JPH0325372Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The present invention is a linear actuator used in parts that require linear motion such as vending machines and office equipment, and in particular a self-holding actuator that is small and has low collision noise. Regarding type linear actuators.

In the conventional self-holding linear actuator of this kind, as shown in the structural example of FIG. A magnetic yoke 3 is covered from the opposite side of the coil to the outside of the coil. A movable core 4 made of soft iron or the like is supported in a hollow portion of the solenoid coil 1 by a spring 5 and an arm 6. In this figure, a magnetic flux Φ _P is constantly emitted from the magnet 2. Now, when a current I flows between terminals 1a and 1b of the coil as shown by the solid arrow, magnetic flux Φ flows due to the current, and the total magnetic flux flowing to the yoke is the sum of Φ and Φ _P. As a result, the movable iron core 4 is attracted to the magnet side with a large magnetic force. At this time, even if the current is cut off, the movable iron core 4 remains attracted to the magnet 2.

Next, when a current is passed in the opposite direction between the coil terminals 1a and 1b as shown by the broken arrow,
In the yoke 3, the magnetic flux -Φ generated by the current and the magnetic flux Φ _P emitted from the magnet cancel each other out, and the magnetic force acting on the movable iron core 4 becomes almost zero. In this state, the movable iron core 4 returns to its original position by the force of the spring 5.

However, in such a conventional self-holding linear actuator, not only does the size increase due to the use of the spring 5, arm 6, etc.
When the movable iron core 4 moves left and right, the stopper 7 collides with the arm or the yoke, producing a large collision noise.

[Purpose of invention]

The purpose of the present invention is to provide a small self-holding linear actuator that eliminates the above-mentioned conventional drawbacks, reduces the number of parts, facilitates assembly, and reduces collision noise during use. It's about doing.

[Structure of the idea]

The self-holding linear actuator according to the present invention includes a non-magnetic pipe, two windings placed around both ends of the pipe, and a wire inserted and fixed into the pipe inside these windings. , two cylindrical iron cores each having a shaft hole in the center and having approximately the same length as the winding, and slidably inserted between the two iron cores in the pipe; A cylindrical permanent magnet that is magnetized in the longitudinal direction and has a shaft extending outside through a shaft hole, and an elastic disk that acts as a damper and a spacer that is joined to both end surfaces of the permanent magnet. Consisting of:

[Example of idea]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The self-holding linear actuator according to the present invention will be described in detail below using examples and drawings.

FIG. 1 is a sectional side view showing the structure of a first embodiment of the present invention. In this figure, two coils, a winding 12 and a winding 13, are provided around the outer circumference near both ends of a non-magnetic pipe 11. Inside the pipe 11 corresponding to the positions of the windings 12 and 13, there are a cylindrical iron core 14 having approximately the same length as each coil and having an axial hole in the center. 15 has been inserted. Furthermore, between the two iron cores 14 and 15, a magnet 16 is housed slidably within the pipe 11, and is magnetized in the length direction and has a non-magnetic shaft 17 inserted therein that protrudes from both ends. has been done. Plastic discs 18 are attached to both end faces of the magnet 16. Note that the winding 12 and the winding 13 are connected in series with the winding directions of the wires being reversed.

When no current flows through the winding, the magnet 16
For convenience of explanation, it is assumed that the north pole of the magnet is attracted to iron core 15. From this state, N
When a current is passed so that a pole is generated, the north pole of the magnet 16 and the north pole of the iron core 15 repel each other. On the other hand, at the same time,
Since an N pole is generated on the magnet attraction side of the iron core 14, the magnet moves toward the iron core 14 side by attracting the S pole of the magnet 16, and is attracted to the iron core 14. Next, when the direction of the current is reversed, the magnet moves toward the iron core 15 and is attracted to the iron core 15 by an operation opposite to that described above.
As described above, by changing the direction of the current, it is possible to control the magnet so that it can be moved left and right, and even when the current is turned off, the magnet can be stably held in an attracted state.

In the above embodiment, the plastic discs 18 attached to both end faces of the magnet act as a damper to reduce the collision noise when the magnet and the iron core collide, and also act as a damper to reduce the collision noise when the magnet and the iron core collide. It also plays the role of a spacer. This spacer has the function of weakening the strength of the magnetic pole generated in the iron core by the magnet and reducing the current value required for repulsion, and the appropriate thickness is selected depending on the required holding force and the current value required for repulsion. It can be done.

FIG. 2 is a side sectional view showing the structure of a second embodiment of the present invention. This example is the same as the embodiment shown in FIG. 1 except that the outer sides of the windings 12 and 13 are covered with a magnetic yoke 19. This magnetic yoke can further increase the efficiency of generating magnetic flux generated by the windings 12 and 13.

[Effect of idea]

As is clear from the above explanation, according to the present invention, the number of parts is reduced to facilitate assembly.
In addition, it is possible to reduce collision noise during use, which not only improves operational stability and mass productivity, but also has great effects in that it is suitable for use in places where noise is averse.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing the structure of the first embodiment of the present invention, Fig. 2 is a side sectional view showing the structure of the second embodiment of the invention, and Fig. 3 is a conventional self-holding type linear FIG. 3 is a side sectional view showing a structural example of an actuator. In the figure, 11 is a pipe, 12 and 13 are windings, 14 and 15 are iron cores, 16 is a magnet, 17 is a shaft, 18 is a disk, and 19 is a magnetic yoke.

Claims (1)

[Scope of utility model registration request] A non-magnetic pipe, two windings placed around the vicinity of both ends of the pipe, and the windings each having a shaft hole in its center, the windings being inserted and fixed into the pipe inside these windings. Two cylindrical iron cores having approximately the same length as the wire, and a shaft rod that is slidably inserted between the two iron cores in the pipe and extends outside through the shaft holes of the two iron cores. In addition, a self-holding linear actuator is constructed of a cylindrical permanent magnet magnetized in the length direction and an elastic disc that is bonded to both end faces of the permanent magnet and acts as a damper and spacer. Eta.