JP3649700B2

JP3649700B2 - Cutting wheel

Info

Publication number: JP3649700B2
Application number: JP2002083214A
Authority: JP
Inventors: 大介井手; 誠也緒方
Original assignee: Noritake Co Ltd; Noritake Super Abrasive Co Ltd
Current assignee: Noritake Co Ltd; Noritake Super Abrasive Co Ltd
Priority date: 2002-03-25
Filing date: 2002-03-25
Publication date: 2005-05-18
Anticipated expiration: 2022-03-25
Also published as: JP2003275968A

Description

【０００１】
【発明の属する技術分野】
本発明は、コンクリート、コンクリート二次製品、セメント系建材、窯業系建材などの切断に用いられる切断ホイールにかかり、詳しくは、ろう付けにより基板に一層配列する砥粒の配列を改良してホイールの切れ味と寿命を向上させた切断ホイールに関する。
【０００２】
【従来の技術】
コンクリート、コンクリート二次製品、セメント系建材、窯業系建材などの切断用として、円盤状の基板の外周部に砥粒をろう付け法により一層配列した切断ホイールが使用されている。このような切断ホイールには、切れ味に優れ、しかもその切れ味が長期にわたって安定的に持続することが要求される。ところが、切断ホイールは切断作業の進行に伴い切れ味と寿命が低下する。
【０００３】
その主な原因として、基板への砥粒の固着状態が不安定で砥粒が脱落しやすいこと、チップポケットが小さいこと、砥粒間隔のコントロールが不十分なために切断作業中に切粉によって目詰まりが生じることが挙げられる。とくに砥粒間隔に関しては、基板の表面に砥粒を所定の配列状態に配設するのが難しく、砥粒どうしが近接した状態にある部分においては、切粉が排出されにくく、切れ味の低下につながる。
【０００４】
ろう付け法による切断ホイールの製造において、砥粒を均一に分散させるための方策として、特開平９−１９８６７号公報には、金属被覆したダイヤモンド砥粒を基板外周面と金型の間隙に充填し、基板と金型を加熱しながら銀ろうを間隙に溶浸させる切断ホイールの製造方法が開示されている。また特開平１０−１１８９３７号公報には、１個または集合した複数個の超砥粒の一層によって作用砥粒を形成し、作用砥粒間の外周方向の間隔を作用砥粒の粒径以上とした切断ホイールが記載されている。
【０００５】
【発明が解決しようとする課題】
ところで、特開平９−１９８６７号公報に記載の切断ホイールは、基板の外周面に連続的に環状の砥粒層を形成したものであるので、切断時に発生する切粉の排出性が良くないという難点がある。一方、特開平１０−１１８９３７号公報に記載の切断ホイールは基板外周部に基板半径方向のスリットを複数個設けているので、切粉の排出性は良好である。しかし、この切断ホイールにおいては、スリットとスリットの間の砥粒層形成範囲において、ホイール回転方向にみた砥粒の分布が均一に分散配置されている。このため、切断ホイールの使用に伴って、各スリット間のホイール回転方向前部に含まれる砥粒は、回転方向後部に比べて破砕磨耗の程度が大きく、逆に回転方向後部は殆ど磨耗していないという状況が生じる。
【０００６】
このような磨耗の違いは、各スリット間の砥粒層が最初に被削材に食い込む先端部が被削材への食い込み量も多く加工量が大きくなること、切断中発生する切粉を掻き出し、外部へ排出することが切断においては必要であるが、切粉掻き出しの面でも先端部により多く負担がかかること、セグメントは最初に被削材に食い込む先端部がより大きな衝撃を受けること、などから、回転方向前部の摩耗が大になるものと考えられる。このようにホイール回転方向にみて砥粒を均一に分散配置した従来の切断ホイールでは、回転方向先端部が早く磨耗し以下のような問題を生じる。
【０００７】
（１）先端部の砥粒が少なくなるため、被削材への食い込みが充分でなく切れ味が低下する。（２）先端の端面が丸まって面積が減少するため、切粉の掻き出し効果が低下する。（３）後部に使用可能な砥粒層を残した状態で切れ味低下のため切断ホイールが使用できなくなり、全体として不経済である。
【０００８】
本発明が解決すべき課題は、従来考慮されていないホイール回転方向の耐摩耗性を変化させることによって、ホイール回転方向の前部の切れ味を高め、寿命の長い切断ホイールを得ることにある。
【０００９】
【課題を解決するための手段】
本発明は、円盤状の基板の外周面および外周部側面に砥粒を一層配列してろう付けした切断ホイールにおいて、基板の外周部に一定間隔で基板半径方向にスリットを設けて砥粒層形成範囲をセグメントチップ状に形成し、前記砥粒層形成範囲のホイール回転方向前部側の砥粒粒径を後部側の砥粒粒径より大きくしたことを特徴とする。
【００１０】
ここで、ホイール回転方向前部側から後部側にかけて砥粒粒径を連続的に変化させたり、また２段階あるいは３段階に段階的に変化させたりすることができる。その際全体の砥粒数を従来品と同数とし、前部側の砥粒粒径の大きい砥粒数と後部側の砥粒粒径の小さい砥粒数とをバランスさせることもできる。
【００１１】
また、ホイール回転方向前部側の砥粒粒径を大きくする高切れ味部の範囲は、セグメントチップ状の砥粒層形成範囲の周方向長さにおいて１０〜４０％の範囲とし、この前部側の砥粒粒径を残りの後部側の砥粒粒径の１．２倍以上とするのが望ましい。高切れ味部の範囲が周方向長さの１０％未満であると、切れ味向上効果が期待できず、４０％を超えると、切断時の振動が大きくなり、被研削材のチッピングが大きくなる。また必要以上に粒径が大きい砥粒を使用するとコストも高くなる。
【００１２】
また、前部側と後部側の砥粒粒径の比は、後部側１００に対して前部側が１２０〜２００の範囲とするのが望ましい。この比が１２０より低いと、前部側が高切れ味部として作用するには不十分であり、２００を超えると、切断時の負荷が分散されずに前部側のみに集中するため、前部側の砥粒の脱落が生じて切れ味が低下する。
【００１３】
本発明の切断ホイールにおいては、セグメント状の砥粒層形成範囲のホイール回転方向前部側の砥粒粒径を後部側の砥粒粒径より大きくしたことにより、前部側の切れ味を向上させることができ、また前部側と後部側の砥粒粒径を適正化することにより、セグメント状の砥粒層が偏磨耗することなく、全体として均一に磨耗するようになる。
【００１４】
【発明の実施の形態】
図１および図２は本発明の第１の実施形態の切断ホイールを説明する図であり、図１の（ａ）は切断ホイールの正面図、（ｂ）は（ａ）のＡ−Ａ線断面図であり、図２の（ａ）は基板外周部の拡大断面図、（ｂ）は基板の外周面の基板周方向にみた一部の展開図、（ｃ）は基板の外周部側面の基板周方向にみた一部の展開図である。図中、砥粒および砥粒の配置は模式的に示している。
【００１５】
本実施形態の切断ホイール１０は、コンクリートやセメント系建材などの切断用のホイールである。基板１は外径１００ｍｍ、厚さ１．２ｍｍのスチール製基板であり、砥粒２はダイヤモンド砥粒であり、ろう材３はＡｇ−Ｃｕ−Ｔｉ系の活性金属入りろうである。
【００１６】
基板１の外周部には切粉排出のためのスリット１１が形成され、各スリット１１の間に砥粒２が配設されている。基板１の外周部は図２の拡大図に示すように、外周面１ａに３列、外周部側面１ｂに２列、砥粒２（２ａ，２ｂ）が基板周方向に間隔をおいて配設され、ろう材３により基板１に固着されている。
【００１７】
つぎに砥粒２の配設状態について説明する。本実施形態の切断ホイール１０においては、図２の（ｂ）および（ｃ）に一部の砥粒層形成範囲を拡大展開して示すように、砥粒２を配設した外周面１ａと外周部側面１ｂを基板周方向に展開した状態で、砥粒層形成範囲のホイール回転方向前部側には粒径の大きい砥粒２ａを配設し、後部側には粒径の小さい砥粒２ｂを配設している。具体的には、砥粒層形成範囲の周方向長さにおいて回転方向前部側の約３５％の範囲に平均粒径約６００μｍの砥粒２ａを配設し、回転方向後部側には平均粒径約３５０μｍの砥粒２ｂを配設している。これにより、前部側の切れ味を向上させながら、後部側によって低振動と負荷の分散を確保することができる。
【００１８】
図３は砥粒の配設形態の別の例を示す図で、基板の外周面の基板周方向にみた一部の展開図である。図中、砥粒および砥粒の配置は模式的に示している。
【００１９】
図３（ａ）の例では、基板１の外周面１ａに２列の砥粒２ａ，２ｂが配設され、ろう材により基板１に固着されている。ホイール回転方向前部側の約３５％の範囲には平均粒径約６００μｍの砥粒２ａが配設され、回転方向後部側には平均粒径約３５０μｍの砥粒２ｂが配設されている。
【００２０】
図３（ｂ）の例では、基板１の外周面１ａに１列の砥粒２ａ，２ｂ，２ｃが配設され、ろう材により基板１に固着されている。ホイール回転方向前部側の約３０％の範囲には平均粒径約６００μｍの砥粒２ａが配設され、ホイール回転方向後部側の約３０％には平均粒径約３５０μｍの砥粒２ｂが配設され、残りの中央部には平均粒径約４５０μｍの砥粒２ｃが配設されている。
【００２１】
図３（ａ）、（ｂ）の実施形態の場合も、ホイール回転方向前部側の砥粒粒径を後部側に比して大きくしているので、前部側の切れ味を向上させながら、後部側によって低振動と負荷の分散を確保することができる。
【００２２】
第１の実施形態の切断ホイール１０の製造手順はつぎの通りである。
・基板１として外径１００ｍｍ、厚さ１．２ｍｍのスチール製基板を準備する。
・砥粒２ａとして平均粒径約６００μｍのダイヤモンド砥粒を、砥粒２ｂとして平均粒径約３５０μｍのダイヤモンド砥粒を準備する。
・直径０．６０ｍｍの孔と直径０．３５ｍｍの孔を図２の（ｂ）および（ｃ）に示すかたちに配列したスクリーンを用いて、基板１の外周面１ａと外周部側面１ｂに有機接着剤を塗布する。
・この有機接着剤の上に砥粒２ａ，２ｂを配置する。この状態で砥粒２ａ，２ｂは基板１の外周面１ａと外周部側面１ｂに図２の（ｂ）および（ｃ）に示すかたちに配列される。
・これを乾燥炉中で１２０℃、１時間乾燥させ、砥粒を仮固定する。
・三次元移動が可能なアプリケータ（吐出機）を用いて、接着部にろう材とバインダーの混合物を砥粒粒径の約１／２の高さに塗布する。
・これを非酸化性雰囲気中で１０００℃、１時間加熱し、砥粒を基板に本固定する。
図３の実施形態の切断ホイールの製造手順も、基本的には上記の製造手順と同様である。
【００２３】
〔試験例〕
図１に示した実施形態の切断ホイール（発明品１）と図３（ａ）に示した実施形態の切断ホイール（発明品２）、および、第１実施形態の基板と同じ形状で同じ数の砥粒を基板周方向に均等に配設した切断ホイール（比較品）を製造して切断加工試験を行った。
【００２４】
〔試験条件〕
切断機械：日立製丸のこＣ４ＹＡ１
機械回転数：１３０００ｍｉｎ^−１
被切断材：押し出し成形セメント板
切り込み量：１５ｍｍ／ｐａｓｓ
切断方式：乾式切断
送り速度：負荷電流８Ａになるよう調節
【００２５】
表１に試験結果を示す。
【表１】

【００２６】
発明品１，２の切断速度およびホイール寿命は、比較品の切断速度およびホイール寿命を１００としたときの指数で示す。同表からわかるように、ホイール回転方向前部側の砥粒粒径を大きくして切れ味を高めた発明品１，２の切断ホイールは、比較品の切断ホイールに比べて切断速度、ホイール寿命とも１．３〜１．５倍程度に向上している。
【００２７】
【発明の効果】
セグメント状の砥粒層形成範囲のホイール回転方向前部側の砥粒粒径を後部側の砥粒粒径より大きくしたことにより、前部側の切れ味を向上させることができ、また前部側と後部側の砥粒粒径を適正化することにより、セグメント状の砥粒層が偏磨耗することなく、全体として均一に磨耗するようになる。
【図面の簡単な説明】
【図１】本発明の実施形態の切断ホイールを説明する図であり、（ａ）は切断ホイールの正面図、（ｂ）は（ａ）のＡ−Ａ線断面図である。
【図２】（ａ）は図１の切断ホイールの基板外周部の拡大断面図、（ｂ）は基板の外周面の基板周方向にみた一部の展開図、（ｃ）は基板の外周部側面の基板周方向にみた一部の展開図である。
【図３】砥粒の配設形態の別の例を示す図である。
【符号の説明】
１基板
１ａ外周面
１ｂ外周部側面
２，２ａ，２ｂ，２ｃ砥粒
３ろう材
１０切断ホイール
１１スリット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cutting wheel used for cutting concrete, concrete secondary products, cement-based building materials, ceramic-based building materials, and the like. Specifically, the arrangement of abrasive grains arranged on a substrate by brazing is improved to improve the wheel. The present invention relates to a cutting wheel with improved sharpness and life.
[0002]
[Prior art]
For cutting concrete, concrete secondary products, cement building materials, ceramic building materials, etc., a cutting wheel is used in which abrasive grains are further arranged on the outer periphery of a disk-shaped substrate by a brazing method. Such a cutting wheel is required to have excellent sharpness and to maintain the sharpness stably over a long period of time. However, the cutting wheel has a reduced sharpness and life as the cutting operation proceeds.
[0003]
The main causes are that the abrasive grains are unstablely fixed to the substrate and the grains are easy to fall off, the chip pockets are small, and the control of the abrasive grain spacing is insufficient, so that the chips are cut during the cutting operation. It may be clogged. Especially with regard to the abrasive grain spacing, it is difficult to arrange the abrasive grains in a predetermined arrangement on the surface of the substrate, and in the part where the abrasive grains are close to each other, it is difficult for chips to be discharged, resulting in a decrease in sharpness. Connected.
[0004]
In manufacturing a cutting wheel by brazing, as a measure for uniformly dispersing abrasive grains, Japanese Patent Application Laid-Open No. 9-19867 discloses that metal-coated diamond abrasive grains are filled into a gap between a substrate outer peripheral surface and a mold. A method for manufacturing a cutting wheel is disclosed in which a silver solder is infiltrated into a gap while heating a substrate and a mold. Japanese Patent Application Laid-Open No. 10-118937 discloses that a working abrasive is formed by one or a group of a plurality of superabrasive grains, and that the interval in the outer peripheral direction between the working abrasive grains is equal to or larger than the grain size of the working abrasive grains. A cutting wheel is described.
[0005]
[Problems to be solved by the invention]
By the way, the cutting wheel described in Japanese Patent Laid-Open No. 9-19867 is formed by continuously forming an annular abrasive grain layer on the outer peripheral surface of the substrate. There are difficulties. On the other hand, the cutting wheel described in Japanese Patent Application Laid-Open No. 10-118937 has a plurality of slits in the radial direction of the substrate on the outer periphery of the substrate, so that the chip dischargeability is good. However, in this cutting wheel, the distribution of the abrasive grains as viewed in the wheel rotation direction is uniformly distributed in the abrasive layer formation range between the slits. For this reason, with the use of the cutting wheel, the abrasive grains contained in the front part in the wheel rotation direction between the slits have a larger degree of crushing wear than the rear part in the rotation direction, and conversely, the rear part in the rotation direction is almost worn. There will be no situation.
[0006]
This difference in wear is due to the fact that the abrasive layer between the slits first bites into the work piece, the amount of bite into the work piece increases and the amount of work increases, and scraps generated during cutting are scraped off. It is necessary to discharge to the outside in cutting, but the tip is also burdened even on the chip scraping surface, the segment receives the greater impact at the tip that bites into the work material first, etc. Therefore, it is considered that the wear at the front part in the rotational direction is increased. As described above, in the conventional cutting wheel in which the abrasive grains are uniformly distributed as viewed in the wheel rotation direction, the front end portion in the rotation direction is quickly worn and causes the following problems.
[0007]
(1) Since the abrasive grains at the tip end are reduced, the biting into the work material is not sufficient and the sharpness is lowered. (2) Since the end face of the tip is rounded to reduce the area, the chip scraping effect is reduced. (3) The cutting wheel cannot be used due to the sharpness reduction while leaving the usable abrasive grain layer in the rear portion, which is uneconomical as a whole.
[0008]
The problem to be solved by the present invention is to improve the sharpness of the front part in the direction of rotation of the wheel by changing the wear resistance in the direction of rotation of the wheel, which has not been considered in the past, and to obtain a cutting wheel with a long life.
[0009]
[Means for Solving the Problems]
The present invention provides a cutting wheel in which abrasive grains are arranged and brazed on the outer peripheral surface and the outer peripheral side surface of a disk-shaped substrate, and the abrasive layer is formed by providing slits in the substrate radial direction at regular intervals on the outer peripheral portion of the substrate. The range is formed in the shape of segment chips, and the abrasive grain size on the front side in the wheel rotation direction of the abrasive layer formation range is made larger than the abrasive grain size on the rear side.
[0010]
Here, the grain size of the abrasive grains can be continuously changed from the front side to the rear side in the wheel rotation direction, or can be changed stepwise in two or three steps. At that time, the total number of abrasive grains can be the same as that of the conventional product, and the number of abrasive grains having a large abrasive grain diameter on the front side and the number of abrasive grains having a small abrasive grain diameter on the rear side can be balanced.
[0011]
Moreover, the range of the high sharpness part which enlarges the abrasive grain diameter of the wheel rotation direction front side is set to a range of 10 to 40% in the circumferential direction length of the segment chip-shaped abrasive grain layer formation range. It is desirable to set the abrasive grain size to be 1.2 times or more of the remaining rear grain size. When the range of the high sharpness portion is less than 10% of the circumferential length, the sharpness improvement effect cannot be expected, and when it exceeds 40%, vibration at the time of cutting increases, and chipping of the material to be ground increases. In addition, if abrasive grains having a larger particle size than necessary are used, the cost also increases.
[0012]
The ratio of the grain size of the front side and the rear side is preferably in the range of 120 to 200 on the front side with respect to the rear side 100. If this ratio is lower than 120, the front side is insufficient to act as a high sharpness part, and if it exceeds 200, the load at the time of cutting is concentrated only on the front side without being distributed. The abrasive grains fall off and the sharpness decreases.
[0013]
In the cutting wheel of the present invention, the sharpness on the front side is improved by making the abrasive grain size on the front side in the wheel rotation direction of the segment-shaped abrasive layer formation range larger than the abrasive grain size on the rear side. In addition, by optimizing the grain size of the front side and the rear side, the segment-like abrasive layer wears uniformly as a whole without uneven wear.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are diagrams for explaining a cutting wheel according to a first embodiment of the present invention. FIG. 1 (a) is a front view of the cutting wheel, and FIG. 1 (b) is a cross-sectional view taken along line AA in FIG. 2A is an enlarged cross-sectional view of the outer peripheral portion of the substrate, FIG. 2B is a partial development view of the outer peripheral surface of the substrate in the substrate peripheral direction, and FIG. 2C is the substrate on the side surface of the outer peripheral portion of the substrate. It is a partial development view seen in the circumferential direction. In the drawing, the abrasive grains and the arrangement of the abrasive grains are schematically shown.
[0015]
The cutting wheel 10 of this embodiment is a wheel for cutting concrete or cement-based building materials. The substrate 1 is a steel substrate having an outer diameter of 100 mm and a thickness of 1.2 mm, the abrasive grains 2 are diamond abrasive grains, and the brazing material 3 is a brazing material containing an Ag—Cu—Ti based active metal.
[0016]
Slits 11 for discharging chips are formed on the outer periphery of the substrate 1, and abrasive grains 2 are disposed between the slits 11. As shown in the enlarged view of FIG. 2, the outer periphery of the substrate 1 has three rows on the outer peripheral surface 1a, two rows on the outer peripheral side surface 1b, and abrasive grains 2 (2a, 2b) arranged at intervals in the substrate circumferential direction. And fixed to the substrate 1 by the brazing material 3.
[0017]
Next, the arrangement state of the abrasive grains 2 will be described. In the cutting wheel 10 of the present embodiment, as shown in FIGS. 2B and 2C in which a part of the abrasive layer formation range is expanded and shown, the outer peripheral surface 1a and the outer periphery on which the abrasive grains 2 are disposed. In a state where the side surface 1b is developed in the circumferential direction of the substrate, the abrasive grains 2a having a large particle diameter are disposed on the front side in the wheel rotation direction of the abrasive layer formation range, and the abrasive grains 2b having a small particle diameter are disposed on the rear side. Is arranged. Specifically, the abrasive grains 2a having an average particle diameter of about 600 μm are arranged in a range of about 35% on the front side in the rotational direction in the circumferential length of the abrasive grain layer forming range, and the average grains are arranged on the rear side in the rotational direction. Abrasive grains 2b having a diameter of about 350 μm are disposed. Thereby, low vibration and load distribution can be secured by the rear side while improving the sharpness of the front side.
[0018]
FIG. 3 is a diagram showing another example of the arrangement form of the abrasive grains, and is a development view of a part of the outer peripheral surface of the substrate viewed in the circumferential direction of the substrate. In the drawing, the abrasive grains and the arrangement of the abrasive grains are schematically shown.
[0019]
In the example of FIG. 3A, two rows of

abrasive grains

2 a and 2 b are disposed on the outer peripheral surface 1 a of the substrate 1 and are fixed to the substrate 1 with a brazing material. Abrasive grains 2a having an average particle diameter of about 600 μm are disposed in a range of about 35% on the front side in the wheel rotation direction, and abrasive grains 2b having an average particle diameter of about 350 μm are disposed on the rear side in the rotation direction.
[0020]
In the example of FIG. 3B, a row of

abrasive grains

2 a, 2 b, 2 c is disposed on the outer peripheral surface 1 a of the substrate 1 and is fixed to the substrate 1 with a brazing material. Abrasive grains 2a having an average particle diameter of about 600 μm are arranged in a range of about 30% on the front side in the wheel rotation direction, and abrasive grains 2b having an average grain diameter of about 350 μm are arranged in about 30% on the rear side in the wheel rotation direction. In the remaining central portion, abrasive grains 2c having an average particle diameter of about 450 μm are disposed.
[0021]
In the case of the embodiment of FIGS. 3 (a) and 3 (b), the abrasive grain size on the front side in the wheel rotation direction is larger than that on the rear side, so improving the sharpness on the front side, Low vibration and load distribution can be ensured by the rear side.
[0022]
The manufacturing procedure of the cutting wheel 10 of the first embodiment is as follows.
A steel substrate having an outer diameter of 100 mm and a thickness of 1.2 mm is prepared as the substrate 1.
Prepare diamond abrasive grains having an average particle diameter of about 600 μm as the abrasive grains 2a, and diamond abrasive grains having an average particle diameter of about 350 μm as the abrasive grains 2b.
Using a screen in which holes having a diameter of 0.60 mm and a hole having a diameter of 0.35 mm are arranged in the form shown in FIGS. Apply the agent.
The

abrasive grains

2a and 2b are disposed on the organic adhesive. In this state, the

abrasive grains

2a and 2b are arranged on the outer peripheral surface 1a and the outer peripheral side surface 1b of the substrate 1 in the form shown in FIGS.
-This is dried at 120 degreeC for 1 hour in a drying furnace, and an abrasive grain is temporarily fixed.
-Using an applicator (dispenser) capable of three-dimensional movement, a mixture of a brazing filler metal and a binder is applied to the adhesive portion at a height of about 1/2 of the grain size of the abrasive grains.
This is heated at 1000 ° C. for 1 hour in a non-oxidizing atmosphere, and the abrasive grains are permanently fixed to the substrate.
The manufacturing procedure of the cutting wheel of the embodiment of FIG. 3 is basically the same as the manufacturing procedure described above.
[0023]
[Test example]
The cutting wheel (invention product 1) of the embodiment shown in FIG. 1 and the cutting wheel (invention product 2) of the embodiment shown in FIG. 3 (a) and the same number as the substrate of the first embodiment. A cutting wheel (comparative product) in which abrasive grains were evenly arranged in the circumferential direction of the substrate was manufactured and a cutting test was performed.
[0024]
〔Test conditions〕
Cutting machine: Hitachi round saw C4YA1
Machine rotation speed: 13000 min ⁻¹
Material to be cut: Extruded cement board cutting depth: 15mm / pass
Cutting method: Dry cutting feed rate: Adjust to load current 8A.
Table 1 shows the test results.
[Table 1]

[0026]
The cutting speed and wheel life of the

inventive products

1 and 2 are indicated by an index when the cutting speed and wheel life of the comparative product are taken as 100. As can be seen from the table, the cutting wheels of

Inventions

1 and 2 with increased abrasive grain size on the front side in the wheel rotation direction have improved cutting speed and wheel life compared to the comparative cutting wheel. It is improved by about 1.3 to 1.5 times.
[0027]
【The invention's effect】
By making the abrasive grain size on the front side in the wheel rotation direction of the segment-shaped abrasive layer formation range larger than the abrasive grain size on the rear side, the sharpness on the front side can be improved, and the front side By optimizing the abrasive grain size on the rear side, the segment-like abrasive layer wears uniformly as a whole without uneven wear.
[Brief description of the drawings]
1A and 1B are diagrams illustrating a cutting wheel according to an embodiment of the present invention, in which FIG. 1A is a front view of the cutting wheel, and FIG. 1B is a cross-sectional view taken along line AA in FIG.
2A is an enlarged cross-sectional view of the outer peripheral portion of the substrate of the cutting wheel of FIG. 1, FIG. 2B is a partial development view of the outer peripheral surface of the substrate in the substrate peripheral direction, and FIG. 2C is the outer peripheral portion of the substrate. It is a partial development view seen in the substrate peripheral direction of the side.
FIG. 3 is a diagram showing another example of the arrangement of abrasive grains.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 1a Outer peripheral surface 1b Outer

peripheral side surface

2, 2a, 2b, 2c Abrasive grain 3 Brazing material 10 Cutting wheel 11 Slit

Claims

In a cutting wheel in which abrasive grains are arranged and brazed on the outer peripheral surface and the outer peripheral side surface of a disk-shaped substrate, slits are provided in the substrate radial direction at regular intervals on the outer peripheral portion of the substrate, and the abrasive grain layer forming range is defined as a segment chip. The abrasive grain size on the front side in the wheel rotation direction of the abrasive grain formation range is larger than the abrasive grain size on the rear side, and the abrasive grain size on the front side and rear side in the wheel rotation direction A cutting wheel characterized in that the ratio is in the range of 120 to 200 on the front side with respect to the rear side 100 .

The cutting wheel according to claim 1, wherein the abrasive grain size is changed continuously or stepwise from the front side to the rear side in the wheel rotation direction.

The cutting wheel according to claim 1 or 2, wherein the range in which the abrasive grain size on the front side in the wheel rotation direction is enlarged is 10 to 40% in the circumferential length of the segment chip-shaped abrasive layer forming range.