JPH0124928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention particularly relates to a bearing device for a rotating shaft that is designed to improve the rotational performance of a rotating shaft that is rotatably supported by a sliding bearing.

Conventional Technology Conventionally, due to the nature of the products, such as audio products, video-related products, and general home appliances targeted at general consumers, it is difficult to expect maintenance to maintain their performance after the consumer purchases them. . Despite the fact that rotating shafts and their bearings, which are subject to severe wear and deterioration, are important elements that determine product performance and lifespan, there is a strong demand to make products as cheap and compact as possible. Therefore, methods such as hydrostatic bearings and forced lubrication, which are used in expensive equipment and devices, are not used.In general, porous oil-impregnated bearings are used for lubrication or lubrication using only the impregnated oil contained inside. Partial oiling is performed using oil-impregnated materials such as felt.

Problems to be Solved by the Invention The above-described conventional bearing devices certainly did not meet cost requirements. However, the oil contained in porous oil-impregnated bearings is extremely small;
Considering the amount of oil lost through evaporation and other factors, there was great concern about long-term performance guarantees. Furthermore, when felt is used, there is a problem in that felt fibers enter the gap between the rotating shaft and the bearing, resulting in a rotational load. For this reason, great care must always be taken from product development and design to manufacturing.

The present invention has been made in view of this situation.

Means for Solving the Problems The present invention provides a porous oil-impregnated sliding bearing member, a shaft made of a magnetic material supported by the bearing member, and a shaft that is magnetized in the axial direction and is concentric with the shaft and the bearing member A ring-shaped magnet is provided in close contact with the end face of the shaft, and the ring-shaped magnet is filled between the shafts.

Effect The present invention efficiently retains the magnetic fluid between the magnet and the shaft with the above configuration, and prevents leakage and evaporation of the lubricating oil from the bearing member, thereby improving the performance of the bearing device with special maintenance. To provide a structure suitable for cases where it is desired to maintain the structure for a long period of time.

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

FIG. 1 is a main sectional view of an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the same essential part. Also the third
The figure shows another embodiment of the main parts constituting the present invention.

In Figure 1, 1 is the rotation axis, for example
Made of magnetic materials such as SUS420 or SK material. A housing 2 is made of a non-magnetic material such as die-cast aluminum or synthetic resin. 3 is a bottom plate, and a regulating member 4 for regulating the downward movement of the rotary shaft 1 is attached thereto. A rotor 5 is fixed to the rotating shaft 1 with screws 11 and rotates integrally with the rotating shaft 1. Note that the rotating shaft 1 or the rotor 5 is rotationally driven by a driving means such as a motor (not shown) via a transmission means or directly.

Reference numeral 6 denotes bearing means, and in this embodiment, three porous oil-impregnated bearing members 6a, 6b, and 6c are press-fitted and fixed into the housing 2. Among these three porous oil-impregnated bearing members 6a, 6b, 6c, two oil-impregnated bearing members 6a,
The inner diameter of the oil-impregnated bearing member 6b is determined to have a clearance with the rotating shaft 1 so as to obtain an appropriate bearing load capacity.
The inner diameter of the rotary shaft 1 is larger than that of the rotary shaft 1, and the gap 10 between the rotary shaft 1 and the rotary shaft 1 is filled with lubricating oil. In addition, the oil content of the oil-impregnated bearing members 6a and 6b is set at around 20%, which is generally expressed by volume, but the oil-impregnated bearing member 6c in the center is set to have as large an oil content as possible. So 35-40%
is selected and impregnated with more lubricant.

7a and 7b are ring-shaped magnets, which are magnetized in the thickness direction as shown in FIGS. 1 and 2. The magnets 7a, 7b are provided with holes 8a, 8b that are slightly larger than the outer diameter of the rotating shaft 1, and the holes 8a, 8b and the rotating shaft 1 are substantially concentric. The magnets 7a and 7b are
The end faces of the porous oil-impregnated bearing members 6a and 6 are respectively
The oil-impregnated bearing members 6a, 6b are attached in close contact with the ends of
Most of the ends of the magnets 7a and 7b are covered with magnets 7a and 7b, and the portions exposed to the outside are extremely small. Further, in order to explain the structure of this part, the main part is shown in an enlarged manner in FIG. What is shown using dotted lines in FIG. 2 is the flow of magnetic flux from the end of the hole 8a of the magnet 7a. The magnetic flux emitted from the north pole at the upper end of the magnet 7a passes through the inside of the rotating shaft 1, which is a magnetic material, and returns to the south pole at the lower end of the magnet 7a, forming a loop. Therefore, the holes 8a of the rotating shaft 1 and the magnets 7a, 7b,
If the gap 8b is filled with magnetic fluids 12a and 12b made by colloidally dispersing fine particles of iron oxide in kerosene, for example, the magnetic flux described above will cause the magnetic fluid 12 to
a and 12b will be retained.

The example shown in FIG. 3 is intended to more effectively retain the magnetic fluid. That is, in the example shown in FIG. 2, the magnetic fluids 12a and 12b are held simply by utilizing the leakage magnetic flux at the end faces of the holes 8a and 8b of the magnets 7a and 7b, but in the example shown in FIG. The cross section of the portion 16 is substantially doglegged, and the inner diameter _d2 of the upper and lower end portions in the thickness direction of the magnet 7c is smaller than the inner diameter _D2 of the central portion. As a result, the upper end 15a and the lower end 15b become protruding, and if magnetization is performed in the thickness direction, magnetic flux will concentrate on the upper end 15a and the lower end 15b, resulting in higher magnetic flux density and more effective magnetic properties. It will be able to hold fluid. Note that the reason why the magnet 7c is divided into two parts, an upper magnet 7d and a lower magnet 7e in FIG. 3, is due to a manufacturing problem.The division is done in order to cope with the existence of an undercut part of the hole 16 and to make it easier to manufacture. This is what I did.

Referring again to FIG. 1, reference numeral 9 is a ring-shaped magnet which is magnetized in the thickness direction and whose pole direction is in the direction in which it is attracted by the magnet 7a, that is, the south pole faces the magnet 7a in the figure. The magnet 7a is attached to the bottom surface by adhesive or other means.
The rotary shaft 1 is fixed substantially parallel to the upper surface of the rotary shaft 1 so that the hole 14 and the rotating shaft 1 are substantially concentric with each other. Therefore, the rotor 5 is attracted downward in the figure due to the attraction force between the magnets 7a and 9, and the rotor 5 is attracted downwardly in the figure.
is pressed against the above-mentioned regulating member 4.
Further, the inner diameter D ₁ of the hole 14 of the magnet 9 is set larger than the inner diameter d ₁ of the hole 8a of the magnet 7a. This is to prevent the magnetic flux flow of the magnet 7a from being disturbed by the effect of the magnet 9, which would adversely affect the retention of the magnetic fluid 12a.

In addition, in the embodiment shown in FIG.
is provided to urge the rotating shaft 1 downward, but a magnetic material may be provided instead of the magnet 9.
It is clear that the same effect can be obtained even if the rotor itself is made of a magnetic material and an attractive force is generated between it and the magnet 7a.

Effects of the Invention As is clear from the above description based on the embodiments, the present invention utilizes a ring-shaped magnet that is closely attached to the end of a porous oil-impregnated bearing member fixed in a housing and magnetized in the thickness direction, and a magnetic body. The magnetic fluid is held by the rotating shaft, and the lubricating oil between the bearing and the rotating shaft is sealed, so the magnetic fluid can be held with an extremely simple and low-cost structure, and the lubricating oil can be effectively used. Since it is contained within the bearing, it is possible to realize a bearing structure with excellent longevity. Furthermore, although a porous oil-impregnated bearing member is used as the bearing member, since the end portion of the bearing member is covered with the magnet, there is very little exposed portion to the outside, and this prevents evaporation or leakage of lubricating oil from the end portion of the bearing member. This makes it possible to effectively prevent this, and effectively utilize the lubricating oil contained in the oil-impregnated porous material. Furthermore, by fixing the magnet and the bearing member in the same housing, ease of assembly and precision can be improved.

In addition, if the cross-sectional shape of the magnet hole is approximately dogleg-shaped to improve the magnetic flux density, the holding power of the magnetic fluid will be improved without increasing the cost, and the lubricating oil will be contained more reliably. By dividing the bearing member of the bearing means into three parts and making the inner diameter of the central part larger than the inner diameter of both ends, the contact length between the bearing and the rotating shaft is shortened, the rotational load is reduced, and more lubricating oil can be sealed. It is something. on the other hand,
By increasing the oil content in the central part, which does not have a large effect on the load capacity of the bearing, more lubricating oil can be retained, and since the bearing members are divided into three parts, increasing the oil content increases strength. The center part, which tends to become weak and have poor molding accuracy, can be easily press-fitted into the housing, and by increasing the inner diameter of the center part, it does not affect finishing such as inner diameter sizing, making it possible to precisely finish the inner diameter of both ends of the bearing means. It can be done easily and has great manufacturing merits. Furthermore, since both end faces of the central bearing member, which has a high oil content, are in contact with the end faces of the other two bearing members, the lubricating oil held in the bearings at both ends effectively supports the rotating shaft. It moves easily to the parts and provides good lubrication. As described above, according to the present invention, a great effect can be expected in that a long life, low load, and highly accurate rotation can be realized with almost no need for maintenance using an extremely inexpensive and simple configuration.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view of the same main part, and FIG. 3 is a sectional view of the main part of another embodiment. 1...Shaft, 2...Housing, 6a, 6b, 6
c...Bearing member, 12a, 12b...Magnetic fluid.

Claims (1)

[Scope of Claims] 1. A housing, a porous sliding oil-impregnated bearing member fixed in the housing so as to expose at least one of the axial end faces of the bearing member, and cover the outer peripheral surface of the bearing member; A rotating shaft made of a magnetic material that penetrates through a bearing means and is rotatably supported, and a ring-shaped magnet that is magnetized in the axial direction and is provided with a hole having a diameter larger than the outer diameter of the rotating shaft. The magnet is fixed so that the rotating shaft and the hole of the magnet are substantially concentric and close the exposed end surface of the porous oil-impregnated bearing member, and the inner surface of the hole of the magnet and the rotating shaft are substantially concentric with each other. A bearing device for a rotating shaft, characterized in that a gap between the porous oil-impregnated bearing member and the shaft is filled with magnetic fluid to seal an exposed end face of the porous oil-impregnated bearing member. 2. A hole for fixing the porous oil-impregnated bearing member in the housing and a hole for fitting the outer diameter of the ring-shaped magnet are provided coaxially, and by fixing the magnet to this hole, the hole of the magnet and the shaft are approximately concentric. A bearing device for a rotating shaft according to claim 1, characterized in that the bearing device is configured to have a shape. 3. Claims characterized in that the cross-sectional shape of the hole of the magnet is substantially dogleg-shaped, and the inner diameter of the upper and lower ends in the thickness direction is smaller than the inner diameter of the central part. 2. The rotating shaft bearing device according to item 1. 4. The bearing means is composed of three bearing members fixed in the housing, and the inner diameter of the bearing member located at the center is larger than the inner diameter of the bearing members located at both ends, and the bearing member located at the center is made larger than the inner diameter of the bearing members located at both ends. The other two bearing members are configured to be in close contact with both ends of the bearing member, and the oil content of the bearing member located at the center is set to be the same as the other two bearing members.
2. The rotating shaft bearing device according to claim 1, wherein the oil content is greater than that of each bearing member.