A precision machining tool and method for long-axis features in a narrow space

Abstract

A precision machining tool for long-axis features in a narrow space, comprising a boring tool shank (1), a sleeve boring tool bar (2) and a boring tool blade (3). A fine adjustment dial (11) with scale lines is provided on the boring tool shank (1). The boring tool shank (1) is sleeved on the sleeve boring tool bar (2), and the sleeve boring tool bar (2) is fastened to the boring tool shank (1) by a setscrew. The boring tool blade (3) is installed at the lower end of the sleeve boring tool bar (2). It is characterized in that the sleeve boring tool bar (2) is of a cylindrical structure and is divided into three sections from top to bottom. The upper part is a solid cylinder (21), and a chip removal groove (24) is provided beside the blade groove. The sleeve boring tool bar 2 with a cylindrical hollow structure in the present invention not only reduces the weight of the tool bar, ensures the rigidity of the tool bar, but also improves the length-diameter ratio of the processed product.

Description

Technical Field

[0001] The present invention relates to a precision machining tool and method for long-axis features in a narrow space, and particularly relates to using an adjustable boring tool holder to clamp a replaceable insert sleeve boring bar to machine long-axis workpieces in a narrow space, belonging to the field of machining. Background Art

[0002] Common shaft parts are mostly machined by turning, and high-precision shaft features can also be machined by boring. Boring tools are divided into internal hole boring tools and external circle boring tools. The internal hole boring tool consists of a boring tool holder, a boring bar, and a blade. The boring bar is generally single-edged. The boring tool holder has a radial adjustment function and can directly adjust the boring blade to the dimension to be machined through micro-adjustment. The boring bar is fixed on the tool holder by a side set screw. The external circle boring tool consists of a boring tool holder, a slider, and a blade. The tool holder of the external circle boring tool does not have a radial adjustment function, and the boring diameter can be adjusted by radially moving the boring tool slider equipped with the blade. The other side of the slider is a counterweight to ensure that the boring tool will not be eccentric during high-speed boring. Generally, the larger the boring diameter, the larger the diameter of the boring bar of the internal hole boring tool, and the larger the size of the slider and counterweight of the external circle boring tool. Schematic diagrams of the internal hole boring tool and the external circle boring tool are shown in FIGS. 1 and Figure 2 as shown.

[0003] For a workpiece 4 with long-axis features in a narrow space as Figure 7 shown, the intermediate gap is less than 6 mm, the shaft length is 60 mm, and the outer diameter dimension is φ13 ± 0.01 mm.

[0004] If an internal hole boring tool is used for machining, a slender boring bar with a large length-diameter ratio needs to be customized. When the length-diameter ratio exceeds 5, the rigidity of the boring bar will become poor. In addition, the cutting edge of the internal hole boring tool is small, and high-efficiency machining cannot be achieved. There is currently no such small external circle boring tool and turning tool bar. Therefore, conventional turning and boring cannot machine such long-axis workpieces. The existing method is to mill from both sides of the milling cutter, and multiple tool joints are required for the narrow space part. The disadvantage of this method is low efficiency, and multiple flips and machining are required on both sides, and multiple clamping and alignment affect the final machining dimension accuracy. Summary of the Invention

[0005] The present invention provides a precision machining tool and method for long-axis features in a narrow space to overcome the problems that precision long-axis features in a narrow space cannot be machined by boring and turning, and at the same time, the milling machining efficiency is low.

[0006] A precision machining tool for long-axis features in a narrow space, comprising a boring tool shank 1, a sleeve boring tool bar 2, and a boring tool blade 3. A micro-adjustment dial 11 is provided on the boring tool shank 1, and the micro-adjustment dial 11 has scale lines. The boring tool shank 1 is sleeved on the sleeve boring tool bar 2, and the sleeve boring tool bar 2 is fastened to the boring tool shank 1 by a setscrew. A boring tool blade 3 is installed at the lower end of the sleeve boring tool bar 2. It is characterized in that the sleeve boring tool bar 2 is a cylindrical structure, and the sleeve boring tool bar 2 is divided into three sections from top to bottom. The upper part is a solid cylinder 21, the cylinder 21 is connected to a circular tube 22 with a diameter smaller than that of the cylinder 21. The circular tube 22 coincides with the central axis of the cylinder 21. One or two blade support rods 23 are provided at the lower part of the circular tube 22. A blade groove is provided on one side of the lowermost end of the support rod 23, and the boring tool blade 3 is fastened in the blade groove by a screw. A chip removal groove 24 is provided beside the blade groove.

[0007] The cylinder 21, the circular tube 22, and the blade support rod 23 are of an integral structure.

[0008] A precision machining method for long-axis features in a narrow space using the precision machining tool for long-axis features in a narrow space specifically includes the following steps:

[0009] Step 1: Install the sleeve boring tool bar 2 on the boring tool shank 1 by a setscrew, and adjust the machining diameter d of the tool by adjusting the dial on the boring tool shank 1.

[0010] Step 2: Fix the long-axis feature workpiece 4 on the machine tool workbench, align the rotation center of the long axis, install the boring tool shank 1 on the machine tool spindle, and lower the machine tool spindle to extend the long axis of the long-axis feature workpiece into the hollow of the sleeve boring tool bar 2, thereby realizing precision boring of the long axis.

[0011] The beneficial effects of the present invention: The present invention designs a precision machining tool and method for long-axis features in a narrow space. By radially adjusting the eccentricity between the tool shank and the sleeve boring tool bar with a cylindrical hollow structure, precision boring machining of long-axis workpieces is realized. The gap in the narrow space is the sum of the wall thickness of the tool bar and the eccentricity. For long-axis features with different diameters, only the dial on the tool shank needs to be adjusted, and there is no need to disassemble the tool bar, which is convenient and easy to implement, thereby improving the machining efficiency and quality. When the cutting edge of the blade is on the inner side of the tool bar, shaft features can be bored, and when the cutting edge of the blade is on the outer side of the tool bar, hole features can be bored. This tool can be used on a milling machine or a lathe, expanding the field of boring machining. The sleeve boring tool bar 2 with a cylindrical hollow structure of the present invention not only reduces the weight of the tool bar, ensures the rigidity of the tool bar, but also improves the length-diameter ratio of the processed product. Description of the Drawings

[0012] Figure 1 Schematic diagram of the structure of an internal hole boring tool in the prior art;

[0013] Figure 2, Schematic diagram of the structure of the existing external turning boring tool;

[0014] Figure 3 , Schematic diagram of the structure of the present invention;

[0015] Figure 4 , is Figure 3 A - A sectional view thereof;

[0016] Figure 5 , Schematic diagram of the structure of the sleeve boring bar 2 of the present invention;

[0017] Figure 6 , is Figure 5 B - B sectional view thereof;

[0018] Figure 7 , Schematic diagram of the structure of the workpiece with long - axis features in a narrow space to be machined according to the present invention;

[0019] Figure 8 , Front view of the workpiece with long - axis features in a narrow space to be machined;

[0020] Figure 9 , Figure 8 Left view thereof;

[0021] Figure 10 , Schematic diagram of the process of machining the workpiece according to the present invention.

[0022] Among them, 1 is the boring tool handle, 2 is the sleeve boring bar, 3 is the boring blade, 4 is the workpiece with long - axis features, 11 is the fine - adjustment scale disk, 21 is the cylinder, 22 is the circular tube, 23 is the blade support rod, and 24 is the chip - removal groove. Specific implementation mode

[0023] The technical solution is as follows: The present invention includes a radially adjustable internal - hole boring tool handle made of alloy structural steel, a relatively long tubular hollow - structure sleeve boring bar made of high - speed steel, and two boring blades made of cemented carbide. The internal - hole boring tool handle has scale lines. Through the fine - adjustment scale disk, the eccentricity of the boring bar relative to the tool handle can be adjusted, that is, the machining diameter of the tool can be adjusted. The boring bar is fastened to the tool handle by a setscrew. The boring bar is of a hollow structure, which can machine long - axis features and reduce the weight of the boring bar at the same time. There is a flat surface on the outer circle at the connection end of the boring bar and the tool handle, which is used to prevent the boring bar from rotating relative to the tool handle after being fastened by the setscrew. The other end of the boring bar is an open structure, and there is a blade groove at each of the two openings on both sides. The two boring blades are fastened in the blade grooves by screws. The two boring blades can be used alternately, reducing the number of tool setup times and improving the tool usage time and machining efficiency. There is a chip - removal groove at the blade groove, which is convenient for chip removal.

[0024] As shown in the figure below, the inner hole diameter of the sleeve boring bar is D, the wall thickness of the bar is δ, and the eccentricity between the tool holder and the bar is △. Then the diameter d of the workpiece that can be machined is d = D - 2△, and at the same time d ≤ D - 2δ. The clearance W for the tool to pass through is W = 2△ + δ. By adjusting the eccentricity, the machining of shaft features with different diameters can be achieved, which is convenient, efficient, simple and easy to implement.

[0025] A precision machining method for long shaft features in a narrow space specifically includes the following steps:

[0026] In the first step, the sleeve boring bar is installed on the tool holder through a setscrew. The end of the setscrew tightly presses against the plane of the outer circle of the bar. By adjusting the dial on the tool holder, the machining diameter d of the tool is adjusted.

[0027] In the second step, two boring inserts are fixed in the insert slots of the bar opening groove through screws.

[0028] In the third step, the long shaft feature workpiece is fixed on the machine tool workbench, the rotation center of the long shaft is aligned, the sleeve boring tool is installed on the machine tool spindle, and through the lowering of the spindle, the long shaft is extended into the hollow of the bar, thereby realizing the precision boring of the long shaft.

[0029] In order to make the technical means, method process, achieved purpose and efficacy realized by the present invention easy to understand, the present invention will be further elaborated below in combination with specific workpiece machining.

[0030] Precision long shaft workpieces in a narrow space such as Figure 1 shown, the material is titanium alloy, the shaft diameter is φ13 ± 0.01 mm, the length is 60 mm, and the narrow space clearance is 5.5 mm.

[0031] The assembly of the sleeve boring tool is as Figure 3 shown, where 1 is the inner hole boring tool holder, 2 is the hollow sleeve boring bar. In order to improve the rigidity of the bar, the upper end is a solid structure and the lower end is a hollow structure. The inner diameter D of the bar is 20 mm, the inner hole depth L is 70 mm, the wall thickness δ of the bar is 3 mm, and 3 is the rhombic boring insert. The machining process is as follows:

[0032] In the first step, the sleeve boring bar is installed on the tool holder through an M5 setscrew. The end of the screw tightly presses against the plane of the outer circle of the bar. By adjusting the scale on the tool holder, the eccentricity △ = 0.5 mm, and the diameter d that can be machined is d = D - 2△ = 19 mm. At the same time, it is verified that d ≤ D - 2δ = 14 mm. Therefore, the shaft feature with a diameter of φ13 ± 0.01 mm can be machined. The clearance W for the tool to pass through after adjustment is W = 2△ + δ = 5 mm, which is less than the clearance of 5.5 mm in the narrow space of the shaft to be machined, and the depth of the bar is greater than the length of the shaft, so there will be no interference during machining.

[0033] In the second step, two rhombic boring inserts are fixed in the insert slots of the bar opening groove through an M2 screw.

[0034] In the third step, fix the workpiece to be processed on the machine tool workbench, align the rotation center of the long shaft, install the sleeve boring tool on the machine tool spindle, and continuously insert the long shaft into the hollow of the tool bar by lowering the spindle along the Z-axis, thereby realizing the precision boring of the long shaft.

[0035] The main features, specific implementation, and advantages of the present invention have been described in detail above. It should be noted that those skilled in the art can make several improvements and changes on the premise of the technical principle of the present invention, but these improvements and changes should also be regarded as within the protection scope of the present invention.

Claims

1. A precision machining method for long-axis features in a narrow space, characterized in that, Machining is carried out by using a precision machining tool for long-axis features in a narrow space. The tool includes a boring tool shank (1), a sleeve boring bar (2) and a boring blade (3). A fine adjustment dial (11) with scale lines is provided on the boring tool shank (1). The boring tool shank (1) is sleeved on the sleeve boring bar (2), and the sleeve boring bar (2) is fastened to the boring tool shank (1) by a setscrew. The boring blade (3) is installed at the lower end of the sleeve boring bar (2). It is characterized in that the sleeve boring bar (2) is of a cylindrical structure and is divided into three sections from top to bottom. The upper part is a solid cylinder (21), and the cylinder (21) is connected to a circular tube (22) with a diameter smaller than that of the cylinder (21). The circular tube (22) coincides with the central axis of the cylinder (21). Two blade support rods (23) are provided at the lower part of the circular tube (22). A blade groove is provided on one side of the lowermost end of the support rod (23), and the boring blade (3) is fastened in the blade groove by a screw. A chip removal groove (24) is provided beside the blade groove. The cylinder (21), the circular tube (22) and the blade support rod (23) are of an integral structure. Specifically, it includes the following steps: Step 1: Install the sleeve boring bar (2) on the boring tool shank (1) by a setscrew, and adjust the machining diameter d of the tool by adjusting the dial on the boring tool shank (1). Step 2: Fix the two boring blades in the blade grooves of the tool bar opening groove by screws. Step 3: Fix the long-axis feature workpiece (4) on the machine tool workbench, align the rotation center of the long axis, install the boring tool shank (1) on the machine tool spindle, and lower the machine tool spindle to extend the long axis of the long-axis feature workpiece into the hollow of the sleeve boring bar (2), so as to achieve precision boring of the long axis.

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