JPH0650833Y2 - Pinch roller device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a pinch roller used in a magnetic recording / reproducing apparatus such as a video tape recorder for recording a signal on a tape or reproducing a signal recorded on a tape. Regarding the device.

2. Description of the Related Art A conventional pinch roller device will be described with reference to FIG. FIG. 2 is a side sectional view of a conventional pinch roller device. Second
In the figure, a cylindrical elastic body 2 made of, for example, rubber is integrally attached to the outer circumference of a cylindrical holder 1, and a ball bearing 3 is provided on the inner circumference of the cylindrical holder 1.
The outer ring 3a is sandwiched and fixed by the step portion 1a of the cylindrical holder 1 and the sleeve 4 fitted to the inner peripheral portion of the cylindrical holder 1.

On the other hand, the inner ring 3b of the ball bearing 3 fitted in the small diameter portion 5a of the support shaft 5 is fixed by the stopper 6 fitted in the small diameter portion 5a of the support shaft 5. In the ball bearing 3 of the pinch roller 7 configured as described above, a so-called rattling is provided between the support shaft 5 and the pinch roller 7 by a gap between the ball 3c and the outer ring 3a and between the ball 3c and the inner ring 3b. Occurs, and this is the amount of automatic alignment. Therefore, when the pinch roller 7 is pressed against the capstan with a predetermined force in order to transfer the tape by the cooperation of the pinch roller 7 and the capstan (not shown), the pinch roller 7 is pressed against the capstan for some reason. Even if the support shaft 5 is in a non-parallel state, if the self-aligning amount is large, the pinch roller 7 is uniformly pressed along the inclination of the capstan by the self-aligning action, so that the tape runs well. Can be realized.

However, the conventional pinch roller 7 has a large number of parts, its assembly is complicated, and the ball bearing 3 that requires high dimensional accuracy for the ball is used, resulting in a very high cost. Was becoming.

Further, in order to stabilize the running of the tape, automatic alignment is performed by utilizing the gap between the balls 3c of the ball bearing 3 and the ball raceways of the inner ring 3b and the outer ring 3a, so the amount of automatic alignment is small. Therefore, when the inclination of the capstan and the pinch roller support shaft 5 is very large, there is a problem that the self-aligning action does not function and the running of the tape becomes unstable.

Further, in the recording / reproducing apparatus configured to relatively insert and mount the pinch roller 7 in the space of the cutout opening provided in the tape cassette around which the tape is wound, the cutout opening is limited. Insert the pinch roller 7 into the space,
In order to dispose the pinch roller 7, it has been desired to reduce the diameter of the pinch roller 7, but there are the following problems.

In order to reduce the diameter of the conventional pinch roller 7 upstream, it is conceivable to first reduce the thickness of the cylindrical elastic body 2 in the radial direction. However, as the thickness of the cylindrical elastic body 2 becomes smaller, the pinch roller 7 is pressed against the capstan by sandwiching the tape, and when the tape is transferred at a constant speed, the cylindrical elastic body 2 becomes more uniform along the capstan. In addition, there is a problem in that the tape is less likely to be elastically deformed and the force of driving the tape of the pinch roller 7 is significantly reduced.

Further, as the thickness of the cylindrical elastic body 2 becomes thinner, uneven hardness caused by a weld portion during molding of the cylindrical elastic body 2 may cause wow and flutter during tape transfer.

As a second method for reducing the diameter of the conventional pinch roller 7, it is conceivable to reduce the diameter of the ball bearing 3. However, since each component of the ball bearing 3 becomes small, it is not suitable for mass production, and the cost of the ball bearing 3 becomes high.

In view of the above problems, the present invention can easily reduce the diameter of the pinch roller without reducing the thickness of the cylindrical elastic body, has a large self-aligning amount, and does not use a ball bearing. The present invention provides a pinch roller device which has less cost and is excellent in economic efficiency.

Means for Solving the Problems In order to solve the above-mentioned problems, a pinch roller device of the present invention comprises a cylindrical support shaft having a concave spherical groove on the outer peripheral surface and a concave spherical groove of the support shaft on the inner peripheral surface. A cylindrical cylindrical elastic member attached to the outer peripheral surface of the holding member, and a cylindrical elastic member attached to the outer peripheral surface of the holding member. It is configured to be integrally attached to the holding member by molding.

Effect The present invention, due to the configuration described above, can increase the range of automatic alignment even if the support shafts of the capstan and the pinch roller are relatively large and tilted, so that stable tape transfer can be realized and the pinch roller can be used. Since the support shaft of the roller is integrally attached to the holding member of the pinch roller by insert molding, it is possible to provide an inexpensive pinch roller device with a reduced number of parts and a reduced diameter.

EXAMPLE A pinch roller device of the present invention will be described with reference to FIG.

FIG. 1 is a side sectional view of an embodiment of the pinch roller device. In FIG. 1, the columnar support shaft 9 of the pinch roller 8 has a concave spherical groove 10 on its outer peripheral surface. The concave spherical groove 10 is provided at an axial position having substantially the same height as the axial center of a tape (not shown) transported by the cooperation of the pinch roller 8 and a capstan (not shown). Has been. The support shaft 9 is made of a metal material such as stainless steel, and the concave spherical groove 10 is formed by cutting or the like. Alternatively, the support shaft 9 may be formed of a hard material made of ceramic and having good wear resistance. The cylindrical holding member 11 having a convex spherical bulging portion 11a fitted on the concave spherical groove 10 of the support shaft 8 with a predetermined gap and slidably abutting on the inner peripheral surface is made of resin. There is a cylindrical elastic body made of rubber etc. on its outer peripheral surface.
12 is stuck. The holding member 11 is formed of, for example, a thermoplastic resin such as polyacetal, polyamide, or polyethylene, or an oil-impregnated plastic impregnated with the lubricating oil of the resin material, or graphite or disulfide of the resin material. It is made of a composite resin material mixed with a solid lubricant such as molybdenum or tetrafluoroethylene.

Now, the support shaft 9 is integrally attached to the resin holding member 11 by insert molding using, for example, an injection molding method. Therefore, the convex spherical bulging portion 11a of the holding member 11 is made of the resin material melted and injected into the molding die of the holding member 11,
Since it is formed by flowing the support shaft 9 fixed in the forming metal along the shape of the concave spherical groove 10, it is not necessary to provide the forming die with a shape for forming the convex spherical bulging portion 11a. However, the structure of the molding die can be made very simple. Further, the gap between the concave spherical groove 10 of the support shaft 9 and the convex spherical bulge portion 11a of the holding member 11 for obtaining the self-aligning action is equal to the metal support shaft 9 during insert molding of the holding member 11. It is made by utilizing the difference in the coefficient of thermal expansion of the resin holding member 11. That is, the molten resin material having a high coefficient of thermal expansion injected into the molding die is cooled and contracted, so that a gap for performing the self-aligning action is formed between the concave spherical groove 10 of the support shaft 9. It occurs in. As described above, since the spindle 9 and the holding member 11 can be integrally manufactured by insert molding very easily without using a molding die having a complicated shape, an inexpensive pinch roller device 8 having high mass productivity can be provided. Can be provided. Further, unlike the conventional pinch roller 7, it is possible to provide a pinch roller device having a very small number of parts and excellent assemblability without using a ball bearing.

The radial dimension of the pinch roller 8 configured as described above is the same as that of the conventional pinch roller 7 using a ball bearing.
In comparison with at least the inner ring 3b of the ball bearing 3,
Since the outer ring 3a can be made smaller by the amount that is unnecessary, the pinch roller 8 can be made smaller in diameter without making the thickness of the cylindrical elastic body 12 thinner.

When the pinch roller 8 configured as described above is pressed against a capstan (not shown) with the tape sandwiched, the rotation of the capstan is transmitted to the pinch roller 8. As a result, the convex spherical bulging portion 11a of the holding member 11 slides and rotates around the concave spherical groove 10 of the support shaft 9, and the pinch roller 8 rotates integrally with the cylindrical elastic body 12 and the holding member 11. . At this time, even if the capstan and the support shaft 9 of the pinch roller 8 are not parallel to each other, the concave spherical groove 10 of the support shaft 9 and the convex spherical protruding portion 11a of the holding member 11 are brought into contact with each other by the rolling contact. The parallelism between the capstan and the pinch roller 8 is automatically adjusted.

As described above, according to the present invention, the cylindrical support shaft having the concave spherical groove on the outer peripheral surface and the concave spherical groove of the support shaft fitted on the inner peripheral surface are slidably abutted. A resin-made cylindrical holding member having a convex spherical bulge portion and a cylindrical elastic body attached to the outer peripheral surface of the holding member, wherein the support shaft is integrally formed with the holding member by insert molding. Since it is attached, compared to the conventional pinch roller that uses a ball bearing, an expensive ball bearing is not used, so the number of parts is small, cost can be reduced, and a pinch roller device that is easy to assemble is used. Can be provided. In addition, the gap between the concave spherical groove of the support shaft and the convex spherical bulge of the holding member allows the control range of the self-aligning action to be set wider, and the support shafts of the capstan and pinch roller are not parallel. Even in this case, stable tape transfer can be realized, and the diameter of the pinch roller can be easily reduced without reducing the thickness dimension of the cylindrical elastic body.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the pinch roller device of the present invention, and FIG. 2 is a side sectional view of a conventional pinch roller device. 9 ... Support shaft, 10 ... Concave spherical groove, 11 ... Holding member, 11a
...... Convex spherical bulge, 12 ...... Cylindrical elastic body.

Claims (1)

[Scope of utility model registration request] 1. A cylindrical support shaft having a concave spherical groove on its outer peripheral surface, and a convex spherical bulging portion fitted on the inner peripheral surface of the concave spherical groove of the support shaft so as to slidably abut. And a cylindrical elastic body attached to the outer peripheral surface of the holding member, wherein the support shaft is integrally attached to the holding member by insert molding. Characteristic pinch roller device.