JPH0710101Y2 - Friction transmission mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a friction transmission mechanism provided on a take-up reel stand or the like of a tape recorder.

[Prior art]

Conventionally, the friction transmission mechanism provided on the take-up reel base of the tape recorder of FIG. 3 has the configuration of FIG. 5 or the configuration of FIG.

In the configuration shown in FIG. 5, the upper drive side rotating body 2 is rotatably fitted in the shaft cylinder 1a of the lower driven side rotating body 1, and the recess 1e of the upper surface 1b of the lower rotating body 1 is arranged. Toroidal Teflon sheet 9
Is bonded and fixed, and the annular felt 10 is bonded and fixed to the concave portion 2d of the lower surface 2a of the upper rotating body 2, and the upper surface 2c of the upper rotating body 2 is fixed.
The compression spring 4 was placed on the shaft cylinder 1a, the bush 5 was fitted to the shaft cylinder 1a, the bush 5 was caulked and fixed to the shaft cylinder 1a, and the Teflon sheet 10 and the felt 9 were pressed against each other.

In the configuration shown in FIG. 6, the upper drive side rotating body 2 is rotatably fitted in the shaft cylinder 1a of the lower driven rotating body 1, and a plurality of annular projections are formed on the upper surface 1b of the lower rotating body 1. The portion 1c is provided, the annular felt 10 is adhesively fixed to the concave portion 2d of the lower surface 2a of the upper rotating body 2, and the compression spring 4 is placed on the upper surface 2c of the upper rotating body 2 and fitted to the shaft cylinder 1a. At the same time, the bush 5 is caulked and fixed to the shaft cylinder 1a, and the plurality of annular convex portions 1c and the felt 10 are pressed against each other.

The upper and lower rotating bodies 1 and 2 were made of Duracon, and the felt 10 was made of 100% wool.

The friction torque characteristics of the friction transmission mechanism of the conventional example are C curve (configuration in FIG. 5) and D curve (configuration in FIG. 6) of FIG. There is a large decrease, for example, in order to maintain a torque of about 28 gcm, the initial torque must be set to 40 gcm or more, and if the initial torque is high, current consumption increases and headphones are used. The small tape recorder has a drawback that the battery is consumed in a short time.

[Purpose of device]

In view of the above-mentioned drawbacks, the present invention reduces initial torque and current consumption, and reduces torque reduction even after long-term use.
It is to propose a friction transmission mechanism that can reduce the cost by omitting the bonding step.

[Constitution of device]

The present invention relates to a friction transmission mechanism in which a rotor is pressed against a felt, and the felt is sandwiched between the rotors from both sides for pressure contact, and the material of the rotor is made different, and the surface is in sliding contact with the felt. This is because the diameters of the formed annular protrusions on both sides are different from each other.

〔Example〕

Hereinafter, the present invention will be described with reference to an illustrated embodiment. 1 and 2, in the friction transmission mechanism, the upper drive side rotary body 2 is rotatably fitted to the shaft cylinder 1a of the lower driven side rotary body 1.

A plurality of annular convex portions 1c are formed on the upper surface 1b of the lower rotating body 1, and a plurality of annular convex portions 2b having a diameter different from the diameter of the annular convex portion 1c are formed on the lower side 2a of the upper rotating body 2. An annular felt 3 is sandwiched between the annular protrusions 1c and 2b.

The compression spring 4 is placed on the upper surface 2c of the upper rotating body 2 so that the bush 5 is fitted to the shaft cylinder 1a and the shaft cylinder 1a.
The bush 5 is caulked and fixed on the
Felt 3 is pressed by 1c and 2b.

In FIG. 1, a drive pinion 6 is engaged with the upper drive side rotating body 2, and a driven gear 7 for driving a tape end detecting device or the like is engaged with the lower driven side rotating body 1. Further, when it is incorporated in the tape recorder of FIG. 3, a take-up reel stand 8 is attached to the upper portion of the driven body 1 on the lower side, as shown in FIG.

The lower rotary body 1 is made of, for example, polybutylene terephthalate resin, and the upper rotary body 2 is made of, for example, boriacetal resin. When the materials are compared in terms of heat distortion temperature, the former material of the rotating body 1 is on the high temperature side.

For felt 3, 100% wool felt or synthetic leather is used.

The friction torque characteristic of the friction transmission mechanism of the present invention is the fourth.
With the A curve (wool felt) and B curve (synthetic fiber felt) in the figure, there is little decrease in torque even after the aging time, and the initial setting torque can be made small, so the current consumption is small and the headphone is small. A tape recorder can be used for a long time.

As described above, if one of the materials of the lower rotating body 1 and the upper rotating body 2 is a high temperature material and the other is a low temperature material,
It is possible to reduce the fluctuation of the friction torque with respect to the temperature difference due to the seasonal temperature.

Further, if the felt 3 is sandwiched between the plurality of annular convex portions 1c and 2b on both sides as described above, the bonding step can be omitted, and the cost can be reduced.

In FIG. 1, the plurality of annular convex portions 1c and 2b on both sides are configured so that the ridges / valleys face each other and have different diameters, but they may be configured to face each other. The former configuration in which the peaks and valleys face each other has less wear on the convex portions.

[Effect of device]

Since the present invention is configured as described above, it is possible to reduce initial torque and current consumption, reduce torque even after long-term use, and reduce the cost by eliminating the bonding process. A friction transmission mechanism can be provided.

[Brief description of drawings]

An embodiment of the present invention is shown in the drawings, FIG. 1 is a sectional side view of a main part of a friction transmission mechanism, and FIG. 2 is a perspective view of a lower rotating body.
FIG. 3 is an exploded perspective view of a main portion of a tape recorder incorporating a friction transmission mechanism, FIG. 4 is a friction torque characteristic diagram of the friction transmission mechanism, and FIG. 5 is a sectional side view of a main portion of a conventional friction transmission mechanism. FIG. 6 is a sectional side view of a main part of another conventional friction transmission mechanism, and FIG. 7 is a friction torque characteristic diagram of the conventional friction transmission mechanism of FIG. 1, 2 ... Rotating body, 1c, 2b ... Plural annular convex portions, 3 ... Felt.

Claims (1)

[Scope of utility model registration request] 1. A friction transmission mechanism of a type in which a rotating body is pressed against a felt, wherein the felt is sandwiched between the rotating bodies from both sides to be in pressure contact, and the material of the rotating body is made different, and the surface is in sliding contact with the felt. A friction transmission mechanism characterized in that the diameters of the formed annular convex portions on both sides are made different from each other.