JPH0628738A - Reel base for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To wind a tape in an excellent way by making a back tension to a magnetic tape stable even when a cone thrust bearing section for a height adjustment screw is worn. CONSTITUTION:A reel blade support cylinder 3 is fitted to a reel base main body as a spline, a reel cap 4 is press-fit to an inner cylinder 1a of the reel base main body 1, a cone thrust bearing 5a of a height adjustment screw 5 screwed to the reel cap 4 is received by an upper end cone 6a of a reel shaft 6 to form a partial cone thrust bearing 7. A press-fit escaping torus concaved part 5c is formed between an upper end of the reel shaft 6 and the abutting part of a height adjustment screw 5 of the reel base with respect to the upper end of the reel shaft 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reel stand in a magnetic recording / reproducing apparatus using a magnetic tape such as a VTR, and more particularly to a conical thrust receiving reel stand.

[0002]

2. Description of the Related Art FIG. 5 shows a cross section of a conventional conical thrust receiving type reel stand.

In the figure, reference numeral 1 denotes a reel stand body in which a concentric inner cylinder portion 1a and an outer cylinder portion 1b are integrated, and a compression coil spring 2 is loosely fitted in the inner cylinder portion 1a of the reel stand body 1. At the same time, the reel blade holding cylinder 3 having a plurality of reel blades 3a on the peripheral surface is spline-fitted in a vertically slidable manner, the lower surface of the reel blade holding cylinder 3 is supported by the compression coil spring 2, and the reel cap 4 is reeled. Blade holder 3
The inner cylindrical portion 1 of the reel stand main body 1 in a state of being loosely fitted inside.
Pressed into a and fixed. A height adjusting screw 5 having a conical thrust bearing portion 5a is screwed into the reel cap 4, and the conical thrust bearing portion 5a of the height adjusting screw 5 abuts against the upper end conical portion 6a of the reel shaft 6. It is supported. The contact portion constitutes a partial conical thrust bearing 7. Below the reel stand body 1, a felt 8, a slip gear 9, a felt plate 10, and a compression coil spring 11 are provided.
Is provided with a slip mechanism.

The height of the reel stand after it is inserted into the reel shaft 6 is adjusted by rotating the height adjusting screw 5 relative to the reel cap 4. When the reel of the video cassette tape is placed on the reel stand body 1, the thrust load applied to the reel stand along the axial direction of the reel shaft 6 is received by the upper conical portion 6 a of the reel shaft 6. At this time, the conical portion 6a
A load torque is generated that is determined by the angle and the friction coefficient of the tape, and an appropriate back tension is applied to the tape during high-speed rotation, enabling stable winding of the tape.

[0005]

FIG. 6 is an enlarged view of the partial cone thrust bearing 7 in the initial stage of use of the magnetic recording / reproducing apparatus. The partial conical thrust bearing 7 configured by abutting the conical thrust bearing portion 5a of the height adjusting screw 5 and the conical portion 6a of the reel shaft 6 adjusts the height of at least the lower half of the conical portion 6a of the reel shaft 6. The entire surface is in contact with the conical thrust bearing portion 5a of the screw 5. This is because the inclination angle of the conical portion 6a and the inclination angle of the conical thrust bearing portion 5a are exactly the same.

FIG. 7 shows a height adjusting screw 5 with continued use.
The situation when the conical thrust bearing portion 5a of FIG. The lower end 5b ₁ of the worn portion 5b is not a conical shape but a cylindrical shape, and the lower end corner portion 6a ₁ of the conical portion 6a of the reel shaft 6 bites into the lower end portion 5b ₁ . Therefore, the light press-fitting portion 7a is generated in the partial conical thrust bearing 7, and the load torque increases. As a result, there is a problem that the back tension on the magnetic tape increases at the time of high speed rotation, and it becomes difficult to stably wind the tape.

The present invention has been devised in view of the above circumstances, and a partial conical thrust bearing caused by abrasion of a conical thrust bearing portion can be produced without a great increase in cost due to only a simple structural improvement. The purpose is to avoid the light press-fitting phenomenon.

[0008]

In the reel stand of the magnetic recording / reproducing apparatus according to the present invention, the upper end of the reel shaft and the contact portion of the height adjusting screw of the reel stand with the upper end of the reel shaft are formed in a conical shape. And a reel stand configured to receive the thrust load of the reel stand by the partial conical thrust bearing which is the abutting portion, and the height adjustment of the reel stand with respect to the upper end of the reel shaft and the upper end of the reel shaft. An annular recess for press-fitting escape is formed between the abutting portions of the screws.

[0009]

Since the press-fit escape annular recess is formed between the upper end of the reel shaft and the contact portion of the height adjusting screw of the reel base with respect to the upper end of the reel shaft, the magnetic recording / reproducing apparatus can be used continuously. Even if the conical thrust bearing portion is worn, no bite occurs, so that the light press-fit phenomenon of the partial conical thrust bearing is avoided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a reel stand of a magnetic recording / reproducing apparatus according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing a structure of a conical thrust receiving type reel stand in a VTR (video tape recorder), and FIG. 2 is an enlarged sectional view showing an essential part of a partial conical thrust bearing in an initial stage of use of the VTR. .

As in the case of the conventional example, a concentric inner cylindrical portion 1
The reel coil holder 2 has a compression coil spring 2 loosely fitted to the inner cylinder 1a of the reel stand body 1 in which a and the outer cylinder 1b are integrated, and has a plurality of reel blades 3a on its peripheral surface.
Is vertically slidably fitted, the lower surface of the reel blade holding cylinder 3 is supported by the compression coil spring 2, and the reel cap 4 is loosely fitted in the reel blade holding cylinder 3 so that the reel stand main body It is press-fitted and fixed to the inner cylindrical portion 1a of No. 1. A height adjusting screw 5 having a conical thrust bearing portion 5a at the lower inner circumference is screwed into the reel cap 4, and the conical thrust bearing portion 5a of the height adjusting screw 5 is attached to the upper end conical portion 6a of the reel shaft 6. It is abutted and pivotally supported. The contact portion constitutes a partial conical thrust bearing 7. Below the reel stand body 1, a slip mechanism including a felt 8, a slip gear 9, a felt plate 10, and a compression coil spring 11 is provided. Regarding the above structure, the conventional example and the present example are the same.

This embodiment is different from the conventional example in the following points. That is, as shown in the enlarged cross-sectional view of the main part of FIG. 2, on the lower end side of the partial conical thrust bearing 7, the height adjusting screw 5 is provided in a state corresponding to the lower end corner portion 6a ₁ of the upper conical portion 6a of the reel shaft 6. An annular recess 5c for press fit escape is formed in the conical thrust bearing portion 5a. At the initial stage of using the VTR, the upper cone portion and the lower corner portion 6a of the reel shaft 6 are
Reference numeral ₁ does not serve as the abutting portion of the partial conical thrust bearing 7 and corresponds to the press-fit escape annular recess 5c, and has a margin in the axial direction at the press-fit escape annular recess 5c. Located in position.

When the reel of the video cassette tape is placed on the reel stand main body 1, the thrust load applied to the reel stand along the axial direction of the reel shaft 6 is received by the upper conical portion 6a of the reel shaft 6. A load torque that is determined by the angle of the conical portion 6a and the friction coefficient is generated, and an appropriate back tension is applied to the tape during high-speed rotation, enabling stable winding of the tape.

Now, FIG. 3 shows a state in which the conical thrust bearing portion 5a of the height adjusting screw 5 is worn as the VTR is continuously used. Due to the occurrence of the worn portion 5b, the reel shaft 6 moves up relative to the height adjusting screw 5. However, since the press-fit escape annular recess 5c exists,
The lower end corner portion 6a ₁ of the upper conical portion 6a enters in the press-fit escape annular recess 5c, but is still in the press-fit escape annular recess 5c.
Since it remains in c, it does not bite into the worn portion 5b. That is, the light press-fitting phenomenon as in the case of the conventional example is avoided. Therefore, the load torque does not increase when the reel of the magnetic tape is placed on the reel stand, and a stable load torque can be obtained. As a result,
The back tension on the magnetic tape does not increase during high-speed rotation, and the winding of the magnetic tape can be made stable.

As another embodiment of the present invention, as shown in FIG. 4, a press-fit escape annular recess 6 is provided on the reel shaft 6 side.
b may be formed.

[0017]

As described above, according to the present invention, even if the conical thrust bearing portion of the height adjusting screw is worn, the presence of the annular recess for press-fitting escape avoids the light press-fitting phenomenon of the partial conical thrust bearing. Therefore, the load torque can be stabilized when the magnetic tape reel is placed on the reel stand. In other words, it is possible to stabilize the back tension applied to the tape during high-speed rotation without increasing the cost only by a simple structural improvement of forming the press-fit escape annular recess, and always keep the magnetic tape in a stable state. Can be wound up.

[Brief description of drawings]

FIG. 1 shows a magnetic recording / reproducing apparatus (V according to an embodiment of the present invention.
FIG. 3 is a sectional view showing the structure of a conical thrust receiving type reel stand in (TR).

FIG. 2 is an enlarged sectional view of an essential part showing a partial conical thrust bearing at an initial stage of use in the reel stand of the embodiment.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a partial conical thrust bearing at a stage where wear occurs due to continued use in the reel stand of the embodiment.

FIG. 4 is an enlarged sectional view corresponding to FIG. 2 of another embodiment of the present invention.

FIG. 5 is a sectional view showing the structure of a conical thrust receiving type reel stand in a magnetic recording / reproducing apparatus (VTR) according to a conventional example.

FIG. 6 is an enlarged sectional view of an essential part showing a partial conical thrust bearing at an initial stage of use in a reel stand of a conventional example.

FIG. 7 is an enlarged cross-sectional view of an essential part showing a partial conical thrust bearing at the stage of wear occurring with continued use in the reel stand of the conventional example.

[Explanation of symbols]

1 reel stand body 3 reel blade holding cylinder 4 reel cap 5 height adjusting screw 5a conical thrust bearing part 5b worn part 5c, 6b press-fit escape annular recess 6 reel shaft 6a upper conical part 6a ₁ lower end corner 7 partial conical thrust bearing

Claims (1)

[Claims] 1. A portion of the reel shaft, wherein the upper end of the reel shaft and the contact portion of the height adjusting screw of the reel base with respect to the upper end of the reel shaft are formed in a conical shape, and the thrust load of the reel base is the contact portion. A reel stand configured to be received by a conical thrust bearing, wherein a press-fit escape annular recess is formed between the upper end of the reel shaft and the contact portion of the height adjusting screw of the reel stand with respect to the upper end of the reel shaft. A reel stand of a magnetic recording / reproducing apparatus characterized by being provided.