JPH0140348Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electromagnetic brake device used in a rotating device, and can be used in a tape recorder or the like.

(Prior Art) For example, various rotating devices are used in tape recorders. The reel stand device is one such device, in which an electromagnetic brake device is built into the reel stand device or a relay rotating body that transmits driving force to the reel stand in order to apply appropriate back tension to the tape during transportation. There may be cases where One of these is described in the specification and drawings of Utility Application No. 140272/1987 filed by the present applicant. Such an electromagnetic brake device is incorporated not only in a rotating device in a tape recorder but also in various types of rotating devices.

(Problems to be solved by the invention) A conventional electromagnetic brake device consists of many components. For example, there is a mounting plate to support a fixed iron core, a coil is placed on top of this, insulating paper, a case forming a yoke, felt as a friction material, a friction plate, a felt as a friction material,
It is designed to have a stack of suction plates, etc. that are attracted by a fixed iron core. Therefore, the configuration is complicated,
There were also limits to the ability to respond to demands for miniaturization.

An object of the present invention is to provide an electromagnetic brake device whose configuration can be simplified and which can also be downsized.

(Means for solving the problem) The electromagnetic brake device of the present invention includes a rotating body that rotates in response to driving force, a friction plate that rotates integrally with the rotating body, and a friction plate that moves in the axial direction of the rotating body. a fixed iron core that attracts the suction plate and brings the suction plate into pressure contact with the friction plate via a friction material, a coil that excites the fixed iron core, and this coil and the friction plate. a friction member provided between the friction member and the friction member for applying a braking force to the friction plate;
a support plate that supports the coil, the friction plate and the support plate are made of a magnetic material, and the friction plate or the support plate is bent toward the support plate or the friction plate to create an electromagnetic magnet that includes the coil. It is characterized by forming a magnetic path.

(Function) The magnetic flux generated by excitation of the coil passes through a magnetic path formed by a fixed iron core made of a magnetic material, a friction plate, a support plate, or a bent portion of the friction plate and the support plate.
When the coil is energized, the fixed iron core attracts the suction plate, the suction plate is pressed against the friction plate through the friction material, the friction plate is pressed against the friction member, and a braking force is applied to the friction plate. . Since the rotating body is provided integrally with the friction plate in the rotational direction, the braking force acts as a braking force on the rotating body.

(Embodiment) In FIG. 1, a reel shaft 1 rotatably supports a reel stand 2, and is entirely made of a magnetic material such as iron. A fixed iron core 3 is integrally formed at the lower end of the reel shaft 1. As shown in FIG. 2, the small diameter portion 1a at the lower end of the reel shaft 1 and lower than the fixed core 3 is inserted into a hole 4c provided in the center of the mounting plate 4, and is crimped. As a result, the reel shaft 1 is fixed to the mounting plate 4. The fixed iron core 3 has a small diameter portion 3a.
and a large diameter portion 3b that continues below this small diameter portion 3a.
A flat knurling is formed on the outer periphery of this large diameter portion 3b. Small diameter portion 3a of fixed iron core 3
A washer 16 is fitted around the outer periphery of the washer 16, and a collar 5 made of magnetic material such as iron is placed on top of the washer 16.
is fitted. These washers 16 and collars 5 rest on the stepped portion between the small diameter portion 3a and the large diameter portion 3b of the fixed iron core 3. A molded suction plate attachment collar 6 is press-fitted into the large diameter portion 3b of the fixed core 3 and fixed thereto.

The mounting plate 4 is made of a magnetic material such as a steel plate, and as shown in FIG. It has a plurality of bent parts 4b. In the mounting plate 4, a coil 9 constituting an electromagnet is housed via an insulating paper 8 in a space surrounded by the bent portion 4b. coil 9
On top is a ring-shaped felt 1 as a friction member.
0 is fixed by adhesive. A friction plate 11 is placed on the felt 10. Friction plate 11
is made of a magnetic material such as an iron plate, and has a plurality of protrusions 11a formed on its outer peripheral edge. These protrusions 11
The friction plate 11 can rotate integrally with the reel stand 2 by engaging the recess 2 a provided on the inner periphery of the reel stand 2 .
The friction plate 11 is designed to be able to move to some extent in the direction of the reel axis 1 relative to the reel stand 2.

A suction plate 13 made of a magnetic material is arranged above the friction plate 11. The suction plate 13 is connected to the reel shaft 1
It is provided so as to be movable in the direction, and is biased upward by a coil spring 12 interposed between the mounting collar 6 and the mounting collar 6. The suction plate 13 has a pair of holes 13a,
This hole 13a is penetrated by a pair of claw portions 6a that are integrally formed so as to project upward from the mounting collar 6, and when the claw portions 6a engage, the spring 12 is attached. Attraction board 1 by force
3 is prevented from coming off. Said washers 16
is interposed for adjusting the gap between the collar 5 and the suction plate 13.

A ring-shaped felt 14 as a friction material is bonded to the lower surface of the suction plate 13.
4 faces the friction plate 11 with a predetermined gap therebetween. The inner diameter of the felt 14 is formed to match the outer diameter of the felt 10, so the two felts 14, 10 can be made by double punching the material along concentric circles, This makes it possible to reduce material costs.

The reel stand 2 is a rotating body that rotates by receiving a driving force through an idler (not shown) or the like. Further, the diameter of the lower part of the reel stand 2 is gradually increased, and each of the above-mentioned components is located within the space formed by the lower half of the reel stand 2.

The bent portion 4b of the support plate 4 extends toward the friction plate 11, and the magnetic flux generated by excitation of the coil 9 is transmitted to the fixed core 3 made of magnetic material, the collar 5, the friction plate 11, and the support plate 11. It passes through a magnetic path formed by the bent portion 4b of the plate 4 and the support plate 4.

Now, if we energize coil 9 and energize it,
The magnetic flux generated by the coil 9 passes through the above magnetic path. When the fixed iron core 3 and the collar 5 are magnetized by this magnetic flux, the suction plate 13 is attracted toward the collar 5, and the suction plate 13 is brought into pressure contact with the friction plate 11 via the felt 14. This pressing force brings the friction plate 11 into pressure contact with the felt 10, and a frictional force is generated between the friction plate 11 and the felt 10. This frictional force becomes a braking force against the rotation of the friction plate 11. Since the friction plate 11 is substantially integral with the reel stand 2 in the rotational direction, the above braking force acts as a braking force on the reel stand 2. thus,
Appropriate back tension can be applied to the tape by applying a brake to the reel stand on the tape supply side while the tape is being transported. The braking force can be controlled by the voltage applied to the coil 9.

In this way, according to the above embodiment, since the felt 10 is placed directly on the coil 9 and the friction plate 11 is placed thereon, the structure can be simplified, and the felt 10 and the coil 9 Since there is no need to place an insulating paper between the coil and the coil, the number of coil windings can be increased. Furthermore, by bending a part of the mounting plate 4 to form a part of the magnetic path, the mounting plate 4 can also serve as a case for the coil, reducing the number of parts and simplifying assembly. Yes, it can also reduce costs.

Next, the embodiment shown in FIG. 3 will be described. Third
In the figure, 20 is a reel shaft, 21 is a reel stand, 22 is a fixed core, 23 is a movable core, 24 is a suction plate, 25 is a suction plate mounting collar, 26 is a coil,
27 is a support plate, 28 is a friction plate, 29 is a coil spring, 10 is a felt as a friction member, and 14 is a felt as a friction material. The difference between this embodiment and the embodiments shown in FIGS. 1 and 2 is that the movable iron core 23 is provided so that a part thereof overlaps with a part of the suction plate 24, and the movable iron core 23 is movable by the claw part 25a of the mounting collar 25. It prevents the iron core 23 and the suction plate 24 from coming off, and the movable iron core 23 is attached to the conical surface 2 of the fixed iron core 22.
2a, the collar 5 in the above embodiment
In addition, a plurality of bent portions 28a are formed on the outer periphery of the friction plate 28 toward the support plate 27, and one of the magnetic paths of the electromagnet including the coil 26 is formed at the bent portions 28a. Accordingly, the supporting plate 27 is formed into a simple flat plate shape. The suction plate 24 and the movable iron core 23 are urged upward by a spring 29, and the felt 14 is bonded to the lower surface of the suction plate 24 so as to face the friction plate 28, and the felt 14 is bonded on the coil 26.
0 is directly adhered, and a friction plate 28 is placed on top of the felt 10. Fixed iron core 22, movable iron core 2
3. Both the support plate 27 and the friction plate 28 are made of magnetic material such as iron.

In this embodiment, the bent portion 28a of the friction plate 28 is
constitutes a part of the path of the magnetic flux generated by the excitation of the coil 26. When the coil 26 is excited, the movable iron core 23 is attracted toward the fixed iron core 22, and the suction plate 24 is moved together with the movable iron core 23 toward the friction plate 28. Similarly, the brake is applied to the reel stand 21.

In the embodiments shown in FIGS. 1 and 2, the support plate side is bent toward the friction plate side, and in the embodiment shown in FIG. 3, the friction plate side is bent toward the support plate side, thereby forming part of the magnetic path. However, both the friction plate and the support plate may be bent so as to face each other.

In the embodiment shown in FIG. 4, the friction plate 30 itself is molded with resin, and an iron plate 31 is integrated with the resin friction plate 30.
By insert-molding a part of the iron plate 31 toward the support plate 27, the iron plate 31 forms part of the magnetic path. Therefore, the support plate 27 may have a simple flat plate shape. 6 is the suction plate mounting collar, 9 is the coil,
12 is a spring, 13 is a suction plate, and 10 and 14 are felts, and these components are the same as those in the embodiment shown in FIGS. 1 and 2.

The embodiment shown in FIG. 4 also operates in the same manner as the previous embodiments, but according to the embodiment shown in FIG. It has the advantage of stabilizing the friction torque when pressed.

The brake device of the present invention can be widely used not only as a reel stand device for a tape recorder but also as a brake device for rotating bodies.

In addition, when a movable core is used as in the embodiment shown in FIG. 3, the movable core may be integrally provided to the suction plate by press-fitting, caulking, or the like. In that case, in order to adjust the gap between the movable core and the fixed core, a gap adjustment washer is interposed between the movable core and the suction plate, or the press fit or caulking position of the movable core to the suction plate is adjusted. You may also do so.

In each embodiment, felt 10 is used as a friction member.
Both are bonded directly onto the coil, but if necessary, insulating paper or a coil protection material may be interposed between the felt 10 and the coil.

(Effect of the invention) According to the invention, the friction plate that rotates integrally with the rotating body and the support plate that supports the coil are made of magnetic material, and the friction plate or the support plate is replaced with the support plate or the friction plate. Since the magnetic path of the electromagnet is formed by bending the support plate toward This makes it possible to simplify assembly work and reduce costs. Also, since the friction member is placed on top of the coil, this friction member isolates the coil from other parts, so there is no need to intentionally place special insulating paper or protective material on top of the coil. Therefore, the number of coil windings can be increased accordingly. Furthermore, since it is possible to eliminate the need for a case, insulating paper, protective material, etc. as described above, it is also possible to downsize the electromagnetic brake device.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the present invention;
Fig. 2 is an exploded perspective view of the same embodiment, Fig. 3 is a side sectional view showing another embodiment of the invention, and Fig. 4 is a side sectional view showing the main parts of yet another embodiment of the invention. be. 2, 21... Reel stand as a rotating body, 3, 22
...Fixed iron core, 4,27...Support plate, 9,26...Coil, 10...Felt as friction member, 11,2
8, 30...Friction plate, 13, 24...Suction plate, 14...
Felt as a friction plate.

Claims (1)

[Claims for Utility Model Registration] A rotating body that rotates in response to a driving force; a friction plate that rotates integrally with the rotating body; a suction plate supported movably in the axial direction of the rotating body; a fixed iron core that attracts a suction plate and presses the suction plate against the friction plate through a friction material; a coil that excites the fixed iron core; and a coil that is provided between the coil and the friction plate, the friction plate a friction member for applying a braking force to the coil; and a support plate for supporting the coil; the friction plate and the support plate are made of a magnetic material; An electromagnetic brake device formed by bending the coil toward the side to form a magnetic path for an electromagnet including the above-mentioned coil.