JP2021065982A - Diamond dresser - Google Patents

Abstract

To provide a diamond dresser that hardly causes interference of a form-grinding stone with a bond layer and insufficient cooling and also hardly causes breakage and crack of a columnar diamond, in work for dressing the form-grinding stone and work for forming the form-grinding stone.SOLUTION: A diamond dresser 10 comprises: a support body 1 having a recessed part 1c on a tip surface 1b in an axis center C direction, and a columnar diamond 2 fastened into the recessed part 1c by bond layers 3 including active wax materials, where the columnar diamond 2 is fastened so that a tip part 2a thereof protrudes over the whole circumference from the tip surface 1b of the support body 1. Heat stress relaxation layers 4 in which metallic elements contained in the active wax material, which form carbons and metal carbide in the columnar diamond 2 are concentrated are provided at boundaries between the bond layers 3 and the columnar diamond 2.SELECTED DRAWING: Figure 4

Description

The present invention relates to a diamond dresser used for dressing work and forming work on the grindstone surface of a grinding wheel that grinds the entire shape of a workpiece.

The diamond dresser has been used for the work of correcting the sharpness of the grinding wheel, but in recent years, the demand for high-efficiency machining and high-precision machining by the grinding wheel has increased, and the grinding wheel is ground according to the machining shape of the workpiece. It is also used in forming work to form a surface shape to produce a total grinding wheel.

In the dressing work of the total grinding wheel, a diamond dresser using natural granular diamond or artificial columnar diamond has been conventionally used. Diamond dressers using natural granular diamonds have the problem that the dressing area changes due to wear caused by dressing work, and diamond dressers using artificial columnar diamonds interfere with the bond layer and supply coolant to the processing point. There are problems in terms of points, and the actual situation is that they are used in a state where there are problems with processing stability and grinding accuracy, respectively.

In recent years, high precision is required in the grinding process using the total shape grindstone, and along with this, a diamond dresser having high accuracy and excellent stability is also required in the dressing work of the total shape grindstone which affects the grinding accuracy. In particular, in the grinding of the inner ring raceway surface and the outer ring raceway surface of bearing parts, the demand for higher accuracy is more remarkable, and a technique capable of solving various problems of the current diamond dresser is required.

As one of the dressers widely used in the market, there is a diamond dresser using an artificial prismatic diamond (hereinafter, may be abbreviated as "prism dresser"). This prismatic dresser is widely used because it has a constant dressing surface and can be used continuously in a stable manner. (See, for example, Patent Documents 1 and 2).

Further, as a means for preventing the bond layer and the support portion of the diamond dresser from interfering with the grindstone when dressing according to the total shape of the grindstone, a dresser having a relief shape in the bond layer or a bond layer A dresser or the like in which an interfering portion is removed to expose a part of a side surface of a columnar diamond has been proposed (see, for example, Patent Documents 3 and 4).

Further, a dresser has been proposed in which cooling of the diamond by a coolant is promoted by exposing a part of the side surface of the columnar diamond (see, for example, Patent Documents 4 and 5).

On the other hand, although it is known to use an active raw material as a method for firmly fixing diamond to a support, a dresser in which granular diamond that can tolerate residual stress more than columnar diamond in shape is fixed with an active raw material has been proposed. (See, for example, Patent Document 6).

Japanese Patent No. 2725660 Japanese Unexamined Patent Publication No. 2000-167769 Japanese Unexamined Patent Publication No. 2001-341573 Japanese Patent No. 5608623 Japanese Patent No. 4105624 Japanese Unexamined Patent Publication No. 2000-2466637

Since the prismatic dresser described in Patent Documents 1 and 2 is manufactured by a method of embedding prismatic diamond in sintered metal, the dressing action surface of diamond, the sintered metal surface, and a part of the support are flush with each other. It is generally a shape.

However, when the diamond dresser described in Patent Documents 1 and 2 is used for dressing a grindstone that requires the formation of the grindstone grinding surface described above, for example, a grindstone for processing an inner ring raceway surface or an outer ring raceway surface of a bearing component, Since not only diamond but also the sintered metal and the support portion interfere with the grindstone, there are problems such as blunting of the sharpness of the grindstone and inability to stably perform high-precision molding.

In addition, since diamond has the property of deteriorating in a high temperature environment, when performing dressing work or forming work with a diamond dresser, it is possible to supply a cooling liquid to the processing point and cool the diamond that stores heat by the processing heat. Although it is necessary, due to its shape, the total shape grindstone may not be able to supply sufficient coolant to the machining point, and the diamond may deteriorate due to the thermal effect, wear may be promoted, and stable machining may not be possible. ..

The dresser described in Patent Documents 3 and 4 can be used without interference at the initial stage of use by forming the tip portion of the diamond that acts during dressing into a tapered shape to create a protruding portion of the diamond. Since the design is such that the bond layer and the grindstone interfere with each other when the wear disappears, it is necessary to appropriately modify the shape of the diamond portion, which causes a problem in tool life.

Dressing a full-form grindstone is a task in which it is difficult to supply a coolant to the dressing point due to the shape of the grindstone. In particular, in a diamond dresser in which only the dressing surface of the columnar diamond is exposed and the other portion is embedded in the bond layer, the coolant is supplied to the bond layer or the support portion, and the columnar diamond is indirectly cooled. Due to the structure, a sufficient cooling effect cannot be obtained, wear is promoted due to thermal deterioration of diamond, and there is a problem in stability during dressing work.

In order to deal with this problem, Patent Documents 4 and 5 propose a technique for accelerating the cooling of diamond by a coolant by exposing a part of the side surface of the columnar diamond, but the cooling effect is not sufficient.

As a result of investigating the above-mentioned problem of interference between the bond layer and the grindstone and the problem of insufficient cooling of diamond, diamond near the dressing action part protruded from the surface of the bond layer like a diamond dresser using natural granular diamond. With the structure, it was expected that only the protruding diamond would exert a dressing effect, the coolant could be directly supplied to the diamond, and the above two problems could be solved at the same time.

However, due to the shape of the columnar diamond, the contact area when the diamond is held by the bond layer is small, the holding force by the bond layer tends to be insufficient, and the diamond tends to fall off during use. , All of the longitudinal dimensions of the diamond are embedded in the bond layer. Therefore, in order to project a part of the columnar diamond, it is difficult to fix the diamond by a general sintering method, and a technique capable of sufficiently holding the diamond with a small number of buried portions is required.

In order to deal with this, a fixing method using an active brazing material is known as a fixing method having a stronger diamond holding force than the fixing technique by the sintering method, but thermal stress is generated in the diamond during the fixing process, and this remains. Since it becomes stress, there is a problem that diamonds are likely to be broken or chipped due to a load during the manufacturing process or during use, which is practically difficult.

On the other hand, Patent Document 6 describes a diamond dresser in which granular diamonds that can tolerate residual stress more than columnar diamonds in shape are fixed with an active raw material. The diamond dressers are diamonds, temporary fixing materials, and active materials. Since it is composed of brazing material, cushioning material, metal bond and support, the manufacturing method is complicated, and the obtained effect is limited to the extent that diamond breakage and chipping are reduced, which is a practically satisfactory level as a product. The reality is that it has not reached.

Therefore, the problem to be solved by the present invention is that in the dressing work and forming work of the total shape grindstone, interference between the total shape grindstone and the bond layer and insufficient cooling are unlikely to occur, and the columnar diamond is unlikely to be broken or chipped. It is to provide a diamond dresser.

The diamond dresser according to the present invention includes a support having a recess on the tip surface in the axial direction, and a columnar diamond fixed in the recess by a bond layer containing an active brazing material.
The tip of the columnar diamond is fixed so as to project from the tip surface of the support over the entire circumference.
The boundary between the bond layer and the columnar diamond is provided with a thermal stress relaxation layer in which the metal element contained in the active raw material and the metal element forming the columnar diamond and the carbide is concentrated.

With such a configuration, the dressing action surface of the columnar diamond is in a state of protruding from the surface of the bond layer, so that it is possible to prevent a part of the bond layer and the support from interfering with the total grindstone during the dressing operation. be able to.

Further, since the cooling liquid can be directly supplied to the tip portion (protruding portion) of the columnar diamond including the dressing surface, insufficient cooling is unlikely to occur.

Further, if the coefficient of thermal expansion of the thermal stress layer interposed at the boundary between the columnar diamond and the bond layer is set to about an intermediate value of the coefficient of thermal expansion of the active raw material and diamond, specifically
If the coefficient of thermal expansion of the active raw material> the coefficient of thermal expansion of the thermal stress relaxation layer> the coefficient of thermal expansion of the columnar diamond, the presence of this thermal stress relaxation layer causes it to occur during the sintering operation in the manufacturing process of the diamond dresser. Since the residual stress in the columnar diamond due to thermal stress can be reduced and relaxed, the columnar diamond is less likely to be broken or chipped.

In the diamond dresser, the active brazing material is Ti (titanium), V (vanadium), Cr (chromium), Zr (zirconium), Nb (niobium), Mо (molybdenum), Hf (hafnium), Ta (tantalum). ), W (tungsten), it is desirable that it contains one or more.

In the diamond dresser, it is desirable that the active brazing material is any of Ag-Cu-Ti-In type, Ag-Cu-Ti type, and Au-Ni-Cr type.

In the diamond dresser, it is desirable that the shape of the columnar diamond is prismatic or columnar.

In the diamond dresser, the shape of the tip of the columnar diamond may be flat, conical or pyramidal.

In the diamond dresser, the columnar diamond may have a single crystal structure or a polycrystalline structure.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a diamond dresser in which interference between the total shape grindstone and the bond layer and insufficient cooling are unlikely to occur in dressing work and forming work of the total shape grindstone, and breakage and chipping of columnar diamonds are unlikely to occur. ..

It is a front view which shows the diamond dresser which is an embodiment of this invention. It is an enlarged plan view seen from the direction of arrow A in FIG. It is a partially enlarged view of FIG. It is a partially omitted sectional view in line BB in FIG. It is a front view which shows the diamond dresser which is another embodiment. It is a partial notch enlarged view of FIG.

Hereinafter, the diamond dressers 10 and 20 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6.

First, the diamond dresser 10 will be described with reference to FIGS. 1 to 4. As shown in FIGS. 1 to 4, the diamond dresser 10 includes a columnar support 1 having a truncated cone-shaped tip portion 1a, a columnar diamond 2, and a bond layer 3. A recess 1c is formed on the tip surface 1b of the support 1 in the axial direction C direction, and the columnar diamond 2 is fixed in the recess 1c by a bond layer 3 containing an Ag-Cu-Ti-In active brazing material. There is. Since the active brazing material is not limited to the Ag-Cu-Ti-In type, an Ag-Cu-Ti type or Au-Ni-Cr type active brazing material can also be used.

The columnar diamond 2 has a square columnar shape in which the tip portion 2a is planar, the size thereof is 0.6 mm × 0.6 mm × 3.0 mm, and the outer peripheral surface 2b of the tip portion 2a is the tip surface of the support 1. It is fixed in a state of protruding from 1b over the entire circumference. The protruding dimension of the columnar diamond 2 (the length from the tip surface 1b of the support 1 to the tip 2a of the columnar diamond 2) P is preferably 0.3 mm or more. The size of the columnar diamond 2 described above is an example and is not limited to this. For example, in the case of a prismatic shape, the prismatic surface size at the tip is about 0.2 mm to 2.0 mm, and the length is 1. It is preferably about 0.0 mm to 3.0 mm.

The shape of the columnar diamond 2 is a quadrangular prism shape, but the shape is not limited to this, and therefore, it may be another polygonal columnar shape or a columnar shape. The shape of the tip portion 2a of the columnar diamond 2 is flat, but the shape is not limited to this, and therefore, it may be conical or pyramidal. The crystal structure of the columnar diamond 2 may be either a single crystal structure or a polycrystalline structure.

The tip portion 1a of the support 1 is formed with a clearance angle E of 90 degrees, leaving a tip surface 1b having a diameter of 2 mm to which the columnar diamond 2 is fixed. A thermal stress relaxation layer 4 is provided at the boundary between the bond layer 3 and the columnar diamond 2 in which the metal elements contained in the active raw material and the metal elements forming the columnar diamond 2 and the carbide are concentrated.

In the diamond dresser 10, the dressing action surface (tip portion 2a) of the columnar diamond 2 is in a state of protruding from the surface of the bond layer 3, so that the bond layer 3 and a part of the support 1 are partially exposed during the dressing operation. Since it is possible to prevent the grindstone and the total shape grindstone from interfering with each other, the sharpness and molding accuracy of the grindstone and the total shape grindstone after dressing with the diamond dresser 10 are improved.

Further, since the cooling liquid can be directly supplied to the tip portion 2a (protruding portion) of the columnar diamond 2 including the processing point at the time of dressing or forming, the deterioration of the columnar diamond 2 due to insufficient cooling is reduced, and the columnar diamond 2 is columnar. The durability of diamond 2 is improved.

Further, the coefficient of thermal expansion of the thermal stress relaxation layer 4 in which the metal element contained in the active brazing material and the metal element forming the carbide and the columnar diamond 2 (Ti in the present embodiment) are concentrated, and the heat of the active brazing material. Regarding the expansion coefficient and the coefficient of thermal expansion of the columnar diamond 2, the magnitude relationship of the coefficient of thermal expansion of the active raw material> the coefficient of thermal expansion of the thermal stress relaxation layer 4> the coefficient of thermal expansion of the columnar diamond 2 is established. Due to the presence of such a thermal stress relaxation layer 4, the residual stress in the columnar diamond 2 due to the thermal stress generated during the sintering operation in the manufacturing process of the diamond dresser 10 can be reduced and relaxed, so that the columnar diamond 2 is broken. And chipping is less likely to occur.

Next, the diamond dresser 20 will be described with reference to FIGS. 5 and 6. As shown in FIGS. 5 and 6, the diamond dresser 20 includes a columnar support 1 having a truncated cone-shaped tip portion 1a, a columnar diamond 5, and a bond layer 3. A recess 1c is formed on the tip surface 1b of the support 1 in the axial direction C direction, and the columnar diamond 5 is fixed in the recess 1c by a bond layer 3 containing an Ag-Cu-Ti-In active brazing material. There is.

The columnar diamond 5 has a square columnar shape in which the tip portion 5a has a conical shape, the size thereof is 0.6 mm × 0.6 mm × 3.0 mm, and the tip portion 5a and the tip portion 5a of the square columnar portion connected thereto have a size of 0.6 mm × 0.6 mm × 3.0 mm. The outer peripheral surface 5b of the near portion is fixed so as to project from the tip surface 1b of the support 1 over the entire circumference. The protruding dimension of the columnar diamond 5 (the length from the tip surface 1b of the support 1 to the apex of the tip portion 5a of the columnar diamond 5) P is preferably 0.3 mm or more.

The tip portion 1a of the support 1 is formed with a clearance angle E of 90 degrees, leaving a tip surface 1b having a diameter of 2 mm to which the columnar diamond 2 is fixed. A thermal stress relaxation layer 4 containing a compound of a metal element in the active raw material and carbon in the columnar diamond 5 is provided at the boundary between the bond layer 3 and the columnar diamond 5. The apex angle F of the tip portion 5a of the columnar diamond 5 is set to 130 degrees, but the present invention is not limited to this.

In the diamond dresser 20, the dressing action surface (tip portion 5a) of the columnar diamond 5 is in a state of protruding from the surface of the bond layer 3, so that the bond layer 3 and a part of the support 1 are partially exposed during the dressing operation. Since it is possible to prevent the grindstone and the total shape grindstone from interfering with each other, the sharpness and molding accuracy of the grindstone and the total shape grindstone after dressing with the diamond dresser 20 are improved.

Further, since the cooling liquid can be directly supplied to the tip portion 5a (protruding portion) of the columnar diamond 5 including the processing point at the time of dressing or forming, the deterioration of the columnar diamond 5 due to insufficient cooling is reduced, and the columnar diamond 5 is columnar. The durability of diamond 5 is improved.

Further, the coefficient of thermal expansion of the thermal stress relaxation layer 4 in which the metal elements contained in the active brazing material and in which the columnar diamond 5 and the metal element forming the carbide (Ti in the present embodiment) are concentrated is the same as that of the active brazing material. Since the coefficient of thermal expansion of the columnar diamond 5 is about an intermediate value, the residual stress in the columnar diamond 5 due to the thermal stress generated during the sintering operation in the manufacturing process of the diamond dresser 20 is the thermal stress relaxation layer 4. Since it is reduced and relaxed by the presence of the columnar diamond 5, it is unlikely that the columnar diamond 5 is broken or chipped.

Here, a method for manufacturing the diamond dresser 20 will be described. The method for producing the diamond dresser 20 is not limited, but the diamond dresser 20 can be produced, for example, by the following steps.

(1) Ag-Cu-Ti-In-based active raw material in the recess 1c formed on the tip surface (the surface that becomes the tip surface 1b) in the axial direction of the columnar support raw material (not shown). The mixture (paste) of the binder and the columnar diamond is charged.
(2) The support raw material in which the columnar diamond, the active brazing material and the binder have been charged into the recess 1c is sintered in a vacuum heating furnace. The sintering temperature is preferably about 600 ° C. to 1000 ° C., and the holding time is preferably about 20 minutes to 120 minutes.
(3) When the temperature inside the vacuum heating furnace drops to room temperature after the completion of sintering, the support raw material is taken out from the vacuum heating furnace, and the tip surface thereof has a diameter of 2 mm around the fixed portion (recess 1c) of the columnar diamond. Grinding leaving the portion (tip surface 1b) to form a clearance angle E of 90 degrees.
(4) After that, the diamond dresser 20 is completed by processing the tip of the columnar diamond protruding from the tip surface 1b of the support 1 into a conical shape with an apex angle F = 130 degrees.

The diamond dresser 20 manufactured by the above-mentioned process and the conventional diamond dresser (hereinafter, may be abbreviated as the conventional product) are dressed with a grindstone based on the following conditions, and the diamond dresser 20 is compared with the conventional product. An experiment was conducted.

The specifications of the conventional product are as follows.
Diamond dresser variety: Single stone dresser Columnar diamond shape: Square columnar columnar diamond size: 0.6 mm x 0.6 mm x 3.0 mm (0.6 mm x 0.6 mm is the dressing surface)
Columnar diamond fixing method: Metal sintering method Columnar diamond tip shape: Conical shape with apex angle = 130 degrees Columnar diamond crystal: Polycrystal

(A) Specifications of diamond dresser 20 Size of columnar diamond 5: 0.6 mm x 0.6 mm x 3.0 mm (0.6 mm x 0.6 mm is the dressing surface)
Shape of tip 5a of columnar diamond 5: Conical shape with apex angle F = 130 degrees Crystal of columnar diamond 5: Polycrystal (single crystal is also possible)
Projection dimension of columnar diamond 5 (length from the tip surface 1b of the support 1 to the apex of the tip 5a of the columnar diamond 5) P: 0.50 mm

(B) Specifications of the grindstone to be dressed Grindstone type: CXZ # 60
Whetstone dimensions: φ405 x 75T x 127H
Whetstone shape: Angular shape 90 degrees corner tip R0.5

(C) Dressing condition Cut amount: φ20 μm
Dress lead: 0.1 mm / r. o. w
Grindstone peripheral speed: 45 m / sec

(D) Grinding conditions Grinding method: Wet cylindrical plunge grinding Grinding stone Peripheral speed: 45 m / sec

(E) Evaluation item Abrasion volume during dressing work Power consumption during grinding work Work R roundness Roundness of rough diamond (columnar diamond 5) during dressing work

Comparing the wear volume during dressing work, it was possible to reduce the wear volume by 40% compared to the conventional product.
Comparing the power consumption during grinding work, it was possible to reduce the power consumption by 5% compared to the conventional product.
Regarding the roundness of the work R part, the conventional product tends to be finished with an R dimension larger than the target value, whereas the diamond dresser 20 has a work finish closer to the set value, and variation is also reduced. ..
Comparing the temperature of rough diamond (columnar diamond 5) during dressing work, it was possible to reduce it by 30% compared to the conventional product.

The diamond dressers 10 and 20 described with reference to FIGS. 1 to 6 exemplify the diamond dressers according to the present invention, and the diamond dressers according to the present invention are not limited to the diamond dressers 10 and 20 described above. ..

The diamond dresser according to the present invention can be widely used in various industrial fields as a tool for dressing work and forming work on the grindstone surface of a grinding wheel for performing total shape grinding of a workpiece.

1 Support 1a, 2a, 5a Tip 1b Tip surface 1c Recess 2, 5 Columnar diamond 2b Outer surface 3 Bond layer 4 Thermal stress relaxation layer 10, 20 Diamond dresser C Axis center E Escape angle F Top angle P Protrusion dimension

The diamond dresser according to the present invention includes a support having a recess on the tip surface in the axial direction, and a columnar diamond fixed in the recess by a bond layer containing an active brazing material.
The tip of the columnar diamond is fixed so as to project from the tip surface of the support over the entire circumference.
At the boundary between the bond layer and the columnar diamond, a thermal stress relaxation layer in which the metal element contained in the active raw material and forming the columnar diamond and the carbide is concentrated is provided .
The coefficient of thermal expansion of the active raw material> the coefficient of thermal expansion of the thermal stress relaxation layer> the coefficient of thermal expansion of the columnar diamond .

Claims (6)

A support having a recess on the tip surface in the axial direction and a columnar diamond fixed in the recess by a bond layer containing an active brazing material are provided.
The tip of the columnar diamond is fixed so as to project from the tip surface of the support over the entire circumference.
A diamond dresser provided with a thermal stress relaxation layer in which a metal element contained in the active raw material and a metal element forming a carbide is concentrated on the boundary between the bond layer and the columnar diamond. The active brazing material is Ti (titanium), V (vanadium), Cr (chromium), Zr (zirconium), Nb (niobium), Mо (molybdenum), Hf (hafnium), Ta (tantalum), W (tungsten). The diamond dresser according to claim 1, which comprises one or more of the above. The diamond dresser according to claim 1 or 2, wherein the active raw material is any one of Ag-Cu-Ti-In type, Ag-Cu-Ti type, and Au-Ni-Cr type. The diamond dresser according to any one of claims 1 to 3, wherein the shape of the columnar diamond is prismatic or columnar. The diamond dresser according to any one of claims 1 to 4, wherein the shape of the tip of the columnar diamond is flat, conical or pyramidal. The diamond dresser according to any one of claims 1 to 5, wherein the columnar diamond has a single crystal structure or a polycrystalline structure.

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