JPH073605Y2 - Plunger type electromagnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a plunger type electromagnet.

[Conventional technology]

FIG. 8 shows a typical configuration example of a tapered plunger type electromagnet. A magnetic closed circuit is constituted by the fixed iron core 1, the plunger 2 acting as a movable iron core that cooperates with the fixed iron core 1, the frame 3 also serving as the exterior, and the front frame 4 forming a container closed by the frame 3. A coil 6 wound around a coil bobbin 5 is arranged in the inner region of the frame 3 and the front frame 4. A guide tube 7 for guiding the axial movement of the plunger 2 is provided inside the coil bobbin 5 over substantially the entire length in the axial direction in a form fixed to the front frame 4 and the fixed iron core 1. . The guide tube 7 is made of a non-magnetic material such as brass or stainless steel. A remanent magnet stop 8 is adhered to the end surface of the plunger 2 in order to improve the separating operation at the time of deenergization. The figure shows a state where no current is applied to the coil 6, that is, a deenergized state. When the coil 6 is energized, that is, when the coil 6 is energized, a magnetic flux is generated in the magnetic closed circuit, and the plunger 2 is fixed. Adsorbed to the iron core 1. When the coil 6 is deenergized, the plunger 2 returns to the illustrated deenergized position by its own weight or the spring force of a return spring (not shown).

FIG. 9 shows a tapered plunger type electromagnet similar to that shown in FIG. 8, but the structure for guiding the plunger 2 is slightly different from that shown in FIG. The rear end surface portion of the frame 3 is constituted by a rear frame 9 which is a separate member, and the fixed iron core 1 is fixed to the rear frame 9.
The rear frame 9 is locked to the frame 3 by a C-shaped retaining ring 11 mounted in a hole formed at the end of the tubular frame 3. The guide of the plunger 2 is carried out on the one hand by a bearing 10 provided in the opening of the front frame 4, and on the other hand a shaft 12 mounted at the tip of the plunger 2.
Is performed by sliding in the through hole of the rear frame 9.

[Problems to be solved by the device]

In the electromagnet of FIG. 8, when a DC voltage is applied to the coil 6, a current flows, which causes a magnetic flux to flow through a magnetic path formed by the fixed iron core 1, the plunger 2, the front frame 4, and the frame 6. In that case, a variable-length space is provided between the fixed iron core 1 and the plunger 2. When applying DC voltage,
The current gradually increases from zero to the steady current value, and accordingly, the magnetic flux also increases in a substantially proportional relationship with the current. The change in the magnetic flux induces a secondary voltage in the guide cylinder 7, causing a short-circuit current to flow back to the guide cylinder 7. The secondary circuit formed by the guide cylinder 7 acts so as to prevent the current rise of the coil 6 and prolongs the response time of the plunger 2 from the deenergized state to the energized state. Further, in the electromagnet of FIG. 8, an eddy current is also generated in the fitting portion between the guide cylinder 7 and the front frame 4 due to the change of the magnetic flux, and like the above, the current rise of the coil 6 is prevented and the response time of the plunger 2 is increased. Lengthen. The above is a discussion of the case where a direct current is passed, but when an alternating current is passed through the coil 6, the short-circuit current and eddy current of the guide tube 7 described above become more prominent and cannot be used at all. Becomes

The electromagnet of FIG. 9 was proposed in order to eliminate the above inconvenience, and the guide cylinder 7 of FIG. 8 is not provided, and the space between the fixed iron core 1 and the shaft 12, and between the plunger 2 and the bearing. 10 and 10 are configured to slide while allowing magnetic flux to flow therethrough. This structure has a fixed iron core 1
In order to eliminate the runout between the shaft core of the bearing 10 and the shaft core of the bearing 10, the precision management of the fitting portions of the fixed iron core 1, the rear frame 9, the frame 3, and the front frame is complicated, and the plunger 2 and It is also quite difficult to manage the axis of the shaft 12 so that it does not bend.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a plunger type electromagnet capable of improving current rising characteristics, that is, response characteristics, with a simple and inexpensive structure.

[Means for Solving the Problems]

In order to achieve the above object, the plunger type electromagnet of the present invention is provided with a slit running in the axial direction so as to be electrically closed when viewed in the circumferential direction in a metal guide tube for guiding the axial movement of the plunger. To form a gap portion, and a gap piece made of an insulating material is inserted and fixed in the gap portion.

[Action]

By forming a gap in the metal guide cylinder that runs in the axial direction so as to be electrically opened when viewed in the circumferential direction, and inserting and fixing a gap piece made of an insulator in the gap, the magnetic flux is generated when the electromagnet is energized. Voltage does not induce in the guide tube even when changes in
Therefore, short-circuit current does not flow in the guide tube. Therefore, the current rise is not hindered when the electromagnet is energized, and the response time of the plunger can be shortened.

〔Example〕

1 and 2 show an embodiment of the essential part of the plunger type electromagnet according to the present invention. The basic structure of this embodiment is the same as that of FIG. The difference from that of FIG. 8 lies in the vicinity of the guide tube. The guide cylinder 21 in FIG. 1 (corresponding to the guide cylinder 7 in FIG. 8) is made of a non-magnetic metal material, and its characteristic is that the sliding rails run axially so as to be electrically opened when viewed in the circumferential direction. A gap 22 is formed by splitting, and a gap piece 23 made of an insulating material is inserted into this gap 22 to form a guide tube.
Tighten the entire circumference of 21 with insulating band 24. The gap piece 23 and the insulating band 24 may be formed separately or integrally.

By using the guide cylinder 21 configured as described above instead of the guide cylinder 7 of FIG. 8, when a voltage is applied to the coil 6, a secondary short-circuit current does not flow in the guide cylinder 21,
The current of the coil 6 rises quickly, and the response time of the plunger 2 can be shortened.

3 to 5 show various modifications of the gap piece.

In FIG. 3, the leg portion of the gap piece 25 having a T-shaped cross section is inserted into the gap portion 22 and is tightly bound with the insulating band 24 from above. In FIG. 4, the leg portion of the gap piece 26 having an L-shaped cross section is inserted into the gap portion 22 and is tightly bound with the insulating band 24.
Further, in FIG. 5, two gap pieces 26 having an L-shaped cross section are used, and the legs thereof are aligned back to back and inserted into the gap portion 22, and they are commonly bound by an insulating band 24.
Also in each of the embodiments described above, the same action and effect as those of the embodiments of FIGS. 1 and 2 can be obtained.

6 and 7 show an embodiment in which the guide tube and the coil bobbin are shared by a common member. That is, in this embodiment, the cylindrical guide tube 31 made of a non-magnetic metal material also serves as the tubular portion of the coil bobbin, and the guide tube
Collar parts 32 and 3 as coil bobbins at both ends of 31
3 is fixed. The brim portions 32 and 33 are materials normally used in coil bobbins, for example, Bakelite (trade name)
Made of resin such as. A gap 22 is formed in the guide cylinder 31 by a slit that electrically opens in the circumferential direction, and a gap piece 23 made of an insulating material is inserted between the gaps 32 and 33. The gap piece 23 has a guide tube 3 between the collar portions 32 and 33.
It is tightly bound by an insulating band 24 wrapped over 1. The insulating band 24 constitutes an insulating sheet for the guide cylinder 31 made of a conductive material as a coil bobbin constituted by the guide cylinder 31 and the two flange portions 32, 33, and a coil (not shown) is wound around it. According to this embodiment, the guide cylinder and the coil bobbin are shared by the common constituent members in addition to achieving the action and effect when the guide cylinder in each of the above embodiments is used, so that the parts management and the assembly process are rationalized. Can be achieved.

[Effect of device]

According to the present invention described in detail above, the following effects can be obtained.

(1) Since the current rising characteristic when a voltage is applied to the coil is improved, the response speed of the plunger, that is, the electromagnet is increased.

(2) Since the guide tube can be composed of one pipe material,
No runout or bending of the shaft core. Therefore,
There is no need for centering adjustment work, and the dimensions do not change and the plunger does not move erratically.

(3) Since the size of the gap can be adjusted by changing the width of the gap piece inserted into the gap, it is possible to use a commercially available metal pipe and a round bar for a plunger to design with a high degree of freedom. it can.

(4) The fixed iron core, the rear frame, the frame, and the fitting portion of the front frame can be easily machined.

Thus, it is possible to provide a plunger type electromagnet capable of improving the current rising characteristic with a simple and inexpensive structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an essential part of an embodiment of the present invention, and FIG.
The left half of the figure is a vertical sectional view of the plunger type electromagnet of FIG.
The right half of the figure is the front view of the plunger type electromagnet,
FIGS. 4 and 5 are cross-sectional views showing different structural examples of the main part of the present invention, and FIGS. 6 and 7 show the main part of another embodiment of the present invention. Figure 6 is VI of Figure 7
Fig. 7 is a transverse sectional view taken along the line -VI, Fig. 7 is a longitudinal sectional view taken along the line VII-VII in Fig. 6, and Figs. 8 and 9 show conventional plunger type electromagnets, respectively. Half is a front view and the right half is a vertical sectional view. 1 ... Fixed core, 2 ... Plunger, 3 ... Frame,
4 ... Front frame, 5 ... Coil bobbin, 6 ...
Coil, 9 ... Rear frame, 21,31 ... Guide tube, 22 ...
… Gap, 23,25,26 …… Gap piece, 24 …… Insulation band, 3
2,33 …… Brim part.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A metal guide tube for guiding the axial movement of a plunger is provided with a slit running in the axial direction so as to be electrically opened when viewed in the circumferential direction to form a gap, and the gap is formed. A plunger type electromagnet, characterized in that a gap piece made of an insulating material is inserted and fixed in.