JPH05154579A - Manufacture of plate part - Google Patents

Abstract

PURPOSE:To improve the life of a plate shaped part high in bending stress by pressing out nearly half a part actuated by a high stress when it is used after it is worked from one side, then, pressing it back from the reverse side and pressing back this part again from one side. CONSTITUTION:At the 1st stage, an upper press die 191 is lowered to a bias leaf spring 7 and a part for a welding small hole 21a is pressed out by an emboss pun 121a nearly half of a plate thickness. At the 2nd stage, a lower press die 102 rises simultaneously with the rise of an upper press die 101, a part 21A which is already pressed out by an emboss pin 121a is pressed out, then, pressed back nearly half a plate thickness and pushed up. In this way, the part 21A in the welding small hole 21a is cut off in the small hole 21a. At the 3rd stage, the upper press die 101 is lowered simultaneously with the fall of the lower press die 102, the part 21A in the small welding hole 21a which is already cut off is extracted by the emboss pin 121a from the inner part of the small hole 2a, dropped as scrap to form the welding small hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a plate-shaped component such as a biasing leaf spring for swingably supporting an armature having a print wire fixed thereto in an impact printer.

[0002]

2. Description of the Related Art Conventionally, an impact printer in which a printing wire is driven so that the printing wire impacts a printing medium through an ink ribbon to perform printing has a high degree of freedom in the printing medium and is relatively inexpensive. Therefore, it is used in various fields including output devices such as information processing systems. The impact printer includes a wire dot printing type, a plunger type, a spring charge type, a clapper type, and the like. Among them, in the spring charge type, an armature to which a printing wire is fixed is swingably supported by a bias leaf spring, and this armature is previously fixed to a core by a permanent magnet against the elastic force of the bias leaf spring. It has a structure in which the armature is opened by attracting the coil and exciting the coil wound around the core during printing to generate a magnetic flux in the direction opposite to that of the permanent magnet. Therefore, this spring charge type wire dot print head, which has good high-speed response, is often used.

FIG. 4 is a structural view of a main part of a conventionally known spring-charge type wire dot print head. In FIG. 4, in this print head, a base 3, a permanent magnet 4, a base plate 5, a spacer 6, a bias leaf spring 7 and a yoke 8 are sequentially laminated between the guide frame 1 and the cap 2, These are fixed together by a clamp 9.

Further, the bias leaf spring 7 is formed as a ring-shaped flat plate by etching. And
As shown in FIG. 5, a projecting piece portion 7b is integrally formed from the ring-shaped main body portion 7a toward the center corresponding to the portion to which the armature 10 to which the print wire 11 is fixed is attached. An opening S is formed at the center of the portion 7b, and a swing spring portion 7c is integrally formed in the opening S from the tip end side of the protruding piece portion 7b toward the ring-shaped main body portion 7a. Further, the bias leaf spring 7 is provided with welding small holes 21a and 21b penetrating vertically in the ring-shaped body portion 7a and the swing spring portion 7c. In addition,
The armature 10 is provided in the swing spring portion 7c in a state of being extended in the center direction, and thereafter fixed to the small hole 21a by welding or the like. On the other hand, the ring-shaped main body portion 7a is sandwiched between the spacer 6 and the yoke 8, and thereafter the small hole 21
It is fixed by welding or the like at the portion b. FIG. 6 shows a state in which the bias leaf spring 7, the armature 10, the spacer 6, and the yoke 8 are integrated in this way. A core 12 is provided at the center of the base 3, and a coil 13 is wound around the core 12. Reference numeral 14 is a substrate for energizing the coil 13, 15 is a space sheet for positioning the substrate, 16 is a thermistor for temperature detection, and 17 is a filler having good thermal conductivity that covers the coil 13 and the thermistor 16.

Next, the operation of this wire dot print head will be described. First, in this print head, the magnetic flux of the permanent magnet 4 flows through the base plate 5, the spacer 6, the yoke 8, the armature 10, the core 12 and the base 3 so as to return to the permanent magnet 4. When the coil 13 is not energized, the armature 10 is attracted to the core 12 while biasing the biasing leaf spring 7, and strain energy is accumulated in the biasing leaf spring 7 to cause a biased state. As a result, the print wire 11 is drawn into the guide frame 1. FIG. 4 shows this state. Then
When a current is applied to the coil 13 to excite it, a magnetic flux in the direction opposite to the exciting circuit is generated. Then, the force attracting the armature 10 is reduced, the strain energy accumulated in the bias leaf spring 7 is released, and the bias leaf spring 7 is released.
Returns. Further, upon this return, the print wire 11 attached to the tip of the armature 10 projects from the guide 1a of the guide frame 1, and presses the ink ribbon and print medium (not shown) against the platen. As a result, characters and graphic patterns can be printed. Also,
The heat generated in the coil 13 by energizing the coil 13 at the time of printing is transmitted to the thermistor 16 by a filler such as an epoxy resin having a high thermal conductivity, and rises in the part of the thermistor 16 inside the wire dot print head. By monitoring the temperature, the temperature of the coil 13 is maintained and controlled below the heat resistant temperature.

[0006]

As described above, in the conventional wire dot print head, the leaf spring 7 for bias is manufactured by etching. However, when manufactured by etching, the dimensional accuracy is generally poor. For this reason, there is a problem in that the characteristics of the printing wire 11 vary greatly and the printing quality is not stable. Further, the manufacturing by etching has a problem that the cost is high.

Therefore, a method of press-working the leaf spring 7 for bias has been conventionally studied, and some methods have been carried out. However, the conventional leaf spring 7 for bias manufactured by pressing has a problem that it is easily damaged by microcracks on the fracture surface generated during pressing and has a short life. This will be further described with reference to FIGS. 7 and 8.

FIG. 7 is a schematic diagram showing a state in which the armature 10 fixed to the bias leaf spring 7 is attracted to the core 12 by the permanent magnet in the standby state in the dot print head shown in FIG. In this case, the maximum bending stress of the bias leaf spring 7 is the bending fulcrum portion 7e of the spacer 6.
(Boundary portion between the ring-shaped body portion 7a and the protruding piece portion 7b). On the other hand, FIG. 8 shows that in the dot print head shown in FIG. 4, the armature 10 collides with the core 12 by suction after printing, and the tip end 10a of the armature 10 is moved in the direction of arrow A by inertia and the rear end 10b is reversed. It is the schematic diagram which showed the state which was lifted up. In this case, since the tongue portion 7d holding the rear end portion 10b of the armature 10 of the bias leaf spring 7 is lifted, the maximum stress is often applied to the boundary portion 7f between the swing spring portion 7c and the protruding piece portion 7b. .. Therefore, if there are micro cracks around the boundary portion 7f of the bias leaf spring 7 and the bending fulcrum portion 7e, which are caused by the fracture surface in the press working, etc., the micro cracks further develop into cracks, There are many cases where breakage occurs.

Particularly, in the bias leaf spring 7 used in the dot print head of the printer, 9 to 24 armatures 10 are fixed, and characters, graphic patterns, etc. are expressed by the dot construction of each dot. Therefore, each armature 10 has a permanent magnet 4
When there is a large variation in strain energy that is sucked by the core 12 and is bent and stored in each swing spring portion 7c, the print quality deteriorates. Further, the bias leaf spring 7 that vibrates at a high speed requires a material having high fatigue strength, and as this material, a carbon tool steel (SK material) or the like having a hardness of Hv 400 to 600 is used. Therefore, when the bias leaf spring 7 is manufactured by press-punching a high-hardness material, the sheared surface is generally 5 to 15% of the cut surface, and the rest is a fractured surface. Therefore, for such a reason, it is impossible to use the press working which is relatively low in cost and can be inexpensively performed on the plate-shaped component used in the portion such as the bias leaf spring 7 where the bending stress is high.

The present invention has been made in view of the above problems, and an object thereof is to provide a manufacturing method capable of improving the life of a plate-shaped component having high bending stress.

[0011]

In order to achieve the above-mentioned object, a method for manufacturing a plate-shaped component according to the present invention comprises press-punching a plate-shaped component having flexibility. A first step of punching out a portion to which a high stress is applied during use from one surface side by approximately half of the plate thickness, a second step of pushing back the punched portion from the opposite surface side, and the second step The portion punched back in is subjected to the third step of returning from the one surface side again, and is processed by using the half-pressing press system.

[0012]

According to this method, the punching is performed in three steps, but the punching force required for the punching in the first and second steps is about half that in the conventional punching. .. Further, in the first and second steps, shear planes due to plastic flow tend to be formed, and therefore, among the cut planes, there are many shear planes that are strong against stress, and it is possible to reduce fracture surfaces where microcracks occur. As a result, it is possible to obtain a plate-shaped component that is not damaged even when subjected to bending stress and has a long life. Therefore, it can be used also for a leaf spring for a bias of a dot print head, which has been conventionally difficult to press due to a problem of strength reduction due to microcracks generated by press working. Therefore, when it is applied to a bias leaf spring of a printer, it can be expected that an inexpensive dot printing head with high accuracy and high printing quality can be obtained.

[0013]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a diagram showing a manufacturing process of a plate-shaped component to which the manufacturing method of the present invention is applied, and FIGS. 2 and 3 show an example of a press die used in the manufacturing method of the present invention. In this embodiment, when the bias leaf spring 7 in the dot print head shown in FIGS. 4 to 8 is manufactured as the plate-shaped component, the swing spring portion 7 is particularly attached to the protrusion 7b.
The case of forming c will be described as an example. Therefore,
1 to 3, the same reference numerals as those in FIGS. 4 to 8 denote the same as those in FIGS. 4 to 8.

First, the press die shown in FIGS. 2 and 3 will be described. The press die 101 shown in FIG. 2 is an upper die and the press die 102 shown in FIG. 3 is a lower die. More specifically, in the press die 101, the launch pin 121a corresponding to the welding small hole 21a, the launch pin 121b corresponding to the welding small hole 21b, and the outer opening S of the swing spring portion 7c (FIG. 5). Launch pin 12 corresponding to
1c, 121d, 121e, etc. are provided. On the other hand, the press die 102 has a launch pin 121A corresponding to the launch pin 121a and a launch pin 121b.
Corresponding to the launch pin 121B and the launch pin 12
Launch pin 12 corresponding to 1c, 121d, 121e
1C etc. are provided. And press dies 101, 1
The amount of protrusion of 02 with respect to the work can be adjusted by changing the strokes of the press dies 101 and 102 moving up and down.

Next, the press die 1 shown in FIGS. 2 and 3.
A case where the manufacturing method of the present invention is carried out using 01 and 102 will be described with reference to FIG. In addition, in FIG.
In order to simplify the explanation, the small hole 2 for welding of the bias leaf spring 7 is formed by the hammer pin 121a and the hammer pin 121A.
The place where 1a is stamped and formed will be described.
The other small holes 21b for welding and the outer opening S are also formed in the same manner.

In this manufacturing method, three steps are performed.
The small hole 21a for welding is formed through (a), (b), and (c). That is, (a) in the first step, the upper press die 101 descends with respect to the set work (the leaf spring 7 for bias), and the portion (21A) of the welding small hole 21a is approximately half the sheet thickness ( Only the dimension t) in the figure is punched out by the punching pin 121a. (b) In the second step, the upper press die 101 rises and the lower press die 102 rises, and the punching pin 121a
Then, the portion (21A) already punched out is punched back by the punching pin 121A by about half the plate thickness and pushed up.
As a result, the portion (21A) in the welding small hole 21a is
It cuts in this welding small hole 21a. (c) In the third step, the lower press die 102 descends and the upper press die 101 descends, and the portion (21A) in the small hole 21a for welding that has already been cut is punched out by the pin 12.
It is pulled out from inside the welding small hole 21a by 1a and dropped as scrap. As a result, the welding small hole 21a is formed.

Therefore, through each of these steps, the punching force in the first and second steps is about half that in the case where the conventional punching is performed once, and the shearing surface due to the plastic flow tends to occur. As a result, 40 of the cut surfaces
Since ~ 50% is a shear surface that is strong against bending stress, and the rest is a fracture surface, 5-15% is a shear surface in the conventional structure, and there is less damage due to microcracks compared to the remainder being a fracture surface. Therefore, the bias leaf spring 7 having excellent strength and long life can be formed.

In the above embodiment, as the plate-shaped component,
Although the case where the present invention is applied to the bias leaf spring 7 of the wire dot print head has been described, the present invention is not limited to this, and is applied to all plate-shaped parts that are susceptible to bending stress.
The same effect can be obtained.

[0019]

As described above, according to the method for manufacturing a plate-shaped component of the present invention, punching is performed in three steps, but the punching force required for punching in the first and second steps is , It is about half compared to the case of hitting once in the past. Further, in the first and second steps, shear planes due to plastic flow tend to be formed, and therefore, among the cut planes, there are many shear planes that are strong against stress, and it is possible to reduce fracture surfaces where microcracks occur. As a result, it is possible to obtain a plate-shaped component that is not damaged even when subjected to bending stress and has a long life.
Therefore, it can be used also for a leaf spring for a bias of a dot print head, which has been conventionally difficult to press due to a problem of strength reduction due to microcracks generated by press working. Therefore, when it is applied to a bias leaf spring of a printer, it can be expected that an inexpensive dot printing head with high accuracy and high printing quality can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of a plate-shaped component to which a manufacturing method of the present invention is applied.

FIG. 2 is a diagram showing an example of an upper press die used in the manufacturing process of the present invention.

FIG. 3 is a diagram showing an example of a lower press die used in the manufacturing process of the present invention.

FIG. 4 is a structural view of a main part of a conventionally known spring charge type wire dot print head.

5 is an enlarged perspective view of an essential part of the same wire dot print head as shown in FIG.

FIG. 6 is an enlarged cross-sectional view of an essential part of the wire dot print head shown in FIG.

7 is a schematic diagram showing a state where the armature is on standby in the wire dot print head shown in FIG.

8 is a schematic diagram showing a state in which the armature enters a standby position immediately after printing is completed in the wire dot printing head shown in FIG. 4;

[Explanation of symbols]

7 Bias leaf spring (plate-shaped component) 10 Armature 101 Upper press die 102
Lower press type

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Umezawa 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (1)

[Claims] 1. In a method for manufacturing a plate-shaped component formed by press-punching a flexible plate-shaped component, a portion to which a high stress is applied during use after processing has a plate thickness of approximately one side. A first step of punching out only half, a second step of stamping out the stamped portion from the opposite surface side, and a third step of stamping out the stamped portion from the one surface side again. A method for manufacturing a plate-shaped component, characterized by being processed by using a half-pressing press method.