JPS5916316A - Rotary device - Google Patents

Abstract

PURPOSE:To stabilize the characteristic without making a device large-sized by a method wherein grooves whose size changes from the side of rotational center toward the outside are formed on at least one of opposed surfaces of a rotary transformer. CONSTITUTION:Coils 29a and 29b are wound around grooves 28a and 28b of the main body of core of the rotary transformer. The surface except for the grooves is covered with non magnetic substance 39, and the shallow grooves 40a is so formed that the outer peripheral side becomes larger than the center side. When current flows into a stator coil 41, resulting in the increase of rotary speed to some degree, the lubricant which fills the space between opposed surfaces of a rotary side core 9 and a fixed side core 10 is fed to the center side under pressure and then generates a high pressure in a thrust direction, and then a dynamic fluid thrust bearing 26S is formed and holds the rotary part by balancing with the force generated by a thrust bearing 17S. Thus, the gap between the opposed surfaces of the rotary transformer can be determined with a good accuracy without making whole the rotary head cylinder large-sized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating device, and more particularly to a rotating device having a rotary transformer for transmitting signals between a rotating member and a stationary member, such as a rotating head cylinder of a magnetic recording/reproducing device. It is.

Hereinafter, in this specification, a case will be described in which the present invention is applied to a rotary head cylinder of a magnetic recording/reproducing device.

FIG. 1 is a diagram showing an example of a conventional rotary head cylinder. 1 is a fixed cylinder as a fixed member of the present invention; 2;
3.4 is a rotating member of the present invention, 2 is a rotating shaft member, 6 is a supporting member, and 4 is a rotating upper cylinder having a magnetic head 5.

rotates as one. The rotating shaft member 2 is rotatably supported by a roller bearing 6.7 with respect to the fixed lower cylinder 1. A roller 8 is a member for applying an axial force to the bearing 7.

In addition, the support member 3 has a rotating side core 9 of a rotary seat.
The fixed cylinder 1 is provided with a fixed core 10 that faces the rotating core 9 .

11 to 14 are motor parts for rotating the rotary upper cylinder 4, 11 is a rotary yoke, 12 is a rotary magnet, 13 is a stator yoke, and 14 is a stator building.

The smaller the gap between the rotating core 9 and the stationary core 10, the higher the signal transmission efficiency. On the other hand, since the two need to rotate relative to each other, the gap must be kept in the range of several tens of microns to a hundred and several tens of microns.

In the rotating head cylinder shown in FIG. 1, there are large variations in the @ (indicated by t in FIG. 1) of the rolling bearings 6.7.

Therefore, it is necessary to attach the rotating side core 9 and stationary side core 10 of the rotary transformer with high precision, and also to provide an adjusting member 15 such as a washer to adjust the gap, and to change the thickness of the adjusting member 15. It was extremely troublesome.

FIG. 2 is a diagram showing another conventional example of a rotary head cylinder. Components that are the same as those in FIG. 1 are given the same numbers. 16.17 is a fluid bearing. Rotating shaft member 2
At the fitting part 18 of the fixed cylinder 1, the rotating shaft member 2
It has a fishbone-shaped groove. When the rotating shaft member 2 rotates, a lubricant such as grease or oil filled in the fitting portion 18 is pumped and generates high pressure. This allows the fishbone-shaped groove to form a radial fluid bearing 1.
6R and 17B, the rotating shaft member 2 is held at the center of the hole in the fixed cylinder.

Further, the upper surface of the fixed cylinder and the lower surface of the support member 6 facing thereto, and the lower surface of the fixed cylinder and the upper surface of the preload member 8 facing thereto form fluid bearings 168 and 178 in the thrust direction, respectively. That is, a groove is formed in at least one of each facing surface so that the lubricant can be pumped by the rotation of the shaft member 20, and pressure is generated in a direction parallel to the rotation axis.

In the configuration shown in FIG. 2, by accurately attaching the rotation side core 9 and the output side core 10 with precision, it is possible to make the gap between several tens of microns to a hundred and several tens of microns. However, since the thrust bearing portions 16S and 17S are provided and a rotary transformer is further provided outside of the thrust bearing portions 16S and 17S, the entire rotating head cylinder becomes large in size. Conversely, when the size of the cylinder is determined, the size of the rotary transformer is limited, making it difficult to increase the number of channels of the rotary transformer.

The object of the present invention is to eliminate the drawbacks of the conventional examples as described above and to provide a rotating device that stabilizes the characteristics of a rotary transformer without increasing the size of the device. FIG. 5 is a diagram showing a rotary head cylinder as an embodiment of the present invention. The same components as in FIG. 2 are given the same numbers. A groove is formed in one or both of the facing surfaces of the rotating side core 9 and stationary side core 100 of the rotary transformer so that the lubricant filled in the fitting part 19 can be pumped by 20 rotations of the shaft member, and a groove is formed in the thrust direction. It acts as a fluid bearing 26S.

For example, the configuration is as shown in FIGS. 4 and 5. FIG. 4 is a plan view showing the facing surface of the rotating core 9 or the stationary core 100 of the rotary transformer, and FIG. 5 is a sectional view of the core shown in FIG. 4.

Grooves 23a and 28b provided in a part of the core body 19
Coils 29 to 79b are wound around each of the coils 29 to 79b. In addition, the opposing surface of the core except for the grooves 2sa and 28b is made of a non-magnetic material filter 9.
covered by Shallow grooves 40a, which correspond to the grooves of the present invention, are formed on the surface of the non-magnetic material 690 from the outer circumferential side to the center side of the core. When the transformer core shown in FIG. 4 rotates in the direction of arrow 41, the shallow groove 401L is formed so that the size (groove depth x groove width) is larger on the outer circumference side than on the center side. ing. This forces the lubricating fluid (grease, oil, or air) filled between both transformer cores 19, 2 (E7)i on the same plane toward the center,
A hydrodynamic thrust bearing 268 can be formed by generating high pressure in the thrust direction.

The hydrodynamic thrust bearing 26S as described above is provided at the position shown in FIG. 6, and is formed by the lower surface of the fixed cylinder 1 and the upper surface of the preload member facing thereto. The force in the thrust direction generated by the thrust bearing 17S and the force in the thrust direction generated by the above-mentioned thrust bearing 26S interact with each other.

Next, the operation of the configurations shown in FIGS. 6, 4, and 5 will be explained. When the rotating part including the shaft member 2 and the support member 6 is not rotating, the bearing 26S is
The gap is 0, and the facing surfaces of the core 9 and the core 100 are in contact with each other. When a current flows through the stator coil 14 and the rotating section starts rotating, the core 9 and the core 100 initially rotate while the facing surfaces thereof remain in contact with each other. However, by reducing the diameter of the opposing surfaces in contact, the coefficient of friction can be reduced, and the torque loss will not become so large. When the rotation speed increases to a certain extent, the core 9 is lifted away from the core 10 due to the above-mentioned pressure increase due to the shallow groove 4D&, and the rotating part is held by the force generated by the thrust bearing 17S.

If the shaft member 2 is placed horizontally, the radial bearings 16R and 17R will come into contact with the fixed lower cylinder F1 and begin to rotate when the rotating part is not rotating.

In this case, thrust bearings 173 and 26S do not receive any load. The radial bearings 16R and 17R have small diameters and their contact area is extremely small, so the friction torque can be minimized and the shaft member 2 can be lifted up with a certain amount of rotation.
can be held in the center of the bore of the fixed lower cylinder 1.

The amount of force generated in the two thrust bearings 268 and 178 described above is determined by the area of each opposing surface, the structure of the groove, and the viscosity of the lubricant. For example, if the area of the opposing surfaces of the cores 9 and 10 is large, a lubricant with low viscosity may be used, and if the area of the opposing surfaces is small, a lubricant with high viscosity may be used.

As described above, according to the configurations shown in FIGS. 6, 4, and 5, it is possible to accurately determine the distance between the facing surfaces of the rotary transformer without increasing the size of the entire rotating head cylinder. be.

FIG. 6 is a diagram showing a rotary head cylinder as another embodiment of the present invention. The same components as in FIG. 3 are given the same numbers. This example uses a 4-channel large rotary transformer. One radial bearing (2
6R) only, both cores of rotary transformer 9.1
A thrust bearing 26S that utilizes an opposing surface of 0 and a thrust bearing 178 that generates pressure in the opposite direction are used. A surface facing type motor is used as the rotary drive motor, and the suction force between the rotary magnet 12 and the stator yoke 16 is used to apply a preload in the direction of pressing the opposing surface of the thrust bearing 17S. This makes startup easier. That is, when stopped, the bearing 17S is pressed into contact by the suction force of the motor, and a large gap is left between the facing surfaces of the bearing 26S. At this time, when the motor starts and the shaft member 2 starts rotating, the bearing 1
Although the opposing surfaces of 780 are in contact with each other, this contacting portion is near the center of rotation and the generation of torque due to υ friction is small. As the rotational speed increases, the opposing surfaces of the bearing 178 are released from contact, and the distance between the opposing surfaces increases.

At this time, as the gap between the bearing 26B becomes smaller, the bearing 26B becomes smaller.
Pressure is also generated at the bearing 26S, and the pressure is stabilized at a position where the force generated by the bearing 17S, the suction force of the motor, and the force generated by the bearing 26S are combined.

In this example, there is only one radial bearing (26R), but since the diameter of the thrust bearing 26S is large, the shaft sag, and the rigidity is the same as when two radial bearings are used.

Now, in this example, the area of the facing surface of the thrust bearing 26S is large and the force is generated in the same direction as the suction force of the motor, so air is used as the lubricant. 8 is a sectional view of the core shown in FIG. 7.

As shown in FIG. 8, the core body 190 is
The surface and the grooves 2sa, 28b, 280 and 284 are covered to smooth the opposing surface. The left half of FIG. 7 is a diagram with the non-magnetic material 69 removed. In this example, it is possible to form shallow grooves 40a in almost the entire portion of the opposing surface, and even if the lubricant is air with low viscosity, pressure can be generated.

As mentioned above, in the configurations of the other embodiments of the present invention shown in FIGS. 6, 7, and 8, it is possible to avoid increasing the size of the rotary head cylinder as a whole, and to reduce the distance between the opposing surfaces of the rotary transformer. Intervals can be determined accurately. Furthermore, in this configuration, air with a small change in viscosity is used as the lubricant for the thrust bearing 268, so FIGS. 9 and 10 are cross-sectional views showing still another embodiment of the core of the rotary transformer. 9th
In the illustrated example, the core body 190 is
The front surface, winding groove, back surface, and side surfaces are also covered.

This makes it possible to protect the core body 19, which is made of a very brittle material such as Ferrai F, which is a material that is easily broken.

In the example shown in FIG. 10, only a part of the opposing surface is coated with the non-magnetic material 39. When using a lubricant with a very strong viscosity, sufficient pressure can be obtained even if the area in which the shallow grooves 40a are provided is made small.

In this specification, a non-magnetic material is used as a coating for the opposing surface of the core of a rotary transformer used as a thrust bearing, but a soft magnetic material may also be used.

Further, the shallow groove 4Oa as the groove of the present invention may be carved anywhere as long as it is carved in a part or the entire area of the facing surface of the core.

Further, in this specification, an embodiment in which the present invention is applied to a rotating head cylinder used in a magnetic recording/reproducing device, etc. has been described as an example, but a fixed member, a rotating member, and signals are transmitted between these members. Any device having a rotary transformer is applicable.

As described above, according to the present invention, a rotating device is obtained that can accurately determine the gap between opposing surfaces of a rotary transformer without increasing the size of the device.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an example of a conventional rotary head cylinder, Fig. 2 is a diagram showing another conventional example of a rotary head cylinder, Fig. 5 is a diagram showing an embodiment of the present invention, and Fig. 4 is a diagram showing an example of a conventional rotary head cylinder. FIG. 6 is a plan view showing opposing surfaces of the core of the rotary transformer; FIG. 5 is a sectional view of the core shown in FIG. 4; FIG. 6 is a view showing another embodiment of the present invention; FIG. A plan view showing opposing surfaces of the core of the rotary transformer shown in FIG. 6, and FIG. 8 a cross-sectional view of the core shown in FIG. 7. 9 and 10 are diagrams showing other embodiments of the core of the rotary transformer. 1 is a fixed cylinder as a fixed member, 2 is a rotating shaft member,
Reference numeral 5 indicates a support member, 4 indicates a rotating cylinder, 9 indicates a rotating core of a rotary transformer, 10 indicates a stationary core of a rotary transformer, 69 indicates a non-magnetic material, and 40a indicates a shallow groove. Applicant Canon Co., Ltd. Agent Gi Marushima − 66 −

Claims (1)

[Claims] 1) A rotating device including a fixed member, a rotating member, and a rotary transformer for transmitting a signal between the rotating member and the fixed member, the rotating device having at least one opposing surface of the rotary transformer. A rotating device characterized in that a groove whose size changes from the rotation center side toward the outside is formed.