JPS58143905A - Chamfering tool for through hole - Google Patents

Abstract

PURPOSE:To remove inside burrs of a through hole on a rotary driving shaft or to chamfer the inside corner thereof easily on the outside of the through hole by using a chamfering tool made up of shape memorizing alloy. CONSTITUTION:The chamfering tool 12 is provided with a notch 14 in the middle of a shaft 13 made up of shape memorizing alloy and a cutting edge 16 on one side of the front end portion 15 of the notch. The cutting tool 16 is made by welding tool steel, etc. into the shaft by a well-known process. When the tool is inserted into the hole of the work 2 and heated by frictional heat or injected hot water, etc. the front end portion 15 is bent are burrs and removed or the corner is chamfered by the cutting edge 16. After working, cool air is injected to recover the bend and remove the tool.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chamfering tool suitable for deburring or chamfering a narrow part where it is difficult to insert a tool, such as the back side of a through hole.

As shown in FIG. 1, when a through hole 3 is provided on the outer circumferential surface of a cylindrical workpiece 2, when removing the burr generated inside the through hole 3 or performing chamfering, Conventionally, a tool guide tube 8 is inserted into the workpiece 2 from one end side, and the rotation of the drive shaft 7 supported by the guide tube 8 is controlled by a bevel gear 6.
5 to a shaft 9, and a grindstone or cutter 4 supported on this shaft 9 is used to remove or remove particles.

Such chamfering of the through hole 3 has problems such as when the workpiece 2 is long and narrow, it is difficult to position the grindstone or cutter 4 and the through hole 3, and the work efficiency is poor.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a chamfering tool that can easily perform chamfering or chamfering on the inside of a through hole from the outside.

For this reason, the configuration of the present invention is such that the rotationally driven shaft is made of a shape memory alloy, and a cut J is provided at the tip of the shaft.
The shaft is straight at low temperatures, the tip is bent at high temperatures, and the cutting edge is inclined with respect to the proximal end of the shaft.

To explain the present invention based on an embodiment, as shown in FIG. A cutting edge 16 is provided on one side edge. The cutting edge 16 is bonded to a known tool steel or carbide depth by suitable means such as thermal spraying.

Shape memory alloys change to a matrix structure at higher temperatures than the transformation point and become hard, and at lower temperatures transform to martensitic structures and become soft. alloys have been discovered. The tool 12 is inserted into the shaft 1 from the notch 14 as shown in FIG.
3: The shape is stored in advance so that the tip portion 15 is bent. This transformation point can be set by blending the alloy components to a concentration lower than the friction temperature during chamfering, for example, about 60''C.

Since the present invention is configured as described above, as shown in FIG. It is inserted from the outside and rubbed against the wall of the hole 3 while being rotated. When the tool 12 reaches the transformation point due to frictional heat, the tip 15 bends as shown by the chain line, and the cutting edge 1
6, the inner end of the hole 3 can be chamfered or chamfered.

After finishing the machining, blow cooling air or inject cooling liquid into the through hole 3 to cool the tool 12.]
[The tool 12 becomes straight as shown by the solid line in FIG. 4, and can be pulled out from the through hole 3. Note that the tool 12 may be heated by pouring hot water or the like instead of using frictional heat.

Since the present invention is constructed as described above, only a small amount of shape memory alloy is required to be used as a tool for deburring or chamfering the inner end of a deep hole where chamfering is particularly difficult. Therefore, it is not very expensive,
Compared to using conventional tools as shown in Figure 1,
This method is advantageous in that the tool can be easily positioned and there is no risk of the inner surface 2a of the workpiece being damaged by the tool.

[Brief explanation of drawings]

Fig. 1 is a side cross-sectional view showing the state of chamfering the inner end of a through hole provided in a cylindrical object in the past; Fig. 2 is a side view of the chamfering tool made using this light; FIG. 4 is a side view showing the state of use of the chamfering tool according to the present invention. 2: Workpiece 3: Hole 4: Cutter 5.6: Bevel gear 7
: Shaft 8: Guide cylinder 12: Tool ] 3: Shaft 14: Notch
15: Tip 16: Cutting blade Patent applicant Jidosha Kiki Co., Ltd. Agent Patent attorney Toshio Yamamoto 5- 6 School 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A rotationally driven shaft is made of a shape memory alloy, and a cutting blade is provided at the tip of the shaft, and the shaft is straight at low temperatures, and the tip bends at high temperatures, causing the cutting blade to bend. A tool for chamfering a through hole, characterized in that a portion thereof is configured to be inclined with respect to the base end side of the shaft.