JPH0337965Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an actuator assembly used in an impact printer.

[Background of the idea]

FIG. 3 is a front view showing a schematic configuration of the printing mechanism section of the impact printer. When the electromagnetic coil 2 wound around the upper part of the yoke 1 is excited, the armature 3 is attracted to the yoke 1 and its upper part pushes out the push rod 4. The push rod 4 drives a printing hammer 5, and the impact surface of the printing hammer 5 is pressed against the type on the type drum 8 via the paper 6 and the ink ribbon 7 to print.

The armature 3 is repeatedly driven at a high speed of 2000 to 3000 times per minute and collides with the yoke 1 at a speed of 2.5 to 3 m per second. In order to obtain this characteristic, the electromagnetic coil 2 generates heat and its temperature increases by 30 to 50 degrees. Furthermore, at the time of a collision, an impact force of several tens of kilograms is applied to the yoke 1. As a result, the adhesive may peel off at the joint between the yoke 1 and the electromagnetic coil 2, and the electromagnetic coil 2 may
There was a fear that it would slip out of York 1.

On the other hand, as described above, it is essential that the electromagnetic coil 2 be mounted in close contact with the yoke 1 in order to improve heat dissipation characteristics. That is, the gap between the electromagnetic coil 2 and the yoke 1 is required to be 0.05 to 0.1 mm. It is also necessary to use an adhesive that is uniform and has good thermal conductivity over the entire contact surface, or to apply a heat conduction aid.

FIG. 5 is a diagram showing details of the electromagnetic coil 2,
Bobbin 21, electric wire 2 wound around the bobbin 21
2. It is composed of a lead wire 23, an encapsulant 24, and the like. The bobbin 21 is made of a material such as nylon 66, and is manufactured by molding. The inner wall of the bobbin 21 that contacts the yoke 1 is made as thin as about 0.2 mm in order to improve heat dissipation characteristics. Around the outer periphery of the bobbin 21, an electric wire 22 is wound around several hundred turns. The outer periphery of the electric wire 22 is molded with an encapsulant 24 made of a material with good thermal conductivity, such as epoxy resin, at a high temperature of 100 to 200°C.

Since the electromagnetic coil 2 is manufactured through the above-described structure and manufacturing process, it is difficult to avoid deformation of the dimensions of each part of the bobbin 21. In particular, since the entrance side inserted into the yoke 1 has a convex shape, it is easy to deform inward from the root of the convexity.
Further, there is a structural problem in that the vicinity of the central portion of the bobbin 21 is subject to compressive force due to the winding of the electric wire 22 and is easily deformed inward.

As described above, there are problems such as deformation of the bobbin 21, variations in the processing accuracy of the yoke 1, and variations in the viscosity and application amount of the adhesive, which prevent the adhesive from being applied uniformly between the bobbin 21 and the yoke 1. ,
A failure occurs in the mounting portion of the electromagnetic coil 2.

On the other hand, since there are a large number of actuator assemblies, for example 132, if there are variations in the heat dissipation characteristics of the individual actuator assemblies, the excitation current flowing through the electromagnetic coil 2 will fluctuate, which will adversely affect the attraction force of the armature 3. This will cause the alignment to deteriorate.
Furthermore, if the heat dissipation characteristics deteriorate, the adhesive strength of the adhesive may be reduced, and there is a fear that the electromagnetic coil 2 may fall off. Furthermore, depending on how the bobbin 21 is deformed,
The gap between the yoke 1 and the yoke 1 becomes smaller, and when the bobbin 21 is inserted into the yoke 1, the excess adhesive applied to the yoke 1 is pushed up, and the yoke 1 and bobbin 2
There is also a risk that the liquid may flow out through the gap between the yoke 1 and the armature 3 and adhere to the collision surface between the yoke 1 and the armature 3, impeding the operation of the armature 3.

[Purpose of invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, improve the bonding strength of the electromagnetic coil attached to the yoke, and maintain stable operating characteristics of an armature that repeatedly operates at high speed over a long period of time.

[Summary of the idea]

This invention focuses on the fact that the bonding strength of the electromagnetic coil attached to the yoke increases in proportion to the effective contact area between the yoke and the bobbin, and that there is a strong correlation between the gap between the yoke and the bobbin. , the shape of the bobbin has been devised. The present invention will be described below with reference to FIGS. 1 and 2, which show embodiments.

[Example of idea]

A plurality of grooves 32 extending along the direction of insertion into the yoke 1 are provided on the inner wall side surface of the bobbin 31 . The groove 32 spans the entire length of the bobbin 31 or the contact portion with the yoke 1, and has a depth of 0.05 to
It is approximately 0.1mm. When the groove 32 is deepened,
Although the amount of adhesive applied can be increased and the adhesive force can be increased, there is a problem that the thickness of the bobbin 31 also increases and heat conduction deteriorates. On the other hand, if the depth is too shallow, the amount of adhesive applied will be insufficient and the desired bonding strength will not be obtained.

When inserting the bobbin 31 into the yoke 1,
The adhesive applied to the upper surface and both side surfaces indicated by diagonal lines is filled in the groove 32, and the yoke 1 and bobbin 31 are
Adhesive leakage at the contact surface is prevented.
At least one bridge 33 is provided between both walls of the bobbin 31 on the yoke insertion side. The bridge 33 has an appropriate clearance (for example, 0.1 to 0.2 mm) between both sides of the yoke 1 and the bobbin 31 so that the adhesive applied to the yoke 1 does not flow out when the bobbin 31 is inserted into the yoke 1. It is to be ensured. That is, when the exterior part is molded with an encapsulant such as epoxy resin, the temperature reaches a high temperature of 100 to 200 degrees Celsius, but the bridge 33 prevents thermal deformation between both walls of the bobbin 31, thereby preventing both sides of the yoke and the bobbin 3 from forming.
1 is maintained within a predetermined range. As a result, the dimensions of the insertion opening for the bobbin 31 can be ensured with high accuracy.

The inner wall of the bobbin 31 has a tapered shape with a wide dimension m on the yoke insertion side and a narrow dimension n on the opposite side. As mentioned above, the side where the bobbin 31 is inserted into the yoke 1 tends to become narrower due to thermal deformation, and taking this amount of shrinkage into consideration, the clearance between the yoke 1 and the bobbin 31 after molding is adjusted to the optimum size. There is. On the other hand, the opposite side dimension n is the dimension n of yoke 1.
In other words, the clearance is made to be small. As a result, when the bobbin 31 is inserted, the adhesive applied to the yoke 1 is prevented from being pushed out from the side opposite to the insertion side. Therefore, since the adhesive does not adhere to the collision surface between the yoke 1 and the armature 3, the repetitive high-speed operation of the armature 3 is not hindered in any way, and stable operation can be maintained.

[Effect of idea]

According to the present invention, since the inner wall of the bobbin is tapered and provided with a groove, an appropriate gap can be secured between the bobbin and the yoke, and the adhesive can be uniformly filled over the entire contact surface. As a result, sufficient bonding strength can be ensured, making it possible to prevent failures such as electromagnetic coils falling off and misalignment, as well as preventing problems such as printing errors, omissions, and poor character alignment, making it possible to prevent long-term problems. This ensures stable print quality.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing one embodiment of the main part of the armature assembly of the present invention, Fig. 2 is a left side view, front view, and right side view showing the bobbin that constitutes the present invention, and Fig. 3 is a printing mechanism. FIG. 4 is a front view showing an example of a detailed configuration of the armature assembly, and FIG. 5 is a perspective view showing an electromagnetic coil section. In the figure, 1 is a yoke, 2 is an electromagnetic coil, and 3 is a yoke.
is an armature, 4 is a push rod, 5 is a printing hammer, 6 is paper, 7 is an ink ribbon, 8 is a type drum, 21, 31 are bobbins, 22 is an electric wire, 23 is a lead wire, 24 is an enclosing material, 32 is a groove, 33 is bridge.

Claims (1)

[Claims for Utility Model Registration] 1. An actuator assembly comprising an electromagnetic coil wound around a yoke via a bobbin, and an armature that is attracted to the yoke when the electromagnetic coil is excited, the actuator assembly having an armature attached to the inner wall of the bobbin. . An actuator assembly characterized in that a plurality of grooves are provided extending in the direction of insertion into the yoke, and at least one bridge is formed at an upper portion between both side walls of the bobbin to have a slight clearance from the upper surface of the yoke. 2. The actuator assembly according to claim 1, wherein the bobbin has a tapered inner diameter that is wider on the yoke insertion port side and narrower on the opposite side.