JPH04366414A - Rotary drum device - Google Patents

Abstract

PURPOSE:To enable a track which is recorded on a magnetic tape to be traced accurately by allowing an axis one-piece type bearing with a plurality of external races in one piece to be supported with a longest distance at two positions of a bearing housing portion of a fixed drum. CONSTITUTION:An external race 37 of an axis one-piece type bearing 36 is supported at two points on a fixed surface which is divided through a stepped recessed portion 23d. In this case, since the length of the fixed surface can be extended, a shaft 31 of the above bearing retains a highly accurate vertical property without being inclined and is fixed at the bearing housing portion 23 and is supported. Also, since the bearing housing portion 23 is obtained by providing a fixed surface 23c and the stepped recessed portion 23d at a middle portion of the fixed surface 23c, thus enabling a degree of cylindrical property to be retained highly accurately and easily as compared with a case when there is no stepped recessed portion 23d. Therefore, the magnetic head can trace a track on the magnetic tape accurately without allowing the rotary surface to be inclined.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating drum device for a magnetic recording/reproducing apparatus for recording and reproducing information on a magnetic tape such as a VTR or DAT.

0002

[Prior Art] FIG. 4 shows, for example, Japanese Patent Laid-Open No. 59-223927.
FIG. 5 is a sectional view of the conventional rotating drum device shown in the publication.
5 is a sectional view of a shaft-integrated bearing used in the rotating drum device shown in FIG. 4. FIG. In the figure, 10 is a rotating drum unit, 11 is a rotating drum, 12 is a magnetic head, 13 is a flange, and 14 is a rotary transformer. 20
2 is a fixed drum unit, 21 is a fixed drum, 22 is a fixed rotary transformer, and 23 is a bearing housing provided on the fixed drum 21. 30 is a shaft-integrated bearing;
31 is a shaft that is a rotating shaft, 32 and 33 are outer races,
32a, 33a are inner race surfaces provided integrally with the shaft 31, 32b, 33b are steel balls, 32c,
33c is an outer race surface provided on each of the outer races 32 and 33, 34 is a spring, and 35 is a spring receiver. Further, 40 is a motor unit, 41 is a stator, 42 is a rotor, and 43 is an end ring for fixing the rotor 42 to the shaft 31. 50 is a screw.

Next, a procedure for assembling the above-mentioned rotating drum device will be explained. After the outer race 32 of the shaft-integrated bearing 30 is press-fitted and fixed from the rotary drum 11 side to the press-fit surface 23a provided on the bearing housing portion 23, the shaft-integrated bearing 30 is The shaft-integrated bearing 30 is fixed to the fixed drum 21 by adhesively fixing the outer race 33 to the adhesive surface 23b provided on the housing part 23. At this time, the shaft-integrated bearing 30 and the fixed drum 21
The dimensional relationship between the outer race 32 and the bearing housing part 23 is as follows.
is larger than the outer diameter of the outer race 33, the diameter of the press-fit surface 23a of the bearing housing portion 23 is larger than the diameter of the bonding surface 23b, and the diameter of the bonding surface 23b is larger than the outer diameter of the outer race 33. The following conditions must be met: Outer diameter of outer race 32>Diameter of press-fit surface 23a>Adhesive surface 23b
Diameter > Outer diameter of the outer race 33 Next, the fixed side rotary transformer 22 is attached to the fixed drum 2.
1 side, and the other rotation side rotary transformer 14 is adhered to the flange 13, and the flange 13 is fixed to the shaft 31. Subsequently, the magnetic head 12 is fixed to a predetermined location on the lower surface of the rotary drum 11 with screws 50, and then the rotary drum 11 is fixed to the flange 13 with screws 50. Further, the rotor 42 is attached to the shaft 31 by fixing the stator 41 to the fixed drum 21 with screws 50 and fixing the end ring 43 to the shaft 31 with the screws 50.

0004

According to the rotating drum device configured as described above, the perpendicularity of the shaft-integrated bearing with respect to the fixed drum mounting surface is determined by the degree of press-fitting of one outer race. The shaft of the integrated shaft bearing tends to tilt, and due to the tilt of the shaft, the rotating surface of the magnetic head tilts, and as a result, the magnetic head cannot accurately trace the track on the magnetic tape on which information is recorded. There was a problem.

The present invention has been made to solve the above-mentioned problems, and provides a rotating drum that can accurately trace tracks on a magnetic tape on which information is recorded without tilting the rotating surface of the magnetic head. The purpose is to provide equipment.

[0006]

[Means for Solving the Problems] A rotating drum device according to the present invention includes a shaft having a plurality of inner race surfaces for receiving steel balls of a ball bearing, and a plurality of outer race surfaces provided corresponding to the inner race surfaces. a shaft-integrated bearing comprising an outer race having a race surface; and a bearing housing portion having a fixed surface having a smaller diameter than the outer diameter of the outer race separated by a stepped recess having a diameter larger than the outer diameter of the outer race. and the outer race is fixed to the fixed surface.

Further, the bearing housing portion is provided with a receiving surface for determining the axial position of the shaft-integrated bearing or the shaft. Furthermore, an adhesive insertion hole is provided that reaches the fixing surface.

[0008]

[Function] According to the rotating drum device of the present invention, the outer race of the shaft-integrated bearing is supported at two points by the fixed surface separated by the step-like recess, and the length of the fixed surface can be made long. The shaft of the bearing is fixedly supported by the bearing housing portion while maintaining highly accurate verticality without tilting. Therefore, the magnetic head can accurately trace tracks on the magnetic tape without tilting its rotating surface.

[0009]

【Example】

Example 1. FIG. 1 is a sectional view of a rotating drum device of the present invention.
FIG. 2 is a half-sectional view of the shaft-integrated bearing used in the rotating drum device of FIG. In the figure, parts that are the same or equivalent to those of the above-mentioned conventional device are given the same reference numerals, and explanations thereof will be omitted. 2
3 is a bearing housing portion provided on the fixed drum 21, 23c is a fixing surface, and 23d is a stepped recess. 36
is a shaft-integrated bearing, specifically, as shown in FIG. 2, the shaft 3 has two inner race surfaces 32a and 33a.
1, an outer race 37 having two outer race surfaces 32c and 33c is attached via steel balls 32b and 33b. Due to the precision of each component, preload is applied to the shaft-integrated bearing.
Runout of the outer circumference of the outer race 37 relative to the shaft 31 is managed with high precision. 60 is a drum base to which the fixed drum 21 is fixed.

Next, the steps for assembling the rotating drum device described above will be explained with respect to the differences from the conventional device. As shown in FIG. 1, the shaft-integrated bearing 36 is press-fitted into the bearing housing portion 23 formed on the fixed drum 21 from the rotating drum 11 side. At this time, the bearing housing portion 23 includes a stepped recess 23d having a diameter larger than the outer diameter of the outer race 37 and tapered at both ends, and an outer race provided on both sides of the stepped recess 23d to sandwich the stepped recess 23d. 37 and a fixed surface 23c having a diameter smaller than the outer diameter of the fixing surface 23c. In other words, the bearing housing part 23 and the shaft-integrated bearing 36
The relationship with must satisfy the following conditions. Diameter of stepped recess 23d>Outer diameter of outer race 37>Fixing surface 2
Diameter of 3c When these conditions are met, the shaft-integrated bearing 36 is press-fitted and supported on the outer peripheral surface of the outer race 37 by the two fixing surfaces 23c of the bearing housing portion 23.

[0011] Here, the two outer race surfaces 32c and 33c
By using the outer race 37 having the outer races 32 and 33, the press-fit length can be made longer than when using the conventional shaft-integrated bearing 30 having independent outer races 32 and 33, respectively.

Furthermore, the bearing housing portion 23 also has a fixed surface 23.
Since the stepped recess 23d is provided at the intermediate portion between the fixed surface 23c and the fixed surface 23c, compared to the case where there is no stepped recess 23d,
The cylindricity of the fixing surface 23c can be easily maintained with high precision.

[0013] Generally speaking, in press-fitting or shrink-fitting, the longer the length of the part to be press-fitted or shrink-fitted, the more accurate the press-fitting or shrinkage-fitting becomes. Further, the accuracy of press-fitting and shrink-fitting is greatly influenced by the accuracy of the cylindricity of the bearing housing portion 23, etc. In the above embodiment, the shaft-integrated bearing 3
Since the outer race 37 of No. 6 is supported by the upper and lower fixing surfaces 23c and 23c of the bearing housing part 23, the press-fit length can be made longer in the upper and lower parts, and high-precision machining is required. Since the area of the fixed surface 23c is small, the fixed surface 23c can be provided with high precision, and as a result, the perpendicularity of the shaft 31 with respect to the mounting surface of the fixed drum 21 can be realized with high precision.

Example 2. In the first embodiment, the shaft-integrated bearing 36 is press-fitted into the bearing housing part 23, but the present invention is not limited to this, and shrink-fitting may also be used.

Example 3. In the first embodiment, the shaft-integrated bearing 36 is inserted into the bearing housing section 23 from the rotating drum 11 side and fixed therein, but the invention is not limited to this, and the shaft-integrated bearing 36 can be inserted and fixed from the motor unit 40 side. There is no problem.

Example 4. In the first embodiment, the case where the step-shaped recess 23d is disposed approximately at the midpoint of the fixed surface 23c in the bearing housing part 23 is illustrated, but the present invention is not limited to this, and the two fixed surfaces 23c, 23c are separated. The position may be any position as long as the position is the same, and the area ratio with respect to the fixed surface 23c may also be different from that in the first embodiment.

Example 5. In the first embodiment, the diameter of the fixing surfaces 23c at two locations is the same, but the relationship between the bearing housing portion 23 and the shaft-integrated bearing 36 is different from that of the stepped recess 23d. diameter > outer diameter of outer race 37 > fixed surface 2
As long as the diameter condition 3c is satisfied, the diameters of the two fixed surfaces may be different.

Example 6. In the above-described first embodiment, a case is illustrated in which tapered portions are provided at both ends of the step-like recessed portion 23d, but the tapered portions may be provided only on the shaft-integrated bearing insertion direction side without being limited to this.

Example 7. In Example 1 above, the case where the press-fitting height is controlled using a jig or the like when inserting a shaft-integrated bearing is illustrated, but a bearing surface is provided in the bearing housing part on the insertion direction side of the shaft-integrated bearing and press-fitting is performed. Height management may also be performed.

Example 8. In the above-described first embodiment, the case where the shaft-integrated bearing 36 is fixed to the fixed drum 21 only by press-fitting is illustrated, but as shown in FIG.
A plurality of adhesive insertion holes 24 may be provided in the bearing housing portion 23, and an adhesive reservoir 25 may be provided in the bearing housing portion 23, and an adhesive may be used in combination to increase the fixing strength. Here, the adhesive reservoir 25 may also be used as the stepped recess 23d, and a relief part (not shown) is provided in the bearing housing part 23 or the outer race 37 to prevent the adhesive from flowing to unnecessary parts. You can.

[0021]

As described above, according to the present invention, a shaft-integrated bearing in which a plurality of outer races are integrated is supported at two locations in the bearing housing portion of a fixed drum over the longest possible distance. Therefore, the perpendicularity of the shaft with respect to the fixed drum mounting surface becomes highly accurate, and therefore, the rotating surface of the magnetic head is not tilted, making it possible to accurately trace the tracks recorded on the magnetic tape.

Furthermore, since a shaft-integrated bearing with multiple outer races integrated is used, even if the span between the upper and lower bearings is shortened,
The press-fit surfaces are formed at least in two places on the top and bottom of the outer race,
As a result, the press-fit length can be made longer, which has the effect of making the rotary drum device itself thinner while maintaining highly accurate verticality of the shaft-integrated bearing within the rotary drum. be.

Furthermore, since the shaft does not fall, the gap between the rotating side and the stationary side of the rotary transformer can be easily managed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a rotating drum device showing a first embodiment of the present invention.

FIG. 2 is a half-sectional view of a shaft-integrated bearing used in the rotating drum device of FIG. 1;

FIG. 3 is a sectional view of a fixed drum showing an eighth embodiment of the present invention.

FIG. 4 is a sectional view of a conventional rotating drum device.

5 is a sectional view of a shaft-integrated bearing used in the rotating drum device shown in FIG. 4. FIG.

[Explanation of symbols]

11 Rotating drum 21 Fixed drum 23 Bearing housing part 23c Fixed surface 23d Step-shaped recess 31 Shaft 32a Inner race surface 33a Inner race surface 32b steel ball 33b Steel ball 32c outer race surface 33c outer lace surface 36　　　Shaft-integrated bearing 37 Outside lace

Claims (3)

[Claims] Claim 1: In a rotating drum device consisting of a rotating drum equipped with a magnetic head for recording and reproducing information on and from a magnetic tape, and a fixed drum guiding the magnetic tape, a rotating drum device for receiving steel balls of a ball bearing. A shaft-integrated bearing comprising a shaft having a plurality of inner race surfaces and an outer race having a plurality of outer race surfaces provided corresponding to the inner race surface, and a step having a diameter larger than the outer diameter of the outer race. The rotating device is characterized in that the fixed drum is provided with a bearing housing portion having a fixed surface having a smaller diameter than the outer diameter of the outer race separated by a shaped recess, and the outer race is fixed to the fixed surface. drum device. 2. The rotating drum device according to claim 1, wherein the bearing housing portion is provided with a receiving surface for determining the axial position of the shaft-integrated bearing or the shaft. 3. The rotating drum device according to claim 1, further comprising an adhesive insertion hole that reaches the fixed surface.