JP2005186179A - Broaching tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a broaching tool, capable of broaching without uneven abrasion of a cutting blade even in the case of broaching a high hard material with a hardness of 45 to 65HRC at 40 to 80 m/min, and having good working accuracy of a work piece. <P>SOLUTION: This broaching tool 20 includes: a front gripping part 1 provided at one end of a rod-like broaching body 21; a front guide 2 connected to the front gripping part; and a broaching cutting blade part 26 connected to the rear end of the guide and provided with a number of cutting blades 3. The broaching tool 20 broaches a work piece with a hardness of 45 to 65 HRC. At least one or more hard coating film layers is formed on the surface of the guide in the broaching tool. The material quality of the front guide is a cemented carbide steel. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a broach tool for processing a high hardness material having a hardness of 45 to 65 HRC.

Conventionally, the thing of patent document 1 is known as a broach tool which processes high hardness material of hardness 45-65HRC (Rockwell hardness C scale: the same hereafter). This is because the workpiece that has been pre-processed with a margin of about 0.1 mm on one side with respect to the finished dimensions is heat-treated to obtain a predetermined hardness, and then the rear end of the front guide of the broach tool. Broaching is performed at a cutting speed of 40 m / min or more with the disposed cutting edge made of cemented carbide. The front guide of the broach tool is made of alloy steel, and guides the position of the following cemented carbide cutting edge while sliding in contact with the workpiece.
JP 2002-137118 A

  However, when a high-hardness material whose work piece is 45 to 65 HRC is broached at a high speed cutting of 40 to 80 m / min using the broach tool of Patent Document 1, the cutting edge of the broach tool causes uneven wear, There was a problem that the processing accuracy of the workpiece deteriorated.

  The present invention has been made to solve the problems of the prior art, and even if a high hardness material of 45 to 65 HRC is broached at 40 to 80 m / min, the cutting edge is processed without causing uneven wear. An object of the present invention is to provide a broaching tool that can be processed with good processing accuracy.

  As a result of studying the uneven wear of the cutting edge described above, the present inventors have found that uneven wear is caused not only in the cutting edge but also in the front guide. That is, the front guide wears due to rubbing with the workpiece during broaching, and the gap between the front guide and the workpiece increases quickly, so that the cutting edge that follows the rear end of the front guide is covered. Uneven contact with the workpiece. For this reason, it was found that the cutting edge was unevenly worn and the accuracy of the workpiece was deteriorated. With this knowledge, in the present invention, a front grip portion provided at one end of the rod-shaped broach body, a front guide provided following the front grip portion, and a rear end of the front guide are provided. A broach cutting tool having a number of cutting edges disposed thereon, and a broaching tool for processing a workpiece having a hardness of 45 to 65 HRC, wherein at least one hard coating layer is formed on a surface of the front guide. The above-mentioned problem was solved by providing the formed broach tool (claim 1). That is, by forming at least one hard coating layer on the front guide provided following the front grip portion of the broach main body, it is fast at a high speed with a slight clearance from the quenched HRC workpiece of 45 to 65. Even if rubbing occurs, damage due to wear in the front guide is suppressed. The material used for the front guide may be a commonly used alloy steel.

  In addition, a front grip portion provided at one end of the rod-shaped broach body, a front guide provided following the front grip portion, and a number of cutting blades provided following the rear end of the front guide are provided. And a broaching tool for processing a workpiece having a hardness of 45 to 65 HRC, wherein the material of the front guide is a cemented carbide material. That is, by using a cemented carbide material for the front guide that follows the front grip of the broach body, high-speed rubbing is generated with a slight clearance from the quenched HRC work piece of 45-65. Even so, the front guide is less damaged by rubbing.

  As described above, according to the present invention, the front grip portion provided at one end of the rod-shaped broach body, the front guide provided following the front grip portion, and the rear end of the front guide are provided. A broach cutting tool having a number of cutting edges disposed thereon, and a broaching tool for processing a workpiece having a hardness of 45 to 65 HRC, wherein at least one hard coating layer is formed on a surface of the front guide. Since the formed broaching tool is used, wear due to rubbing of the front guide coated with the hard coating is suppressed even if rubbing occurs at a high speed with a slight gap from the quenched 45-65 HRC workpiece. The cutting edge can be processed without causing uneven wear, and a broaching tool with good processing accuracy of the workpiece can be provided.

  In addition, a front grip portion provided at one end of the rod-shaped broach body, a front guide provided following the front grip portion, and a number of cutting blades provided following the rear end of the front guide are provided. A broach tool having a hardness of 45 to 65 HRC and a broach tool in which the material of the front guide is a cemented carbide material. Even if the hardened 45-65 HRC work piece is rubbed at a high speed with a slight gap, wear due to rubbing is suppressed in the front guide made of cemented carbide material. The cutting edge can be processed without causing uneven wear, and a broaching tool with good processing accuracy of the workpiece can be provided.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1A is a plan view of a broach tool showing a first embodiment of the present invention, FIG. 1B is a longitudinal sectional view of FIG. 4A, and FIG. 4 is a plane of a workpiece machined by the broach tool of the present invention. FIG. As shown in FIGS. 1A and 1B, the broach body 21 of the broach tool 20 of the present invention is manufactured using a high-speed tool steel material, and the rear grip 14 and the broach tool 20 are pulled out at both ends thereof. For this purpose, a front grip 1 is formed. A front guide 2 is formed on the rear grip 14 side of the front grip 1, and a gradually increasing portion 23 is provided on the front guide 2 so that the diameter gradually increases from the front grip 1 side. . In the cylindrical portion 30 that continues from the rear end 28 of the gradually increasing portion 23, there are four guide portions 22 in the longitudinal direction that can be fitted into the large-diameter spline portions 6 to 9 that are workpieces of the workpiece 5 shown in FIG. It is provided and performs positioning in the rotation direction with the workpiece. The broach main body 21 extending from the front guide 2 is fitted with a hollow cylindrical cemented carbide broach cutting edge portion 26 having a cutting edge 3, and is held by a lock nut 25. The front guide 2 is coated with at least one hard coating layer. Using this broach tool, a high hardness material of 40-60 HRC is processed at a high speed of 40-80 m / min. The workpiece 5 has a margin of about 0.1 to 0.2 mm on one side with respect to the finished dimensions, heat-treats the pre-worked workpiece to a predetermined hardness (45 to 65 HRC), and then the broach of the broach tool 21 Broaching is performed by the cutting edge portion 3 of the cutting edge portion 26 at a cutting speed of 40 to 80 m / min.

  Next, a second embodiment of the present invention will be described. Fig.2 (a) is a top view of the broach tool which shows 2nd embodiment of this invention, (b) is a longitudinal cross-sectional view of (a). Components similar to those in FIGS. 1A and 1B are denoted by the same reference numerals and description thereof is omitted. In the second embodiment of the present invention, the broach cutting edge portion and the front guide described in the first embodiment are fitted from the front grip portion side. As shown in FIGS. 2 (a) and 2 (b), a broach tool 40 showing a second embodiment of the present invention has a cutting edge 3 toward a rear guide 41 provided on a broach main body 42. A hard-cylindrical hollow cylindrical broach cutting edge portion 26 and the front guide 2 are sequentially fitted and clamped by a lock nut 43. The front guide 2 is made of high-speed tool steel and covers at least one hard coating layer. Alternatively, the front guide 2 is a cemented carbide material. Using this broach tool, a high hardness material of 40-60 HRC is processed at a high speed of 40-80 m / min.

  Next, a third embodiment of the present invention will be described. FIG. 3A is a plan view of a broach tool showing a third embodiment of the present invention, and FIG. 3B is a longitudinal sectional view of FIG. Parts similar to those in FIGS. 1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b) are denoted by the same reference numerals and description thereof is omitted. In the third embodiment of the present invention, the broach cutting edge portion and the front guide described in the second embodiment are manufactured as a single body. As shown in FIGS. 3 (a) and 3 (b), the broach tool 50 showing the third embodiment of the present invention has a front guide 51 and a cutting edge 52 made of cemented carbide and integrally manufactured. The broach cutting edge 53 is fitted to the broach main body 42 and is sandwiched between lock nuts 43. Using this broach tool, a high hardness material of 40-60 HRC is processed at a high speed of 40-80 m / min.

  The above embodiments of the present invention all show examples of four-groove angular spline broaches, but it goes without saying that the present invention can be applied to processing broaches having a free-form cross section composed of straight lines or curves such as involute spline grooves and ball grooves. Yes. It goes without saying that the hard coating may be coated on the front guide 51 made of cemented carbide shown in the third embodiment of the present invention.

  The hard film covering the front guide 2 of the broach tool 20 shown in FIGS. 1 (a) and 1 (b) described in the first embodiment of the present invention is mainly composed of Ti and Al by arc ion plating. A TiAlN film having a thickness of 5 μm was coated, and the workpiece 5 shown in FIG. 4 was processed at a cutting speed of 60 m / min using the coated film. The workpiece 5 had a hardness of 62 HRC, and a large diameter margin was 0.1 mm on one side. As a result, even when the number of workpieces exceeded 5000, the front guide 2 showed almost no wear, and the cutting edge showed no uneven wear.

(A) is a top view of the broach tool which shows 1st embodiment of this invention, (b) is a longitudinal cross-sectional view of (a). (A) is a top view of the broach tool which shows 2nd embodiment of this invention, (b) is a longitudinal cross-sectional view of (a). (A) is a top view of the broach tool which shows 3rd embodiment of this invention, (b) is a longitudinal cross-sectional view of (a). It is a top view of the workpiece | work processed with the broach tool of this invention.

Explanation of symbols

1 Front grip part 2, 51 Front guide 3, 52 Cutting edge 20, 40, 50 Broach tool 21, 42 Broach body 26, 53 Broach cutting edge part

Claims (2)

A front grip provided at one end of the rod-shaped broach body, a front guide provided following the front grip, and a number of cutting blades provided following the rear end of the front guide are provided. A broach tool for processing a workpiece having a hardness of 45 to 65 HRC, wherein at least one hard coating layer is formed on the surface of the front guide. Brooch tool. A front grip provided at one end of the rod-shaped broach body, a front guide provided following the front grip, and a number of cutting blades provided following the rear end of the front guide are provided. A broaching tool for processing a workpiece having a hardness of 45 to 65 HRC, wherein the material of the front guide is a cemented carbide material.

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