JP2657585B2 - Rotary head device used for tape players - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a digital audio (DAT)
The present invention relates to a rotary head device used for a tape player such as io Tape), and more particularly to a support mechanism for an upper drum 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 cross-sectional view of a conventional rotary head device, and FIGS. 7 and 8 are explanatory views showing a mounting state of an upper drum and a lower drum shown in FIG. A 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 rotatably mounted opposite to each other. A coil spring 11 is interposed between the rolling bearing 5 and the upper drum 7, and the rolling bearing 5 is provided with a threaded portion 4 a formed at the upper end of the support shaft 4.
Is pressed by a nut member 10 screwed into the nut. As a result, an appropriate preload is applied to the rolling bearings 5 and 6. Note that rotary transformers 8 and 9 are mounted inside the upper drum 7 and the lower drum 3.

Incidentally, the inner race 5 of the rolling bearings 5, 6
In many cases, the a and 6a and the support shaft 4 have a loose fit in consideration of the assembly and the like of the two. With this loose fit, a small gap is formed between the support shaft and the inner ring.
In the state where the gap is thus generated, the upper drum 7 is attached to the support shaft 4 at an angle as shown in FIG. 7 or the upper drum 7 rotates from the center D of the support shaft 4 as shown in FIG. An eccentric state where the center E is shifted is obtained.

[0004]

Assuming that the upper drum 7 is rotated in such a state, the upper drum 7 rotates while swinging in the state shown in FIG. In this state, it rotates with eccentricity. However, if a magnetic tape (not shown) is wound around the upper drum 7 in such a rotating state, the distribution of the pressure applied to the magnetic tape is not uniform or the pressure periodically changes suddenly. Result. In such a state, the problem of having a serious adverse effect on the original function of data processing, such as reading magnetic data accurately from a magnetic tape and accurately recording magnetic data, remains unsolved. Therefore, an object of the present invention is to provide a rotary head device used for a tape player that does not cause eccentricity or inclination of an upper drum even when there is a gap between a rolling bearing and a support shaft.

[0005]

In order to achieve the above-mentioned object, the present invention provides a support shaft formed so as to protrude from a fixed lower drum, and a support shaft rotatably supported on the support shaft via a rolling bearing. In the rotary head device used for the tape player having the 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 a gap dimension generated between the support shaft and the rolling bearing. A biasing member that is eccentric in one direction and has a groove formed in a side surface opposite to the eccentric direction of the support shaft, and urges an inner ring of a rolling bearing fitted to the support shaft in a direction opposite to the eccentric direction; Is provided in the groove.

[0006]

The operation of the present invention having the above configuration will be described. Taking into account the gap between the support shaft and the rolling bearing in advance, 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 on the support shaft. The inner ring of the fitted rolling bearing is urged in a direction opposite to the eccentric direction by an urging member inserted into a groove in a side surface of the support shaft. Thus, the rolling bearing coincides with the rotation center of the lower drum tape guide surface at the beginning. 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. Thus, even when there is a gap between the rolling bearing and the support shaft, the upper drum does not tilt with respect to the support shaft and does not cause eccentricity.

[0007]

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

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

The upper drum 15 shown in FIG. 1 has a bottomed cylindrical shape having an opening on the surface (lower surface) facing the lower drum 13 and having a boss 15a projected so as to coincide with the center of rotation. is there. A pair of rolling bearings 16 and 17 are inserted into both ends of the boss 15a, and the upper and lower ends of the inner peripheral surface of the boss 15a are adapted to the inserted rolling bearings 16 and 17 respectively. Step 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 15a are
The upper and lower ends are positioned by the steps 15c and 15d, respectively.

[0010] Of the pair of rolling bearings 16 and 17 inserted into the boss portion 15a, the inner ring 17a of the rolling bearing 17 arranged on the end facing the lower drum 13 is fitted to the support shaft 14. The mounted compression coil spring 18 abuts. The upper end of the compression coil spring 18 is pressed against the inner ring 17 a (shown in FIG. 2) of the rolling bearing 17, and the lower end is pressed against the upper end surface of the lower drum 13.

The lower drum 13 has a bottomed cylindrical shape with an open upper end surface in the figure, and a cylindrical support shaft 14 having a screw portion 14a formed in the upper end in the figure is fixed substantially at the center thereof. . The support shaft 14 is formed integrally with the lower drum 13 or is combined separately. The center O1 of the support shaft 14 is, as shown in FIG.
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. The dimension A is an amount corresponding to a clearance dimension formed by a clearance fit formed between the inner rings 16a and 17a of the rolling bearings 16 and 17 attached to the upper drum 15 and the 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, that is, 1/2 of the difference between the inner diameters.
Is preferably set to a value corresponding to A groove 14b is formed on a side surface of the support shaft 14 opposite to the eccentric direction B. The urging member 20 shown in FIGS. 4A and 4B is inserted into the groove 14b.

The urging member 20 shown in FIGS.
Is a spring formed to substantially match the length dimension F and the width dimension C of the groove 14b. This spring 20
The bent portions 20a and 20b are formed at positions of the rolling bearings 16 and 17 fitted to the support shaft 14 and in contact with the inner races 16a and 17a, respectively, in the state where they are inserted into the grooves 14b.
The bent portions 20a and 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 screw portion 14a formed on the support shaft 14
, A nut member 19 is screwed. This nut member 1
Reference numeral 9 denotes a roller which comes into contact with and presses the rolling bearing 16 fitted in the step portion 15c of the upper drum 15, and the lower surface of the drawing 9 is formed so as to be inclined so as to contact only the inner ring 16a of the rolling bearing 16 to be contacted. ing.

The operation of the rotary head device having the above configuration will be described with reference to FIG. FIG. 5 is an explanatory diagram showing an assembled state of the upper drum 15 and the lower drum 13. First, rolling bearings 16 and 17 are fitted into the boss 15a of the upper drum 15, while a coil spring 18 is fitted on the support shaft 14 and a spring 20 as an urging member is inserted into the groove 14b. Keep it. Then, the upper drum 15 on which the rolling bearings 16 and 17 are mounted 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 displaceable in the axial direction of the support shaft 14. In this state, the nut member 19 is screwed and screwed to the screw portion 14a of the support shaft 14. Due to the tightening of the nut member 19, both the rolling bearings 16 and 17 are pre-loaded by the urging force of the spring 18, and the inner rings 16a and 17a and the outer rings 16b and 17b of the respective rolling bearings are respectively opposed in the axial direction. Is displaced. Accordingly, the positioning of the support shaft 14 in the radial direction and the axial direction can be accurately performed, and the deflection of the support shaft 14 can be suppressed.

As described above, when the upper drum 15 is inserted to a predetermined position by adjusting the nut member 19, the bent portions 20a and 20b of the spring 20 inserted in the grooves 14b of the support shaft 14 are moved to the respective rolling bearings 16a. , 17 inner ring 1
6a and 17a. By this contact, the rolling bearings 16 and 17 are urged in the direction of arrow G opposite 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 tilting with respect to the support shaft 14, and the eccentricity of the support shaft 14 is offset by this displacement, and the rotation center of the upper drum 15 is The center O of

In the embodiment described in detail above, even when 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 rotates while being eccentric. Problems such as swinging and swinging. Therefore, the contact pressure with the wound magnetic tape can be kept constant, and the recording of magnetic data,
Does not adversely affect reproduction. Further, since there is no abrupt pressure fluctuation, it is possible to extend the life of the magnetic tape itself. The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the invention.

[0017]

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

[0018]

[Brief description of the drawings]

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

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

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

FIGS. 4A and 4B are a side view and a front view, respectively, of an urging member.

FIG. 5 is an explanatory view showing a state in which an upper drum and a lower drum are assembled.

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

FIG. 7 is an explanatory view showing an attached state of an upper drum and a lower drum of the conventional rotary head device shown in FIG.

FIG. 8 is an explanatory view showing an attached state of an upper drum and a lower drum of the conventional rotary head device shown in FIG.

[Explanation of symbols]

 Reference Signs List 15 upper drum 13 lower drum 16, 17 one set of rolling bearings 14 support shaft 20 biasing member 16a, 17a inner ring

Claims (1)

(57) [Claims] 1. A rotary head device for use in a tape player having a support shaft protruding from a fixed lower drum and an upper drum rotatably supported on the support shaft via a rolling bearing. The support shaft is eccentric in one direction with respect to a tape guide surface on the outer periphery of the lower drum by a distance corresponding to a gap dimension 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. And a biasing member for biasing an inner ring of the rolling bearing fitted on the support shaft in a direction opposite to the eccentric direction is provided in the groove. Rotating head device.