A machine for floating reaming of flexible tool shanks

Abstract

The application discloses a machine clamp flexible cutter handle floating reamer device and belongs to the technical field of machining. The device comprises a cutter handle, an inner spring, a transition sleeve, an outer spring, a floating sleeve, a connecting piece and a reamer. The reamer is fixed in the floating sleeve through the connecting piece, the outer spring is sleeved on the floating sleeve, and the floating sleeve is sleeved in the transition sleeve. A semicircular protrusion is arranged at a flange position of the transition sleeve, and a semicircular groove is formed in an outer circle of the floating sleeve. The relative rotation between the floating sleeve and the transition sleeve is limited through alignment assembly. The inner spring is inserted into an end far from a taper handle of the cutter handle. The end of the cutter handle with the inner spring is connected with the transition sleeve, and the axial movement distance of the floating sleeve is ensured to be less than or equal to 10 mm. The application improves the roughness grade of the machine clamp reamer surface from less than Ra1.6 microns to more than Ra0.4 microns, and solves the problem of radial eccentric load of the machine clamp reamer during machining.

Description

Technical Field

[0001] This invention belongs to the field of machining technology and relates to a floating reaming device for a mechanically clamped flexible tool holder. Background Technology

[0002] When a reamer is clamped in a machining equipment for reaming operations, radial off-center loading can occur due to a combination of errors, including equipment positioning errors, bottom hole machining errors, and tool feed position errors. Radial off-center loading can cause machining instability or even complete loss of stability, frequently resulting in a surface roughness grade of the reamed hole lower than Ra1.6μm, as well as chip extrusion and groove formation. Summary of the Invention

[0003] This invention overcomes the shortcomings of the prior art and proposes a floating reaming device for a mechanically clamped flexible tool holder.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution.

[0005] A mechanically clamped flexible tool holder floating reaming device includes a tool holder, an inner spring, a transition sleeve, an outer spring, a floating sleeve, a connector, and a reamer. The reamer is fixed inside the floating sleeve by the connector. The outer spring is sleeved on the floating sleeve, and then the floating sleeve is inserted into the transition sleeve. A semi-circular protrusion is provided at the flange position of the transition sleeve, and a semi-circular groove is opened on the outer circle of the floating sleeve. By aligning and assembling, the relative rotation between the floating sleeve and the transition sleeve is restricted. The inner spring is inserted into the end away from the tapered shank of the tool holder, and the end of the tool holder with the inner spring is connected to the transition sleeve, ensuring that the axial movement distance of the floating sleeve is ≤10mm.

[0006] Furthermore, the connector includes a spring clip and a locking nut, and the reamer is fixed inside the floating sleeve by the spring clip and the locking nut.

[0007] Furthermore, the reamer's floating angle is within the range of 0 to 1 degree, and the radial floating range is within the range of 0 to 0.051 mm.

[0008] Furthermore, the transition sleeve and the floating sleeve are connected with a clearance fit of H8 / g7.

[0009] Furthermore, the connection is made through the external thread of the tool holder and the internal thread of the transition sleeve.

[0010] Furthermore, one end of the tool holder taper shank is connected to the machine tool spindle taper hole via a pull stud for reaming.

[0011] The beneficial effects of this invention compared to the prior art are as follows: The floating sleeve and the transition sleeve are clearance-fitted, utilizing this clearance to allow them to float and self-align with the axis. Because the reamer (with the floating sleeve clamping) can float during machining, it reams with the hole surface and self-aligns with the axis, thus compensating for adverse effects caused by workpiece installation errors or spindle guide wear. This eliminates radial off-center loading during reaming, ensuring stable cutting by the reamer and improving the surface roughness of the hole wall. Furthermore, it avoids or improves machining defects such as hole diameter enlargement and uneven allowance caused by misalignment between the reamer and the hole's axis centerline, resulting in chip extrusion and grooves. The mechanically clamped flexible floating reaming technology can be widely applied to the field of hole finishing, saving machining and financial costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the external structure of the floating reaming device with a mechanically clamped flexible tool holder according to the present invention; Figure 2 for Figure 1 Sectional view along line AA; Figure 3 for Figure 2 Sectional view along the BB direction; Figure 4 for Figure 3 Enlarged view of point C in the image; In the picture: 1-Tool holder, 2-Inner spring, 3-Transition sleeve, 4-Outer spring, 5-Locking nut, 6-Floating sleeve, 7-Spring collet, 8-Reamer, 9-Semi-circular groove. Detailed Implementation

[0013] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0014] like Figure 1-4 As shown, this embodiment proposes a floating reaming device for a mechanically clamped flexible tool holder, comprising a tool holder 1, an inner spring 2, a transition sleeve 3, an outer spring 4, a locking nut 5, a floating sleeve 6, a spring clip 7, and a reamer 8; wherein, the reamer 8 is fixed in the floating sleeve 6 by the spring clip 7 and the locking nut 5.

[0015] Place the outer spring 4 onto the floating sleeve 6, and then insert the floating sleeve 6 into the transition sleeve 3. The flange of the transition sleeve 3 is provided with a semi-circular protrusion, and the outer circle of the floating sleeve 6 is provided with a semi-circular groove. By aligning and assembling, the relative rotation between the floating sleeve 6 and the transition sleeve 3 is restricted. Insert the inner spring 2 into the end away from the tapered shank of the tool holder 1, and connect the end of the tool holder 1 with the inner spring 2 to the transition sleeve 3 through internal and external threads to ensure that the axial movement distance of the floating sleeve 6 is ≤10mm.

[0016] The floating angle of the reamer 8 is in the range of 0 to 1 degree, and the radial floating range is in the range of 0 to 0.051 mm; The transition sleeve 3 and the floating sleeve 6 are connected with a clearance fit of H8 / g7 after calculating the comprehensive errors such as equipment positioning error, bottom hole machining error, and tool infeed position error.

[0017] The installation and use process of this device is as follows: Insert the outer spring 4 onto the floating sleeve 6 and into the transition sleeve 3. Note the semi-circular protrusion at the flange position of the transition sleeve 3 (enlarged view at point C). The outer circumference of the floating sleeve 6 has a semi-circular groove 9. By aligning and assembling, the relative rotation between the floating sleeve 6 and the transition sleeve 3 is restricted. Then, insert the inner spring 2 into the other end of the tapered shank of the tool holder 1 and connect it through the external thread of the tool holder 1 and the internal thread of the transition sleeve 3 to ensure that the axial movement distance of the floating sleeve 6 is within 10mm. Insert the spring clip 7 and screw in the lock nut 5. Then, insert the reamer 8 into the spring clip 7 and tighten the lock nut 5. Finally, connect the flexible tool holder to the machine tool spindle through the pull stud, and the reaming can be performed.

[0018] This invention employs optimal clearance control technology for floating reamer holders. To ensure the reamer 8 has a certain degree of floating during machining, a suitable fit accuracy should be selected between the floating sleeve 6 and the transition sleeve 3; this fit is a clearance fit. Choosing the right clearance fit is crucial to ensuring the requirements of hole machining. Too large or too small a clearance will affect the machining accuracy of the hole. Too large a clearance will affect the surface roughness of the hole; too small a clearance cannot adequately compensate for axial errors. After calculating the combined errors of equipment positioning error, bottom hole machining error, and tool feed position error, a clearance fit connection of H8 / g7 is selected.

[0019] This invention is based on the principle of floating boring and designs a device for reaming holes on a CNC milling machine. This device can automatically compensate for axial errors, thereby ensuring the dimensional accuracy and surface roughness of the hole. The use of inner and outer springs buffers the axial cutting force during machining, and the radial floating range becomes soft contact, thus reducing circumferential rigid contact and eliminating machining vibration, resulting in an ideal surface roughness for the hole after floating reaming.

[0020] This invention utilizes floating reaming technology, a finishing hole method that automatically compensates for adverse effects caused by tool installation errors or tool holder runout. During operation, the floating sleeve 6 is not fixed but slides freely within the transition sleeve 3. A semi-circular protrusion is provided at the flange position of the transition sleeve 3 (enlarged view at point C). A semi-circular groove 9 is formed on the outer circumference of the floating sleeve 6. After alignment and assembly, this groove restricts the relative rotation between the floating sleeve 6 and the transition sleeve 3. The cutting force generated by the multiple symmetrical cutting edges of the reamer 8 automatically balances its position, thereby achieving automatic error compensation.

[0021] The floating sleeve 6 and the transition sleeve 3 are in clearance fit. This clearance allows the floating sleeve 6 and the transition sleeve 3 to float, enabling them to self-align with the axis. Because the reamer (floating sleeve clamp) can float during machining and reams with the hole surface, self-aligning with the axis, it can compensate for the adverse effects caused by workpiece installation errors or spindle guide wear, thereby eliminating radial off-center load during reaming, ensuring stable cutting by the reamer, and thus improving the surface roughness grade of the hole wall.

[0022] This invention targets machine-clamped reaming products. Through research on floating reaming with flexible machine-clamped tool holders, it breaks through key process technologies such as floating reaming with machine-clamped tool holders and optimal clearance control of floating reaming tool holders, and completes the manufacturing of machine-clamped reaming products. This improves the surface roughness grade of machine-clamped reaming from below Ra1.6μm to above Ra0.4μm, providing technical support for stabilizing and improving the surface quality of machine-clamped reaming.

[0023] The mechanically clamped flexible tool holder floating reaming device described in this invention can be widely applied to the field of hole finishing, saving processing and financial costs for hole finishing. Compared with existing boring tools using conventional boring methods, as shown in Table 1, machining a Φ10mm hole in 45# steel with a hole depth of 24mm takes 30s.

[0024] 1) Boring requires at least two passes: rough boring and fine boring. There is also time for tool adjustment in between, which is estimated to take 200 seconds.

[0025] 2) Using the reamer 8 of the reaming device described in this embodiment, more than 1,000 holes can be machined at once, while a boring bar can machine about 60. The tool cost of the reamer is only 1 / 16 of that of the boring bar. If this project can be completed and implemented, and then widely promoted and applied, the cost of hole machining will be greatly reduced, while machining efficiency and machining accuracy can be guaranteed.

[0026] This invention replaces the rigid connection between the spindle and the reamer via the tool holder with a flexible connection through a designed flexible tool holder. This solves the problem of radial off-center loading during machining operations, caused by a combination of errors such as equipment positioning error, bottom hole machining error, and tool feed position error. Radial off-center loading leads to machining instability or even loss of stability, frequently resulting in a surface roughness grade of the hole below Ra1.6μm after reaming, as well as chip extrusion and groove formation.

[0027] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all of these should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. A floating reaming device for a mechanically clamped flexible tool holder, characterized in that, The assembly includes a tool holder (1), an inner spring (2), a transition sleeve (3), an outer spring (4), a floating sleeve (6), a connector, and a reamer (8). The reamer (8) is fixed inside the floating sleeve (6) by the connector. The outer spring (4) is placed on the floating sleeve (6), and then the floating sleeve (6) is installed inside the transition sleeve (3). The flange of the transition sleeve (3) is provided with a semi-circular protrusion, and the outer circle of the floating sleeve (6) is provided with a semi-circular groove. By aligning and assembling, the relative rotation between the floating sleeve (6) and the transition sleeve (3) is restricted. The inner spring (2) is inserted into the end away from the tapered shank of the tool holder (1), and the end of the tool holder (1) with the inner spring (2) inserted is connected to the transition sleeve (3) to ensure that the axial movement distance of the floating sleeve (6) is ≤10mm. The connector includes a spring clip (7) and a locking nut (5), and the reamer (8) is fixed in the floating sleeve (6) by the spring clip (7) and the locking nut (5); The reamer (8) has a floating angle of 0 to 1 degree and a radial floating range of 0 to 0.051 mm.

2. The floating reaming device for a mechanically clamped flexible tool holder according to claim 1, characterized in that, The transition sleeve (3) and the floating sleeve (6) are connected by a clearance fit of H8 / g7.

3. The floating reaming device for a mechanically clamped flexible tool holder according to claim 1, characterized in that, The connection is made through the external thread of the tool holder (1) and the internal thread of the transition sleeve (3).

4. The floating reaming device for a mechanically clamped flexible tool holder according to claim 1, characterized in that, The tool holder (1) is connected to the taper hole of the machine tool spindle via a pull stud for reaming.

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