks 21 and is respectively fitted with the corresponding guide holes 211. The nuts 13 on the upper screw of the connecting guide post 22 are tightened to position the middle part of the long shaft 10 in the two sets of V-groove positioning blocks 21 arranged in pairs.
[0025] This structure significantly improves the positioning accuracy of the long shaft 10. The V-groove positioning blocks 21 can be moved on the milling machine table 20 to meet the precise positioning needs of long shafts 10 of different lengths. After rotating the long shaft 10 and the two pairs of V-groove positioning blocks 21 around the axis of the long shaft 10 by 180°, they are repositioned in the T-groove 201 of the milling machine table 20 by the positioning key 212. Then, symmetrical keyway machining is performed, effectively reducing the symmetry error of the symmetrically arranged keyways 101 on both sides of the long shaft 10.
[0026] like Figure 2 and Figure 5 As shown, the lower end of the connecting guide post 22 extends laterally to form an anti-rotation waist-shaped head 221. The anti-rotation waist-shaped head 221 is embedded in the oblong countersunk hole 214 at the lower end of the guide hole 211, which can effectively prevent the connecting guide post 22 from rotating when tightening the nut 13, thereby affecting the precise positioning of the long shaft 10 in the upper and lower paired V-groove positioning blocks 21.
[0027] When the shape of the upper and lower paired V-groove positioning blocks 21 of this utility model is changed to be spliced into a regular hexagon, the V-groove positioning blocks and the long shaft can be flipped six times to complete the milling of the hexagonal shaft, thus expanding the scope of application of this utility model.
[0028] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.
Claims
1. A long-axis symmetrical keyway milling fixture, comprising three sets of clamping assemblies, the three sets of clamping assemblies arranged at intervals respectively pressing against the two ends and the middle of a long shaft, the clamping assembly comprising an upper pressure plate and two T-bolts, the V-shaped grooves in the middle of the upper pressure plate being located at the upper part of the corresponding positions on the outer circle of the long shaft, the lower ends of the T-bolts being embedded in the corresponding T-shaped grooves of the milling machine worktable, the upper ends of the T-bolts passing through the two ends of the upper pressure plate, and by screwing nuts onto the upper ends of the T-bolts, the V-shaped grooves in the middle of the upper pressure plate respectively press against the middle and two ends of the long shaft; characterized in that: It also includes at least two sets of positioning components. The positioning components include a pair of V-groove positioning blocks and two connecting guide posts. The lower V-groove positioning blocks are arranged at intervals on the milling machine worktable, and the lower part of the lower V-groove positioning blocks is positioned in the corresponding T-groove of the milling machine worktable. The middle part of the long shaft is supported on the lower V-groove positioning blocks, and the upper V-groove positioning blocks are pressed on the middle part of the long shaft, and the upper and lower V-groove positioning blocks are in corresponding positions. The connecting guide posts pass through the guide holes at both ends of the upper and lower V-groove positioning blocks from bottom to top. By tightening the nuts on the upper end of the connecting guide posts, the middle part of the long shaft is positioned in the upper and lower V-groove positioning blocks.
2. The long-axis symmetrical keyway milling fixture as described in claim 1, characterized in that: The V-groove positioning block extends outward from the center of the plane of the V-groove to form a positioning key, and the two sides of the positioning key are in clearance fit with the upper opening of the T-groove of the milling machine table.
3. The long-axis symmetrical keyway milling fixture as described in claim 1, characterized in that: The V-groove positioning blocks have guide holes at both ends. The connecting guide posts pass through the guide holes at both ends of the upper and lower V-groove positioning blocks and are respectively fitted with the corresponding guide holes with clearance. The nuts on the upper screws of the connecting guide posts are tightened to position the middle part of the long shaft in the two sets of V-groove positioning blocks that are arranged in pairs.
4. The long-axis symmetrical keyway milling fixture as described in claim 3, characterized in that: The lower end of the connecting guide post extends laterally into an anti-rotation waist-shaped head, which is embedded in the elongated countersunk hole at the lower end of the guide hole.
5. The long-axis symmetrical keyway milling fixture as described in claim 2, characterized in that: The clearance between the two sides of the positioning key and the upper opening of the T-slot of the milling machine table is 0.05 to 0.10 mm.
6. The long-axis symmetrical keyway milling fixture as described in claim 3, characterized in that: The gap between the connecting guide post and the guide hole is 0.08 to 0.12 mm.