JP2012240126A

JP2012240126A - Super abrasive grinding stone

Info

Publication number: JP2012240126A
Application number: JP2011109276A
Authority: JP
Inventors: Shinji Soma; 伸司相馬; Naoto Ono; 直人小野
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2011-05-16
Filing date: 2011-05-16
Publication date: 2012-12-10

Abstract

PROBLEM TO BE SOLVED: To provide a super abrasive grinding stone 6 hardly causing cracks in a coating layer 1 even if a high impact load is applied to an abrasive 2, and capable of maintaining an abrasive holding force.SOLUTION: A coated abrasive is manufactured by forming the coating layer 1 over the abrasive 2 made from cBN or diamond, using a fiber-reinforced glass highly adhesive to the abrasive 2. A grinding stone layer 5 is constituted by holding the coated abrasive by a sintered metal bond layer 3 formed by the powder metallurgical method, using metals such as copper, brass, nickel, and iron as a bonding material. The super abrasive grinding stone is constituted by integrally bonding the grinding stone layer 5 to the surface of an optionally shaped grinding stone core 4. The fiber-reinforced glass does not easily cause cracks because of high toughness owing to a crack development preventive action of fiber. Accordingly, the coating layer 1 does not easily cause cracks and does not come off even if the high impact load is applied, and the abrasive does not easily come off even if a grinding efficiency is high.

Description

本発明は、超砥粒を用いたメタルボンド砥石に関するものである。 The present invention relates to a metal bond grindstone using superabrasive grains.

ｃＢＮ又はダイヤモンドの砥粒をメタルボンドで保持した砥石において、砥粒の保持力を強くするために、砥粒に砥粒との密着性の高いガラス又はセラミックの被覆層を形成し、被覆層の表面の凹凸によりメタルボンドとの結合力を強くする従来技術１（例えば、特許文献１参照）がある。 In a grindstone in which cBN or diamond abrasive grains are held by metal bonds, a glass or ceramic coating layer having high adhesion to the abrasive grains is formed on the abrasive grains in order to increase the holding power of the abrasive grains. There is a prior art 1 (for example, see Patent Document 1) in which the bonding strength with a metal bond is strengthened by surface irregularities.

特開平３−１０４５６４号公報JP-A-3-104564

従来技術１では、ガラス質又はセラミックスを用いて被覆層を形成することで砥粒保持力を大きくしている。ガラス質又はセラミックスは高脆性材料であり、過大な衝撃荷重が作用すると割れを発生する恐れがある。砥粒の被覆層に割れが発生すると、被覆層が細分化されて脱落するため、砥粒の保持力が低下する。
研削効率の向上のためさらなる高能率研削が求められており、それに伴い砥粒に作用する衝撃荷重も大きくなっている。
本発明は上記事情に鑑みてなされたものであり、砥粒に大きな衝撃荷重が作用しても被覆層に割れを発生することが少なく、砥粒の保持力が低下しない超砥粒砥石を提供することを目的とする。 In the prior art 1, the holding power of the abrasive grains is increased by forming a coating layer using glass or ceramics. Glass or ceramics is a highly brittle material, and cracking may occur when an excessive impact load is applied. When a crack occurs in the coating layer of the abrasive grains, the coating layer is subdivided and falls off, so that the holding power of the abrasive grains decreases.
In order to improve the grinding efficiency, further high efficiency grinding is required, and the impact load acting on the abrasive grains is also increased accordingly.
The present invention has been made in view of the above circumstances, and provides a superabrasive grindstone in which the coating layer is less likely to crack even when a large impact load is applied to the abrasive and the holding power of the abrasive is not reduced. The purpose is to do.

上記の課題を解決するため、請求項１に係る発明の特徴は、ｃＢＮ又はダイヤモンドの砥粒に繊維強化ガラスを用いた被覆層を形成しメタルボンドで保持することである。 In order to solve the above-mentioned problems, a feature of the invention according to claim 1 is that a coating layer using fiber reinforced glass is formed on cBN or diamond abrasive grains and held by a metal bond.

請求項２に係る発明の特徴は、請求項１に係る発明において、前記繊維強化ガラスの母材に、ケイ酸ガラスまたはホウケイ酸ガラスを用いることである。 A feature of the invention according to claim 2 is that, in the invention according to claim 1, silicate glass or borosilicate glass is used as a base material of the fiber-reinforced glass.

請求項３に係る発明の特徴は、請求項１または請求項２に係る発明において、前記繊維強化ガラスの繊維として、アルミナウイスカまたはジルコニアウイスカまたは珪灰石または珪酸ジルコニウムの少なくも１種類を配合することである。 A feature of the invention according to claim 3 is that, in the invention according to claim 1 or claim 2, at least one of alumina whisker, zirconia whisker, wollastonite, or zirconium silicate is blended as the fiber reinforced glass fiber. It is.

請求項1、請求項２、請求項３に係る発明によれば、繊維強化ガラスは母材がガラスなので砥粒との密着性が高く、かつ繊維によるクラック進展防止作用により靭性が高いため割れが発生しにくい。このため、大きな衝撃荷重が作用しても被覆層に割れを発生することが少なく、研削能率が大きくても砥粒の脱落が少ない。結果として高能率研削を実施しても寿命の長い超砥粒砥石を実現できる。 According to the inventions according to claim 1, claim 2, and claim 3, since the fiber reinforced glass is a base material, since the base material is glass, the adhesiveness with the abrasive grains is high, and cracking is prevented because of high toughness due to the effect of preventing crack propagation by the fiber. Hard to occur. For this reason, even if a large impact load is applied, the coating layer is less likely to crack, and even if the grinding efficiency is high, the abrasive grains are less likely to fall off. As a result, a superabrasive grindstone with a long life can be realized even if high-efficiency grinding is performed.

本実施形態の超砥粒砥石の断面部分図である。It is a section partial view of the superabrasive grindstone of this embodiment. 本実施形態の被覆層の詳細図である。It is detail drawing of the coating layer of this embodiment.

以下、本発明の実施の形態を図１、図２に基づき説明する。
図１において、超砥粒砥石６は、砥石層５が所望形状の砥石コア４の表面に一体的に結合されて構成されている。砥石層５は、繊維強化ガラスがコーティングされた被覆層１を備えたｃＢＮ又はダイヤモンド砥粒２が、銅、黄銅、ニッケル、鉄等の金属を結合材として粉末冶金法で形成された焼結メタルボンド層３に埋め込み結合されて構成されている。
ここで、繊維強化ガラスとは図２に示すように、ガラスの母材１１中にセラミックスからなる繊維組織１２を数パーセント程度分散させたもので、繊維組織１２としては、径が１μｍ以下で長さが１０〜１００μｍ程度の結晶であるウイスカ又は径が２０μｍ以下で長さが１００μｍ以下であるファイバーを用いる。
母材１１のガラスとしては砥粒との接着性の良いケイ酸ガラス、ホウケイ酸ガラスが好適である。繊維組織１２としては母材と線膨張係数が近いアルミナウイスカまたはジルコニアウイスカまたは珪灰石または珪酸ジルコニウムなどが好適である。 Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, a superabrasive grindstone 6 is configured by integrally bonding a grindstone layer 5 to the surface of a grindstone core 4 having a desired shape. The grindstone layer 5 is a sintered metal in which cBN or diamond abrasive grains 2 having a coating layer 1 coated with fiber reinforced glass are formed by a powder metallurgy method using a metal such as copper, brass, nickel, or iron as a binder. It is configured to be embedded and bonded to the bond layer 3.
Here, as shown in FIG. 2, the fiber reinforced glass is a glass base material 11 in which a fiber structure 12 made of ceramics is dispersed by several percent, and the fiber structure 12 has a diameter of 1 μm or less and is long. A whisker that is a crystal having a length of about 10 to 100 μm or a fiber that has a diameter of 20 μm or less and a length of 100 μm or less is used.
As the glass of the base material 11, silicate glass and borosilicate glass having good adhesion to abrasive grains are suitable. As the fiber structure 12, alumina whisker, zirconia whisker, wollastonite, zirconium silicate or the like having a linear expansion coefficient close to that of the base material is suitable.

製造方法は砥粒２の周面に粘結剤等により繊維強化ガラス粉末を満遍なく付着させ、それを加熱炉の中で加熱して、ガラスを融かして砥粒２に密着させた後、冷却すると砥粒２の表面が繊維強化ガラスの被覆層１で被覆された被覆砥粒が得られる。 The manufacturing method uniformly adheres the fiber reinforced glass powder to the peripheral surface of the abrasive grain 2 with a binder or the like, heats it in a heating furnace, melts the glass, and adheres to the abrasive grain 2. When cooled, coated abrasive grains in which the surface of the abrasive grains 2 is coated with the coating layer 1 of fiber reinforced glass are obtained.

次に、その被覆砥粒と銅、黄銅、ニッケル、鉄等の金属粉末とを混合したものを金型の内周面と砥石コア４の外周面との空間に充填した上で、焼成する。
こうして、ｃＢＮ又はダイヤモンド砥粒２に繊維強化ガラスの被覆層１が形成された被覆砥粒がメタルボンド層３に埋め込まれ強固に保持された砥石層５が砥石コア４と一体化した超砥粒砥石６が形成される。 Next, a mixture of the coated abrasive and a metal powder such as copper, brass, nickel, iron or the like is filled in the space between the inner peripheral surface of the mold and the outer peripheral surface of the grindstone core 4 and then fired.
Superabrasive grains in which the coated abrasive grains in which the fiber-reinforced glass coating layer 1 is formed on the cBN or diamond abrasive grains 2 are embedded in the metal bond layer 3 and firmly held are integrated with the grinding stone core 4. A grindstone 6 is formed.

本発明の超砥粒砥石６を用いて高能率の研削を行うと、砥粒２に作用する衝撃力が母材１１のガラスの破壊靭性値を超えると被覆層１の母材１１にはクラックが発生するが、配合された繊維組織１２のブリッジング効果によりクラックの進展が阻止される。このため、クラックが被覆層１を貫通して被覆層１が小片に分割され分離脱落することが防止され、砥粒２の保持力低下を防止できる。結果として、高能率研削においても砥粒２の脱落の少ない超砥粒砥石５を実現できる。 When high-efficiency grinding is performed using the superabrasive grindstone 6 of the present invention, if the impact force acting on the abrasive grain 2 exceeds the fracture toughness value of the glass of the base material 11, the base material 11 of the coating layer 1 is cracked. However, the development of cracks is prevented by the bridging effect of the blended fiber structure 12. For this reason, it is prevented that the crack penetrates the coating layer 1 and the coating layer 1 is divided into small pieces and separated and dropped off, and the holding power of the abrasive grains 2 can be prevented from being lowered. As a result, it is possible to realize a superabrasive grindstone 5 in which the abrasive grains 2 are less dropped even in high efficiency grinding.

１：被覆層２：砥粒３：焼結メタルボンド層４：砥石コア５：砥石層６：超砥粒砥石 1: Coating layer 2: Abrasive grain 3: Sintered metal bond layer 4: Whetstone core 5: Whetstone layer 6: Superabrasive grindstone

Claims

ｃＢＮ又はダイヤモンドの砥粒に繊維強化ガラスを用いた被覆層を形成しメタルボンドで保持する超砥粒砥石。 A superabrasive grindstone in which a coating layer using fiber reinforced glass is formed on abrasive grains of cBN or diamond and held by metal bonds.

前記繊維強化ガラスの母材に、ケイ酸ガラスまたはホウケイ酸ガラスを用いる請求項１記載の超砥粒砥石。 The superabrasive grindstone according to claim 1, wherein silicate glass or borosilicate glass is used as a base material of the fiber reinforced glass.

前記繊維強化ガラスの繊維として、アルミナウイスカまたはジルコニアウイスカまたは珪灰石または珪酸ジルコニウムの少なくも１種類を配合する請求項１または請求項２記載の超砥粒砥石。 The superabrasive grindstone according to claim 1 or 2, wherein at least one of alumina whisker, zirconia whisker, wollastonite, or zirconium silicate is blended as the fiber reinforced glass fiber.