JPH08257921A - Grinding wheel for grinding work and grinding method - Google Patents

Abstract

PURPOSE: To provide a grinding wheel for grinding work and a grinding method which can restrain generation of a dimensional error and degradation of flatness clue to a change in cutting width for an object such as a work even if the grinding wheel is deformed. CONSTITUTION: This grinding wheel 30, which grinds a work W by its rotation, is provided with an outer peripheral part 40 whose cross section is circular along the radial direction, and a relief valve 50 which is formed so as to meet the outer peripheral part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding wheel and a grinding wheel for grinding an object such as a magnetic head chip used in a magnetic recording / reproducing apparatus such as a video tape recorder (VTR) apparatus. It is about the method.

[0002]

2. Description of the Related Art In recent years, magnetic recording using a magnetic head
In the field of reproducing apparatus, high density recording is progressing. This is because, for example, a magnetic recording / reproducing device such as a video tape recorder device is required to have high image quality and high sound quality. Therefore, for example, a magnetic recording / reproducing device for recording information used in a computer or the like. Then, it is required to increase the capacity of the recording medium. Therefore, high-precision processing technology is required for processing the magnetic head.

FIG. 8 shows an example of a magnetic head for a video tape recorder. The magnetic head 1 has a magnetic core 4
have. The sliding surface 1 a of the magnetic core 4 includes the magnetic gap 2 and the glass 3. A winding window 5 is formed near the glass 3. The magnetic head 1 is made of a magnetic material (mainly ferrite), and a grinding grindstone 10 as shown in FIG. 9 is used for processing the magnetic head 1. The grindstone 10 for grinding is a grindstone in which abrasive grains 11 such as diamond are bonded by a bond material 12 such as resin or metal, and has pores 13. As shown in FIG. 10, the disk-shaped grinding stone 10 for grinding grinds the work W placed on the jig 15 while applying the grinding liquid 14. When processing the flat surface of the work, a cup wheel as shown in FIG. 11 is used. This cup wheel is
It has a grinding surface 16 on its side surface. But work W
On the other hand, when grooving is performed, a grinding wheel 100 called a flat type as shown in FIG. 12 is used.
As shown in FIG. 13, the flat grinding wheel 100 for grinding is a straight grinding wheel having a radial cross section 10a of a simple rectangular shape.

On the other hand, a flat grinding wheel 100 for grinding
As another example, the shape shown in FIGS. 14 and 15 may be used for the purpose of reducing processing resistance during grinding. The cross section of the grinding wheel 100 for grinding processing shown in FIG. 14 is substantially inverted T-shaped, and the grinding wheel 100 for grinding processing shown in FIG. 15 has a notch 10b. As for the size (count) of the abrasive grains, in the case of grooving, fine abrasive grains such as # 3000 are used, but when deep cutting such as cutting is performed, it is comparatively around # 600. Coarse abrasive grains are used.

[0005]

By the way, conventionally, in the process of manufacturing a magnetic head, a magnetic head chip is manufactured by a cutting process for dividing a work in a block state into a large number of chips. In this cutting process, the block-shaped work is divided into a large number of chips by deep cutting. Therefore, depending on the magnitude of the hydraulic pressure of the grinding fluid, a large grinding force is applied to the grinding wheel 10 for grinding, and
As shown in 6, the grindstone 10 for grinding may be bent. In this case, the cutting width CT of the work W changes from a predetermined dimension to cause a dimensional error, and the grinding side surface ST becomes a curved surface. Therefore, the bent shape of the chip of the magnetic head manufactured in this way has a drawback that it also affects the processing accuracy in the subsequent steps.

Therefore, the present invention has been made in order to solve the above problems. Even if the grindstone is deformed, a dimensional error is generated during the grinding process due to a change in the cutting width of an object such as a work. An object of the present invention is to provide a grinding stone and a grinding method capable of suppressing a decrease in flatness.

[0007]

According to the invention of claim 1, a grinding wheel for grinding and processing an object by rotating is provided with a cross section along a radial direction. Is a circular outer peripheral portion, and a relief portion formed in association with this outer peripheral portion, by a grinding stone for grinding,
Achieved. In the invention of claim 2, preferably, the object is a chip of a magnetic head of a magnetic recording / reproducing apparatus. In the invention according to claim 3, in the grinding process for grinding and processing an object, the grinding wheel is rotated so that a cross section along the radial direction of the grinding wheel is circular. By applying the outer peripheral portion of the shape to the target object, grinding the target object, by the grinding processing method in which the escape portion formed in relation to the outer peripheral portion avoids hitting the target object and the grinding wheel for grinding,
Achieved.

[0008]

According to the first aspect of the invention, the outer peripheral portion having a circular cross section along the radius has the object to be deformed even if a large grinding force is applied to the grinding wheel for grinding or a large hydraulic pressure of the grinding fluid is applied. There is no change in the cutting width at. Further, since there is the relief portion, the grinding stone does not hit the side surface forming the cutting width, and the flat portion on the side surface of the cutting width is not obstructed. According to the second aspect of the invention, the chip of the magnetic head for high density recording can be accurately manufactured. In the invention of claim 3, while rotating the grindstone for grinding, the outer peripheral portion having a circular cross section is applied to the object to grind the object,
Even if a large grinding force is applied to the grindstone for the grinding process or the grindstone is bent due to the influence of the hydraulic pressure of the grinding fluid, it is possible to grind the object with the same width in the outer peripheral portion having the circular cross section. Moreover, at the time of this grinding, the relief portion formed in relation to the outer peripheral portion avoids contact between the object and the grinding wheel. Thereby, the flatness of the side surface of the ground groove can be maintained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The examples described below are
Since it is a preferred specific example of the present invention, various technically preferable limitations are attached, but the scope of the present invention is, unless otherwise stated to limit the present invention, in the following description.
It is not limited to these modes.

FIG. 1 shows a preferred embodiment of the grinding stone of the present invention. The grindstone 30 for grinding is disk-shaped or disk-shaped, and has a structure in which, for example, diamond abrasive grains are bonded by a bonding material to have pores inside. In FIG. 1, a grinding wheel 30 for grinding
The outer peripheral portion 40 has a substantially circular shape in the radial cross section 30a of the grinding wheel 30 for grinding. That is, the outer peripheral portion 40 of the grindstone 30 for grinding is substantially ring-shaped, and the diameter 42 of the outer peripheral part is larger than the width 45 of the base portion 30b of the grindstone 30 for grinding. Thereby, the vicinity of the outer peripheral portion 40 or the base portion 30 of the outer peripheral portion 40
The escape portion 50 is formed on the entire circumference b.

By using the grinding wheel 30 for grinding as described above,
FIG. 2 shows an example of grooving the workpiece W which is an object. In FIG. 2, a grindstone 30 for grinding is provided with a groove M.
An example of processing 1 and an example of processing the groove M2 are shown.
In the example in which the groove M1 is processed, the grinding wheel 30 for grinding is a case where a large grinding force or a large pressure by a grinding liquid is not applied, and the base portion 30b of the grinding wheel 30 for grinding is in a state of not being bent. In this case, the processed portion 40a corresponding to a substantially semicircular portion of the outer peripheral portion 40 grinds the bottom portion of the groove M1 with the cutting width D1. On the other hand, if a large grinding force is applied to the grinding wheel 30 or is affected by the pressure of the grinding fluid, the base portion 39b
May turn. Even in this case, the outer peripheral portion 40
The substantially semicircular processed portion 40b grinds the bottom of the groove M1 with the cutting width D2. Moreover, since there is a relief part 50,
The base portion 30b does not hit the side surface 60 of the groove M1. As described above, when a large grinding force is applied to the grinding wheel 30 or the pressure of the grinding fluid is affected, the cut width D2 of the formed groove M2 does not receive a large grinding force. Moreover, it is the same as the cut width D1 of the groove M1 when the pressure of the grinding fluid is not applied. Therefore, in the groove processing by the deep cutting in the work W, the dimensional error due to the change of the cutting width and the decrease in the flatness of the side surface 60 of the groove do not occur.

FIG. 3 shows an example of a work to be processed by the grinding wheel 30 for grinding according to the present invention. This work W is obtained by fusing a ferrite plate 70 and another ferrite plate 70 with a fusion glass 74. A plurality of grooves 76 are formed on the ferrite plate 70, and a fused glass 74 is provided between these grooves 76, 76. Generally, a magnetic head is manufactured by providing a magnetic material such as the ferrite plates 70, 70 with a gap called a magnetic gap that determines the recording wavelength of magnetic recording. Thereafter, the work W is divided into chips by using the grinding stone 30 for grinding shown in FIG. The work W (also called a block) shown in FIG.
This ferrite plate 70, 70
Is processed into a groove, a gap is formed, and the glass is fused with a fusion glass 74 to form a block.

Then, the work W set in the jig 80
However, as shown in FIG. 4, using the grindstone 30 for grinding according to the present invention, cutting is performed by deep grooving for each chip thickness. In this case, the grinding stone 30 moves in the direction of arrow X1. Workpiece W that was cut after that
Is fixed using a resin 90 such as red follow, and the back side of the work W is cut by the grinding stone 30 for grinding.
As a result, the magnetic head chip 1 as shown in FIG. 8 is obtained.

Here, FIGS. 5 and 6 show examples of conventional groove machining of a work as a comparative example. A comparison will be made between the conventional groove processing example shown in FIGS. 5 and 6 and the processing example using the grinding stone of the present invention shown in FIG. In the processing example of FIG. 5, when a large grinding force is applied to the straight grinding wheel 100 for grinding or a pressure of a grinding fluid is applied, the straight type conventional grinding wheel 100 grinds the work W. Is
It becomes a large part shown by 10d. That is, the cut width D3 of the obtained groove becomes larger than the cut width D4 originally thought. That is, a dimensional error due to a change in the cut width and a decrease in the flatness of the side surface 10e of the groove occur, so that highly accurate chip processing cannot be performed. Further, in the conventional grinding wheel having a relief portion shown in FIG. 6, when a large grinding force or a pressure of a grinding fluid is applied, the grinding wheel 10 is bent, and the cutting width D5 is larger than the predetermined cutting width D6. turn into. That is, a dimensional error due to a change in the cut width and a decrease in the flatness of the side surface 10e of the groove occur, and highly accurate chip processing cannot be performed.

However, by using the grindstone 30 for grinding according to the present invention, as described above, the cutting width D1 shown on the left side of FIG. 2 and the cutting width D2 shown on the right side of FIG. 2 do not change. This is because the outer peripheral surface of the outer peripheral portion 40 has a circular peripheral shape, so even if a large grinding force is applied to the grinding wheel 30 or the base 30b is slightly bent due to the pressure of the grinding fluid, the outer peripheral portion is slightly bent. This is because the cut width D2 of 40 is the same as the cut width D1. Moreover, since the relief portion 50 is formed in the grindstone 30 for grinding, the base portion 30b does not contact the side surface 60 of the groove M2. Since a dimensional error and a decrease in flatness of the side surface 60 do not occur due to a change in the cut width D2, highly accurate chip processing is possible. Since the dimensional error and the decrease in flatness due to the change in the cut width do not occur, the chip is attached to the base in a process of manufacturing the magnetic head by attaching the obtained chip to the chip base in a later step. There is an advantage that it can be surely positioned and attached with high accuracy.

Consider a case where the relief portion 50 of the grinding wheel 30 for grinding is too large. The case where the relief portion 50 is large is, for example, the case where the width of the base portion 30b is extremely smaller than the diameter of the outer peripheral portion 40. In this case, when a large grinding force or a pressure of the grinding liquid is applied to the grinding wheel 30 for grinding, the base portion 30b may be largely deformed. If such a large deformation occurs, as shown in FIG. 7, the base portion 30b may hit the side surface 60 of the groove M2 to form the side portion 61. Therefore, it is necessary to prevent the escape amount of the escape portion 50 from increasing so much that the rigidity of the base portion 30b is not lowered.

From the above description, in the embodiment of the present invention, the outer peripheral portion of the grindstone for grinding is circular in cross section in the radial direction, and the relief portion is provided near the outer peripheral portion or on the base side of the outer peripheral portion. Have Therefore, when the object is ground by the grinding stone for grinding, even if the grinding stone is deformed by the grinding force, the width of the processed groove does not change. Further, the flatness of the side surface of the processed groove of the chip can be maintained. Therefore, the obtained magnetic head chip has a highly accurate shape, and if this magnetic head chip is used in a magnetic recording / reproducing apparatus such as a video tape recorder, highly accurate magnetic recording / reproducing can be performed. it can.

The present invention is not limited to the above embodiment. The grindstone for grinding according to the embodiment of the present invention is used for manufacturing a chip of a magnetic head of a magnetic recording / reproducing apparatus. However, the grinding stone of the present invention can be used not only for magnetic head chips but also for grinding work in other fields.

[0019]

As described above, according to the present invention, even if the grindstone is deformed, a dimensional error is generated during grinding due to a change in the cutting width of an object such as a work, and the flatness is lowered. Can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a preferred embodiment of a grindstone for grinding according to the present invention, which has a partially cutaway portion.

FIG. 2 is a cross-sectional view showing an example in which an object is grooved using the grinding stone of FIG.

FIG. 3 is a perspective view showing a block which is an object.

FIG. 4 is a diagram showing a state in which the block of FIG. 3 is processed by a grinding stone of the present invention to form a chip.

FIG. 5 is a cross-sectional view showing a state in which an object is grooved by a conventional straight type grinding wheel for comparison, for comparison.

FIG. 6 is a cross-sectional view showing a state in which an object is grooved by a conventional grinding wheel for relief grinding, for comparison.

FIG. 7 is a diagram showing an example of use of a grinding stone for grinding processing outside the scope of the present invention.

FIG. 8 is a perspective view showing a generally used magnetic head chip.

FIG. 9 is a perspective view showing a conventional grinding stone.

FIG. 10 is a diagram in which an object is being ground by a conventional grinding stone.

FIG. 11 is a perspective view showing a conventional cup wheel type grinding wheel for grinding, which has a partially cutaway portion.

FIG. 12 is a perspective view showing a conventional straight type grinding wheel for grinding, which has a partially cutaway portion.

13 is a perspective view showing an outer peripheral portion of the straight type grinding wheel of FIG. 12;

FIG. 14 is a view showing a part of a conventional grinding wheel with a clearance.

FIG. 15 is a side view showing a part of a conventional grinding stone having a notch.

FIG. 16 is a view showing a state in which a groove is formed on an object by a conventional straight type grinding stone for grinding.

[Explanation of symbols]

 30 Grinding Wheel 30b Base 40 Outer Perimeter 50 Relief W Object (Work) D1, D2 Cutting Width M1, M2 Groove

Claims (3)

[Claims] 1. A grinding wheel for grinding and processing an object by rotating the object, comprising a circular outer peripheral portion having a circular cross section along a radial direction, and a circular outer peripheral portion formed in association with the outer peripheral portion. A grindstone for grinding process, which is provided with a relief portion. 2. The object is a block for making a chip of a magnetic head of a magnetic recording / reproducing apparatus.
The grindstone for grinding processing according to. 3. In a grinding process for grinding and processing an object, the grinding wheel is rotated and an outer peripheral portion of the grinding wheel having a circular cross section along the radial direction is applied to the object. A grinding method, wherein an object is ground by means of a grinding process, and a relief portion formed in relation to an outer peripheral portion avoids contact between the object and a grinding wheel.