JPH01287853A - Pinch roller device - Google Patents

Abstract

PURPOSE:To execute the small diameter of a pinch roller by using an automatic aligning action due to a clearance of the convex spherical shape protruding part of a pinch roller shaft and the concave spherical groove of a cylinder member. CONSTITUTION:The title device is composed of a metallic pinch roller shaft 9 having a convex spherical shape protruding part 9a at a tip part, a resin-made cylinder member 10 to have a hollow groove part 10b engaged to the convex spherical shape protruding part 9a of the pinch roller shaft 9 at the edge surface part of an axial direction and to form a concave spherical shape groove 10a abutted freely slidably and shaped so as to idly fit freely turnably and formed so that it is outside-fitted to the pinch roller shaft 9 and a cylindrical elastic member 11 made of rubber bonded at the outer circumferential surface of the cylinder member 10. When the pinch roller shaft 9 is fitted in a single body with the cylinder member 10 by an inserting mold, the automatic aligning action due to a clearance 12 of the convex spherical shape protruding part 9a of the pinch roller shaft 9 and the concave spherical shape groove 10a of the cylinder member 10 is used. Thus, the small diameter of the pinch roller can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to recording and reproducing devices such as video tape recorders (hereinafter referred to as VTRs) that record signals on tape or reproduce signals recorded on tape. This invention relates to a pinch roller device used in the device.

2. Description of the Related Art A conventional pinch roller device will be explained with reference to FIG. FIG. 3 is a side sectional view of a conventional pinch roller device. Third
In the figure, a cylindrical elastic body 2 made of, for example, rubber is integrally attached to the outer periphery of a cylindrical holder 1, and an outer ring 3a of a ball bearing 3 is attached to the inner periphery of the cylindrical holder 1. It is clamped and fixed by a step part 11 of the cylindrical holder 1 and a sleeve 4 fitted to the inner peripheral part of the cylindrical holder 1. On the other hand, the inner ring 3b of the ball bearing 3 fitted into the small diameter portion 6& of the long shaft 6 is connected to the support shaft 5.
It is fixed by a stopper 6 fitted into the small diameter portion 6a of the. In the ball bearing 3 of the pinch roller 7 configured as described above, there is a so-called play between the support shaft 6 and the pinch roller 7 only by the gap valve between the ball 3c and the outer ring 3a and between the pawl 3c and the inner ring 3b. This is the amount of automatic alignment. Therefore, when the pinch roller 7 and the capstan (not shown) work together to transfer the tape, when the pinch roller 7 is pressed against the capstan with a predetermined force, for some reason the pinch roller 7 is pressed against the capstan. Even when the support shaft 5 is in a non-parallel state, the pinch roller 7 uniformly presses the capstan along the inclination due to the self-aligning action of the self-aligning amount, so that good tape transfer can be achieved. I can do it.

Problems to be Solved by the Invention In a recording and reproducing apparatus configured so that the pinch roller 7 is relatively fitted and mounted in a space of a notch opening provided in a tape cassette in which a tape is wound, the notch opening In order to fit and arrange the pinch roller 7 in a limited space, it is desired to reduce the diameter of the pinch roller 7. When attempting to reduce the diameter of the conventional pinch roller 7 described above in order to meet this demand, the first consideration is to reduce the thickness of the cylindrical elastic body 2 in the radial direction. However, as the thickness of the cylindrical elastic body 2 becomes thinner, when the pinch roller 7 pinches the tape and presses it against the capstan, and the tape is transferred at a constant speed, the cylindrical elastic body 2 becomes more along the capstan. There were problems in that it was difficult to uniformly elastically deform the tape, and the force of the pinch roller 7 to drive the tape was significantly reduced. In addition, as the thickness of the cylindrical elastic body 2 becomes thinner, there is a problem in that the uneven hardness due to the weld portion that occurs during molding of the cylindrical elastic body 2 causes wow and flutter when the tape is transferred. A second method for reducing the diameter of the conventional pinch roller 7 is to reduce the diameter of the ball bearing 3. However, unless the pressing force of the pinch roller 7 on the capstan is reduced, there will be a problem that the radial load capacity of the ball bearing 3 will decrease as the diameter of the ball bearing 3 becomes smaller and the bearing life will be shortened. There are problems in that a plurality of bearings 3 must be used, the number of assembly steps increases, and the amount of self-alignment decreases. Furthermore, since each component of the ball bearing 3 is small, it is not suitable for mass production, and there is also the problem that the ball bearing 3 becomes expensive.

In addition, with the conventional component configuration as described above, the number of parts is large, and the processing precision is required to be at a mediocre level.
There was also a problem that the pinch roller device itself was expensive. In view of the above problems, the present invention realizes stable tape transport even when the spindles of the capstan and the pinch roller are non-parallel, and also has a cylindrical shape. The present invention provides an inexpensive pinch roller device that can be made smaller in diameter without reducing the thickness of a shaped elastic body, has a small number of parts, and has a simple structure.

Means for Solving the Problems In order to solve the above-mentioned problems, the pinch roller device of the present invention includes a pinch roller shaft having a convex spherical protrusion at the tip end, and a convex spherical surface on the axial end surface of the pinch roller shaft. It has a hollow groove shaped so as to be rotatably loosely fitted into the concave spherical groove that fits into the shaped protrusion and slidably abuts, and is formed so as to be externally fitted onto the pinch roller shaft. The pinch roller shaft is composed of a cylindrical member made of resin and a cylindrical elastic member fixed to the outer peripheral surface of the cylindrical member, and a pinch roller shaft is integrally attached to the cylindrical member by insert molding.

Function: With the above configuration, the present invention achieves stable tape transport even if the spindles of the capstan and pinch roller are non-parallel, due to the self-aligning effect created by the gap between the convex spherical protrusion and the concave spherical groove. Moreover, it is possible to reduce the diameter of the pinch roller without reducing the thickness of the cylindrical elastic body, and to provide a pinch roller device that is simple in structure, has a small number of parts, and is inexpensive.

EXAMPLE A pinch roller device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a side sectional view of an embodiment of the pinch roller device of the present invention.

In FIG. 1, the pinch roller 8 includes a pinch roller shaft 9 made of metal such as stainless steel having a convex spherical protrusion 9a at the tip, and a convex spherical protrusion 9 & The pinch roller shaft 9 has a hollow groove 10b formed with a concave spherical groove 10& that is slidably abutted on the pinch roller shaft 9. A cylindrical elastic member 1 made of rubber or the like is fixed to the outer peripheral surface of the cylindrical member 10 by bonding, baking, press-fitting, etc.
1, the pinch roller 1IfIb9 is located at approximately the center of gravity of the cylindrical member 10, that is, the center of the convex spherical protrusion 9a of the pinch roller shaft 9 is approximately at the axial center of the cylindrical member 10, and The roller device is insert-molded and integrally attached to the cylindrical member 1o so as to be located at the center of the tape when used in a cutting device.

By insert molding the pinch roller shaft 9 into the resin cylindrical member 1o, the resin of the cylindrical member 1o hardens and contracts, and as a result, the convex spherical protrusion 9a and the concave spherical groove of the pinch roller shaft 9 are formed. A gap 12 of 10a is created. The gap 12 causes a self-aligning effect.

By setting the relationship between the radius R of the convex spherical protrusion 9a and the radius r of the hollow groove 10b to be R) r, it is possible to prevent the cylindrical member 10 from coming off in the X direction.

Here, suitable resins for use in the cylindrical member 1o include thermosetting resins such as epoxy resins, polyester resins, polyimide resins, and phenol resins, and thermoplastic resins such as polyamide resins, polyacetal resins, and polycarbonate resins.

Furthermore, in order to improve the abrasion resistance or reduce the coefficient of friction of the resin material mentioned above, a composite material containing graphite, molybdenum disulfide, ethylene tetrafluoride, etc. may be used.

Furthermore, it is desirable to interpose a lubricating oil such as grease between the convex spherical groove 9a and the concave spherical groove 10a.
This problem can be solved by using an oil-impregnable material for the cylindrical member 1o provided with the oil groove 13 as shown in the figure.

As described above, the pinch roller shaft has a convex spherical protrusion at its tip end, and the concave spherical groove in the axial end face fits into the convex spherical protrusion of the pinch roller shaft and comes into sliding contact. A resin cylindrical member having a hollow groove shaped so as to be freely rotatably fitted into the pinch roller shaft, and a resin cylindrical member formed to fit around the pinch roller shaft; In addition to the pinch roller shaft being integrally attached to the cylindrical member by insert molding, the self-aligning effect created by the gap between the convex spherical protrusion and the concave spherical groove allows the cap to be Stable tape transfer is achieved even if the spindles of the stun and pinch roller are not parallel, and the diameter of the pinch roller can be reduced without reducing the thickness of the cylindrical elastic body, and the structure is simple. The present invention provides a pinch roller device that has a small number of parts and is inexpensive.

Effects of the Invention As described above, the pinch roller shaft has a convex spherical protrusion at the tip end, and the axial end surface of the pinch roller shaft fits into the convex spherical protrusion of the pinch roller shaft, and the freely slidable roller shaft Consisting of a resin cylindrical member formed to be fitted, and a cylindrical elastic member fixed to the outer peripheral surface of the cylindrical member, the pinch roller shaft is integrally attached to the cylindrical member by insert molding. Due to the self-aligning effect created by the gap between the convex spherical protrusion and the concave spherical groove, stable tape transport is achieved even if the spindles of the capstan and pinch roller are non-parallel. To provide a pinch roller device which can reduce the diameter of a pinch roller without reducing the thickness of an elastic body, has a simple structure, has a small number of parts, and is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of the pinch roller device of the present invention, FIG. 2 is a side sectional view of the second embodiment of the pinch roller device of the present invention, and FIG. 3 is a conventional pinch roller device. FIG. 9... Pinch roller shaft, 9 &... Convex spherical shaped part, 10... Cylindrical member, 10a... Concave spherical groove, 10b... Hollow groove part, 11... Cylindrical elastic member. q-11 pinch row axis <7. lL - 11 convex surface shape O large part 10 - 1 yen space p face l θ unit u te wooden surface structure. // ---Fl note form Western a master figure 1 figure 2

Claims (1)

[Claims] a pinch roller shaft having a convex spherical protrusion at its tip;
The axial end face has a hollow groove shaped to be rotatably fitted into the convex spherical protrusion of the pinch roller shaft and a concave spherical groove that slidably abuts on the pinch roller shaft. and a resin cylindrical member formed to be fitted onto the pinch roller shaft, and a cylindrical elastic member fixed to the outer peripheral surface of the cylindrical member, and the pinch roller shaft is formed by insert molding. A pinch roller device, characterized in that it is integrally attached to the cylindrical member.