JPS60212845A - Grinding disc for information signal reproducing stylus - Google Patents

Abstract

PURPOSE:To improve the grinding efficiency and to stabilize the ground shape of styluses, by using a grinding disc provided with plural kinds of spiral or concentric grinding grooves at different intervals on the same plane and properly using the grinding grooves. CONSTITUTION:A grinding disc 1 is provided with grinding grooves 2a, whose ratio W/P of the groove width W to groove interval P is smaller, and grinding grooves 2b, whose ratio W/P is larger, and a projected section with an effective electrode part width which is eseveral times wider than a desired electrode widt lis manufactured at the end of a triangular-pyramidal stylus base body 7 by using the grinding grooves 2b having the larger ratio W/P and then the projected section 5 is guided to the grinding grooves 21 having the smaller ratio W/P and ground to the desired electrode width l. When an information signal reproducing stylus is ground (finish grinding) to the desired shape after a projected section which becomes the guide of the finish grinding groove is formed (rough grinding) by properly using the two kinds of grinding grooves having different pitches, grinding of excellent reproducing styluses becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention manufactures a capacitive reproduction needle that scans a disk on which information signals are recorded as changes in unevenness and reproduces the unevenness as changes in capacitance. Regarding the polishing machine used in the process.

Conventional structure and its problems As one of the capacitance method for manufacturing regenerated needles, Japanese Patent Application Laid-Open No. 58
As disclosed in Japanese Patent No. 73029, an electrode is provided on one side of a triangular pyramidal needle base made of a non-conductive material, and a polishing disk having a polishing groove with a flat bottom as shown in FIG. 1 is driven to rotate. Polishing is performed by rotating the tip of the triangular pyramidal needle base within a predetermined angular range and pressing the side surface of the needle base against the side wall of the polishing groove, thereby forming a protrusion on the tip of the triangular pyramidal needle base. A method has been considered in which an effective electrode portion having a substantially constant width is left on one side of the protrusion.

However, if the ratio (W/P) of the groove width W to the groove interval P (hereinafter referred to as pitch) of the polishing disk shown in FIG. Non-following periods (hereinafter referred to as needle skips) easily occur.

In other words, a polishing groove with a small W/P ratio has a low probability of contacting the polishing groove during the gap when the needle base is pressed against the polishing disk, and a similarly low probability of contacting the polishing groove again after the needle jumps. The needle skipping causes uneven polishing amount and deterioration of the polishing groove shape due to the impact when contacting the polishing groove again. Fig. 2 shows an example of the deterioration of the polishing groove caused by skipping.

FIG. 3 shows an example of a regenerated needle manufactured using a polishing disk having the abrasive grooves deteriorated due to needle skipping. The impact when the needle base passes through the inferior portion of the polishing groove affects the electrode formed on one side of the needle base due to adhesion, causing the electrode to retreat or peel off during polishing.

When polishing a triangular pyramidal needle base using a polishing groove with a high ratio of 10,000 W/P, there is a high probability that the needle base will come into contact with the polishing groove when pressed against a polishing plate, and the needle will be polished again after flying off. The probability of contact with the groove is equally high. Therefore, uneven polishing amount and deterioration of groove shape caused by needle skipping are less likely to occur, but by reducing the pitch P (i-), it is easily affected by adjacent polishing grooves. This figure shows an example of the shape of a recycled needle in which an unnecessary protrusion has been formed due to the influence of the above.The protrusion shortens the life of the recycled needle.

OBJECTS OF THE INVENTION The present invention relates to a polishing machine which attempts to solve the above-mentioned problems.

Structure of the Invention By selectively using the polishing grooves of a polishing disk having a plurality of spiral or concentric polishing grooves at different intervals on the same plane, it is possible to improve polishing efficiency and stabilize the polished shape.

Description of examples Hereinafter, the present invention will be explained based on drawings showing examples.

FIG. 5 shows an embodiment of the present invention, in which polishing grooves 2a and 2bQ of different pinches are provided on the inner and outer peripheries of the polishing disk 1, respectively. FIG. 6 shows an enlarged cross-sectional view of each polishing groove.

In the present invention, before polishing with a polishing groove with a small W/P ratio as shown in 28, a polishing groove with a large W/P value as shown in 2b is used to increase the effective electrode width at the tip of the triangular pyramidal needle base 3. The protrusion 5 is manufactured to be several times wider than the required electrode width β, so that the protrusion 5 serves as a guide to the polishing groove 2a when the polishing groove 2a is polished to the required electrode width l.

In other words, by using two types of polishing grooves with different pitches,
Complete formation of protrusions that serve as guides for polishing grooves (hereinafter referred to as rough polishing)
After that, by polishing into the desired shape of the recycled needle (hereinafter referred to as final polishing), it is possible to eliminate the aforementioned problems caused by needle skipping and the effects of adjacent grooves, making it possible to polish the recycled needle in a good manner. FIG. 7 shows an example of a triangular pyramidal needle base, FIG. 8 shows an example of a regenerated needle after rough polishing, and FIG. 9 shows an example of a good regenerated needle.

Effects of the Invention As described above, the present invention provides a driving rotation of a polishing disk having rough polishing grooves for the purpose of following the polishing grooves and finish polishing grooves for the purpose of polishing into a desired shape. By changing the number of needles, it is possible to respond to the pitch difference, thereby improving the polishing efficiency and shape stability of the regenerated needle.

[Brief explanation of drawings]

Fig. 1 is an enlarged sectional view of the polishing groove of a conventional polishing disk, Fig. 2 is a perspective view showing an example of deterioration of the polishing groove shape caused by needle skipping, and Fig. 3
The figure is a perspective view showing an example of a regenerated needle in which electrode retraction has occurred.
The figure is a perspective view showing an example of a regenerated needle affected by the adjacent groove.
Figures 5 and 6 are a plan view and an enlarged sectional view of a polishing groove in an embodiment of the present invention, Figure 7 is a perspective view of an example of a steel substrate, and Figure 8 is a rough polishing finished stage. FIG. 9 is a perspective view showing an example of a regenerated needle. FIG. 9 is a perspective view showing an example of a good regenerated needle. 1... Polishing disc, 2... Polishing groove, 3... Deterioration of polishing groove, 4 - Electrode, 5... Protrusion, 6...
Effective electrode part, 7...needle base body. Name of agent Patent attorney Satoshi Nakao 93 and one other person Figure 1 Figure 2 Figure 3 Figure 4 Evening Figure 5 Figure 611K 77

Claims (1)

[Claims] A polishing disk for an information signal reproducing needle having a plurality of spiral or concentric polishing grooves at different intervals on the same plane.