JPH0333957Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a braking device for a reel stand in a tape recorder.

(B) Prior Art Conventionally, a braking device for a reel stand of a tape recorder requires a wide range of braking torque depending on the operating mode, and various proposals have been made.

FIG. 1 is a sectional view showing a conventional braking device for a reel stand.

1 is a substrate, and 2 is a reel shaft made of a non-magnetic material, which is provided integrally with the fixed iron core 4 so as to penetrate through the fixed iron core 4 of the electromagnetic device. The electromagnetic device includes a coil 3, a fixed core 4, a case 5, a movable core 6, a coil bobbin 7, a lid 8, and the like.

A reel stand 9 is fixed to the reel shaft 2 and is engaged with a friction plate 11.

10 is a movable plate, to which a friction material 12 for braking the friction plate 11 is fixed, and a repulsion spring 13 is interposed between it and the coil bobbin 7.

Reference numeral 14 denotes a friction material, which is disposed between the friction plate 11 and the lid 8.

The operation of the movable iron core 6 of the braking device of the reel stand configured as described above uses the reel shaft 2 as a guide, so machining accuracy is required, the material of the reel shaft 2 is restricted, and the magnetic circuit is The characteristics deteriorate, and the suction characteristics of the movable iron core 6 deteriorate.

However, due to the means for fixing the reel shaft 2, it is very difficult to arrange the base plate 1 of the tape recorder and the reel shaft 2 at right angles. Further, since the reel shaft 2 must be made of a relatively long non-magnetic material, cost reduction cannot be achieved.

Furthermore, when switching from braking to non-braking, a means for returning the movable core 6 (repulsion spring 13) is required.

Due to these causes, it is difficult to construct an inexpensive and highly accurate braking device for the reel stand.

(c) Purpose The purpose of the present invention is to provide a braking device for a reel stand that is inexpensive and highly accurate.

(d) Configuration A reel shaft that rotatably supports the reel stand, a guide shaft fixed to the lower end of this reel shaft, a fixing plate fixed to the lower end of this guide shaft, and engaged with the reel stand. a rotating friction plate that rotates together with the reel stand; a braking plate that is provided below the rotating friction plate and above the fixed plate so as to be movable up and down along a guide shaft; and above the rotating friction plate that is disposed on the guide shaft. an adjustment plate that is vertically adjustable; a friction material provided on the lower surface of the adjustment plate and the upper surface of the brake plate; a movable iron core that pushes the brake plate toward the rotating friction plate; and a movable iron core that operates the movable iron core. A braking device for a reel stand, which includes a coil that causes the movable core to move, and a fixed core that is arranged concentrically with the movable core at a predetermined distance, the movable core having a protrusion formed on the upper surface of the movable core. The part fits into the opening of the fixed core and supports the movable core so that it can move up and down, and the fixed core and the movable core constitute a part of a magnetic path, and the movable core is fixed by the electromagnetic attraction force of the coil. A braking device for a reel stand, characterized in that a rotating friction plate is pushed up via a braking plate by bringing it close to an iron core side, and the rotating friction plate is sandwiched between friction materials of the adjustment plate and the braking plate to perform braking.

(E) Embodiment FIG. 2 is a cross-sectional view showing an embodiment of a braking device for a reel stand according to the present invention.

The braking device for the reel stand includes a rotating part, a braking part that brakes the rotating part, and an electromagnetic device that operates this braking part.

The rotating section includes a reel shaft 2, a reel stand 3, a guide shaft 4, a rotating friction plate 5, and the like.

Reference numeral 1 denotes a board of the tape recorder, to which a fixing plate 7, which will be described later, is fixed.

Reference numeral 2 denotes a reel shaft made of a relatively long magnetic material, and rotatably supports the reel stand 3 with a bearing 2a. The reel stand 3 has a circular shape and is provided with a plurality of projections 3b on the lower peripheral edge of the flange 3a, each of which is engaged with an opening 5a cut in the peripheral edge of a rotating friction plate 5, which will be described later. There is.

4 is a guide shaft with a male thread on the outer periphery;
The reel shaft 2 is fixed to a central opening of a fixing plate 7, which will be described later.

5 is a circular plate-shaped rotating friction plate with a hole in the center, and is disposed above the brake plate 6;
A predetermined gap is interposed between the adjustment plate and the adjustment plate, which will be described later.

The brake section is composed of a brake plate 6, an adjustment plate 8, and the like.

Reference numeral 6 denotes a brake plate having a plurality of protrusions 6a on its lower surface, and these protrusions 6a are respectively fitted into openings of the fixing plate 7 so as to be vertically movable. A plurality of friction materials 16 are fixed to predetermined locations on the upper surface of the brake plate 6.

The fixing plate 7 has an opening in the center, a plurality of openings are cut concentrically with the opening, and is fixed to a magnetic yoke 13 that serves as a case of the electromagnetic device.

Reference numeral 8 denotes an adjustment plate with a female thread in the central opening, which is screwed into the male thread of the guide shaft 4 and fixed from above with a bolt or the like, and this threaded part also prevents rotational friction with the adjustment plate 8. The gap with the plate 5 can be adjusted. A plurality of friction materials 17 are fixed to predetermined locations on the lower surface of the adjustment plate 8.

The electromagnetic device includes a movable core 9, a fixed core 10, a coil 11, a magnetic yoke 14, and the like.

The movable iron core 9 has a conical upper part and a convex shape, and has a relatively short protrusion 9 made of a non-magnetic material at the tip.
It has a. This protrusion 9a fits into a fixed iron core 10, which will be described later, so as to be able to move up and down.
The tip of the magnetic yoke 14 projects upward from the opening of the magnetic yoke 14 and comes into contact with the center of the lower side of the movable plate 15 . The upper side of this movable plate 15 is in contact with the protrusion 6a of the brake plate 6.

Reference numeral 10 denotes a circular fixed core with a hole in the center, the lower part of which is concave and concave, while the upper part is fixed to a magnetic yoke 14 and is spaced apart from the movable core 9 by a predetermined gap. It is arranged so that it passes through.

11 is a coil wound around a coil bobbin 12, and the movable iron core 9 and fixed iron core 10 are inserted into this central opening.

Reference numeral 13 denotes a magnetic yoke serving as a case of the electromagnetic device, and the fixing plate 7 is fixed to the upper peripheral edge of the magnetic yoke, and the coil 11 and coil bobbin 12 are housed inside the magnetic yoke.

14 is a circular plate-shaped magnetic yoke, and its outer peripheral edge is fixed to the magnetic yoke 13.

The operation of the braking device for the reel stand constructed as described above from a non-braking state to a braking state will be described.

The reel stand 3 is engaged with the rotary friction plate 5 and rotates freely, and then the movable iron core 9 is attracted to the fixed iron core 10 by exciting the coil 11. The protrusion 9a of the movable iron core 9 pushes the movable plate 15 upward, thereby pushing the protrusion 6a of the brake plate 6 upward and pressing the rotary friction plate 5 toward the adjustment plate 8. Thus, a braking torque is applied to the rotating friction plate 5, and the friction materials 16 and 17 of the braking plate 6 and the adjustment plate 8 also rub against the rotating friction plate 5, causing the rotating friction plate 5 to be braked. That is, braking torque is also applied to the reel stand 3 that is engaged with the rotating friction plate 5.

Since this braking torque changes depending on the attraction force of the fixed iron core 10, the braking torque of the reel stand 3 can be freely selected by controlling the voltage applied to the coil 11.

Note that if the protrusion 9a of the movable iron core 9 is made to directly push the protrusion 6a of the brake plate 6, the movable plate 15 may not be used.

(F) Effect In the present invention, since the reel shaft does not penetrate into the movable core of the electromagnetic device, there is no need to make this material non-magnetic, and only the protrusion of the movable core is made of non-magnetic material. Since this part is relatively short, it is possible to reduce costs.

Furthermore, since the reel axis is separated from the electromagnetic device, it is easy to make the reel axis perpendicular to the fixed plate, and it is easy to achieve parallelism between the board and the fixed plate, making the arrangement relatively simple.

Furthermore, since the rotating friction plate is pressed against the friction material, no return means such as a spring is required.

Since the above-mentioned effects are achieved, an inexpensive and highly accurate braking device for a reel stand can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional braking device for a reel stand, and FIG. 2 is a sectional view showing an embodiment of the braking device for a reel stand according to the present invention. 2... Reel shaft, 3... Reel stand, 4... Guide shaft, 5... Rotating friction plate, 6... Braking plate, 7...
Fixed plate, 8... Adjustment plate, 9... Movable iron core, 10...
...Fixed iron core, 16, 17...Friction material.

Claims (1)

[Scope of utility model registration request] A reel shaft that rotatably supports the reel stand, a guide shaft fixed to the lower end of the reel shaft, a fixing plate fixed to the lower end of the guide shaft, and a reel stand that engages with the reel stand. a rotating friction plate that rotates together with the rotating friction plate; a braking plate that is provided below the rotating friction plate and above the fixed plate so as to be movable up and down along a guide shaft; and above the rotating friction plate that is vertically adjustable along the guide shaft. an adjustment plate attached to the adjustment plate, a friction material provided on the lower surface of the adjustment plate and the upper surface of the brake plate, a movable iron core that pushes the brake plate toward the rotating friction plate, and a coil that operates the movable iron core; A braking device for a reel stand comprising a fixed iron core arranged concentrically with the movable iron core at a predetermined interval, wherein a protrusion is formed on the upper surface of the movable iron core, and the protrusion is connected to the fixed iron core. The fixed core and the movable core constitute a part of a magnetic path, and the electromagnetic attraction force of the coil causes the movable core to move close to the fixed core. A braking device for a reel stand, characterized in that the rotating friction plate is pushed up through the braking plate by pushing up, and the rotating friction plate is sandwiched between the friction materials of the adjustment plate and the braking plate to perform braking.