JP2005224893A - Abrasion-resistant tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exhibit abrasion resistance equivalent to that of diamond, allow free configuration design, and being favorable in the manufacturing cost. <P>SOLUTION: A lathe center 1 is basically constituted of two components, a head part 2 comprising a tip part 21 functioned as a working face in contact with a work and a leg part 22, and a body part fixing the head part 2. The head part 2 is formed of WC-Co-based cemented carbide, the conical working face 21a in the tip part 21 is covered with a diamond film 4 by a CVD method for exhibiting the abrasion resistance; and the leg part 22 is a columnar part coaxially extending from the tip part 21 and has a sufficient diameter and length for being fixed to the body part 3. The leg part 22 is detachably fitted and fixed to a fitting hole 31 provided in one end of the body part by a shrinkage fit method. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in a wear-resistant jig, for example, a core pressing jig (race center) for a workpiece used in a lathe or a cylindrical grinding machine.

Conventionally, in machining by a lathe or a cylindrical grinder, a race center is used to support the rotation center of a rotating workpiece (see Patent Document 1). In particular, it is essential to accurately center the workpiece in such machining, and the race center used for this purpose is usually made of hard metal such as hardened steel or cemented carbide. is there.
JP-A-11-309651: Claim 1, paragraph (0033), FIG. 1, FIG.

  The tip of the race center is formed in a sharp shape and functions as a working surface that comes into contact with the workpiece, so a strong stress is applied between the workpiece and the material is highly worn, so a material with excellent wear resistance is selected. Is done. However, hard metals such as hardened steel and cemented carbide are used as described above from the viewpoint of ease of processing and cost when manufacturing this race center, but in terms of wear resistance. There was room for improvement.

  In addition, sintered diamond and other materials that have higher wear resistance than these hard metals can give good results in terms of wear resistance, but they are extremely difficult to process such as molding, and the cost of the material itself is high. So it has not spread.

  The present invention has been made in order to solve the above-described problems, and is equivalent to the wear resistance of diamond for wear-resistant jigs that require wear resistance at the tip portion such as a race center. In addition, a wear-resistant jig that is free in shape design and advantageous in manufacturing cost is provided.

  The above-mentioned problem is a wear-resistant jig whose tip portion is required to have wear resistance, and at least the tip of the head portion composed of a tip portion and a leg portion formed of a WC-Co based cemented carbide. The working surface of the part is covered with a diamond film by CVD, the leg part is detachably fixed to the body part, and the head part and the body part are integrated. This can be solved by a wear jig.

  In the present invention, it is preferable that the leg portion of the head portion is fitted and fixed to the body portion by shrink fitting, and the diamond coating has a thickness of 6 to 20 μm. Most preferably, the wear-resistant jig is a race center.

  The wear-resistant jig of the present invention is a jig in which two members, a head part and a body part, are integrated, and the tip part where wear resistance of the head part is required is applied to a WC-Co-based Since it is made of a hard alloy and its working surface is coated with a diamond film formed by CVD, wear resistance equivalent to diamond can be obtained, and the diamond coating is partial so that the manufacturing cost can be reduced. Further, since the diamond film is used, the coating is formed in accordance with the shape of the base material. Therefore, there is no need for shape processing after coating, and cost advantages such as freedom of shape design are obtained.

  And the head part in the present invention comprises a tip part and a leg part, and the leg part is detachably fixed to the body part by a technique such as shrink fitting, so that the entire wear-resistant jig is Is not required to be manufactured from cemented carbide, and the manufacturing cost is advantageous from this point.

  In addition, when the tip portion is worn after use, the head portion can be exchanged for reproduction, so that there is an advantage that the running cost can be suppressed. Further, if the leg portion is fixed by shrink fitting, the rigidity does not change even if the attachment and detachment is repeated, and thus there is an advantage that high accuracy can be maintained. Therefore, the present invention has an extremely large practical value as a wear-resistant jig that solves the conventional problems.

  Next, an embodiment according to the wear-resistant jig of the present invention will be described with reference to FIGS. The present invention relates to a wear-resistant jig whose tip portion is required to have wear resistance. As a representative example, the race center 1 is used to support a rotating workpiece in a lathe or a cylindrical grinder. Explain as an example.

  As described above, this race center 1 is excellent in that it is formed in a sharp shape and functions as a working surface that comes into contact with the workpiece in order to reliably support the workpiece rotating at its tip in machining such as a lathe. It is basically composed of two parts, a head portion 2 composed of a tip portion 21 and a leg portion 22 where wear resistance is required, and a body portion 3 for fixing the head portion 2.

  And this head part 2 is formed from a WC-Co based cemented carbide, but as a form, as shown in FIG. 3, a tip part 21 and a leg part 22 are continuously integrated into a cone. There is a straight type (FIG. 3A) and a conical stepped type (FIG. 3B) in which a leg portion 22 having a diameter reduced from the tip portion 21 is integrated continuously.

However, in any case, the conical working surface 21a formed at the tip portion 21 is covered with the diamond film 4 by the CVD method, and is required to be in contact with a work (not shown). It is configured to demonstrate. The diamond film 4 may be a film formed by an ordinary CVD method, and the film thickness is preferably in the range of 6 to 20 μm from the viewpoint of wear resistance.
The leg portion 22 is a columnar portion extending coaxially from the tip portion 21 and has a diameter and a length sufficient to be fixed to the body portion 3 described later.

  Next, the body portion 3 will be described. The head portion 2 and the body portion 3 can be integrated by fixing the leg portion 22 detachably and coaxially. A form in which the portion 22 is fitted and fixed in a fitting hole 31 provided at one end of the body portion 3 by a shrink fitting method is preferable.

  Thus, if fixed by shrink fitting, the head part 2 can be removed from the body part 3 by reheating the body part 3, so the worn head part 2 can be replaced with a new one or recycled. There is an advantage that the maintenance cost can be easily reduced, and the maintenance cost can be reduced without the need to replace the whole.

  The fitting and fixing by the shrink-fitting method means that the inner diameter of the fitting hole 31 of the body part 3 is formed in advance to be smaller than the outer diameter of the leg part 22, and the body part 3 is once heated. The diameter of the fitting hole 31 is increased by thermal expansion, the leg portion 22 is inserted, the diameter is reduced by cooling, and the inserted leg portion 22 is elastically gripped. Conditions such as the difference between the inner and outer diameters and the heating temperature are set in advance according to the elastic modulus, thermal expansion coefficient, final gripping force, etc. of the material.

  Further, the body portion 3 itself only needs to have an intrinsic strength for fixing the head portion 2 as described above, and is not necessarily formed of a cemented carbide like the head portion 2. For example, steel materials of the SK material class having a hardness HRC of 40 to 45 can be used. Accordingly, since the race center 1 of the present invention is composed of the cemented carbide head portion 2 and the body portion 3 formed of a cheaper material, an advantage of greatly reducing the overall material cost can be obtained. is there.

  In the above description, the race center, which is a preferable example of the present invention, has been described. However, the present invention is not limited to this, and is generally applied to wear-resistant jigs that require wear resistance at the tip portion. It goes without saying.

Cylindrical nitriding using Example 1 as the race center of the structure of the present invention having a head portion provided with a CVD diamond film having a thickness of 6 to 20 μm and Comparative Example 11 as a carbide race center not provided with a CVD diamond film. The silicon fired product was ground for 5 hours a day × 30 days (a total of 150 hours), and the case where the machining accuracy deteriorated was determined as the service life (tool life). As a result, in the comparative example, replacement with a new product was required three times. However, in the example, deterioration of the processing accuracy was not observed, and wear of the diamond film could not be observed.
The results are shown in Table 1 when the lifetime is displayed in total time.

実施例１：ＣＶＤダイヤモンド膜を設けたレースセンタ
比較例１１：ＣＶＤダイヤモンド膜を設けていない超硬レースセンタ

Example 1: Race center comparative example provided with a CVD diamond film 11: Carbide race center not provided with a CVD diamond film

The principal part sectional view showing the race center which is an embodiment of the present invention. The side view which shows the body part of the race center of this invention. Side surface sectional drawing (A) which shows one example of the head part of this invention, Side surface sectional drawing (B) of another example.

Explanation of symbols

1: race center 2: head part, 21: tip part, 21a: working surface, 22: leg part 3: body part, 31: fitting hole 4: diamond film

Claims (4)

  A wear-resistant jig that requires wear resistance at the tip portion, and the working surface of at least the tip portion of the head portion composed of a tip portion and a leg portion formed of a WC-Co cemented carbide is at least A wear-resistant jig, characterized in that it is coated with a diamond film by a CVD method, its leg portion is detachably fixed to the body portion, and the head portion and the body portion are integrated.   The wear-resistant jig according to claim 1, wherein the leg portion of the head portion is fitted and fixed to the body portion by shrink fitting.   The wear-resistant jig according to claim 2, wherein the diamond coating has a thickness of 6 to 20 μm. The wear-resistant jig according to claim 3, wherein the wear-resistant jig is a race center.

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