JPH09131657A - Grinding device of glass panel for cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save the cost for grinding tools and the exchanging cost for the grinding tools by providing a mechanism in which a rotary shaft of a drum grinder is reciprocated on the arc-shaped line in the plane including the line segment with one point on an arbitrary line orthogonal to the rotary shaft as the center of rotation to improve the service life of the grinding tools. SOLUTION: A glass panel 2 is loaded on and fixed to a rotary table 3 and turned at the prescribed speed, and a drum grinding tool 1 above the glass panel is pressed against a face of the glass panel 2 while it is rotated. A supporting frame 4 to which the drum grinding tool 1 is fixed is installed on a rotary shaft 6 through a rotary shaft bearing 5, and the supporting frame 4 is reciprocated on the arc-shaped line as indicated by the arrow S around a center R of the rotary shaft 6. When the drum grinding tool 1 is moved on the arc-shaped line, the movement in the x-direction in the direction of the rotary shaft is synthesized with the movement in the y-direction orthogonal thereto, the follow-up ability of the grinding tool 1 to the curvature of the face is improved, and the whole surface of the grinding tool 1 is uniformly worn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for polishing a glass panel for a cathode ray tube.

[0002]

2. Description of the Related Art Conventionally, a glass panel constituting an image display portion of a cathode ray tube of a television or a display is
A glass gob that has been melted at around 000 ° C. is filled in a mold and pressed to form the glass. However, in the manufacturing method by pressing, minute sharp dent point defects and wrinkle-like line defects are likely to occur on the face surface of the panel used as the screen or image display part. Therefore, these defects are removed to improve the optical surface quality. In order to secure it, the panel face is polished. A known method for polishing a face of a glass panel is a method in which a cylindrical sleeve made of rubber or felt is pressed against the face surface while being rotated around the center axis of the cylinder as a rotation axis (hereinafter referred to as a drum polishing method). Has been. The drum polishing method is a slurry-like polishing agent having appropriate hardness and particle size, which is rotated while being pressed against the face surface of a glass panel having a predetermined curvature while applying an appropriate internal pressure to a flexible hollow cylindrical sleeve. Is used for polishing, and it is suitable as a method for polishing a panel having various curvatures with good followability to the face surface.

[0003]

However, conventionally,
In a normal drum polishing device, the cylindrical polishing tool has only a mechanism that rotates about the central axis, and in that case, only a part of the cylindrical polishing tool, particularly the part where the edge of the glass panel hits is local. However, there is a problem that the tool life is short and the life of the polishing tool is short.

In order to solve the problem, Japanese Patent Laid-Open No. 6-31609
In the publication, there is proposed a polishing device having a structure in which a cylindrical polishing tool is moved in the rotation axis direction. However, this method has the effect of widening the local wear width of the portion touched by the edge of the glass panel, but the drum polishing tool has a full width. It was impossible to evenly wear the entire width and to effectively utilize the entire width, and the effect of extending the life of the drum polishing tool was insufficient.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to provide a polishing apparatus for a glass panel for a cathode ray tube which has not been heretofore known.

[0006]

In order to achieve the above object, the present invention has a table that rotates at a predetermined speed, and a glass object having a three-dimensional curved surface is placed and fixed on the table. In a polishing apparatus for polishing a glass object by pressing a cylindrical drum polishing tool that applies a predetermined internal pressure to a glass object with a predetermined weight, the drum polishing tool has a predetermined speed with a central axis of the cylinder as a rotation axis. A Braun tube that rotates and has a mechanism in which a rotation axis of the drum polishing tool reciprocates on an arc line within a plane including the line segment about a point on an arbitrary straight line orthogonal to the rotation axis as a rotation center. Provided is a glass panel polishing apparatus.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The details of the present invention will be described below.

FIG. 1 shows a top view of a drum polishing apparatus which is an embodiment of the present invention. FIG. 2 shows a side view thereof. The glass panel 2 is placed and fixed on the rotary table 3, and the table 3 is rotated at a predetermined rotation speed. This speed is 5-100
The range of rpm is preferable, and the range of 10 to 50 rpm is particularly preferable. If it is less than 5 rpm, the polishing efficiency is lowered, which is inconvenient. If it exceeds 100 rpm, it is difficult to fix the glass panel, and a large capacity motor is required.

Above the rotary table 3 is a cylindrical drum polishing tool 1, which is pressed against the face surface of the glass panel 2 while rotating with the central axis of the cylinder as the rotational axis. The diameter of the drum polishing tool 1 is preferably in the range of 300 to 800 mm. If it is less than 300 mm, it is difficult to increase the peripheral speed of the drum polishing tool, and if it is more than 800 mm, it is unsuitable because the strength of the polishing tool against the internal pressure decreases. The length of the drum polishing tool in the axial direction has an appropriate rigidity, and when the drum polishing tool is pressed against the glass panel, the size of the glass panel to be polished is obtained in order to obtain good followability to the face surface. The relationship between the diagonal diameter A of the glass panel and the length B of the drum polishing tool is preferably 1.5A <B <2.5A. 1.5A
In the following, the followability to the face surface is insufficient and 2.5
This is because when the value is A or more, the amount of deformation of the polishing tool when the drum polishing tool is pressed against the glass panel is large, and the polishing efficiency is reduced due to problems such as generation of vibration due to rotation of the drum polishing tool.

The rotation number of the drum polishing tool 1 is 100 to 100.
The range of 0 rpm is preferable, and the range of 300 to 800 rpm is particularly preferable. When it is less than 100 rpm, it is unsuitable because the peripheral speed of the drum polishing tool is lowered and polishing efficiency is lowered, and when it is more than 1000 rpm, vibration is generated and so on.

The drum polishing tool 1 is preferably made of hollow rubber or felt so as to obtain a good followability with respect to changes in the curvature of the face surface, and it is used by applying a predetermined internal pressure. The pressure is preferably in the range of 0.2~2kg / cm ^2, the range of 0.4~1.2kg / cm ² is particularly preferred. If it is less than 0.2 kg / cm ^2, it is not suitable because the polishing efficiency is lowered due to insufficient pressing force.
If it exceeds cm ² , it is unsuitable because the followability to the curvature of the face surface is deteriorated.

The drum polishing tool 1 is fixed to a support frame 4 via a pillow block 10, and this support frame is installed on a rotary shaft 6 on the base structure of the polishing machine via a rotary bearing 5. The support frame 4 is a structure that can reciprocate on the arc line with respect to the base structure with the center R of the rotating shaft 6 as the center of rotation, as indicated by arrow S. The distance C between the rotation center R and the central axis Q of the drum polishing tool 1 should be an appropriate distance depending on the size of the glass panel 2 to be polished and the axial length B of the drum polishing tool 1. , 0.5B <C <1.5B is preferable. It is preferable that the central angle θ of the circular arc movement of the drum polishing tool with the rotation axis 6 as the center of rotation is in the range of 2 to 30 °, and if the movement amount of the drum polishing tool is defined as the x-direction component D of the movement amount of the drum polishing tool, D = 40m given by 2 · C · tan (θ / 2)
The range of m ≦ D ≦ BA is preferable. When it is 40 mm or less, the effect of extending the life of the polishing tool is so small that it is not practical. D is B
If it is larger than -A, the protrusion of the drum polishing tool from the panel becomes large and the polishing efficiency is lowered, which is not preferable. Here, the x-direction component is a direction orthogonal to a line segment connecting the rotation center R of the circular arc motion of the drum polishing tool and the rotation table center N as shown in FIG.

The reducer-equipped electric motor 7 is fixed to the support frame 4, and an eccentric plate is attached to the output shaft. The eccentric plate has a structure that can rotate within the arm 8.
The arm is connected to the base structure 11 via a support shaft member 12. The rotation of the eccentric plate serves as a power source for the arcuate reciprocating motion of the support frame 4. It should be noted that movements other than the rotational movement about the rotation axis 6 are absorbed by the pendulum movement of the arm 8. The cycle of reciprocating motion is controlled by the rotation speed of the motor. Since the support frame 4 and the drum polishing tool 1 have large inertia, it is difficult to operate at a too high speed in terms of equipment, and a range of 1 to 50 cycles / minute is appropriate. The amount of reciprocating motion of the drum polishing tool 1 is adjusted by the amount of eccentricity of the eccentric plate. In addition to the structure of the eccentric plate and the motor 7, the mechanism of reciprocating motion can utilize reciprocating motion by pneumatic or hydraulic cylinder.

Regarding the abrasive, a method of polishing while applying a slurry containing abrasive grains to the contact portion between the drum abrasive and the face surface, and a method of polishing using a drum abrasive made of a material containing abrasive grains There is a method of doing so, but either method may be used.

When the drum polishing tool is reciprocally moved on an arc line, the polishing device (x) is constructed so as to move the cylindrical polishing tool of the above-mentioned JP-A-6-31609 in the rotational axis direction.
(Reciprocating motion only in the direction), the motion of the drum polishing tool in the rotation axis direction (motion in the x direction) and the motion in the direction orthogonal to it (motion in the y direction) are combined, so that the face of the polishing tool is The followability to the surface curvature is improved, and the entire surface of the polishing tool is evenly worn. Therefore, the effect of extending the life of the polishing tool is great. Compared to reciprocating motion only in x direction, x
The reason why the followability of the polishing tool to the face surface is improved when the y-direction motion is added to the directional motion is not fully understood, but during the reciprocating motion of the polishing tool that rotates about the central axis of the cylinder. It is considered that this is due to the fact that the deformation state of No. varies depending on the moving direction.

[0016]

【Example】

(Example) A substantially rectangular 25-inch glass panel 2 having an aspect ratio of 3/4 and a diagonal diameter A of 635 mm was prepared, and the table was rotated on a rotary table 3 of a polishing apparatus having the configurations of FIGS. 1 and 2. The glass panel 2 was fixed so that the panel center coincided with the center N, and the rotary table 3 was rotated at 15 rpm. The support frame 4 has a diameter of 500 mm and a length B of 1
300 mm, wall thickness 10 mm, depth 4 mm in the surface width direction
The rubber drum grinder 1 with the groove of is attached, and the support frame and the drum grinder 1 are rotated at 12 cycles / min.
Was reciprocally rotated around the center of rotation. The distance C between the drum polishing tool central axis Q and the rotation center R of this polishing apparatus is 800 m.
m, the rotation angle (center angle of the arc movement) θ was 8 °.
An internal pressure of 0.8 kg / cm ² was applied to the drum polishing tool 1, and the drum polishing tool 1 was rotated at 500 rpm with the central axis Q of the cylinder as the rotation axis.

Then, while applying a pumice slurry having an average particle diameter of 60 μm, the polishing tool 1 was pressed against the glass panel from above with a force of 500 kg / cm ² to polish the glass panel.
Under these conditions, the polishing was continued for 30 seconds per glass panel. The life of the drum polishing tool was defined as when the groove on the surface of the drum polishing tool disappeared even partially, that is, when the surface of the drum polishing tool was worn by 4 mm even partially.
The number of processed sheets at that time was 28,000. The surface of the drum polishing tool was uniformly worn over the entire surface in contact with the glass panel.

(Comparative Example 1) As the drum polishing tool, a conventional type drum polishing apparatus having a mechanism of only rotating around the central axis of the cylinder was used. Similar to Example 1, the aspect ratio is 3 /
Prepare a substantially rectangular 25-inch glass panel with a diagonal diameter of 635 mm in 4, and fix the glass panel on the rotating table so that the center of the table coincides with the center of rotation of the table. , Drum polishing tool internal pressure,
The glass panel was polished under the same conditions as in Example 1 with the pressing force of the drum polishing tool and the polishing agent.

Polishing was continued for 30 seconds per glass panel. At this time, the number of processed sheets was 8000 when a part of the surface of the drum polishing tool was worn by 4 mm. The polishing tool was in a state in which the abrasion was large locally and only in the part where the edge of the glass panel hits.

(Comparative Example 2) A polishing apparatus having a mechanism in which the drum polishing tool 1 reciprocates in the direction of the rotation axis as shown in FIG. 3 was used. The drum polishing tool was reciprocated with a reciprocating cycle of 12 cycles / minute and a sliding width of 100 mm.

Similar to Example 1, the aspect ratio is 3/4 and the diagonal diameter is 6
Prepare a 25 mm glass panel of approximately rectangular shape of 35 mm,
The glass panel 2 was fixed on the rotary table 3 so that the panel center coincided with the center of rotation of the table, and the number of table rotations, the number of rotations of the drum polishing tool, the internal pressure of the drum polishing tool, the pressing force of the drum polishing tool, and the polishing agent used in the examples The glass panel was polished under the same conditions as in 1.

Polishing was continued for 30 seconds per glass panel. At this time, the number of processed sheets was 16000 when a part of the surface of the drum polishing tool was worn by 4 mm. The abrading tool has a large amount of wear at the panel edge part, but the width of the abraded part is 100 mm as compared with Comparative Example 1.
It has become widespread.

[0023]

The present invention has the effect of extending the life of the polishing tool in the drum polishing of glass panels for cathode ray tubes. By extending the life of the polishing tool, it is possible to save the cost of the polishing tool and the cost of exchanging the polishing tool.

That is, in the polishing apparatus according to the present invention, the cylindrical drum polishing tool is reciprocally swung about a point on a line orthogonal to the axis in the plane including the axis as the center of rotation. The followability to curvature is improved, and the entire surface of the polishing tool is evenly worn. As a result, the polishing tool is not worn out and the service life is extended.

[Brief description of the drawings]

FIG. 1 is a top view of a drum polishing apparatus showing an embodiment of the present invention.

FIG. 2 is a side view of a drum polishing apparatus showing an embodiment of the present invention.

FIG. 3 is a front view of a drum polishing apparatus showing a comparative example (prior art) of the present invention.

[Explanation of symbols]

 1: Drum polishing tool 2: CRT glass panel 3: Rotating table 4: Support frame 5: Rotating bearing 6: Rotating shaft 7: Electric motor with eccentric plate 8: Arm 9: Drum driving motor 10: Pillow block 11: Polishing Machine base structure

Claims (3)

[Claims] 1. A cylindrical drum polishing tool having a table which rotates at a predetermined speed, a glass object having a three-dimensional curved surface placed and fixed on the rotary table, and a predetermined internal pressure applied to the glass object. In a polishing apparatus for polishing the glass object by pressing with a predetermined load, the drum polishing tool rotates at a predetermined speed with a central axis of a cylinder as a rotation axis, and a point on an arbitrary straight line orthogonal to the rotation axis. A polishing apparatus for a glass panel for a cathode ray tube having a mechanism in which a rotation axis of the drum polishing tool reciprocates on an arc line in a plane including the line segment with respect to the rotation center. 2. A polishing apparatus for a glass panel for a cathode ray tube according to claim 1, wherein a straight line including the rotation center and orthogonal to the rotation axis of the drum polishing tool is orthogonal to the rotation axis of the rotary table. . 3. When the diagonal diameter of the glass panel is A, the axial length of the drum polishing tool is B, and the distance between the drum polishing tool rotating shaft and the rotation center is C, 1.5A <B <2. 0.5A and 0.5B <C <1.5B, the central angle θ of the circular arc motion of the drum polishing tool is in the range of 2 to 30 °, and 40 mm ≦ 2 · C · tan (θ / 2) ≦ B-A, The glass panel polishing apparatus for a cathode ray tube according to claim 1, wherein