JPS5919960Y2 - friction transmission device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a friction transmission device that is inserted as a power transmission means between, for example, a reel shaft of a tape recorder and a motor that drives the reel shaft.

For example, in a tape recorder, a friction transmission device is used as a power transmission means between a reel shaft and a motor that drives the reel shaft, and the friction transmission device absorbs an excessive load acting on the reel shaft.

FIG. 1 shows a conventional friction transmission device used for such purposes, in which 1 is a tape recorder board, 2 is a rotary shaft whose lower end is rotatably supported by the board 1, and 3 is a rotary shaft. A reel shaft is installed at the upper end of the rotating shaft 2, 4 is a flat friction plate fixed to the middle part of the rotating shaft 2, and A is rotatable between the reel shaft 3 and the friction plate 4 of the rotating shaft 2. A driving rotary body 5 supported by the rotary shaft 2 has three arm portions extending radially, and a center portion thereof is supported between the reel shaft 3 and the driving rotary body A of the rotary shaft 2, as shown in FIG. A spring member 6 is an annular flat plate-shaped friction member inserted between the driving rotary body A and the friction plate 4, and 7 is a friction member directly connected to the motor shaft 8 and surrounding the driving rotary body A. This is a motor pulley that transmits rotational force to A.

The rotating shaft 2, the reel shaft 3 and the friction plate 4 are a driven rotating body B.
The driven rotating body B is the driving rotating body A.
is rotationally driven via the friction member 6.

That is, the spring member 5 has its center portion pressed against the lower end surface 9 of the reel shaft 3, and its outer peripheral portion (tips of each arm portion) pressed against the upper surface of the driving rotary body A, thereby moving the driving rotary body A in the direction of the friction plate 4. As a result, the lower surface of the drive rotor A and the upper surface of the friction plate 4 come into pressure contact with the friction member 6 from above and below, and the rotational force of the drive rotor A is applied to the friction member 6. It is transmitted to the friction plate 4, that is, the driven rotating body B, via the.

Therefore, when a tape reel is set on the reel shaft 3 and the tape recorder is operated, the reel shaft 3 rotates due to the rotation of the motor and the magnetic tape is wound onto the reel.
When the tape is wound up to the end, the load on the reel shaft 3 increases rapidly because the end is fixed to the reel on the feeding side, and the reel shaft 3 stops.

In other words, between the driving rotary body A and the friction member 6 or the friction plate 4
This causes slip between the reel shaft 3 and the friction member 6, and the excessive load acting on the reel shaft 3 is absorbed between the friction plate 4 and the drive rotating body A, thereby preventing tape breakage and motor burnout. .

However, the conventional friction transmission device configured as shown in FIG. 1 has the following drawbacks.

That is, the reel shaft 3 and the spring member 5 during rotation transmission
Since the frictional transmission torque between the reel shaft 3 and the spring member 5 is small (because the center part of the spring member 5 is in contact with the reel shaft 3), slipping is likely to occur in this part, but the reel shaft 3 and the spring member 5 are in direct contact with each other. Therefore, the slip between the two is not smooth, and the slip causes vibrations and uneven rotation of the driven rotating body B, and furthermore, when applied to the reel shaft drive device of a tape recorder, There was also a risk that the tape feeding speed would fluctuate.

This idea was created based on these circumstances.
The purpose of this is to eliminate vibrations and uneven rotation of the driven rotating body by adding very simple parts to the conventional device as shown in Figure 1, and when applied to the reel shaft drive device of a tape recorder, It is an object of the present invention to provide a friction transmission device that can always transport at a constant speed.

That is, the friction transmission device of the present invention, as shown as an embodiment in FIG. The rotating body B and the surface pressure contact surface 9 of this driven rotating body,
A drive rotating body A rotatably provided between 10 and 10
A rotor is interposed between the drive rotary body A and the one pressure contact surface 9, and has a center portion facing the one pressure contact surface 9, and an outer peripheral portion that urges the drive rotor A toward the other pressure contact surface B. an annular spring member 5, the one pressure contact surface 9 and the spring member 5;
and a pair of annular flat plate-shaped friction members 11 and 6 inserted between the other pressure contact surface 10 and the drive rotary body A, respectively.

In short, the friction member 11 is simply added to the conventional friction transmission member configured as shown in FIG. The upper surface of the plate 4 corresponds to the other pressure contact surface 10.

With the above configuration, the lower end surface (one pressure contact surface 9) of the reel shaft 3 and the center of the spring member 5 are not brought into direct contact with each other, and the friction member 11 is also inserted between them. Even if slip occurs between the pressure contact surface 9 and the friction member 11 or between the spring member 5 and the friction member 11 during rotation transmission, the slip does not involve vibration or noise;
This results in an extremely smooth slip.

Therefore, vibrations and rotational irregularities do not occur in the driven rotary body B, and when applied to a reel shaft drive device in a tape recorder, the tape can always be fed at a constant speed.

Furthermore, the friction member 11 in the friction transmission device of the present invention,
6 is made of the same material such as felt.

The outer diameter of one friction member 11 and the other friction member 6
The inner diameter of the

Therefore, one friction member 11 is formed by using the center portion that is left over from the other friction member 6 as shown in FIG. 4, which not only saves material but also eliminates variations in material quality. , an excellent effect can be obtained in achieving smooth rotation of the driven rotating body B.

Further, the spring member 5 is not limited to a plate spring as shown in FIG. 2, but may be a conical compression coil spring 5' as shown in FIG.

It goes without saying that the friction transmission device of the present invention can be applied to various applications other than the reel shaft drive device of a tape recorder.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing a conventional friction transmission device, Fig. 2 is a plan view of a spring member used in the same device, and Fig. 3 is a longitudinal sectional view of a friction transmission device showing an embodiment of the present invention. , FIG. 4 is a plan view illustrating the material removal of the friction member used in the device, and FIG. 5 is a perspective view showing a modification of the spring member used in the device. A... Drive rotary body, B... Followed rotary body, 5, 5'.
... Spring member, 6, 11... Friction member, 9, 10...
- Pressure contact surface.

Claims (1)

[Scope of utility model registration request] A driven rotating body that is rotatable and has a pair of pressure contact surfaces that are spaced apart from each other in the direction of the rotation axis and are substantially perpendicular to the rotation axis, and a rotatable driven rotary body that is located between the contact surfaces of the driven rotor and is rotatably provided. a driving rotary body; and a spring interposed between the driving rotary body and the one pressure contact surface, the center portion of which faces the one pressure contact surface, and the outer peripheral portion of which urges the drive rotor toward the other pressure contact surface; and a pair of annular flat plate-shaped friction members inserted between the one pressure contact surface and the spring member and between the other pressure contact surface and the drive rotating body. . A friction transmission device, wherein the pair of friction members are made of the same material, and the outer diameter of one friction member is made to match the inner diameter of the other friction member.