JPH11325076A - Oil retaining bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the peeling of a glass solidified body and to surely prevent the bleeding of a lubricant by impregnating the surface of a circular oil retaining bearing other than a through hole face with a material noncompatible with the lubricant to form the glass solidified body. SOLUTION: The surface of an oil retaining bearing 1 other than a through hole 1a face is coated and impregnated with a siloxane polymer solution added with an organic solvent to a siloxane polymer which is a material noncompatible with a lubricant, and it is left at the ordinary temperature and dried and fixed to form a glass solidified body 2. An end section in the axial direction of the portion of the glass solidified body 2 is tapered so that the diameter is increased toward the outside. The portion of the glass solidified body 2 is chemically stabilized by a hard inorganic material, it is not affected by the component of the lubricant, and the bleeding of the lubricant from the surface of the oil retaining bearing 1 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring-shaped oil-impregnated bearing having a through hole for inserting a shaft member at a central portion and impregnated with lubricating oil, and more particularly to a developer for a developing device of an image forming apparatus. The present invention relates to a device that supports a shaft member of a stirring body.

[0002]

2. Description of the Related Art A conventional oil-impregnated bearing is made of a porous metal body obtained by molding a metal powder and then sintering the lubricating oil into the pores of the metal body. The lubricating oil in the bearing performs a lubricating effect by a so-called self-lubricating effect in which the lubricating oil in the bearing oozes into a sliding portion between the rotating shaft and the bearing by a combined effect of the oil and the pumping action.

In this case, since a large number of small holes are formed on the surface of the bearing, part of the lubricating oil seeps from the inner diameter side of the bearing to the outer diameter side due to the influence of the pressure generated during the formation of the oil film. A flow circulating again to the inner diameter side is generated again, and the oil film pressure is generated by the wedge effect due to the rotation of the rotating shaft, but since the oil film pressure decreases from the small holes on the surface, the oil film pressure on the load side is reduced. It is difficult to sufficiently maintain and easily falls into the boundary circulation region.

[0004] In addition, since there is an operating clearance peculiar to a sliding bearing, a load (radial load) in a direction perpendicular to the rotating shaft is provided.
If the operation is performed in a state where the rotation shaft is not subjected to the vibration, there is a problem that the rotation shaft is liable to run out or violently by an amount corresponding to the operation gap, and a stable operation cannot be obtained. On the other hand, in order to cope with these difficulties, as a technique for effectively retaining the lubricating oil component impregnated in the sintered oil-impregnated bearing in the sintered metal, Japanese Utility Model Application Publication No.
There is a bearing made of a sintered metal as described in Japanese Patent No. 29536.

In this method, a joint is formed in a convex shape on one side of an annular inner powder-molded sintered metal part having a bearing part,
Similarly, it is made of an externally compacted sintered metal part having a joint formed on the other side in a convex shape. The two sintered metal parts are joined at their respective joints, and a lubricating oil is provided between the two sintered metal parts. A storage portion is formed, and the lubricating oil stored in the lubricating oil storage portion oozes out of the sintered metal body to provide a lubricating effect when the rotating shaft rotates.

In order to prevent the leakage of the lubricating oil component of the sintered oil-impregnated bearing, a sintered oil-impregnated bearing 12 is pressed into a housing 11 made of die-cast, brass or stainless steel as shown in FIG. As shown, there was a sintered oil-impregnated bearing 12 having a Teflon coat layer 13 formed on the surface.

[0007]

However, in the above-described apparatus, firstly, it is easy to form an oil film with respect to a load (radial load) in a direction perpendicular to the rotation axis. Load (thrust load)
Secondly, in the case of motors with specifications in which the formation of an oil film is small and the allowable value is low, and secondly, radial loads are not applied to the motor, which results in rattling corresponding to the operating gap, resulting in shaft runout of the rotating shaft and hindering motor operation. There are problems such as the fact that many people come.

Thirdly, the supply of the lubricating oil to the sliding portion of the oil-impregnated bearing is generally performed only by seeping out from a hole in the inner (inner) side sliding surface. It is impossible to supply lubricating oil enough to fill the operation gap, and it is easy for rattling or runout of the rotating shaft to occur, which also often hinders motor operation.
Fourth, the bleeding hole of the lubricating oil of the oil-impregnated bearing may lower the oil pressure of the sliding portion, and may also scatter the lubricating oil to a place where the oil is disliked. There was a problem.

According to the bearing structure in which the sintered oil-impregnated bearing described later is press-fitted into the housing, the dimensions of the housing are not always accurate. There is a problem that accuracy is affected by accuracy, and the accuracy is worsened.If the housing is to be machined with high accuracy, the cost will increase, and the housing itself is made of die-cast, brass or stainless steel, which is expensive, and the housing is impregnated with oil. There is a problem in that the operation of press-fitting the bearing is required, so that the assembly cost is increased.

[0010] In general, sintered oil-impregnated bearings are 15 to 22.
%, It is unavoidable to adversely affect the size and roundness of the inner diameter of the sintered oil-impregnated bearing when pressed into a housing such as a die cast as described above. Therefore, it is conceivable to press-fit the sintered oil-impregnated bearing directly to the inner periphery of the mounting hole without using the housing.However, lubricating oil flows out from the outer peripheral surface of the sintered oil-impregnated bearing, and the lubricating oil is insufficient. As a result, problems such as burning of the rotating shaft and adhesion of lubricating oil to other surrounding parts and contamination occur.

In the case where the Teflon coat layer is formed on the surface of the sintered oil-impregnated bearing, the Teflon coat layer is only formed as a film on the surface of the sintered oil-impregnated bearing. There was a problem that peeling of the coat layer occurred.

The present invention has been made in view of the above problems, and by forming a vitrified body on the surface of an oil-impregnated bearing, it is possible to prevent the impregnated lubricating oil from seeping out from the surface other than the contact surface with the shaft member. An object of the present invention is to prevent the use of a housing in which an impregnated bearing is fitted without using the housing.

[0013]

According to a first aspect of the present invention, there is provided an annular oil impregnated with a lubricating oil having a through hole for inserting a shaft member in a center portion. In the bearing, a vitrified body is formed by impregnating at least a surface of the oil-impregnated bearing other than the through-hole surface with a substance incompatible with lubricating oil.

The substance according to the second aspect of the present invention is a solution of a siloxane polymer.

According to the third aspect of the present invention, the exposed surface of the oil-impregnated bearing in use is impregnated with a solution of a siloxane polymer to form a vitrified body.

According to a fourth aspect of the present invention, a vitrified body is formed by impregnating the oil-impregnated bearing and leaving the solution of the siloxane polymer at room temperature or calcining and fixing at a temperature lower than the melting temperature of the material forming the oil-impregnated bearing.

According to a fifth aspect of the present invention, the mixing ratio of the solvent added to the solution of the siloxane polymer is less than 5%.

In the invention according to claim 6, the layer thickness of the impregnated layer of the siloxane polymer is 5 μm or more.

According to a seventh aspect of the present invention, there is provided a ring-shaped oil-impregnated bearing having a through hole for inserting a shaft member at a central portion thereof and impregnated with lubricating oil, wherein at least a surface of the oil-impregnated bearing other than at least the surface of the through-hole. A sealing member for preventing leakage of lubricating oil from the oil-impregnated bearing is fitted to the oil-impregnated bearing, and a contact surface of the oil-impregnated bearing with the sealing member is impregnated with an incompatible substance to form a vitrified body. .

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An oil-impregnated bearing according to a first embodiment of the present invention will be described with reference to FIGS.

First, as shown in FIG. 1, the oil-impregnated bearing 1 is formed of sintered metal in a ring shape having a through hole 1a for inserting a rotating shaft as a shaft member at a central portion thereof. The high quality oil-impregnated bearing 1 was configured by impregnating the pores with lubricating oil.

Then, at least the surface of the oil-impregnated bearing 1 shown by hatching in FIG. 2 other than the surface of the through-hole 1a is formed by adding an organic solvent to a siloxane polymer which is a substance incompatible with lubricating oil to form a solution. The coalescing solution is applied and impregnated, left at room temperature and dried and fixed to form a vitrified body 2. The end in the axial direction of the portion formed in the vitrified body 2 is tapered so that the diameter increases outward.

As described above, the vitrified body 2 is formed by applying and impregnating the oil-impregnated bearing 1 with the siloxane polymer solution, and the vitrified body 2 is made of a hard inorganic material and is scientifically stable. The impregnated bearing 1 is not affected by the components of the lubricating oil, and is in the same state as the state in which the impregnated bearing 1 is housed in a strong glass case.
Leaching of the lubricating oil from the surface of the metal is prevented.

Moreover, since the siloxane polymer solution is applied and impregnated on the surface of the oil-impregnated bearing 1, the vitrified body 2 is formed in a state where the siloxane polymer solution has penetrated from the surface of the oil-impregnated bearing 1 to the inside. It will be. Therefore, a strong film is formed in which the bonding force between the vitrified body 2 and the oil-impregnated bearing 1 is large and a strong film is formed, and the peeling of the vitrified body 2 from the oil-impregnated bearing 1 can be reliably prevented, and the strength of the oil-impregnated bearing 2 is reduced. Can also be stronger.

That is, the surface hardness of the vitrified body 2 is
As shown in Table 1, the substrate SUS304 (which was polished with a # 240 sandpaper and degreased with acetone) was coated with 5-1.
As a result of a pencil strength test performed on a sample sprayed and impregnated at a thickness of 0 μm, 1
The intensity after 4 days is 4H.

Further, the siloxane polymer solution is added in an amount of 5 to 10 μm.
m after spraying and impregnating with a thickness of 80 m
In the case where the vitrified body 2 was formed at a temperature of 150 ° C., 170 ° C., and a baking time of 30 minutes, the surface hardness was as shown in Table 1.

[0027]

[Table 1]

As shown in Table 1 above, the sintering temperature of the siloxane polymer solution was about 170 ° C. as shown in each experimental example, and the melting temperature of the base metal of the oil-impregnated bearing 1 was 800.
Since it is fired at a very low temperature as compared with ~ 1100 ° C, there is no occurrence of deterioration or deterioration of the base metal due to thermal damage.

FIG. 3 shows an embodiment in which the oil-impregnated bearing 1 of the first embodiment is used in a developing device. The oil-impregnated bearing 1 is provided in a main body housing 3 of the developing device, and the oil-impregnated bearing 1 is provided in a through hole 1a. The rotating shaft 5 of the developer stirring member 4 for stirring the developer is inserted therethrough and the seal member 6 is inserted therethrough.

In the developing device having such a configuration, the developer comes into contact with the vitrified body 2 of the oil-impregnated bearing 1 by rotating the developer agitator 4 to stir the developer. This prevents the lubricating oil impregnated into the developer from being sucked out by the developer due to the capillary phenomenon, thereby preventing the problem that the developer hardens.

In addition to the shape as in the first embodiment,
As in Embodiment 2 shown in FIG. 4, the oil-impregnated bearing 1 is formed in a cylindrical shape, and the vitrified body 2 is formed only on the outer peripheral surface of the oil-impregnated bearing 1.
May be formed, and the vitrified body 2 may be formed on the outer peripheral surface and the axial end surface of the oil-impregnated bearing 1 as in Embodiment 3 shown in FIG.

Next, 100%, 98%, 96%, 9
A 4%, 92% siloxane polymer solution was spray-coated and impregnated at a thickness of 5 to 10 μm to form a vitrified body 2 and subjected to a bending test to determine the concentration and viscosity of the siloxane polymer solution (coating agent). Table 2 shows the results of comparison of the adhesion due to

[0033]

[Table 2]

As shown in the experimental results in Table 2, the compounding ratio of the organic solvent was 8%, that is, the concentration of the siloxane polymer solution was 92%.
%, Cracks occur in the bending test, and the compounding ratio of the organic solvent is 6% or less, that is, the concentration of the siloxane polymer solution is 9%.
In the case of 4% or more, it can be seen that cracks did not occur and the film was firmly adhered.

In addition, there is no vitrified material and 1, 2, 3, 4,
Four oil-impregnated bearings 1 each having a vitrified body 2 formed with a thickness of an impregnated layer of a siloxane polymer solution of 5, 6 μm were placed on a piece of paper for 5
Leave at 0 ° C for 138 hours, and lubricate the paper (OI
Table 3 shows the experimental results of confirming the bleeding amount of L).

[0036]

[Table 3]

As shown in Table 3, when the thickness of the impregnated layer of the siloxane polymer solution was 4 μm or less, the seepage of the lubricating oil was confirmed. Is not confirmed, and the seepage of the lubricating oil can be prevented by setting the thickness of the impregnated layer to 5 μm or more.

[0038]

According to the oil-impregnated bearing of the present invention, the vitrified body is formed by impregnating the surface of the oil-impregnated bearing other than the through holes with a substance having incompatibility with lubricating oil. Since the bearing and the bearing are firmly connected to each other and have high adhesion and high hardness of the surface of the oil-impregnated bearing, it is possible to prevent exfoliation of the vitrified body and surely prevent seepage of lubricating oil.

Since the exposed surface of the oil-impregnated bearing in use is impregnated with a solution of a siloxane polymer to form a vitrified body, for example, the impregnated bearing may be used as a bearing for a rotating shaft of a developer stirring body of a developing device. Even if used,
Even if the developer comes into contact with the exposed surface of the impregnated bearing, the oozing of the lubricating oil is prevented by the vitrified body, and the problem that the developer is solidified by the lubricating oil can be reliably prevented.

Furthermore, even when the sealing member is fitted to the oil-impregnated bearing, since the vitrified siloxane polymer is formed on the contact surface with the sealing member, friction with the sealing member is caused. The wear of the oil-impregnated bearing due to the above can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state before a vitrified body is formed in an oil-impregnated bearing according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state after forming a vitrified body in Embodiment 1 of the oil-impregnated bearing of the present invention.

FIG. 3 is a sectional view showing an embodiment of a developing device using the oil-impregnated bearing of the first embodiment.

FIG. 4 is a cross-sectional view showing a state after forming a vitrified body in Embodiment 2 of the oil-impregnated bearing of the present invention.

FIG. 5 is a cross-sectional view showing a state after forming a vitrified body in Embodiment 3 of the oil-impregnated bearing of the present invention.

FIG. 6 is a sectional view showing an example of a conventional oil-impregnated bearing.

FIG. 7 is a sectional view showing another example of a conventional oil-impregnated bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oil-impregnated bearing 1a Through hole 2 Vitrified body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Miyaji 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Masahiro Tsuji 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside the corporation

Claims (7)

[Claims] 1. A ring-shaped oil-impregnated bearing having a through hole for inserting a shaft member in a central portion and impregnated with lubricating oil, wherein at least a surface of the oil-impregnated bearing other than the through-hole surface has an affinity for lubricating oil. An oil-impregnated bearing characterized in that a vitrified body is formed by impregnating a volatile substance. 2. The oil-impregnated bearing according to claim 1, wherein said substance is a solution of a siloxane polymer. 3. The oil-impregnated bearing according to claim 2, wherein the exposed surface of the oil-impregnated bearing in use is impregnated with a siloxane polymer solution to form a vitrified body. 4. A vitrified body formed by impregnating the oil-impregnated bearing and leaving the solution of the siloxane polymer at room temperature or by firing and fixing at a temperature not higher than the melting temperature of the material forming the oil-impregnated bearing. Oil bearing as described. 5. The oil-impregnated bearing according to claim 2, wherein the mixing ratio of the solvent added to the solution of the siloxane polymer is less than 5%. 6. The oil-impregnated bearing according to claim 2, wherein the thickness of the impregnated layer of the siloxane polymer is 5 μm or more. 7. A ring-shaped oil-impregnated bearing having a through hole for inserting a shaft member at a central portion and impregnated with lubricating oil, wherein leakage of lubricating oil from at least a surface other than the through-hole surface of the oil-impregnated bearing. An oil-impregnated bearing characterized in that a sealing member for preventing oil leakage is fitted to the oil-impregnated bearing, and a contact surface of the oil-impregnated bearing with the sealing member is impregnated with an incompatible substance to form a vitrified body.