JP2008071634A - Cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cathode-ray tube equipped with a low-cost reinforcing band excelling in productivity without using a connecting metal plate other than a metal plate as a band body. <P>SOLUTION: The annular reinforcing band 4 composed by jointing both ends of a strip-like metal plate 40 at a linear seam welding part 41 having a length L larger than 115% of the width W of the metal plate 40 is mounted to the circumference of a panel, and clamps the panel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cathode ray tube provided with an explosion-proof reinforcing band.

  In general, as shown in FIG. 3, a cathode ray tube is formed by joining a glass panel 1 having a fluorescent surface (not shown) on its inner surface and a funnel 2 through a joint 3 such as frit glass. A glass bulb (envelope) is provided. The internal space of the glass bulb is kept in a high vacuum state. For this reason, when a physical impact or the like is applied to the panel 1 to cause a crack or the like, the front surface of the panel 1 is broken inward by the pressure difference between the atmospheric pressure outside the glass bulb and the vacuum inside, and the glass 1 A phenomenon called implosion in which fragments are once drawn into the glass bulb and then scattered forward occurs, causing a safety problem. In order to prevent this, a metal explosion-proof reinforcing band 4 is shrink-fitted on the outer peripheral surface of the side wall of the panel 1. The reinforcing band 4 tightens the panel 1 to apply inward pressure to the side wall of the panel 1, thereby generating stress that pushes the front surface of the panel 1 outward in the tube axis direction. The occurrence of the implosion is prevented by canceling out the atmospheric pressure that pushes the front surface of the panel 1 inward in the tube axis direction by this stress.

  An example of a conventional method for manufacturing a reinforcing band will be described with reference to FIG.

  First, as shown in FIG. 4A, a single band-shaped metal plate 51 forming a band body is prepared. Next, as shown in FIG. 4B, a metal plate 51 is formed into a substantially rectangular shape along the outer peripheral surface of the panel side wall of the cathode ray tube, and a connecting metal different from the metal plate 51 is formed at both ends of the metal plate 51. The metal plate 51 and the metal plate 52 are joined by overlapping the plates 52. Thus, an annular reinforcing band made of the metal plates 51 and 52 is obtained.

  The metal plate 51 and the metal plate 52 are coupled as follows. Both ends of the strip-shaped metal plate 51 are butted together, and the metal plate 52 is superimposed on both ends of the metal plate 51. Then, the metal plate 51 and the metal plate 52 are spot welded. FIG. 5A is a plan view of the connecting portion of the reinforcing band thus obtained, and FIG. 5B is a cross-sectional view thereof. 53 shows a spot welding location.

  The reinforcement band 4 is attached to the panel 1 by shrink fitting as follows. A high frequency coil is disposed along the inner peripheral surface or outer peripheral surface of the reinforcing band 4, and the reinforcing band 4 is expanded by induction heating. In this state, the reinforcing band 4 is attached to the outer peripheral surface of the side wall of the panel 1 of the glass bulb. Thereafter, when the reinforcing band 4 is cooled, the reinforcing band 4 is thermally contracted and the outer peripheral surface of the panel 1 is tightened.

  At this time, a tensile force acts on the reinforcing band 4. In order for the reinforcing band 4 not to break at the connecting portion of the reinforcing band, the breaking strength (welding strength) of the connecting portion needs to be equal to or higher than the breaking strength of the metal plate 51.

  The above-mentioned conventional reinforcing band has the following problems.

  First, since the connecting metal plate 52 is required in addition to the metal plate 51 forming the band body, the number of parts and the amount of material used are increased. As a result, the cost of the explosion-proof band increases.

  Second, a shearing force acts on the spot welded portion 53 between the metal plate 51 and the metal plate 52, and the end of the metal plate 51 and the metal plate 52 are deformed as shown in FIG. This deformation is caused by a tensile force F1 generated in the explosion-proof band acting on the surface of the metal plate 52 on the metal plate 51 side, whereby a force F2 in a direction orthogonal to the tensile force F1 acts on the metal plate 52. This is because 52 is curved. As a result, the adhesion between the reinforcing band and the panel 1 is reduced in the vicinity of the metal plate 52, and the explosion-proof effect of the reinforcing band is reduced. Further, the tip 51 a of the metal plate 51 applies a local stress to the panel 1 and damages the surface of the panel 1.

In Patent Document 1, as shown in FIG. 7, a band 61 is formed at one end of a band-shaped metal plate 60 forming a band body, a groove 62 is formed at the other end, and there is a block 61. A reinforcement band in which both ends of the metal plate 60 are connected by welding along a dovetail with which the groove 62 is fitted has been proposed. Since this reinforcing band does not require the connecting metal plate 52 required in the reinforcing band shown in FIG. 4, the above-described problem does not occur.
JP 2001-176429 A

  However, in the reinforcing band of FIG. 7, it is necessary to form the complex dovetail 61 and the dovetail groove 62 at both ends of the metal plate 60, and it is necessary to perform welding along a complicated dovetail shape. It is necessary to perform welding along such a complicated path by laser welding or Tig welding. Therefore, there are problems that productivity is poor, cost is high, and practicality is lacking. Therefore, the reinforcing band in FIG. 7 has not been widely spread.

  The present invention solves the above-mentioned conventional problems, does not use a metal plate for connection other than the metal plate forming the band body, and reduces the adhesion to the panel and the application of local stress due to deformation of the reinforcing band at the connection portion. Another object of the present invention is to provide a cathode ray tube having a reinforcing band which does not occur and has good productivity and low cost.

  The cathode ray tube of the present invention includes an envelope made of a panel and a funnel having a phosphor screen formed on the inner surface, and an annular reinforcing band that is mounted around the panel and fastens the panel.

  The reinforcing band is formed by joining both ends of a belt-shaped metal plate with a straight seam welded portion having a length of 115% or more of the width of the metal plate.

  According to the present invention, since the band-shaped metal plates are joined by the seam welded portion, the connecting portion as shown in FIG. 6 is not deformed. Therefore, it is possible to prevent the explosion-proof effect from being lowered due to the decrease in the adhesion of the reinforcing band to the panel and the damage to the panel. Therefore, it is possible to provide a highly reliable cathode ray tube that stably has high explosion-proof characteristics. Further, the cost can be reduced by reducing the material of the reinforcing band and improving the productivity.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The basic configuration of the cathode ray tube of the present invention is not particularly limited except for a reinforcing band 4 described later, and may be the same as the conventional color cathode ray tube shown in FIG. 3, for example. Therefore, description of the same part as the conventional one is omitted, and the reinforcing band 4 which is a characteristic part of the present invention will be described.

  The reinforcing band of the present invention is manufactured by forming a band-shaped metal plate into a substantially rectangular shape along the outer peripheral surface of the side wall of the cathode ray tube, and joining both ends thereof by seam welding. Thereby, the metal plate 52 for connection essential in the conventional reinforcing band shown in FIG.

  However, if the both ends of the belt-like metal plate are simply joined by seam welding, there is a possibility that the required mechanical strength cannot be obtained at the connecting portion.

  That is, a tensile force at the yield point (YP) strength of the material of the band body acts on the reinforcing band 4 attached to the cathode ray tube, and the welded portion of the connecting portion that connects both ends of the band body is affected by this tensile force. There is a need to have a welding strength that can withstand. For this reason, it is essential that the weld strength of the welded portion is at least the breaking strength (TS) of the band body.

  However, in general, it is difficult to ensure a welding strength equal to or higher than the breaking strength (TS) of the material by seam welding.

  Therefore, in one embodiment of the present invention, as shown in FIG. 1A, both ends 40a and 40b of the band-shaped metal plate 40 forming the band body are linearly formed at an angle θ with respect to the longitudinal direction of the metal plate 40. Next, as shown in FIG. 1B, both ends 40 a and 40 b of the metal plate 40 are joined by a linear seam welded portion 41 that forms an angle θ with respect to the longitudinal direction of the metal plate 40. Here, the length L of the seam welded portion 41 is set to 115% or more of the width W of the metal plate 40. Thereby, since the tensile force acts in a distributed manner on the seam welded portion 41 longer than the width W of the metal plate 40, the weld strength equal to or higher than the breaking strength (TS) of the band body can be ensured only by the seam welded portion 41. .

  Further, since the seam welded portion 41 is linear, it is easy to process both ends 40a and 40b of the strip-shaped metal plate 40 before welding, and the welding path is also straight, so that welding work is also easy. Therefore, the productivity of the reinforcing band 4 can be improved and the cost can be reduced.

  The Example of the reinforcement band for cathode ray tubes whose screen diagonal size is 21 inches is shown. A band-shaped metal plate 40 made of an electric Zn / Ni plated steel plate having a width W of 40 mm and a thickness of 1.2 mm is used, and both ends thereof are joined by a linear seam welded portion by an electric resistance welding method to form an annular reinforcing band. Obtained. The angle θ formed by the straight seam welded portion 41 with respect to the longitudinal direction of the metal plate 40 was changed to four types of 90 °, 75 °, 60 °, and 45 °. Two poles parallel to each other were inserted into the reinforcing band, and a tensile test was performed to break the reinforcing band by applying a tensile force to the reinforcing band by widening the interval between the two poles. Twenty samples were prepared for each angle θ, and the number of samples fractured at the seam weld was counted. The results are shown in Table 1.

  From Table 1, when the angle θ is θ ≦ 60 °, the length L of the seam welded portion 41 is 115% or more of the width W of the metal plate 40, and there is no sample that breaks at the seam welded portion 41 in the tensile test. It was confirmed that the weld strength of the connecting portion was higher than the breaking strength of the band body.

  The strength of the seam welded portion 41 is improved as the angle θ is smaller. However, when θ <30 °, the length L of the seam welded portion 41 exceeds 200% of the width W of the metal plate 40, and the length of the seam welded portion 41 is increased. This is not preferable because the production length is lowered and the production efficiency is lowered.

  In the present invention, the welding method for forming the seam welded portion 41 is not particularly limited, but is preferably any one of an electric resistance welding method, a laser welding method, and a Tig welding method. In the present invention, since the seam welded portion 41 is linear, an electric resistance welding method can be used, thereby improving the efficiency of the welding operation.

  In FIG. 1B, the case where the width W of the metal plate 40 is constant and the straight seam welded portion 41 is inclined with respect to the longitudinal direction of the strip-shaped metal plate 41 has been described. It is not limited to. For example, as shown in FIGS. 2A and 2B, the width of the metal plate 40 is enlarged in the vicinity of the seam welded portion 41, and the linear seam welded portion 41 is in the longitudinal direction of the strip-shaped metal plate 40. It may be perpendicular to. Also in this case, the length L of the seam welded portion 41 may be 115% or more of the width W of the metal plate 40. Here, the width W of the metal plate 40 is defined by the width of the portion excluding the wide portion in the vicinity of the seam welded portion 41.

  The reinforcing band of the present invention is shrink-fitted on the outer peripheral surface of the side wall of the panel 1 of the cathode ray tube as in the conventional case.

  The application field of the present invention is not particularly limited, and can be widely used as a cathode ray tube for various TV sets.

FIG. 1A is a plan view showing both ends of a metal plate before joining of a reinforcing band according to an embodiment used in the cathode ray tube of the present invention, and FIG. 1B shows the cathode ray tube of the present invention. It is the top view which showed the seam weld part of the reinforcement band which concerns on one Embodiment used. FIGS. 2A and 2B are plan views showing a seam welded portion of a reinforcing band according to another embodiment used in the cathode ray tube of the present invention. FIG. 3 is a side view showing an example of a schematic configuration of the cathode ray tube. FIG. 4A is a front view of a band-shaped metal plate used in a conventional reinforcing band, and FIG. 4B is an exploded perspective view showing a conventional method of manufacturing a reinforcing band. FIG. 5A is a plan view showing a connecting portion of a conventional reinforcing band, and FIG. 5B is a sectional view thereof. FIG. 6 is a cross-sectional view for explaining a problem of a conventional reinforcing band. FIG. 7 is a plan view showing a connecting portion of another conventional reinforcing band.

Explanation of symbols

1 Panel 2 Funnel 3 Joint 4 Reinforcement band 40 Metal plate 41 Seam weld

Claims (3)

A cathode ray tube comprising an envelope made of a panel and a funnel with a fluorescent screen formed on the inner surface, and an annular reinforcing band attached around the panel and tightening the panel,
The cathode-ray tube according to claim 1, wherein the reinforcing band is formed by joining both ends of a belt-shaped metal plate with straight seam welds having a length of 115% or more of the width of the metal plate.   2. The cathode ray tube according to claim 1, wherein an angle formed by the straight seam welded portion with respect to a longitudinal direction of the strip-shaped metal plate is in a range of 30 ° to 60 °.   2. The cathode ray tube according to claim 1, wherein the seam welded portion is formed by any one of an electric resistance welding method, a laser welding method, and a Tig welding method.

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