JPS61120366A - Pinch roller device - Google Patents

Abstract

PURPOSE:To pinch roller into contact with a capstan shaft stably with uniform press-contacting force by simple structure unless the capstan shaft is parallel to a pinch roller shaft by making the diameter of the projection or recess part of the 2nd cylindrical member a little bit larger than the diameter of the recess or projection part of the 1st cylindrical member. CONSTITUTION:A projection part 4 having a spherical tip part is formed engaging the recess part 3 of the 1st cylindrical member to the overall inner periphery of the axial center part of the 2nd cylindrical member 7 which has an elastic ring 6 made of rubber, etc., annularly. The radius of curvature of the projection part 4 is made a little bit smaller than the radius of curvature of the recess part 3 and the diameter D of the projection part 4 is made a little bit larger than the diameter (d) of the recess part 3, so the projection part 4 and recess part 3 never disengage from each other and the axial center of the 1st cylindrical member 2 and the axial center of the 2nd cylindrical member 7 slant so as to cross each other. Further, the elastic ring 6 is supported by the rigidity of the 2nd cylindrical member 7, so the elastic modulus is nearly uniform at any point on the outer periphery and a magnetic tape is pressed against the capstan shaft 5 with uniform pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pinch roller device used in magnetic tape devices such as tape recorders and VTRs.

As is well known in the prior art, in a magnetic tape device, a pinch roller presses a magnetic tape against a cabstan, and the cooperative action of the two allows the magnetic tape to be transported at a predetermined speed. Conventional devices of this type generally have the pinch roller bearing section non-eccentrically supported on the pinch roller shaft.Ninth, if the capstan shaft and the pinch roller shaft are not parallel, the outer peripheral surface of the pinch roller will This will cause the tape to not be evenly pressed onto the stand shaft and cause tape running to deteriorate.)9.

For this reason, for example, Jitko No. 40-14430,
-192414. Jitko No. 43-23381, Jitko No. 4
No. 8-36656,! Various types of intransitive stone-carved pinch roller devices have been devised, as seen in J Publication No. 49-4882, etc., but all of them have a structure that is almost the same as the intransitive 6-type bearing structure conventionally used in general machinery and equipment. It is complicated and uses ball bearings, etc., which makes it expensive, and it is not suitable for mass production.

Utility Model Publication No. 48-24245 and Special Publication No. 47-3640
Publication No. 2 discloses a ninth means for solving the nine problems, which will be described later. Practical implementation was difficult due to remaining problems. FIG. 2 is an explanatory diagram of the state of use of the device disclosed in Japanese Utility Model Publication No. 48-24245. Pinch roller shaft 111C is loosely fitted so that it can rotate freely f? :, 5III sex ring 12
An annular concave pinch 1 is formed concentrically with the pinch roller shaft 11 on the upper and lower surfaces of the
3 so that the outer ring portion 14 can be easily bent, so even if the capstan shaft 16 and the pinch roller shaft 11 are not parallel, the outer ring portion 14 can follow the capstan shaft 15 as shown. This means that there is even contact.

FIG. 3 is a cross-sectional view of the pinch row 91 structure of the following device disclosed in Japanese Patent Publication No. 47-38402. In place of the conventional rubber roller, the outer ring portion 16f is made thin enough to be bendable, is connected to the central hub portion 17 by a disk portion 18, and has a one-piece structure made of nine plastic materials. Since the outer ring portion 16 is flexible, the outer ring portion 16 follows the capstan axis and makes uniform contact even if the capstan axis and the pinch roller axis are not parallel.

Problems to be Solved by the Invention However, in the former structure,
As stated in Section 2, Line 18 of the main text of Publication No. 45, problems such as eccentricity of the pinch roller cannot be solved. That is, since the pinch roller is a one-piece structure made of an elastic material such as rubber, the bottom is easily bent in the diameter direction, and when the pinch roller is pressed against the capstan shaft, the pinch roller is crushed and loses its circular shape. On the other hand, there is a contradiction that if the groove bottom is made sufficiently strong, the desired bending due to the groove bottom cannot be obtained. There is also the problem that even if the outer periphery is polished to improve the roundness, the vicinity of the end face is warped and cannot be processed. Furthermore, since the effective elastic modulus of the pinch roller is naturally different between the part with the groove bottom and the part without it, there is a fundamental problem that the magnetic tape cannot be pressed onto the capstan shaft with a uniform force.

Also in the device described in Japanese Patent Publication No. 4γ-36402, as stated in Section 4, lines 8 to 11, the disk portion 1B provides strong support in the radial direction; Naturally, the effective elastic modulus of the pinch row 2 is different between the portion where the plate portion 1B is present and the portion where the plate portion 1B is not present, and the magnetic tape cannot be pressed onto the capstan shaft with a uniform force. Furthermore, since the structure is such that the magnetic tape is crimped onto the capstan shaft only by bending the outer ring portion 1e, variations in the thickness of the outer ring portion 16 directly result in variations in pressure force, making it impossible to obtain stable specific pressure bonding force. There are also problems. In view of the nine problems mentioned above, the present invention provides a pinch roller device that has a simple structure and allows a pinch roller to stably contact a capstan shaft with uniform pressing force even if the capstan shaft and the pinch roller shaft are not parallel. It is something to do.

Means for Solving the Problems In order to solve the above-mentioned problems, the pinch roller device of the present invention has an elastic ring coaxially on the pinch roller shaft and the outer peripheral surface of the pinch roller, and has an elastic ring approximately in the axial direction. Is there an engagement relationship with the recess (or protrusion) of the first cylindrical member on the inner periphery of the central portion? and a second cylindrical member having a convex portion (or concave portion), the diameter of the convex portion (or concave portion) of the second cylindrical member being smaller than the diameter of the concave portion (or convex portion) of the first cylindrical member. The fx configuration is such that it is slightly larger.

Operation The present invention has the above-mentioned structure 7'c, which absorbs the non-parallelism between the pinch roller shaft and the capstan shaft by the self-centering action of the recesses and projections of the first and second cylindrical members, and always maintains elasticity. Since the ring is in uniform contact with the capstan shaft, and is fitted concentrically with the second cylindrical member, and is supported by the rigidity of the second cylindrical member, the elastic modulus of the elastic ring is is the same at every point on the outer periphery, and a uniform pressure bonding force can be obtained.

Practical Example A pinch roller device of a practical hakama according to the present invention will be described below with reference to the drawings.

The first factor is a cross-sectional view of a pinch a-lar device in an elliptical example of the present invention.

In Fig. 1, once the pinch roller shaft 1 is rotatably and loosely fitted, the cylindrical member 2 has a cross-sectional shape that spans the entire outer periphery of the approximately central part; be. In this example, in order to facilitate assembly, the first cylindrical member 2 is made into a split type, and the lower part of the recess 3 is formed in the lower part, and the upper part of the recess 3 is formed in the upper part. As shown in the figure, when the two are combined, a recess 3 is formed. The second cylindrical member 7 coaxially has an elastic ring 6 made of rubber or the like, and is engaged with the recess 3 of the first cylindrical member over the entire inner periphery of the axially central portion; The tip portion forms a spherical convex portion 4. The diameter of the curvature of the convex portion 40 is slightly smaller than the radius of curvature of the concave portion 3, and the diameter of the convex portion 4 is slightly larger than the diameter d of the concave portion 3, so that the convex portion 4 and the concave portion 3 are not engaged. In such a way that it does not come off in the mated state and can be tilted so that the axis of the first cylindrical member 2 and the axis of the second cylindrical member 7 intersect as shown in FIG.
It has become. The first cylindrical member 2 and the second cylindrical member 7 are made of polyacetal resin or nylon resin.

If fluorine resin or the like is used, the friction between the two can be reduced.

As described above, according to this actual winding example, the pinch roller shaft, the first cylindrical member which is coaxial with the pinch roller shaft and has a concave portion (or convex portion) 1fr on the outer circumference approximately at the center in the axial direction, and the outer circumferential a concave portion (or convex portion) of the first cylindrical member having an elastic ring coaxially on the surface and on the inner periphery of the substantially central portion in the axial direction;
Convex portion (or concave portion) f that forms an engaging relationship with: the second
cylindrical member, and the diameter of the convex part (or convex part) of the second cylindrical member is larger than the diameter of the concave part (or convex part) of the first cylindrical member.
The diameter of the recess (or concave part) has been changed to be a hole, so
Even if the capstan shaft 6 and the pinch roller shaft 1 are non-parallel, the self-aligning effect obtained by the engagement relationship between the recess 3 of the first cylindrical member 2 and the protrusion 4 of the second cylindrical member A Therefore, the elastic ring 6 can uniformly contact the capstan shaft 6.

(9) Since the elastic ring e is supported by the rigidity of the second cylindrical member 7, the elastic coefficient is almost uniform at every point on the outer circumference, and the magnetic tape can be pressed onto the capstan shaft 5 with uniform force. I can do it.

In addition, in the actual winding example, the first cylindrical member 2t is loosely fitted directly to the pinch roller shaft 1, but it is also possible to loosely fit it through various bearing materials (or to fix it instead of loosely fitting it). ). Moreover, the first cylindrical member 2° and the second cylindrical member 7
It is obvious that the material is not limited to those mentioned above. Furthermore, it is also clear that similar effects can be obtained by forming a convex portion on the first cylindrical member. Furthermore, it is clear that the same effect cannot be obtained even if the first cylindrical member is formed as a single body instead of being divided into two parts. Further, the shapes of the convex portions and concave portions are not limited to those shown in the drawings. Further, the convex portions and the concave portions may be formed alternately like gears so that the gear of the first cylindrical member and the gear of the second cylindrical member engage with each other.

Effects of the Invention As described above, the present invention includes a pinch roller shaft, a first cylindrical member that is coaxial with the pinch roller shaft and has a concave portion (or convex portion) over the entire outer circumference of the approximately central portion in the axial direction; A convex portion having an elastic ring coaxially on the outer circumferential surface and engaging with the concave portion (or convex portion) of the first cylindrical member over the entire inner circumference approximately at the center in the axial direction; or recess) 1r
, and a second cylindrical member having a hole, the diameter of the convex part (or concave part) of the second cylindrical member being slightly smaller than the diameter of the concave part (or convex part) of the first cylindrical member. By doing so, even if the capstan shaft and the pinch roller shaft are not parallel, the elastic ring is held in place by the self-centering effect caused by the concave portion of the first cylindrical member and the convex portion of the second cylindrical member. Evenly touch the stun shaft.

However, since the elastic ring is coaxially supported by the second cylindrical member, which has relatively high rigidity, it has approximately the same elastic modulus at every point on the outer circumference, and a uniform tape pressing force can be obtained. . Furthermore, since the second cylindrical part supports the material and can be combined with the first cylindrical member after polishing the outer circumferential surface of the elastic ring, the pinch roller device with high roundness accuracy can be easily constructed. Obtained in structure.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a pinch roller device according to an embodiment of the present invention, and FIGS. 2 and 3 are @ side views of conventional pinch roller devices, respectively. 2...First cylindrical member, 3...Recessed portion,
4...Protrusion, e...Elastic ring, 7...
...Second cylindrical member.

Claims (1)

[Claims] a pinch roller shaft; a first cylindrical member coaxial with the pinch roller shaft and having a concave or convex portion on the outer periphery at approximately the center in the axial direction; a second cylindrical member having a protrusion or a recess on the inner periphery of a substantially central portion thereof that engages with the recess or protrusion of the first cylindrical member; A pinch roller device characterized in that the diameter of the convex portion or the concave portion of the second cylindrical member is slightly larger than the diameter of the convex portion.