JPS6178110A - Hammer solenoid - Google Patents

Abstract

PURPOSE:To enhance the magnetic efficiency of the title solenoid, to accomplish a low power consuming operation and to contrive reduction in the cost of manufacture by a method wherein magnetic attraction force is utilized effectively. CONSTITUTION:When a coil 15 is demagnetized in the state wherein the amount of displacement of a plunger 12 reached maximum, the plunger 12 returns to its original position by a return spring 18, an engaging part 24 comes in contact with the second yoke 17 through the intermediary of a buffer material 29, and the plunger 12 returns to a stop position. In this hammer solenoid 11, as the attracting part 23 of the plunger 12 and the end face 13a of a fixed core 13 are opposed each other on the same axis, the receiving area of the magnetic flux can be made larger, and the magnetic efficiency is enhanced. Accordingly, large magnetic attraction force can be obtained with low power consumption, and a high speed operation can be accomplished. Besides, magnetic efficiency can be enhanced still more by forming the attracting part 23 into a conical shape and also forming the end face 13a in the shape corresponding to the attraction part 23. Also, as both yokes 16 and 17 are formed using a magnetic plate material, the title solenoid can be manufactured by performing a simple press work, and the reduction in cost of production can be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention is generally applied to a print head of a serial printer, particularly one that violently strikes the type of a daisy type type wheel. That is, the hammer solenoid 1 includes, as basic components, a movable core 2 having an intermediate stage portion 2a that is freely displaceable in the longitudinal direction, and bearings 3 and 4 that support the movable core 2.
A coil frame 5 disposed on the outer periphery of the movable iron core 2 and a coil 6 wound around the coil frame 5 are lathed into a stepped cylindrical shape, and when the coil 6 is energized, the inner circumferential step 7a is turned into the intermediate step. a first yoke 7 that attracts the portion 2a; a second coke 8 that is lathe-machined into a cylindrical shape with a flanged bottom and constitutes a magnetic circuit and a housing of the electromagnet device 1 together with the first yoke 7;
In order to return the movable core 2 to its original state after it has been displaced, it includes a coil-shaped return spring 9 whose one end abuts against the intermediate step portion 2a.

The magnetic attraction force characteristics and spring load characteristics associated with the displacement of the movable iron core 2 in this hammer solenoid 1 are as shown in FIG. The attraction force characteristics of the iron core 2 are shown respectively.

When a pulse voltage is applied to the coil 6, the movable core 2 is displaced in the direction of the arrow W, and the tip of the movable core 2 (the right end in FIG. 1), which serves as a type drive unit, drives the type of a daisy wheel, for example. (not shown), and then returns to its original state by the spring force of the return spring 9. A printing operation is performed by this series of operations.

Further, the operating state of the hammer solenoid 1 will be explained in detail based on FIG.
The suction force that attracts a overcomes the spring force of the return spring 9, and the movable iron core 2 begins to be displaced in the direction of the arrow W. As the movable iron core 2 is displaced in the direction of the arrow W, the inner peripheral stepped portion 7 described above
The gap between a and the intermediate stage portion 2a also becomes smaller, and the suction force reaches a peak value P1 in the middle of the displacement. After that, when the movable core 2 is further displaced and the magnetic flux exchanged between the first yoke 7 and the movable core 2 becomes orthogonal to the displacement direction,
The suction force rapidly decreases and intersects the line 11 indicating the spring load characteristic at point P2, and further decreases. However, the kinetic energy until reaching this intersection P2 (area AI indicated by diagonal lines in FIG. 2) allows the movable core 2 to resist the spring force of the return spring 9 and reach the displacement completion position. After reaching the displacement completion position, the movable iron core 2 returns to its original position by the spring force of the return spring 9.

In this case, the facing area between the first yoke 7 and the movable core 2, which exchanges the magnetic flux parallel to the displacement direction of the movable core 2, that is, the magnetic flux that effectively acts as a magnetic attraction force, cannot be made large. Therefore, increasing the speed of the movable core 2 (increasing the peak value P1) increases power consumption, and reducing power consumption (reducing the peak value P1) hinders the increase in speed. have. Also, both yokes 7
．． No. 8 has a cylindrical shape and must be manufactured by lathe processing or the like, which results in an increase in manufacturing costs.

[Object of the Invention] The present invention has been made in view of the above reasons, and its purpose is to improve magnetic efficiency and reduce power consumption by effectively utilizing magnetic attraction force. Moreover, it is an object of the present invention to provide a hammer solenoid that can reduce manufacturing costs.

[Disclosure of the Invention] The hammer solenoid according to the present invention is disposed so as to be freely displaceable in the longitudinal direction, and has a type drive section on one side in the longitudinal direction, a magnetic flux transfer section for the outer periphery of the other side, and a middle part on the side of the type drive section. a plunger having a suction part on a step surface and a locking part on an intermediate step surface on the side of the magnetic flux exchange part; a fixed iron core facing the suction part and having an insertion hole in the center through which the type drive part is inserted; and the plunger. a first yoke having a U-shaped cross section and having its connecting piece connected to the fixed iron core and whose side pieces are located on the outer periphery of the coil; a second yoke that is magnetically coupled to one side end of the yoke and has an insertion hole through which the magnetic flux exchange portion can be inserted; and a return spring that biases the plunger away from the fixed iron core; The plunger is characterized in that when the coil is energized, it is attracted to the fixed iron core and displaced, and when the coil is demagnetized, the locking portion abuts on the second yoke.

(Example) An example of the present invention will be described below based on FIGS. 3 to 6.

This hammer solenoid 11 consists of a coil 15, which is a basic component, and a first yoke 16, which magnetically couples a fixed iron core 13.
and magnetically coupled to the first yoke 6 and the plunger 1
a second yoke 17 provided with an insertion hole through which the other side of the outer periphery of the second yoke 17 can be inserted; and a return spring 1 for returning the plunger 12;
8.

The plunger 12 is made of a magnetic material, and has a type drive portion 21 on one side in the longitudinal direction. A magnetic flux transfer part 22 is provided for the outer periphery of the other side.
．． A suction section 23. A locking portion 24 is provided on the intermediate step surface on the side of the magnetic flux transfer portion 22 . The suction part 23 faces the fixed iron core 13 and
It is shaped like a truncated cone, tapering towards the end. Type drive unit 21
penetrates the fixed iron core 13 on the central axis of the suction part 23 and extends to one side. The magnetic flux exchange part 22 is for the outer periphery of the opposite I11 (the other side) to the fixed iron core 13, and its base becomes the locking part 24. Therefore, the outer periphery 12a between the attraction part 23 and the locking part 24 of the plunger 12 is the magnetic flux transfer part 2.
The diameter is larger than 2. Reference numeral 25 denotes an F & center member of the plunger 12, which is positioned by an E-shaped stopper 26 that is fitted into a groove 22a at the end of the magnetic flux transfer section 22. The type drive unit 21 may be provided integrally with the plunger 12, but in the embodiment, it is a separate member made of plastic.

The fixed iron core 13 is made of a magnetic material, and its end face 13a is formed in a shape corresponding to the suction part 23 of the plunger 12, facing through the magnetic air RCI, and has the type drive part 2 at its center.
1 is provided with an insertion hole 13b through which it can be inserted freely. The coil 15 is wound around a coil frame 51 consisting of a cylindrical portion 51a and flange portions 51b and 51c, which is slightly longer than the combined length of the outer periphery 12a of the plunger 12 and the fixed core 13. The inner cylindrical body 51d of the coil frame 51 has a slightly larger diameter than the outer periphery 12a of the plunger 12, so that the plunger 12 is disposed so as to be freely displaceable in the longitudinal direction. ste is a protrusion provided on the flange portions 51b and 51C for positioning the coil frame 51.

The first yoke 16 is made of a magnetic plate material, and has a connecting piece 1 that connects both opposing pieces (side pieces) 16a and both leg pieces 16a.
The fixed iron core 13 is connected to the inside of the connecting piece 16b formed in the shape of an opening at 6b, and both leg pieces 16a are located on the outer periphery of the coil 15 so as to cover it. The second yoke 17 is
The coil frame 51 is made of a magnetic plate material and is formed into a rectangular plate shape.
It is magnetically coupled to both ends 16c of the legs of the first yoke 16 for fixation, and an insertion hole 17a is provided in the center through which the magnetic flux exchange part 22 of the plunger 12 can be inserted. Therefore, the end face of the insertion hole 17a of the second yoke 17 faces the magnetic flux exchange part 22 through the magnetic gap G2, and the magnetic flux exchange part 22 in this case is the one in which the magnetic flux exchange is performed between the second yoke 17 and the magnetic flux exchange part 22. Refers to the outer periphery of the plunger 12. Further, when the plunger 12 returns, the second yoke 17 receives the locking portion 24 and determines the stopping position. 16d is fixed core 13
The connecting hole 11111 is a fitting hole for the protrusion 51e, and the connecting hole 16f is a punching hole, which are formed in the connecting piece 16b. Reference numeral 16g indicates a coupling recess for the second yoke 17 formed at one end of both legs 16c, and 17d indicates a coupling protrusion formed at the end thereof.

Therefore, the plunger 12 (suction part 23)-magnetic air gap G
1 - Fixed iron core 13 - First yoke 16 - Second yoke 1
7-Magnetic air gap G2-Plunger 12 (magnetic flux exchange part 22)
A magnetic circuit can be formed through this route.

Reference numeral 27 denotes a guide frame made of a non-magnetic material such as plastic, which is formed into a tip shape with a flange 27a at the opening edge, and a rectangular insertion hole 27c into which the tip 21a of the type drive unit 21 is inserted into the bottom 27b. is formed.

27d is a mounting hole corresponding to the screw hole 16f of the first yoke 16, and 27e is a fitting hole of the protrusion 51e of the coil frame 51 which corresponds to the fitting hole 16e and has passed through the fitting hole 27e, respectively.
7a. Reference numeral 27f denotes a ventilation hole for high-speed operation, which is formed in the bottom portion 27b so as to intersect with the rectangular insertion hole 27C.

The above-mentioned type drive unit 21 has a tip portion 21a formed into a thin flat plate shape, a base end portion 21b formed into a cylindrical shape, and an intermediate portion 21C formed into a large diameter disk shape. It is desirable that the tip portion 21a be made as thin as possible in order to accommodate the miniaturization of the daisy type type wheel.

Thus, the base end 21b of the type drive unit 21 is connected to the fixed iron core 1.
The guide frame 27 is inserted into the first through hole 13b with the screw 28 so that the coiled return spring 18 is placed on the intermediate portion 21C and the tip end 21a is inserted into the through hole 27c of the guide frame 27. Connecting piece 16 of yoke 16
Attach to b. Therefore, the return spring 18
Since the end face of the base end 21b of the type drive unit 21 comes into elastic contact with the tip of the suction part 23 of the plunger 12, the return spring 18 causes the plunger 12 to move away from the fixed core 13. The spring is biased to separate them. 29 is a buffer member of the plunger 12.

(Operation) FIG. 6 shows the magnetic attraction force characteristics and spring load characteristics associated with the displacement of the plunger 12 in the hammer solenoid 11, and the line 13 indicates the spring load characteristics of the return spring 18;
A line 14 shows the attractive force characteristics of the plunger 12 during emotional excitation, and when a pulse voltage is applied to the coil 15, the plunger 12 is displaced in the direction of the arrow W, and the type drive section 21 of the plunger 12 is activated, for example, by a daisy wheel. The printed characters (not shown) are struck hard, and then as the pulse voltage disappears, the spring force of the return spring 18 restores the original state. A printing operation is performed by this series of operations.

To further explain the operation of the hammer solenoid 11 in detail, the state shown in FIG. Stable in separated position.

When the coil 15 is excited in this state, the magnetic flux φ is transferred to the plunger 12 - magnetic gap G1 - fixed iron core 13 - first yoke 16 - second yoke 17 - magnetic gap G2 - plunger 12 (magnetic flux transfer section 22). flow through the magnetic circuit of the path. Since the magnetic flux φ flows in the magnetic gap G1 in the axial direction of the plunger 12, that is, in the displacement direction, the fixed iron core 13 acts as a magnetic attraction force that attracts the plunger 12, and on the other hand, the flow in the magnetic gap G2 (the magnetic flux exchange of the plunger 12 22 and the end surface of the insertion hole 17a of the second yoke 17) are perpendicular to the axial direction of the plunger 12, so that the magnetic attraction force for displacing the plunger 12 in the longitudinal direction is generated. does not work. This attraction force characteristic is the line 14 and the return spring 1
8, the plunger 12 begins to be displaced in the direction of arrow W.

The state shown in FIG. 5 is the state in which the amount of displacement of the plunger 12 is maximum. When the coil 15 is demagnetized in this state, the plunger 12 is returned by the spring force of the return spring 18, the locking portion 24 contacts the second yoke 17 via the buffer member 29, and returns to the stop position.

In this hammer solenoid 1, the plunger 1
Since the suction part 23 of No. 2 and the end surface 13a of the fixed iron core 13 face each other on the same axis, the opposing area of both members for transferring magnetic flux can be increased, and magnetic efficiency is increased, resulting in low power consumption. A large magnetic attraction force can be obtained and high-speed operation can be achieved. Further, by forming the suction portion 23 into a truncated cone shape and forming the end surface 13a into a shape corresponding to this, the above effect can be further enhanced. Of course, the magnetic attraction force characteristics can also be adjusted by changing the degree of inclination of the truncated cone.

The type drive unit 21 of the plunger 12 may be formed integrally with the plunger 12 to achieve the above-mentioned effect, but it may be formed of a non-magnetic material, supported by a guide frame 27, and fixed to the plunger 12 by a return spring 18. By making elastic contact with the tip of the suction portion 23, even if misalignment of the respective insertion holes that support the displacement operation member occurs, the elastic contact portion absorbs this and ensures stable displacement operation. In terms of manufacturing, costs can also be reduced by using plastic molding for the type drive part, which requires a complicated shape.

Further, since both yokes 16 and 17 are formed of a magnetic plate material, they do not require lathe processing or the like as in conventional yokes, and can be manufactured by simple press processing, thereby reducing costs. In the embodiment, the first yoke 16 is U-shaped and the second yoke 17 is square plate-shaped. The second yoke 17 may be shaped like a disk, and the point is that the first yoke 16 only needs to have a U-shaped cross section.

The hammer solenoid according to the present invention can also be applied as a solenoid that requires low power consumption and high-speed operation.

[Effects of the Invention] Since the hammer solenoid of the present invention is constructed as described above, it effectively utilizes the magnetic attraction force and achieves high magnetic efficiency (lower power consumption and lower manufacturing costs). This has the effect of reducing the

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a general example of a hammer solenoid, Fig. 2 is a magnetic attraction force and spring load characteristic diagram thereof, Figs. 3 to 6 show an embodiment of the present invention, and Fig. 3 4 is a sectional view, FIG. 4 is an exploded perspective view, FIG. 5 is a sectional view showing a state where the amount of displacement of the movable iron core is maximum, and FIG. 6 is a magnetic attraction force and spring load characteristic diagram. 11...hammer solenoid, 12-plunger, 1
3--Fixed iron core, 13a--End face of fixed iron core, 15-Coil, 16--First yoke, 17--Second yoke, 18--Return spring, 21--Plunger type Drive section, 22--Plunger magnetic flux exchange section, 23--
Suction part of plunger, 24... Engagement part of plunger, 2
7-guide frame, 51-.-coil frame. Patent applicant: Matsushita Electric Works Co., Ltd. Representative patent attorney: Toshikuro Takemitsu (two idiots)

Claims (3)

[Claims] (1) Arranged so as to be freely displaceable in the longitudinal direction, with a type drive section on one side in the longitudinal direction, a magnetic flux transfer section on the outer peripheral body on the other side, an attraction section on the intermediate step surface on the side of the type drive section, and a magnetic flux transfer section side. a plunger having a locking part in an intermediate cross section; a fixed core facing the suction part and having an insertion hole in the center through which the type drive part is inserted; a coil wound around the outer periphery of the plunger; a first yoke formed in a U-shape, the fixed iron core being coupled to the connecting piece, and the side pieces of the fixed iron core being magnetically coupled to a first yoke located on the outer periphery of the coil, and an end of one side of the first yoke; The plunger includes a second yoke provided with an insertion hole into which the magnetic flux exchange portion can be inserted, and a return spring that biases the plunger away from the fixed iron core.
The hammer solenoid is attracted to and displaced by the fixed iron core when the coil is energized, and the locking portion abuts against the second yoke when the coil is demagnetized. (2) The type driving portion of the plunger is made of a non-magnetic material, is supported by a guide frame attached to the connecting piece of the first yoke, and is supported by the return spring as the suction portion of the plunger. The hammer solenoid according to claim 1, wherein the hammer solenoid is in elastic contact with the tip. (3) The suction portion of the plunger is formed in a truncated conical shape, and the end surface of the fixed iron core facing the suction portion is formed in a shape corresponding to the suction portion of the plunger. Hammer solenoid described in section 2).