JPH0245056B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a balancing mechanism for rotating equipment such as a VTR rotating head cylinder.

Balancing of rotating equipment is widely performed on equipment in various fields such as VCR equipment, audio equipment, machine tools, and motors.

This is because vibrations caused by imbalance deteriorate the performance of the equipment and significantly shorten its lifespan.

There are two common balancing methods: negative correction and positive correction. Negative correction is a correction method in which the workpiece is partially cut and removed by machining with a drill, end mill cutter, etc. On the other hand, plus correction is a method in which an appropriate amount of a relatively high-density correction substance (usually about 4 to 8 g/cc) is fixed to a desired part of the workpiece using an adhesive or the like.

However, in such negative corrections, it is relatively difficult to make accurate balance corrections;
In addition, there are problems in that sufficient attention must be paid to the disposal of chips removed by cutting, measures to prevent scratches on the workpiece, the effects of machining added to the workpiece during cutting, and the management of cutting tools. It was hot.

On the other hand, in the case of positive correction, it is relatively difficult to properly control the amount of correction, and it is difficult to make accurate balance corrections in the same way as described above.Furthermore, it is difficult to make accurate balance corrections as described above, and there is also a possibility that fixed correction materials may fall off or the workpiece may be damaged by adhesive-type correction materials. There were problems in terms of preventing stains, etc.

A conventional balancing mechanism applied to a VHS-type VTR rotating head cylinder will be further explained with reference to FIG.
is fixed to the chassis 4 side via a fixing member 3 or the like. Reference numeral 5 denotes a rotating shaft, which is rotatably supported by the lower cylinder 1 via bearings 6a and 6b, and the upper cylinder 2 is fixed by screws or the like to a disk 7 fixed to this rotating shaft. There is.

Further, the following required members are integrally assembled into the upper cylinder 2.

That is, a rotor core 8 and a printed circuit board 9 in the rotary transformer are each fixed to a required surface, and a lead wire 10 is connected between the rotary core 8 and the printed circuit board 9 by soldering 11.

Further, a head H is attached with a fastening screw 12 so as to face the slit between both cylinders 1 and 2. Furthermore, a motor magnet 13 for configuring a direct drive motor is attached to the rotating shaft 5 at a lower portion of the rotating shaft 5 via a magnet fixing base 14 and a magnet mounting plate 15. 16 is a PG magnet, and 17 is a bearing stopper. As described above, in the VTR rotating head cylinder, the rotating shaft 5 includes the disk 7, the upper cylinder 2, the rotor core 8, the head H, the printed circuit board 9, the magnet fixing base 14, the magnet mounting plate 15, and the motor magnet 13.
A large number of members such as the above are assembled integrally by overlapping each other by means such as adhesion or screw tightening, and the rotating member _L1 is constituted by a composite body of these members.

By the way, the conventional balancing method for such a rotating member L ₁ is to perform negative correction on the disc 7 etc. as a single item, or when some parts such as the upper cylinder 2 and the rotor core 8 are assembled thereto. A method is being taken to do so.

However, in order to sequentially perform negative corrections on a single item or a part of several parts assembled, it is necessary to position and hold down the number of parts according to each correction stage or the number of parts to be corrected. This method requires jigs and tools, and the number of work steps also increases, resulting in a problem of higher product costs. Further, there are other problems, such as the need for advanced technology to make accurate balance corrections using negative corrections. Furthermore, when the balance is corrected using individual components and the like is assembled as shown in FIG. 1, the final assembled state includes printed circuit board 9, head H, lead wire 10, and solder
There was a problem in that as various first-class parts or members were further attached, the final balance accuracy, which was most needed, was disturbed. The reasons for the unreasonable modifications mentioned above to the VTR rotating head cylinder are as follows. In other words, first of all, if machining is performed for negative correction at the final assembly stage, precision adjustments of various parts that have been made in the previous assembly process, such as the head H posture, the upper cylinder relative to the lower cylinder 1, etc. 2, there is a risk of damage to the circumferential surface of the cylinder where the tape travels, and there is a risk of bearing due to adhesion of chips as described above. That's the reason. Second, when considering positive correction, which is not normally adopted in rotating head cylinders, the method is to first make a recess on the upper surface of the upper cylinder 2 designated as the correction surface 18, as shown in FIG. Drill a hole and insert 1 steel ball into it.
There is a method to insert 9. Here, the correction surface is a surface on which correction can be performed over the entire 360° circumference around the rotating shaft 5, and can be selected and designated as desired. However, since this method requires a considerable amount of pressure during fitting, there is a problem in that the accuracy of assembly of each part may be disturbed, similar to the case with the above-mentioned machining process.

Another method is to apply a clay-like material with adhesive strength and relatively high density (approximately 5 g/cc) to a large number of liquid agent holding parts radially divided by partition walls on the correction surface. Another method is to use a hardening correction agent as a correction surface and fix it to a desired area. However, with the above structure, it is extremely difficult to form an independent liquid agent holding section consisting of a holding space, a partition wall, etc. in a small rotating body. Furthermore, if the liquid correction agent that has spilled out to unnecessary locations adheres to the tape running surfaces of the outer circumferential portions of the lower cylinder 1 and upper cylinder 2, there is a problem in that it will cause a serious problem in terms of functionality. There was also the issue that it could not be said to be aesthetically pleasing.

This invention aims to solve these conventional problems.

The present invention will be explained below based on the drawings. Second
3 and 3 are drawings showing one embodiment of the present invention.

First, the configuration will be described. Reference numeral 23 in the figure is a rotating shaft, and a cylindrical rotating member _L2 having a stepped portion is integrally attached to this rotating shaft. The rotating shaft 23 is supported by a bearing (not shown) and linked to a rotational drive source via an appropriate rotation transmission mechanism. In this case, correction surfaces 18 and 21 are set in the vicinity of the upper and lower surfaces of the rotating member _L2 , respectively, and each correction surface 18 and 21 has a diameter that is approximately equal to the outer diameter of the cylindrical rotating member _L2 . Annular liquid agent holding portions A ₁ and A ₂ , which will be described next, are respectively formed.

As the correction agent 25, for example, a two-component mixed type epoxy adhesive is used. Epoxy adhesives are available with viscosities ranging from several centipoise to several tens of thousands of centipoises and curing times ranging from several minutes to a long time after mixing, and are appropriately selected from these for use. In addition to the above, an ultraviolet curing adhesive may also be used as the corrective agent. Ultraviolet curing adhesives begin curing after being irradiated with ultraviolet light, so use this when you want to specify the curing time.

Next, the fixing operation and effect of the correcting agent will be explained.
In the present invention, the liquid agent holding portion _A3 is formed of a so-called water-absorbing porous member that adsorbs organic solvents, molten resin, and the like. Incidentally, as an example of the porous member, a foamed metal having a three-dimensional network structure and high porosity is used.

In addition, the above-mentioned two-component mixed type epoxy adhesive is used as a correction agent, but the viscosity thereof is slightly lower than that of normal adhesives, and the adhesive is one that can be properly adsorbed (absorbed) and retained by the porous member. use. Due to its viscosity, the liquid correction fluid 25 that has been absorbed and retained is retained in the three-dimensional network of the porous member and does not leak out of the liquid agent holding portion _A3 even if the rotating member _L2 is rotated. Next, the fixing operation and effect of the correction agent 25 will be explained.

The newly manufactured rotating equipment is tested using a balance testing machine, and if there is any unbalance or eccentricity, the testing machine determines how much weight is applied at various angular positions relative to the axis of the rotating shaft 23. You will be instructed as to whether or not to attach the correction agent 25. Based on this instruction, the epoxy adhesive is mixed and adjusted, and the dispenser injects the required amount of epoxy adhesive into the liquid holding portions A ₁ and A ₂ at the specified angular position. If the mixed and adjusted epoxy adhesive has a low specific gravity, a specific gravity adjusting agent such as metal powder is mixed in advance to adjust the specific gravity to a desired value.

The epoxy adhesive has a viscosity of about a few centipoise, and if the rotation speed is set appropriately, it will not come off even when the rotating member L ₂ is rotated, and the liquid holding parts A ₁ , A ₂ provided with a porous material will not come off. is maintained. Therefore, if desired, after injection, it is rotated while in liquid state before hardening to test whether the dynamic balance has been properly corrected. If the amount injected is too large, insert the dispenser needle and suck up the excess amount; conversely, if the amount is insufficient, replenish. In this way, accurate balance corrections can be made.
If the injection amount is too large, balance is achieved by injecting an appropriate amount of epoxy adhesive into the liquid holding parts A ₁ and A ₂ located on opposite sides of the rotating shaft 23 .

Correcting agent 2 in the above balancing operation
When an ultraviolet curing type adhesive is used as 5, the adhesive can be cured at any time, regardless of whether the dynamic balance is tested before or after curing, which improves workability. will improve.

Since the correction agent 25 is injected in a liquid state by a dispenser, it is possible to prevent unnecessary stress from being applied to the rotating member _L2 during this correction, as in the case of negative correction.

Next, an application example of this invention will be described.

First, Figure 4 shows a first application example, in which a capstan flywheel 26 in audio equipment is shown.
It was applied to 27 is a rotating shaft, and the correction surface 18 is set on the upper surface of a capstan flywheel 26, which is a rotating member.

Next, FIG. 5 shows a second application example. In this application example, the present invention is applied to a VHS system VTR rotating head cylinder. In addition, Figures 4 and 5
In the figures, members or parts that are the same as or equivalent to those in FIG.

A VTR rotating head cylinder is made up of a relatively complex set of many parts and components, and requires high-precision dynamic balance during rotation to prevent image shifts from occurring in the reproduced image. be done. If this invention is applied, only one piece of work can be done at the final assembly stage without creating a processing load on the assembled product.
Accurate balance can be achieved by adjusting the residual unbalance only once. Further, it is possible to avoid problems such as damage to the cylinder circumferential surface, which is the tape running surface.

And when applied to a rotating head cylinder,
The present invention is applicable to rotary head systems other than the above-mentioned VHS system, such as those in which the head disk or head bar is fixed and the head disk or head bar rotates, and those in which a drive system other than a direct drive motor such as a belt drive system is used. It can also be applied to things like

Furthermore, by applying the annular porous member to the liquid holding part, the correction agent is held in the three-dimensional network of the porous member, and the correction agent spills out to areas other than this holding part, staining unnecessary areas. This can be prevented.

In addition, by adopting a porous material with excellent injection properties, water absorption, adsorption properties, and retention properties for the liquid holding part, it is not only possible to inject the correction agent into any location regardless of its viscosity, but also Low viscosity modifiers, which used to protrude into other parts of the holding part of the concave groove and make balancing work difficult, can now be used extremely easily.

As described in detail above, according to the present invention, a liquid agent holding portion made of an annular porous member centered around the rotation axis is formed on the correction surface of the rotating member,
A low-viscosity, hardening liquid modifier that is easy to inject is also injected and fixed into the required part of the liquid agent holding part, which improves workability and accuracy without causing any processing load on the workpiece. The effect is that a good balance correction can be made. Therefore, it is possible to provide an extremely suitable balancing mechanism for rotating equipment such as a VTR rotating head cylinder, in which a large number of parts or members are assembled in a highly accurate positional relationship.

[Brief explanation of drawings]

Figure 1 shows the conventional balancing mechanism.
A partially sectional side view showing a VTR rotating head cylinder.
FIG. 2 is a partially cutaway side view of one embodiment of the balancing mechanism for rotating equipment according to the present invention, FIG. 3 is a view taken in the direction of the X arrow in FIG. 2, and FIG. FIG. 5 is a partially sectional side view showing a second application example of the present invention. 1... Upper cylinder, 2... Lower cylinder, 18, 21... Correction surface, 5, 23, 27...
Rotating shaft, 24a... partition wall, 24b... holding space,
25... Correcting agent, 26... Capstan flywheel, _A1 to _A6 ... Liquid agent holding section, _L1 , _L2 ...
Rotating member.

Claims (1)

[Scope of Claims] 1. A liquid agent holding portion is formed on a correction surface for balancing of a rotating member attached to a rotating shaft, and has an annular porous member having an appropriate diameter centered on the rotating shaft, and A balancing mechanism for rotating equipment, characterized in that an appropriate amount of a viscous and hardening liquid balancing agent is injected and fixed into the liquid agent holding portion.