JPH0122115B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a dresser for shaping a grindstone.

For example, as shown in FIG. 1, there may be a workpiece 3 having grooves 2, 2 on the outer peripheral surface of a cylindrical body 1, or a rectangular body 4 with linear grooves on one side as shown in FIG. 5,
When forming the workpiece 6 having the shape provided with 5, processing means such as plastic working and cutting are used. Among these, in the case of cutting, there are various processing methods such as processing using a cutting tool, processing using a milling cutter, processing using a broach, and processing using a grindstone.

The present invention relates to an improvement of a dresser used for appropriately shaping and repairing the grindstone in the processing using the grindstone. That is, when processing the workpieces 3 and 6 having the shapes shown in FIGS. 1 and 2 by grinding with a whetstone, as shown in FIG. A grindstone 9 having pitched circumferential protrusions 8, 8 may be used.

Therefore, when shaping the whetstone 9 having such a shape from a cylindrical material, or when repairing the whetstone 9 which has lost its shape due to use, as shown in FIG. Groove portions 10, 1 corresponding to
A rotary dresser 11 having 0... is used.

As shown in the upper half of FIG. 5, this rotary dresser 11 has a structure in which a diamond holding layer 13 is provided on the surface of a dresser base 12, and granular diamonds 14 are held in this diamond holding layer 13. The cross-sectional shape is equal to the desired finished cross-sectional shape of the workpieces 3 and 6. That is, the shape of the dresser 11 is reversed and transferred to the grindstone 9 during grindstone shaping, and is reversed again and transferred to the workpieces 3 and 6 during grinding by the grindstone 9.

This grinding process using the grindstone 9 is extremely effective as a method of giving the same shape to a large number of workpieces, but for this purpose, as shown in FIG. It is a premise and important that the relative position in the axial direction does not change.

By the way, the grindstone 9 that has been conventionally used is
It is made by bonding abrasive grains that act as cutting edges to grind the workpiece. Diamond, corundum, alumina, zirconia, boron carbide, boron nitride, etc. are used as the abrasive grains, and phenol is used as the bond. Resinoids, silicates, rubbers, etc. using thermosetting synthetic resins such as resins are used, and in any case, they have small thermal expansion. On the other hand, as the base body 12 of the rotary dresser 11, a material having a larger thermal expansion than the grindstone 9, such as stainless steel, is used.

However, when shaping or repairing the grindstone 9 using the above-described grindstone 9 and rotary dresser 11, the rotary dresser 11 may cause relative movement, for example, in the direction of arrow A shown in FIG. . Here, rotary dresser 11
Suppose that it moves relatively by △l in the direction of arrow A, then
The protrusion 8 of the grindstone 9 is shaped or repaired, for example, in the shape shown by the dotted line m. Therefore, the protrusion 8
The width of the protrusion 8 becomes smaller by the amount of △l, and the width of the protrusion 8 becomes smaller.
A stepped portion 15 is formed at the root portion. In addition, when relative movement occurs in the direction of arrow A in the process of gradually cutting the rotary dresser 11 toward the base of the protrusion 8, the right side of the protrusion 8 as shown in an exaggerated manner in FIG. Steps and slopes are formed on the surface.

Therefore, the grindstone 9 and the rotary dresser 1
It is important that no relative movement in the axial direction occurs between the grindstone 9 and the grindstone 9 in order to improve the accuracy of shaping and repair of the grindstone 9.

The main cause of such relative movement in the axial direction is heat generated during shaping and repair. That is, when shaping or repairing the whetstone 9, the whetstone 9 and the rotary dresser 1
The heat added to 1 includes heat generated by various parts of the machine due to operation,
Heat generated at the point of contact between the grinding wheel 9 and the workpiece, the grinding wheel 9
There is heat generated at the contact point between the rotary dresser 11 and the rotary dresser 11.The causes and locations of this heat generation vary, and therefore, the temperature rise and the thermal expansion due to this temperature rise also vary depending on the location. This difference causes relative movement between the grinding wheel shaft and the rotary dresser shaft.

In the past, some machines have been developed in which measures have been taken to minimize the relative movement between the grinding wheel shaft and the rotary dresser shaft, but even so, defects such as those illustrated in Figures 5 and 6 still occur. Plastic surgery and defective repairs may occur. In particular, when the workpiece is long in the axial direction, the grindstone 9 and the rotary dresser 11 may also be long. Although the rotary dresser 11 is made of a material that has relatively little thermal expansion, the rotary dresser 11 is made of a material that causes more thermal expansion than the grinding wheel 9, so this thermal expansion causes the grinding wheel shaft and rotary Relative movement with the dresser shaft may occur, which causes the occurrence of Δl shown in FIG.

For example, the rotary dresser 1 shown in FIG.
1, when the left end portion 11a is positioned and attached to the machine shaft, the right end portion 11b moves rightward when the temperature rises. Here, if the base body 12 of the rotary dresser 11 is made of stainless steel and has a coefficient of thermal expansion of about 15×10 ^-6 /°C, for example, the left end portion 12 serving as the reference
The distance L between a and the groove portion 10a near the right end portion 11b is
When the distance is 200 mm, the movement amount Δl of the groove portion 10a becomes 3 μm per 1° C. temperature rise, and reaches 60 μm when the temperature rises 20° C. Therefore, in precision grinding, such thermal expansion of the rotary dresser 11 is difficult to ignore. Therefore, in the conventional case, in order to perform high-precision shaping or repair of the grinding wheel 9, it is necessary to divide the rotary dresser 11 into a plurality of parts and drive each part to rotate, especially when the grinding wheel 9 is long in the axial direction. It had some problems.

This invention was made in view of the above-mentioned conventional problems, and when shaping or repairing a grindstone using a dresser for shaping a grindstone, there is a problem in the axial relative position between the dresser for shaping a grindstone and the grindstone. Movement is less likely to occur, and as a result, the grindstone can be shaped with high precision using a grindstone shaping dresser (including initial shape shaping of the grindstone and repair shaping after shaping). It is an object of the present invention to provide a dresser for grindstone shaping that eliminates the need for dividing the shaping into a plurality of dressers when shaping.

That is, the dresser for grinding wheel shaping according to the present invention has a structure in which a diamond holding layer is provided on the surface of the dresser base and diamond is held in the diamond holding layer, and has at least one of a circumferential groove and a protrusion. A dresser for shaping a grindstone used for shaping a grindstone, wherein the dresser base is made of a metal, cermet, or ceramic material with a coefficient of thermal expansion of 5×10 ^-6 /°C or less, and the dresser base includes: A cooling medium flow path is provided, and the flow path is provided close to a circumferential protrusion or groove that shapes the circumferential groove or protrusion of the grindstone. It is.

Next, embodiments of the present invention will be described in detail based on the drawings.

FIGS. 7 and 8 are a front view and a partial vertical sectional view, respectively, of a dresser for grinding wheel shaping, which is the basis of this invention. It has groove portions 22, 22, . . . having a shape corresponding to the shape of the workpiece. This grindstone shaping dresser 21 is
As shown in FIG. 8, it has a structure in which a diamond holding layer 24 is provided on the surface of a dresser base 23, and granular diamonds 25 are dispersed and held in the diamond holding layer 24.

In this grindstone shaping dresser 21, the dresser base 23 is made of a low thermal expansion material. As this low thermal expansion material, since the grinding wheel 9 has a low thermal expansion as described above, by using a material with a thermal expansion coefficient of 5×10 ^-6 /°C or less, the grinding wheel 9 and the dresser 21 can be It has been confirmed through various experiments that relative movement in the axial direction can be reduced and highly accurate grindstone shaping is possible. Specifically, as the material for the dresser base 23, for example, Invar, which is a nickel-iron alloy and has a small coefficient of thermal expansion of 2×10 ⁻⁶ /° C. or less, can be used. There is also a super-invar alloy whose thermal expansion coefficient is lower than this, almost close to 0, but it can be said that there is usually no need to use one with such a small thermal expansion coefficient. Furthermore, Kovar, which is a nickel-cobalt-iron alloy and has a coefficient of thermal expansion of about 5×10 ⁻⁶ /° C., can also be used. Other metal materials such as tungsten and molybdenum meet the requirements for low thermal expansion materials, but they have the drawbacks of being expensive and difficult to process.

On the other hand, as a non-metallic material, silica glass has a fairly small coefficient of thermal expansion, approximately 0.4×10 ^-6 /°C.
In addition, some hard glasses have a temperature of about 5×10 ^-6 /℃, but these glasses have poor mechanical properties such as strength, so they are difficult to use as a single unit, let alone when used as a composite material. .

In addition, silicon nitride is used as a ceramic for mechanical structures.Silicon nitride has excellent strength and toughness, and has a coefficient of thermal expansion of 3.2 to 3.5×10 ^-6 /℃.
Therefore, it is suitable as a material for the dresser base 23 described above.

There are several types of silicon nitride ceramics depending on the manufacturing method, additives, etc. Generally, types with excellent mechanical properties are difficult to process, so it is best to select the appropriate one. For example, it is good to choose a material that has slightly inferior mechanical properties but can be processed relatively easily with a diamond tool or the like.
In this case, the dresser base 23 is less subject to tensile stress, which is a weak point of ceramic materials, so it is possible to use a low-grade product that is relatively easy to process even if its mechanical properties are slightly inferior. . Furthermore, it is also possible to use a cermet material, which is a composite material of metal and ceramics and has a small coefficient of thermal expansion of 5×10 ^-6 /°C or less.

In this way, the dresser base 23 can be made of materials such as Invar, Kovar, silicon nitride ceramics, etc., which have a thermal expansion coefficient of 5 × 10 ^-6 /°C, instead of the conventional steel, which has a thermal expansion coefficient of about 11 to 15 × 10 -6 /°C. We use metal cermet or ceramic materials with a temperature of ^-6 /℃ or less, which allows us to stably shape the grinding wheel with high precision over a long period of time even with a dresser that is long in the axial direction with little thermal deformation. ing. The material for the dresser base 23 is not limited to the above-mentioned invar, kovar, and silicon nitride ceramics, but also materials with a thermal expansion coefficient of 5.
×10 ^-6 /°C or less, has excellent mechanical properties and good workability, and a material that satisfies the necessary conditions as the material for the dresser base 23 can be used.

The dresser base 23 is also provided with a cooling medium, such as air, as shown in FIG.
It is desirable to provide a flow path 26 for a cooling medium such as water, and in this case, the flow path 26 should be provided close to the groove 22 that shapes the circumferential protrusion 8 of the grindstone 9. is desirable.

Furthermore, a diamond holding layer 24 is provided on the surface of the dresser base 23, as shown in FIGS. 8 and 9. This diamond holding layer 24 is provided on the surface of the dresser base 23 in the form of a metal sintered body or a metal deposit by powder metallurgy, electroforming, or the like. in this case,
Although the dresser base 23 and the diamond retention layer 24 each have a unique coefficient of thermal expansion, the dresser base 23 and the diamond retention layer 24 are firmly bonded, and the diamond retention layer 24
Since this diamond holding layer 24 is thin,
The dresser base 23 has larger dimensions than this.
Therefore, the shaping error Δl shown in FIG. 5 due to the thermal expansion of the dresser 21 substantially depends on the coefficient of thermal expansion of the dresser base 23.

Then, this diamond holding layer 24 holds granular diamonds 25 to form a dresser 21 for grindstone shaping.

Therefore, if the grindstone 9 is shaped and repaired using the grindstone shaping dresser 21 shown in the above embodiment, even if heat is applied to the grindstone 9 and the dresser 21, the grindstone 9 will originally have little thermal expansion. Furthermore, since the dresser 21 also has a low thermal expansion, there is no mutual movement between the grindstone 9 and the dresser 21, so that the grindstone 9 can be shaped and repaired with high precision.

In addition, during this shaping and repair, the cooling medium flow path 26 provided in the dresser base 23
By flowing a cooling medium such as a cooling liquid or a cooling gas, the cooling of the groove portion 22, which is a heavily machined portion for the protrusion 5 of the grinding wheel 9, is further promoted. Since expansion can be suppressed more effectively, the grindstone 9 can be shaped and repaired with higher precision.

As explained above, according to this invention,
A grindstone used for shaping a grindstone, which has a structure in which a diamond holding layer is provided on the surface of a dresser base, and diamonds are held in the diamond holding layer, and has at least one of a circumferential groove and a protrusion. In the dresser, the dresser base is made of metal, cermet, or ceramic material with a coefficient of thermal expansion of 5×10 ^-6 /°C or less, and the dresser base is provided with a flow path for a cooling medium, and the dresser base is provided with a flow path for a cooling medium, The grooves are arranged close to the circumferential protrusions and grooves for shaping the circumferential grooves and protrusions of the grinding wheel. When using it to shape or repair a whetstone,
It is possible to prevent the temperature rise of the dresser for grinding wheel shaping as much as possible, and also to prevent the thermal expansion of the dresser for grinding wheel shaping as much as possible, so that relative movement does not occur between the dresser for grinding wheel shaping and the grindstone. Taku,
Therefore, it is possible to shape and repair the grindstone with high precision using a grindstone shaping dresser, especially when the grindstone is long and has many grooves or protrusions in the circumferential direction. When shaping or repairing a long grindstone in order to process workpieces with long pitches at once, the dresser for shaping the grindstone can be shaped or repaired in the same long shape without dividing it in the axial direction as in the past. It is possible to shape or repair a grindstone with high precision using the dresser for grinding wheel shaping.The drive source for the dresser for grinding wheel shaping can also be done with a single drive source, which makes the structure extremely simple and at the same time The problem of mutual positioning accuracy when the dresser is divided can also be solved, and processing costs can be significantly reduced, which is an extremely excellent effect.

[Brief explanation of drawings]

1 and 2 are perspective views each showing an example of the shape of a workpiece having a groove, and FIG. 3 is a perspective view showing an example of the shape of a grindstone used to grind the workpiece,
FIG. 4 is a front view showing an example of a grindstone shaping dresser used for shaping and repairing the grindstone, FIG. 5 is a vertical sectional view partially showing the positional relationship between the grindstone and the grindstone shaping dresser, and FIG. A partial cross-sectional view showing an example of the shape of the protrusion of the grindstone that is ground when the grindstone and the dresser for grindstone shaping occur relative movement, and FIGS. 7 and 8 show the dresser for grindstone shaping that is the basis of this invention. 9 is a front view and a partial vertical sectional view, respectively, and FIG. 9 is a partial vertical sectional view of a dresser for grindstone shaping according to an embodiment of the present invention. 8... Protrusion in the circumferential direction, 9... Grindstone, 21...
Dresser for grinding wheel shaping, 22... Groove, 23...
Dresser base, 24...diamond retention layer,
25...Diamond, 26...Cooling medium flow path.

Claims (1)

[Claims] 1. Grindstone shaping used to shape a grindstone, which has a structure in which a diamond holding layer is provided on the surface of a dresser base, and diamond is held in the diamond holding layer, and has at least one of a circumferential groove and a protrusion. The dresser base is made of a metal, cermet, or ceramic material with a coefficient of thermal expansion of 5×10 ^-6 /°C or less, and the dresser base is provided with a flow path for a cooling medium, A dresser for shaping a grindstone, wherein the flow path is provided close to a circumferential protrusion or groove for shaping the circumferential groove or protrusion of the grindstone.