JPH0656543U - Balance structure of rotating body - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a balance structure for a rotating body that facilitates balance adjustment of the rotating body and enables thinning. When a plurality of small holes are formed in the outer peripheral portion of the rotating body at equal intervals over a predetermined range and uneven rotation occurs in the rotating body and balance adjustment is required, the rotating body A balance structure for a rotating body, wherein the balance weight can be embedded in at least one small hole corresponding to an appropriate position among the small holes formed in the.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rotating body balance structure that facilitates balance adjustment of a rotating drum installed in a device body such as a VTR (video tape recorder) or a DAT (digital audio tape recorder).

[0002]

[Prior art]

 Conventionally, a direct drive flat motor (hereinafter referred to as a DD motor) used in the range of 1,000 to 3,000 rpm is used for the rotary drum of this type VTR and DAT, and the rotary drum is stable. In order to maintain the rotation, various balance structures of the rotating body have been proposed, such as a balance weight being fixed to a part of the rotating body such as a DD motor to adjust the balance.

Hereinafter, a conventional balance structure of a rotating body will be described based on the rotating drum of the DAT shown in FIG. First, the rotary drum 1 of the DAT includes a rotary shaft 2, an upper drum 3 and a lower drum 4 for guiding a medium such as a magnetic tape, a rotary transformer 5 forming a magnetic circuit, and an inner race in which the rotary shaft 2 is a direct bearing. It is composed of a direct bearing 6 that also functions as a device. A head 7 is mounted at a predetermined position on the upper drum 3 via a metallic head base 7a, and a DD motor 10 is installed below the rotary drum 1.

The DD motor 10 is composed of a rotor yoke 11, a magnet 12, a stator coil 13, a rotor plate 14 and the like. Then, in order to adjust the balance of the DD motor 10, the outer peripheral portion of the rotor plate 14 is bent downward to form an L-shaped flange 14a, and the L-shaped flange 14a has an inner peripheral side corner portion at an appropriate position. A proper amount of the balance weight 15 was adhered to and the balance adjustment was performed so that stable high speed rotation of the DD motor could be obtained.

As shown in FIG. 5, the structure of the DD motor 10 is such that a stator yoke 13 is provided on a lower surface of the lower drum 4 and a stator coil 13 is provided on the lower surface of the lower drum 4, and a rotor yoke 11 holding a magnet 12 is provided below the stator coil 13. In the case of the installed structure, the outer peripheral portion of the rotor yoke 11 is curved upward so as to enclose the magnet 12. Therefore, in order to adjust the balance, a groove 11a is formed in advance at a proper position on the outer peripheral portion of the rotor yoke 11, and an appropriate amount of the balance weight 15 is put on and adhered to the groove 11a. .

[0006]

[Problems to be solved by the device]

 However, in the above conventional balance structure, the L-shaped flange 14a must be formed on the outer peripheral portion of the rotor plate 14 depending on the structure of the DD motor 10, so that the processing man-hour increases and the bonded balance weight 15 falls off. This is easy, and the height h1 of the L-shaped flange 14a makes it difficult to reduce the thickness of the DD motor. Further, even when the balance weight 15 is mounted on the concave groove 11a formed on the outer peripheral portion of the rotor yoke 11, the balance weight 15 is easily removed, and the mounting height h2 makes it difficult to make the DD motor thin. there were. In the future, high rotation speeds of 7,000 rpm to 13,000 rpm are planned, and more precise rotation balance is required.

An object of the present invention is to solve the above-mentioned conventional problems, and to provide a balance structure of a rotating body that facilitates balance adjustment of the rotating body and enables high rotation and thinning. To get.

[0008]

[Means for Solving the Problems]

 In order to achieve such an object, the balance structure for a rotating body according to the present invention has a plurality of small holes formed at regular intervals on the outer periphery of the rotating body. If there is rotation unevenness and it is necessary to adjust the balance, the balance weight can be embedded in at least one small hole corresponding to the proper position among the small holes formed in the rotating body. It is characterized by that.

[0009]

[Action]

 In the balance structure of the rotating body according to the present invention configured as described above, when the DD motor has uneven rotation and the balance adjustment needs to be performed, the small hole formed in the rotating body of the DD motor. Among these, by burying the balance weight in at least one small hole corresponding to the proper position, it is possible to obtain stable high-speed rotation of the DD motor.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part showing a balance structure of a rotating body according to the present invention, and FIG. 2 is a partially cutaway top view showing the rotor plate of FIG. The parts will be described with the same reference numerals.

First, the rotary drum 1 of the DAT has a rotary shaft 2, an upper drum 3 and a lower drum 4 for guiding a medium such as a magnetic tape, a rotary transformer 5 that constitutes a magnetic circuit, and an inner race whose rotary shaft 2 is a direct bearing. It is composed of a direct bearing 6 that also serves as a bearing. A DD motor 10 is installed below the rotary drum 1.

The rotor plate 20 constituting the DD motor 10 is formed in a disk shape, and a plurality of small holes 20 a are formed in a predetermined range at equal intervals on the outer peripheral portion of the rotary plate 20. Has been done. Then, when the DD motor 10 has uneven rotation and it is necessary to adjust the balance, at least one or more of the small holes 20a formed in the rotary plate 20 corresponding to the proper position are located. By embedding the balance weight 15 in the small hole 20a, balance adjustment can be performed so that stable high-speed rotation of the DD motor can be obtained.

FIG. 3 is a cross-sectional view of an essential part showing a balance structure of another rotating body according to the present invention. The outer peripheral portion of the rotor yoke 21 of the DD motor 10 is curved upward so as to wrap the magnet 12. In the case of the structure, a plurality of small holes 21a are preliminarily formed in the outer peripheral portion of the rotor yoke 21 at equal intervals over a predetermined range. Therefore, in the case where the DD motor 10 has uneven rotation and it is necessary to adjust the balance, at least one of the small holes 21a formed in the rotor yoke 21 that corresponds to an appropriate position is to be adjusted. By embedding the balance weight 15 in the small holes 21a at the positions or more, balance adjustment can be performed so that stable high-speed rotation of the DD motor can be obtained.

In the embodiment according to the present invention, the balance structure in the rotating drum such as DAT has been described, but the present invention is not limited to this and can be applied to the balance structure of this kind of rotating body. Also, the small holes formed in the outer peripheral portion of the rotating body are not limited to round holes.

[0016]

[Effect of device]

 As described in detail above, in the rotating body balance structure according to the present invention, a plurality of small holes are formed at equal intervals in the outer peripheral portion of the rotating body such as the DD motor. When it is necessary to adjust the balance due to uneven rotation of the DD motor, the balance weight is embedded in at least one small hole corresponding to the proper position among the small holes formed in the rotating body. By doing so, stable high-speed rotation of the DD motor can be obtained. Further, since the balance weight embedded in the small hole of the rotating body does not fall off and the embedded balance weight does not protrude from the rotating body, the DD motor can be made thinner.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a balance structure of a rotating body according to the present invention.

FIG. 2 is a partially cutaway top view of the rotor plate of FIG.

FIG. 3 is a sectional view of an essential part showing a balance structure of another rotating body according to the present invention.

FIG. 4 is a sectional view of a rotary drum showing a conventional balance structure.

FIG. 5 is a sectional view of a main part of a rotary drum showing another conventional balance structure.

[Explanation of symbols]

 1 rotating drum 10 direct drive motor 15 balance weight 20 rotor plate 20a small hole 21 rotor yoke 21a small hole

Claims (1)

[Scope of utility model registration request] 1. When a plurality of small holes are formed in the outer peripheral portion of a rotary body at equal intervals over a predetermined range, and the rotation of the rotary body causes uneven rotation, balance adjustment is required.
A balance weight structure for a rotating body, wherein a balance weight can be embedded in at least one small hole corresponding to an appropriate position among the small holes formed in the rotating body.