JP3364504B2 - Method of fixing cathode material of flash discharge tube - Google Patents

Description

BACKGROUND OF THE INVENTION [0001] BACKGROUND OF THE INVENTION This invention relates to an automatic assembling method of the cathode material of the flash discharge tube, and more particularly to a bar-shaped electrodes tubular shade
The present invention relates to a caulking method for inserting an electrode material and fixing it at a predetermined position. 2. Description of the Related Art A flash discharge tube filled with xenon gas is used in a flash device for a camera. The flash discharge tube has an anode and a cathode, and between the two electrodes, the electric charge stored in the main capacitor is instantaneously discharged to obtain a flash. For this reason, the cathode of the flash discharge tube has been devised in various ways to increase the electron emission efficiency.For example, a tungsten rod-shaped part is sintered in a cylindrical shape with powdered metal containing a cesium alloy with high electron emission efficiency. ， The molded cathode material is caulked. The caulking stop position of the cathode material needs to be maintained at a high precision in order to keep the light emission starting voltage of the flash discharge tube and the current density at the time of discharge constant, and to prolong the life of the cathode. In order to caulk a cylindrical part to a rod-like part, the rod-like part is set vertically, the cylindrical part is fitted to a certain position, and then the cylindrical part is deformed by strongly pressing it from its outer periphery. (Japanese Patent Laid-Open No. 3-290)
634). Then, when the cylindrical part is fitted to the rod-shaped part, the inner diameter of the cylindrical part is slightly smaller than the outer diameter of the rod-shaped part so that the cylindrical part does not drop from a predetermined crimping stop position. The cylindrical part is fitted to the rod-shaped part by press-fitting. [0004] However, the above-mentioned method has been proposed.
Fit the cylindrical cathode material used for the flash discharge tube to the rod-shaped electrode
When adopting when writing order, to automate press fitting of the cathode material, it is necessary to perform centering of the rod-shaped electrode and the cylindrical cathode material with high precision, a disadvantage that the assembling device is expensive is there. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art. In caulking a cylindrical cathode material to a rod-shaped electrode , the centering accuracy of both parts is loosened and automatic assembly is simplified. Of the flash discharge tube
An object of the present invention is to provide a method for fixing a cathode material . [0006] SUMMARY OF THE INVENTION The present invention, in order to achieve the above object, performs provisional caulking fitted a cylindrical cathode member in a rod shape of the electrode, then a predetermined a cylindrical cathode member The main caulking is performed firmly after positioning at the caulking position. FIG. 2 shows a flash tube manufactured using the method of the present invention. The flash discharge tube 1 is provided with an anode 3 and a cathode 4 at both ends of a glass tube 2, and the tube is filled with xenon gas. Both ends of the glass tube 2 are sealed with bead glass 6 holding tungsten rods 5, 5, and nickel rods 7, 7 are welded to each of the tungsten rods 5. At a predetermined position of the tungsten rod 5 used for the cathode 4, a cylindrical cathode material 8 is fixed. The cathode material 8 is obtained by sintering and molding a metal powder containing a cesium alloy into a cylindrical shape, and is used to increase the electron emission efficiency during discharge. The cathode material 8 is fixed to the tungsten rod 5 after being positioned with high precision in order to stabilize the discharge characteristics of the mass-produced individual flash discharge tubes 1 and extend the life of the cathode 4. Note that the outer diameter and inner diameter of the cathode material 8 supplied as a cylindrical component are each 1.6.
mm and 0.82 mm. The outer diameter of the tungsten rod 5 (length 18 mm) to which the cathode material 8 is fixed is 0.78 to 0.80 mm, slightly larger than the inner diameter of the cathode material 8, and the cathode material 8 is caulked. It is fixed to the tungsten rod 5. FIG. 3 schematically shows an automatic caulking device used for caulking the cathode material 8 to the tungsten rod 5. This automatic caulking device has a gantry 1
Index table 11 which rotates stepwise by 45 ° in the clockwise direction on the upper part 0, and electrode rod supply units 1 which are sequentially arranged so as to surround the index table 11
2, a cathode material supply / temporary caulking unit 13, a cathode material pushing unit 14, a main caulking unit 15, a height detecting unit 16, and an electrode rod take-out unit 17. The index table 11 has a hole 18a.
Unit 18 having a pair of clamp claws 18b
Are provided. As shown in FIG. 2, a tungsten rod 5, a bead glass 6, a nickel rod 7
Are vertically inserted with the tungsten rod 5 facing upward. Also, the clamp claw 18b is
It is used to clamp the base of the electrode rod inserted into 8a. Each time the holding unit 18 moves to the electrode rod supply station, the electrode rod supply unit 12
Operates to take out the electrode rods arranged on the pallet 12a one by one and insert them vertically into the holes 18a. In the cathode material supply station, the cathode material supply / temporary caulking unit 13 is operated. First , one cathode material 8 sent by the parts feeder 13a is taken out and fitted to the upper end of the vertically held electrode rod. Put in.
As schematically shown in FIG. 4, the cathode material supply / temporary caulking unit 13 includes a transport unit 22 that moves in the horizontal direction by the guide action of the slider 21 and a pair of temporary caulking claws 23 that moves in the horizontal direction. And a temporary fixing portion 24. The transport section 22 is provided with a suction block 27 having a pin 26 projecting downward. The suction block 27 is connected to a vacuum generator, and can suck and hold the cathode material 8 as illustrated. The suction block 27 includes a cylinder device 28 incorporated in the transport unit 22.
Can move up and down in the vertical direction. A spring 29 is provided between the suction block 27 and the cylinder device 28. As shown in FIG. 5, the pair of temporary caulking claws 23 have V-grooves formed at their distal ends, and are movable in the horizontal direction by a cylinder device. Then, as shown by a two-dot chain line in the same figure, when the upper end side of the electrode rod 20 held by the holding unit 18 of the index table 11 is held by the temporary swaging claw 23 and the cathode material 8 is fitted. The upper end of the electrode rod 20 can be positioned.
At this time, the electrode bar 20 is
Has a tip of about 0.5 mm. The temporary caulking claw 23 further includes a cathode material 8 fitted on the upper end of the electrode rod 20 as shown by a solid line in FIG.
Is pressed from the outer peripheral side to be slightly deformed, and the cathode material 8 can be temporarily fixed to the electrode rod 20. This prevents the cathode material 8 from slipping out of the electrode rod 20 or slipping down even if a slight vibration accompanying the rotation of the index table 11 is applied. The cathode material pushing unit 14 is for pushing the cathode material 8 temporarily fixed to the upper end of the electrode rod 20 sent to the pushing station to a predetermined position, and has a pressing force stronger than the temporary fixing force. Press the cathode material 8 downward. The pressing position of the cathode material 8 is predetermined,
As a result, the protruding length of the electrode rod 20 from the cathode material 8 is always constant (for example, 0.3 mm). The caulking station 15 is provided with a caulking unit 15, which presses the cathode material 8 inserted into the electrode bar 20 to a predetermined position from the outer periphery thereof, deforms the cathode material 8 and caulks the electrode bar 20. . For this purpose, the main caulking unit 15 is provided with a pair of main caulking claws 31 and 32 as shown in FIG. 6, and these are moved in the horizontal direction to compress the cathode material 8 from the outer periphery and deform it. This caulking nail 31,
The tip of 32 has a partially hexagonal groove shape as shown. By caulking the cathode material 8 with these actual caulking claws 31, 32, the cathode material 8 and the electrode rod 20 are caulked.
With a large contact area, and a strong caulking force can be obtained. The electrode rod 20 after the caulking is moved to the inspection station by rotating the index table 11. In the inspection station, the height detection unit 16
As a result, the caulking position of the cathode material 8 is photoelectrically inspected. Then, it is determined whether or not the cathode material 8 is fixed at the prescribed height position, and this determination information is used when the electrode rod take-out unit 17 provided at the next discharge station is driven. At the discharge station, the electrode rod take-out unit 17 includes an electrode rod 20 having the cathode material 8 caulked.
And take them out one by one from the index table 11. Then, the non-defective product in which the cathode material 8 is crimped at the specified position and the non-defective product in which the caulked position of the cathode material 8 is deviated from the specified position are discriminated, and only the non-defective product is transferred to the next process for assembling the flash discharge tube. Send out. The caulking process of the cathode material 8 performed by the above-described automatic caulking device will be described in detail with reference to FIG. When the electrode rod 20 is sent to the cathode material supply station, the clamp claw 18b of the holding unit 18 is first opened to release the clamp of the electrode rod 20. Next, the temporary caulking claw 23 operates to sandwich the upper end of the electrode rod 20. Since the V-groove as shown in FIG. 5 is provided at the tip of the temporary caulking claw 23, the upper end of the electrode rod 20 is positioned as described above. Note that the upper end of the electrode rod 20 protrudes from the upper surface of the temporary caulking claw 23 by about 0.5 mm. Further, since the clamp claw 18b is at the release position and the electrode rod 20 is positioned only by the temporary caulking claw 23, an uneven load is not applied to the electrode rod 20.
It won't bend. Next, as shown in FIG.
Is held down. Thereby, the upper end of the electrode rod 20 protruding from the upper surface of the temporary caulking claw 23 is inserted into the hole of the cathode material 8 held by the suction block 27, and the lower surface of the cathode material 8 abuts on the upper surface of the temporary caulking claw 23. At the position, the spring 29 is charged and the suction block 2 is set.
The descent of 7 stops. At this time, the difference between the inner diameter of the hole of the cathode material 8 and the outer diameter of the electrode rod 20 is only about 0.05 mm, but since the tip of the electrode rod 20 is positioned by the temporary caulking claw 23 with the V groove, The cathode material 8 can be easily fitted to the electrode rod 20. Thereafter, the holding by the temporary caulking claw 23 is released as shown in FIG. When the temporary caulking claw 23 is opened, the suction block 23 is lowered by the urging of the spring 29,
The cathode material 8 is further pushed into the electrode rod 20. The pin 26 provided on the lower surface of the suction block 27 contacts the upper end of the electrode rod 20 and retreats to a certain depth position. Even when the temporary caulking claw 23 is released, the cathode material 8 is not dropped because it is held by the suction block 27. Next, as shown in FIG. 2D, the cathode material 8 is pressed and held by the temporary caulking claw 23. Thereby, the cathode material 8 is slightly deformed so as to be in close contact with the electrode rod 20, and the cathode material 8 is temporarily fixed to the electrode rod 20. Thereafter, as shown in (E), the clamp claws 18b sandwich the electrode rod 20, and the suction block 27 is raised, thereby completing the temporary fixing step.
Then, the index table 11 rotates and the electrode rod 2 is rotated.
0 is sent to the next push station. When the index table 11 is rotated, vibrations and the like occur when the electrode rod 2 is rotated.
Even if it is transmitted to 0, since the cathode material 8 is already temporarily fixed to the electrode rod 20, the cathode material 20 does not shift. The cathode material pushing unit 14 is shown in FIG.
A pushing jig 35 as shown in (F) is provided, and this pushing jig 35 can be lowered by a cylinder device. At the lower end of the pushing jig 35, a concave portion 35a for receiving the tip of the electrode rod 20 is formed. As shown in FIG. 3G, the pushing jig 35 is lowered toward the electrode rod 20 that has moved to the pushing station. Since the pressing force of the pushing jig 35 is set to be larger than the temporary caulking force of the cathode material 8, the cathode material 8 is pushed down as the pushing jig 35 descends. Then, the upper end of the electrode rod 20 comes into contact with the concave portion 35a, and the lowering of the pushing jig 35 stops. Therefore, the distance from the tip of the electrode rod 20 to the upper surface of the cathode material 8 is the concave portion 35a.
And this is the final crimping position of the cathode material 8. This distance is set to, for example, about 0.3 mm. Thereafter, the electrode rod 20 held by the clamp claws 18b is sent to the caulking station, and after the clamp by the clamp claws 18b is released, the caulking claws 3 are released.
This caulking is performed by 1,32. This caulking nail 31,
By pressing the cathode material 8 with a strong force at 32, the cathode material 8 is firmly fixed to the electrode rod 20. As shown in FIG. 6, partial hexagonal grooves 31a and 32a are formed at the tips of the caulking claws 31 and 32. The contact area between the material 8 and the electrode rod 20 can be increased. Thereby, when the cathode material 8 generates heat, the heat easily escapes through the electrode rod 20, which is advantageous in extending the life of the cathode of the flash discharge tube. After this caulking, the electrode rod 20 is held by the clamp claw 18b, and is sent to the discharge station via the inspection station by the rotation of the index table 11. Although the present invention has been described with reference to the illustrated embodiment, the tip shape of the temporary caulking nail or the present caulking nail can be appropriately selected other than the illustrated example. As described above, the flash light of the present invention
According to the cathode material sticking method conductive tube, tubular shade rod-shaped electrode
Before caulking the pole material , temporary caulking is performed before the main caulking to hold the cylindrical cathode material on the rod-shaped electrode , and then the cylindrical cathode material is positioned and then caulked. because are then manner, especially in the caulking position of the cathode material where high accuracy is required is easily in the position, yet it is possible to perform centering during assembly easier. Therefore, there is an advantage that the centering mechanism of the automatic caulking device for the cathode material can be simplified by the method of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating the operation of the method of the present invention. FIG. 2 is a sectional view of a flash discharge tube. FIG. 3 is a schematic diagram of an automatic caulking device using the present invention. FIG. 4 is a schematic diagram of a cathode material supply / temporary caulking unit. FIG. 5 is a plan view of a temporary caulking claw. FIG. 6 is a plan view (A) and a sectional view (B) of the caulking nail;
It is. [Description of Signs] 4 Cathode 5 Tungsten rod 8 Cathode material 11 Index table 20 Electrode rod 23 Temporary caulking claw 31, 32 Caulking claw 35 Pushing jig

Claims (1)

(57) fitted to [claimed is: 1. A used in the flash discharge tube tubular cathode material into a rod of the electrode, a method of fixing the cathode material to the electrode at a fixed position, in the cathode material fitting an electrode, it is deformed by applying weak pressure from the outer periphery of the cathode material performs provisional caulking to hold the anode material in the electrode to an extent capable of sliding along the electrode when a load is applied in the axial direction to the cathode material, then positioning is performed by moving the cathode member axially, the flash discharge tube is deformed again pressurized from the outer periphery of the cathode material and performing the crimping of firmly fixing the cathode material to the electrode thereafter Method of fixing cathode material .