JPH04219612A - Rotary head device used for tape player - Google Patents

Abstract

PURPOSE:To generate no eccentricity and no inclination on an upper drum even when a gap is present between rotary bearings and a supporting shaft. CONSTITUTION:The prescribed supporting shaft 14 is made to be eccentric by 1/2 of the gap size generated between the supporting shaft 14 and the rotatory bearings 16, 17 and a groove 14b is also formed at a flank in a direction opposed to the eccentric direction and the energizing member 20 of a spring, etc., energizing the inner rings 16a, 17a of the rotary bearings 16, 17 inserted into the supporting shaft 14 is provided on the groove 14b.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to DAT (Digital Application Field).
The present invention relates to a rotary head device used in a tape player such as Audio Tape, and more particularly to an upper drum support mechanism using a rolling bearing.

0002

2. Description of the Related Art A rotary head device used in a conventional tape player has a structure shown in FIG. FIG. 6 is an enlarged sectional view of a conventional rotary head device, and FIGS. 7 and 8 are explanatory views showing how the upper drum and lower drum shown in FIG. 6 are attached. The rotary head device 1 shown in FIG. 6 includes a lower drum 3 fixed to a chassis 2 to which the rotary head device 1 is attached, a support shaft 4 protruding from the center of the lower drum 3, and a set of rolling bearings 5. , 6, and an upper drum 7 which is rotatably mounted to face each other. In addition, the rolling bearing 5 and the upper drum 7
A coil spring 11 is interposed between the support shaft 4 and the rolling bearing 5, and the rolling bearing 5 is pressed by a nut member 10 that is screwed into a threaded portion 4a formed at the upper end of the support shaft 4. This allows appropriate preload to be applied to both rolling bearings 5 and 6. Incidentally, rotary transformers 8 and 9 are installed inside the upper drum 7 and the lower drum 3.

By the way, the inner ring 5 of the rolling bearings 5 and 6
a, 6a and the support shaft 4 are often fitted with a loose fit in consideration of their assembly, etc., and when this loose fit is used, a gap is created between the support shaft and the inner ring, albeit a small one. In such a state where a gap is created, the upper drum 7 may be installed at an angle with respect to the support shaft 4 as shown in FIG. This results in an eccentric state in which the center E is shifted.

0004

[Problems to be Solved by the Invention] Assuming that the upper drum 7 is rotated in this state, in the state shown in FIG. 7, the upper drum 7 rotates while making an oscillating motion, and as shown in FIG. In this case, it will rotate eccentrically. However, when a magnetic tape (not shown) is wound around the upper drum 7 in such a rotating state, a phenomenon occurs in which the pressure distribution applied to the magnetic tape is not uniform or the pressure changes suddenly and periodically. This results in In such a state, the problem of having a significant adverse effect on the original data processing functions such as accurately reading magnetic data from a magnetic tape and accurately recording magnetic data has remained unsolved. SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary head device used in a tape player that does not cause eccentricity or inclination of the upper drum even when there is a gap between the rolling bearing and the support shaft.

[0005]

[Means for Solving the Problems] The structure of the present invention to achieve the above object includes a support shaft formed protruding from a fixed lower drum, and a support shaft rotatably supported by the support shaft via a rolling bearing. In a rotary head device used in a tape player equipped with an upper drum, the support shaft is moved relative to the tape guide surface on the outer periphery of the lower drum by a distance corresponding to the gap size generated between the support shaft and the rolling bearing. A biasing member that is eccentric in one direction and has a groove formed on the side surface in the opposite direction to the eccentric direction of the support shaft, and that biases the inner ring of the rolling bearing fitted to the support shaft in the opposite direction to the eccentric direction. is provided in the groove.

[0006]

[Operation] The operation of the present invention having the above configuration will be explained. The gap between the support shaft and the rolling bearing is taken into account in advance, and the support shaft is provided eccentrically from the center of the tape guide surface on the outer periphery of the lower drum in accordance with the gap size. Then, a rolling bearing is fitted to this support shaft. The inner ring of the fitted rolling bearing is biased in a direction opposite to the eccentric direction by a biasing member inserted into a groove in the side surface of the support shaft. Thereby, the rolling bearing coincides with the original rotation center of the lower drum tape guide surface. Furthermore, since the inner ring of each rolling bearing is urged in one direction by the urging member, each inner ring comes into contact with the side surface of the support shaft in the eccentric direction. As a result, even if there is a gap between the rolling bearing and the support shaft, the upper drum will not be tilted with respect to the support shaft, and eccentricity will not occur.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to the drawings. 1 is an exploded perspective view including a partial cross section of a rotary head device as an embodiment, FIG. 2 is an enlarged top view of the lower drum of the rotary head device shown in FIG. 1, and FIG. 3 is an exploded perspective view of the lower drum shown in FIG. The front view and FIGS. 4(A) and 4(B) are a side view and a front view, respectively, of the biasing member. Note that the rotary transformer is not illustrated in this embodiment.

The rotary head device 12 shown in FIG. 1 has a lower drum 13 fixed to a chassis (not shown) to which the rotary head device 12 is attached, and is arranged opposite to the lower drum 13 at a predetermined distance. It is equipped with an upper drum 15.

The upper drum 15 shown in FIG. 1 has a bottomed cylindrical shape with an open surface (lower surface) facing the lower drum 13 and a boss portion 15a protruding from the center of rotation of the upper drum 15. be. A pair of rolling bearings 16 and 17 are respectively inserted into both ends of the boss portion 15a, and a pair of rolling bearings 16 and 17 are inserted into the upper and lower ends of the inner circumferential surface of the boss portion 15a. Stepped portions 15c and 15d are formed. As shown in FIG. 5, the outer rings 16b and 17b of the rolling bearings 16 and 17 inserted into the boss portion 15a are
The step portions 15c and 15d are positioned at the upper end and the lower end, respectively.

Of the pair of rolling bearings 16 and 17 inserted into the boss portion 15a, the inner ring 17a of the rolling bearing 17 located at the end facing the lower drum 13 has an inner ring 17a that is fitted onto the support shaft 14. The installed compression coil spring 18 abuts. The compression coil spring 18 has an upper end in pressure contact with the inner ring 17a (shown in FIG. 2) of the rolling bearing 17, and a lower end in pressure contact with the upper end surface of the lower drum 13.

The lower drum 13 has a bottomed cylindrical shape with an open upper end as shown in the figure, and a cylindrical support shaft 14 having a threaded portion 14a formed at the upper end as shown is fixed approximately at the center thereof. . This support shaft 14 is formed integrally with the lower drum 13, or a separate support shaft 14 is combined with the lower drum 13. The center O1 of the support shaft 14 is located at the lower drum 13 as shown in FIG.
It is formed eccentrically by a dimension A from the geometric center O of the tape guide surface 13a on the outer periphery of the tape guide surface 13a. This dimension A corresponds to the gap size due to a loose fit formed between the inner rings 16a, 17a of the rolling bearings 16, 17 attached to the upper drum 15 and this support shaft 14. Specifically, the outer diameter of the support shaft 14 is d2, the rolling bearing 16,
When the inner diameter of the inner ring of No. 17 is d1, the eccentric dimension A
is A=(d1-d2)/2, i.e. 1/2 of the difference in inner diameter
It is preferable to take a value corresponding to . Further, a groove 14b is formed on the opposite side surface of the support shaft 14 in the eccentric direction B. A biasing member 20 shown in FIGS. 4(A) and 4(B) is inserted into this groove 14b.

The biasing member 20 shown in FIGS. 4A and 4B is a spring formed to substantially match the length F and width C of the groove 14b. The spring 20 has bent portions 20a and 20b formed at positions where the spring 20 contacts the inner rings 16a and 17a of the rolling bearings 16 and 17 fitted to the support shaft 14 when the spring 20 is inserted into the groove 14b. The bent portions 20a, 20b are formed such that the top and the vicinity thereof protrude outside the groove 14b when the spring 20 is inserted into the groove 14b.

A threaded portion 14a formed on the support shaft 14
A nut member 19 is screwed into the. This nut member 1
Reference numeral 9 abuts against and presses the rolling bearing 16 fitted into the stepped portion 15c of the upper drum 15, and its lower surface as shown in the figure is formed to be inclined so as to come into contact only with the inner ring 16a of the rolling bearing 16 with which it comes into contact. ing.

The operation of the rotary head device having the above configuration will be explained with reference to FIG. 5 as well. FIG. 5 is an explanatory diagram showing an assembled state of the upper drum 15 and the lower drum 13. First, the rolling bearings 16 and 17 are fitted into the boss portion 15a of the upper drum 15, and the coil spring 18 is fitted into the support shaft 14, and the spring 20 as a biasing member is inserted into the groove 14b. I'll keep it. Then, the upper drum 15 equipped with the rolling bearings 16 and 17 is inserted into the support shaft 14. In the assembled state, the upper drum 15 is elastically supported by the coil spring 18 with respect to the lower drum 13 so as to be freely displaceable in the axial direction of the support shaft 14. In this state, attach the nut member 19 to the support shaft 1.
4 and tighten it. By tightening the nut member 19, a preload is applied to both the rolling bearings 16 and 17 by the urging force of the spring 18, and the inner rings 16a and 17a and the outer rings 16b and 17b of each rolling bearing are moved in opposite directions in the axial direction. Displaced to. Thereby, the support shaft 14 can be accurately positioned in the radial direction and the axial direction, and vibration of the support shaft 14 can be suppressed.

In this way, when the upper drum 15 is inserted to a predetermined position by adjusting the nut member 19, the bent portions 20a, 20b of the spring 20 inserted into the groove 14b of the support shaft 14 are inserted into the respective rolling bearings 16. , 17 inner ring 1
6a, 17a. Due to this contact, each rolling bearing 16, 17 is biased in the direction of arrow G, which is the opposite direction to the direction of arrow B, which is the eccentric direction of the support shaft 14 in FIG. Due to this bias, the upper drum 15 is displaced in the direction of arrow G without being inclined with respect to the support shaft 14, and the eccentricity of the support shaft 14 is offset by this displacement, so that the center of rotation of the upper drum 15 is shifted from the lower drum 14. coincides with the center O of

According to the embodiment described in detail above, even if there is a gap between the inner rings 16a, 17a of the rolling bearings 16, 17 and the support shaft 14, the upper drum 15 will not rotate eccentrically. You can solve problems such as shaking your head or making head-shaking movements. Therefore, the contact pressure with the wound magnetic tape can be kept constant, and magnetic data can be recorded.
It has no negative effect on playback. Furthermore, since it is not subject to sudden pressure fluctuations, it is possible to extend the life of the magnetic tape itself. It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the invention.

[0017]

According to the present invention as detailed above, a rotary head device used in a tape player that does not cause eccentricity or inclination of the upper drum even if there is a gap between the rolling bearing and the support shaft. can be provided.

[0018]

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view including a partial cross section of a rotary head device as an example.

FIG. 2 is an enlarged top view of the lower drum of the rotary head device shown in FIG. 1;

FIG. 3 is a front view of the lower drum shown in FIG. 2.

FIGS. 4A and 4B are a side view and a front view, respectively, of the biasing member.

FIG. 5 is an explanatory diagram showing how the upper drum and lower drum are assembled.

FIG. 6 is an enlarged sectional view of a conventional rotary head device.

FIG. 7 is an explanatory diagram showing how the upper drum and lower drum of the conventional rotary head device shown in FIG. 6 are attached.

FIG. 8 is an explanatory diagram showing how the upper drum and lower drum of the conventional rotary head device shown in FIG. 6 are attached.

[Explanation of symbols]

15 Upper drum 13 Lower drum 16, 17 A set of rolling bearings 14 Support shaft 20 Biasing member 16a, 17a Inner ring

Claims (1)

[Claims] 1. A rotary head device used in a tape player, comprising a support shaft formed to protrude from a fixed lower drum, and an upper drum rotatably supported by the support shaft via a rolling bearing. , the support shaft is eccentric in one direction with respect to the tape guide surface on the outer periphery of the lower drum by a distance corresponding to the gap size generated between the support shaft and the rolling bearing, and a side surface in a direction opposite to the eccentric direction of the support shaft; A groove is formed in the tape player, and a biasing member is provided in the groove to bias an inner ring of a rolling bearing fitted to the support shaft in a direction opposite to the eccentric direction. Rotating head device.