Small-diameter boring cutter extension bar

Abstract

One side of the head portion of the extension bar is in a step shape with the front portion thin and the rear portion thick, an eccentric hole is formed in the head portion of the extension bar, and more than two screw holes communicated with the eccentric hole are formed in the outer wall of one side of the head portion of the extension bar in the length direction. And a strip-shaped plane is arranged on the outer wall of one side of the tail part of the extension rod along the length direction. The extension rod disclosed by the utility model is simple and reasonable in structural design, and one side of the head part is in a step shape with a thin front part and a thick rear part, so that the overall rigidity is increased to a great extent, cutter back-off and vibration are greatly reduced during boring processing, and the extension rod is very good for ensuring the processing precision. The boring cutter is installed in the eccentric hole of the extension rod, and the adaptability of the extension rod to boring machining can be improved through the eccentric installation.

Description

Technical Field

[0001] The utility model relates to the field of mechanical manufacturing technology, specifically to a small-diameter boring tool extension bar in this field, which can greatly increase the length of the small-diameter boring tool for boring stepped deep holes. Background Art

[0002] The main problems of existing standard boring tool bars in practical applications are: insufficient length and inability to machine deep holes; insufficient rigidity, prone to tool deflection and vibration, affecting machining accuracy. Especially for a certain type of workpiece with a stepped hole structure, the dimensional accuracy requirement for the small hole deep inside is H8, and the surface roughness requirement is Ra1.6. Due to the relatively deep distance from the bottom of the hole to the end face, the standard small-diameter boring tool cannot meet the machining requirements of this hole (mainly the insufficient length dimension). The price of custom-made special extended tools is very high, and their adaptability to different workpieces is poor. Summary of the Utility Model

[0003] The utility model provides an extension bar for a small-diameter boring tool to solve the machining problem of stepped holes with a relatively large machining depth.

[0004] To solve the above technical problems, the utility model adopts the following technical solutions:

[0005] A small-diameter boring tool extension bar, the improvement lies in that: one side of the head of the extension bar is a stepped shape with a thinner front and a thicker rear, an eccentric hole is provided at the head of the extension bar, and more than two screw holes communicating with the above eccentric hole are provided along the length direction on the outer wall of one side of the head of the extension bar, and a strip-shaped plane is provided along the length direction on the outer wall of one side of the tail of the extension bar.

[0006] Further, there are four screw holes, and the four screw holes are arranged side by side along the length direction on the outer wall of one side of the head of the extension bar.

[0007] Further, a strip-shaped plane is provided along the length direction on the outer wall of one side of the head of the extension bar, and the screw holes are arranged in this strip-shaped plane.

[0008] Further, set screw bolts are provided on the screw holes.

[0009] Further, a circular protrusion is provided on the outer wall between the head and the tail of the extension bar.

[0010] Further, the extension bar is integrally formed by medium carbon alloy steel 42CrMo.

[0011] The beneficial effects of the utility model are:

[0012] The extension rod disclosed by the utility model has a simple and reasonable structural design. One side of the head is a stepped shape with a thinner front and a thicker rear, which greatly increases the overall rigidity. During boring processing, the tool deflection and vibration are significantly reduced, which is very beneficial for ensuring the machining accuracy. The boring tool is installed in the eccentric hole of the extension rod. This eccentric installation can increase the adaptability of the extension rod for boring processing and reduce the possibility of interference. The eccentric hole fits precisely with the boring tool rod, is accurate and reliable, and is convenient to install. Multiple set screws passing through the screw holes are used to lock the boring tool, making the connection more firm. It is integrally formed by medium carbon alloy steel 42CrMo, with high strength and good durability. Brief Description of the Drawings

[0013] Figure 1 is a schematic structural diagram of the extension rod disclosed in Embodiment 1 of the utility model;

[0014] Figure 2 is a schematic installation diagram of the extension rod disclosed in Embodiment 1 of the utility model.

[0015] Reference Numerals: 1 - extension rod, 11 - eccentric hole, 12 - screw hole, 13 - strip-shaped plane, 14 - strip-shaped plane, 15 - annular protrusion, 2 - boring tool, 3 - set screw, 4 - workpiece, 5 - chuck, 6 - NC lathe tool holder. Detailed Description of the Preferred Embodiments

[0016] In order to make the purpose, technical solutions and advantages of the utility model more clear, the following further details the utility model in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and are not used to limit the utility model.

[0017] Embodiment 1, as Figure 1 shown, this embodiment discloses a small-diameter boring tool extension rod. One side of the head of the extension rod 1 is a stepped shape with a thinner front and a thicker rear, and an eccentric hole 11 is provided at the head of the extension rod. Four screw holes 12 communicating with the above-mentioned eccentric hole are arranged side by side along the length direction on the outer wall of one side of the head of the extension rod, and set screws are provided on the screw holes. A strip-shaped plane 13 is arranged along the length direction on the outer wall of one side of the tail of the extension rod.

[0018] In this embodiment, a strip-shaped plane 14 is arranged along the length direction on the outer wall of one side of the head of the extension rod, and the screw holes are arranged in this strip-shaped plane. A ring of annular protrusions 15 is arranged on the outer wall between the head and the tail of the extension rod. The extension rod is integrally formed by medium carbon alloy steel 42CrMo.

[0019] As Figure 2As shown in the figure, the installation method of the extension rod disclosed in this embodiment is as follows: Install the boring bar of the standard small-diameter boring tool 2 into the eccentric hole at the head of the extension rod 1, with the cutting edge facing the side with a thinner outer wall; Adjust the length of the boring tool extending out of the eccentric hole according to the actual size of the workpiece, and require the extension to be as short as possible; After tightening the four set screws 3 to lock the boring tool, then install the tail of the extension rod 1 into the tool holder 6 of the CNC lathe and lock it. After tool setting and trial cutting according to the general method, semi-finish boring and finish boring can be carried out on the deep hole of the workpiece 4 installed on the chuck 5, and grooving and thread cutting can also be carried out according to the actual conditions.

[0020] In summary, the extension rod disclosed in this embodiment solves the problem of machining small-diameter stepped deep holes. After long-term use and testing, the boring processing size is stable, the surface roughness is good, the durability is high, the cost is low, and the economy is good.

Claims

1. A small-diameter boring tool extension bar, characterized in that: One side of the head of the extension rod is a stepped shape that is thinner at the front and thicker at the back. An eccentric hole is provided in the head of the extension rod. More than two screw holes communicating with the above-mentioned eccentric hole are provided along the length direction on the outer wall of one side of the head of the extension rod. A strip-shaped plane is provided along the length direction on the outer wall of one side of the tail of the extension rod.

2. The small-diameter boring tool extension bar according to claim 1, wherein: There are four of the said screw holes, and the four screw holes are arranged side by side along the length direction on the outer wall of one side of the head of the extension rod.

3. The small-diameter boring tool extension rod according to claim 1, characterized in that: A strip-shaped plane is provided along the length direction on the outer wall of one side of the head of the extension rod, and the screw holes are arranged in this strip-shaped plane.

4. The small-diameter boring tool extension rod according to claim 1, characterized in that: Set a set screw on the screw hole.

5. The small-diameter boring tool extension bar according to claim 1, characterized in that: A circular protrusion is provided on the outer wall between the head and the tail of the extension rod.

6. The small-diameter boring tool extension bar according to claim 1, wherein: The extension rod is integrally formed by using medium carbon alloy steel 42CrMo.

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