JPH0810863Y2 - Pinch roller support structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a pinch roller support structure provided in a VTR (video tape recorder), a tape recorder, or the like, and in particular, an annular engagement of a cylindrical body for a bearing. The present invention relates to a pinch roller support structure in which a contact state between a mating portion and an annular engaged portion of a pinch roller is made into a point contact so that a pinch roller is pressed against a capstan.

(Prior Art) The pinch roller support structure as described above has been conventionally developed.
No. 62-113434. As shown in FIG. 7, this is an arc-shaped surface contact between the spherical portion 2 of the bearing / centering inner ring member 1 and the annular groove 5 of the centering outer ring member 4 forming the inner peripheral surface of the pinch roller 3. In addition, the outer ring member 4 cannot move in the radial direction and the axial direction with respect to the inner ring member 1.

Then, the difference in parallelism between the rotation center axis of the pinch roller 3 and the rotation center axis of the capstan is corrected by sliding the centering outer ring member 4 and the annular recessed groove 5 with each other to perform automatic centering. I am trying.

(Problems to be solved by the invention) Therefore, the contact resistance between the spherical surface portion 2 and the annular groove 5 is large, and due to the resistance, the conformability of self-alignment is poor, and the contact pressure distribution between the pinch roller 3 and the capstan. Is not uniform over the entire axial direction, which causes a problem of unstable tape running.

The present invention has been made in view of the above circumstances. The pinch roller and the capstan have good conformability to self-alignment, the contact pressure distribution is uniform in the entire axial direction, and the pinch roller stabilizes tape running. It is intended to provide a support structure.

(Means for Solving the Problems) In order to achieve the above object, the pinch roller supporting structure of the present invention is provided with a roller shaft provided so as to be movable in a direction orthogonal to the axial direction thereof and moving toward and away from the capstan. A bearing cylindrical body is rotatably fitted, and a pinch roller is rotatably fitted on the outer circumference of the bearing cylindrical body. Particularly, an annular engagement is continuously performed in the circumferential direction on the outer peripheral surface of the bearing cylindrical body. On the other hand, at the center of the inner peripheral surface of the pinch roller in the axial direction, there is an annular cover that is loosely fitted in the annular engaging part with a slight radial gap between the annular engaging part. An engagement portion is continuously provided in the circumferential direction, and the pinch roller is rotatably and slightly movable in the radial direction on the outer circumference of the roller shaft via the bearing cylindrical body. When crimping to the capstan, the crimping surface side The annular engaging portion and the annular engaged portion are in point contact with each other, and the annular engaging portion and the annular engaged portion are separated from each other on the opposite side.

Further, one of the annular engaging portion of the cylindrical body and the annular engaged portion of the pinch roller may be an annular ridge having a triangular cross section, and the other may be an annular groove having a V-shaped cross section.

Further, it is desirable that one of the annular engaging portion of the cylindrical body and the annular engaged portion of the pinch roller is an annular ridge having a semicircular cross section, and the other is an annular groove having a trapezoidal cross section.

(Operation) Since the annular engaged portion provided on the outer peripheral surface of the bearing cylinder is rotatably engaged with the annular engaged portion provided on the inner peripheral surface of the pinch roller in a point contact state, these contact portions Since the resistance is small and the pinch roller is slightly movable in the axial direction and the radial direction with respect to the cylindrical body, the conformability of self-alignment at the time of crimping the pinch roller to the capstan is good, so the pinch roller The contact pressure distribution between the capstan and the capstan becomes uniform over the entire axial direction.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. First
1 is a vertical sectional side view of a pinch roller support structure showing a first embodiment of the present invention, and FIG. 2 is an enlarged sectional view of an essential part of FIG.
In the figure, 10 is a pinch roller arm rotatably supported on a substrate (not shown), and a roller shaft 11 is provided at the tip of the pinch roller arm so as to project upward. The roller shaft 11 has a larger diameter on the lower end side than the upper end side with respect to the substantially middle portion in the axial direction. A bearing cylindrical body 12 is rotatably fitted to the small diameter portion 11a of the roller shaft 11. The cylindrical body 12 is formed by press-fitting an outer cylinder 14 made of synthetic resin on the outer peripheral surface of an oilless metal 13. An annular protrusion (annular engagement portion) 15 having a triangular cross section is integrally formed on the outer peripheral surface of the axially intermediate portion of the outer cylinder 14. A stepped portion 11 between the lower end of the cylindrical body 12 and the small diameter portion 11a and the large diameter portion 11b of the roller shaft 11.
The washer 16 is located on the outer peripheral surface of the small diameter portion 11a.
Is loosely fitted. In addition, the upper end of the cylindrical body 12 and the roller shaft
A washer 17 is loosely fitted on the outer peripheral surface of the small diameter portion 11a, which is located between the head 11d at the upper end of the small diameter portion 11a of 11, and the cylindrical body 12 does not come off from the roller shaft 11 by this washer 17. It is like this. On the outer peripheral surface of the cylindrical body 12, a cylindrical pinch roller 18 is fitted rotatably and slightly movable in the radial direction and the axial direction. The pinch roller 18 is formed by fitting and fixing a rubber elastic cylinder 20 on an outer peripheral surface of a synthetic resin core cylinder 19. An annular groove (annular engaged portion) 21 having a V-shaped cross section is provided on the inner peripheral surface of the middle portion of the core tube 19 in the axial direction, and the annular groove 21 makes point contact with the annular protrusion 15 of the cylindrical body 12. It is fitted so that it can be rolled and rolled freely.

The pinch roller 18 is prevented from coming off from the cylindrical body 12 by a retaining ring 22. That is, the annular stepped portion 23 is integrally formed on the inner peripheral surface of the axially substantially intermediate portion of the core tube 19. The retaining ring 22 is press-fitted into the core cylinder 19 from the upper end side, and the lower end surface 22a thereof is in contact with the upper end surface 23a of the annular step portion 23. Inclined surfaces 22b and 23b are formed on the inner peripheral edge of the lower end of the retaining ring 22 and the inner peripheral edge of the upper end of the annular step portion 23, respectively, and the annular groove 21 is formed by the inclined surfaces 22b and 23b. Incidentally, reference numeral 24 in FIG. 1 denotes a capstan with which the pinch roller 18 comes into contact with and separates from the capstan.

Thus, the pinch roller 18 is separated from the capstan 24 by the cylindrical body 12 with respect to the roller shaft 11.
It is possible to move a little in the axial direction and the radial direction via. When the pinch roller arm 10 is rotated in one direction and the pinch roller 18 is pressure-bonded to the capstan 24 via a tape (not shown), the annular protrusion 15 and the annular groove 21 are formed in the portion corresponding to the pressure-bonding line. And point-contact with each other, and in the other portions, the annular projection 15 and the annular groove 21 are separated from each other with the anti-compression side portion as the maximum separation width. In this state, the rotation of the capstan 24 is transmitted to the pinch roller 18, and the ring-shaped ridge for the ring groove 21 of the pinch roller 18 is transmitted.
While the contact points of 15 are displaced, the cylindrical body 12 rotates with respect to the roller shaft 11. As a result, the contact resistance between the annular ridge 15 and the annular groove 21 becomes small, and the pinch roller 18 becomes a cylindrical body.
Since it is slightly movable in the axial direction and the radial direction with respect to the roller shaft 11 via 12, the capstan 24 of the pinch roller 18
The conformability of self-aligning during crimping against is good, and the pressure distribution on the crimping surface is even over the entire axial direction.
Tape running is stable.

FIG. 3 shows a second embodiment of the present invention. This example is
An annular projection 15 having a triangular cross section is provided on the inner peripheral surface side of the pinch roller 18, and an annular groove 21 having a V-shaped cross section is provided on the outer peripheral surface side of the cylindrical body 12. Then, the annular step portion 23 of the core tube 19
The protrusions 23c and 22c forming the annular protrusion 15 are provided on the inner peripheral edge of the upper end and the inner peripheral edge of the lower end of the retaining ring 22, respectively. The other structure of the second embodiment is the same as that of the first embodiment shown in FIGS. 1 and 2 described above, and therefore the same reference numerals are given to the drawings and the description thereof will be omitted.

4 and 5 show a third embodiment of the present invention. In this embodiment, on the outer peripheral surface of the outer cylinder 14 of the cylindrical body 12 in the substantially axial direction,
An annular ridge 15 having a semicircular cross section is integrally formed, and a core cylinder 19 is made of metal. A pair of synthetic resin retaining cylinders 25, 26 are press-fitted into the inner peripheral surface of the core cylinder 19 from the upper and lower end openings thereof. In combination, an annular groove 21 having a trapezoidal cross section is provided on the inner peripheral surfaces of the retaining cylinders 25 and 26 in the vicinity of the contact portions. Then, the upper retaining cylinder 25
The inclined surfaces 25a and 26a forming the annular groove 21 are provided on the inner peripheral edge of the lower end and the lower peripheral edge of the lower retaining cylinder 26, respectively.

The rest of the configuration of the third embodiment is the same as that of the first embodiment described above, so the same parts in the drawings will be assigned the same reference numerals and explanations thereof will be omitted.

FIG. 6 shows a fourth embodiment of the present invention. This example is
An annular ridge 15 having a semicircular cross section is provided on the inner peripheral surface side of the pinch roller 18, and an annular groove having a trapezoidal cross section on the outer peripheral surface side of the cylindrical body 12.
21 is provided. Then, on the inner peripheral edge of the upper end of the annular stepped portion 23 of the core cylinder 19 and the inner peripheral edge of the lower end of the retaining ring 22, there are provided protrusions 23c, 22c forming the annular protrusion 15, respectively.

Since the other structure of the fourth embodiment is the same as that of the first embodiment described above, the same reference numerals are given to the same portions in the drawings and the description thereof will be omitted.

(Effects of the Invention) As described above, according to the present invention, the annular engaged portion provided on the inner peripheral surface of the pinch roller is rotated in a point contact state with the annular engaging portion provided on the outer peripheral surface of the bearing cylinder. Since the bearing cylinders rotate in a state of being supported by the roller shaft as the pinch roller rotates, the contact resistance between them is small, and moreover, the pinch roller does not rotate with respect to the cylinder shaft. Since it is slightly movable in the radial and radial directions, the conformability of self-alignment when the pinch roller is pressed against the capstan is good, and the contact pressure distribution between the pinch roller and capstan is distributed over the entire axial direction. It has the effect of becoming uniform.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a pinch roller supporting structure showing a first embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG. 3 is a second embodiment of the present invention. Same as Figure 2 and 4
FIG. 5 is a view similar to FIG. 1 showing a third embodiment of the present invention, FIG. 5 is an enlarged cross-sectional view of an essential part of FIG. 4, and FIG. 6 is a second view showing a fourth embodiment of the present invention. The same drawing and FIG. 7 are longitudinal side views showing a conventional pinch roller support structure. 11 ... Roller shaft, 12 ... Cylindrical body, 15 ... Annular ridge (annular engagement part), 18 ... Pinch roller, 21 ... Annular groove (annular engaged part).

Claims (3)

[Scope of utility model registration request] 1. A pinch roller (20) is rotatably supported,
A pinch roller support structure is provided so as to be movable toward and away from a capstan (24), and is provided so as to be movable in a direction orthogonal to the axial direction and being movable toward and away from the capstan (11). ) And a bearing cylindrical body (1
2), an annular engagement portion (15) continuously provided in the outer peripheral surface of the bearing cylinder in the circumferential direction, and a circumferentially continuous portion in the axial center portion of the inner peripheral surface of the pinch roller. And an annular engaged portion (21) which is loosely fitted in the annular engaging portion with a slight gap in the radial direction between the annular engaging portion and the annular engaging portion. When the pinch roller is fitted rotatably and slightly movable in the radial direction through the bearing cylinder, and when the pinch roller is crimped to the capstan, the annular engagement is performed on the crimping surface side. A pinch roller support structure characterized in that the joining portion and the annular engaged portion are in point contact with each other, and the annular engaging portion and the annular engaged portion are separated on the opposite side. 2. One of the annular engaging portion of the bearing cylinder and the annular engaged portion of the pinch roller is an annular groove having a bottom portion having a V-shaped cross section, and the other is sharper than the bottom portion of the annular groove. The pinch roller support structure according to claim 1, wherein the pinch roller support structure is an annular ridge having a triangular shape with a tip. 3. One of the annular engaging portion of the bearing cylinder and the annular engaged portion of the pinch roller is an annular ridge having a semicircular cross section, and the other is an annular groove having a trapezoidal cross section. The pinch roller support structure according to claim 1.