JPS6319419A - Oil immersed bearing and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain stable oil feed for a bearing in the above caption, by forming an oil film initially with oil stored in the pores located on the surface and the shallow layer of the bearing and later from oil stored in the pores located at the deeper layer. CONSTITUTION:For an oil impregnated porous bearing 1, pores 5 located on the surface 3, from where lubricating medium is to flow out, and in a shallow layer 4 are formed to be fine pores while pores 8 in a deeper layer 7 are to be large pores, lubricating medium being impregnated into said pores. When a shaft rotates, lubricating medium oil impregnated in the pores flows out to form an oil film between said shaft and said bearing. Accordingly, said oil film is formed initially with the oil from said pores 5 on said bearing surface 3 and said shallow layer 4, and later with the oil from said pores 8 of said deeper layer 7, the latter purposed to increase the amount of contained oil, the stable oil supply thus being able to be maintained all the time.

Description

DETAILED DESCRIPTION OF THE INVENTION 10 Objects of the Invention (Field of Industrial Application) The present invention relates to an oil-impregnated bearing used in the bearing manufacturing industry and a manufacturing method thereof.

(Prior art) Conventionally, metal powder is pressure-formed in a mold, then sintered to form a porous sintered body, and the pores are further impregnated with a lubricating medium such as oil. Oil-impregnated bearings are already known.

As shown in Figure 6 of the drawing, this conventionally known sintered oil-impregnated bearing includes a mixing process for uniformly mixing fine particles of copper or iron bearing material alone or several types of materials, and a process for uniformly mixing the mixed materials. A pressure forming process in which the pressure-formed product is compression-molded in a mold, a sintering process in which the pressure-formed product is sintered at high temperature in a sintering furnace, and correction in which the sintered product is sized and partially machined. It is manufactured through a manufacturing process consisting of a machining process and an oil impregnation process in which the porous portions of the bearing to be formed are impregnated with oil.

(Problems to be Solved by the Invention) However, in the conventional oil-impregnated bearing, when the shaft rotates while the bearing and the shaft are in contact with each other during use, the oil impregnated in the hole of the bearing flows out and the bearing and shaft become separated. An oil film is formed in between, and this oil film provides lubrication and enables smooth rotation of the shaft.For this reason, the important point is how much lubricating medium can be contained in the porous part, and at the same time In order to ensure that the appropriate amount of lubricating medium always flows out, an important point is how large the holes in the porous section should be.For example, if the holes are too large, more oil, which is the lubricating medium, will flow out. The oil splatters as the shaft rotates and disappears quickly.

7 if the hole is too small? (b) It becomes difficult to form the oil film without flowing out, and problems such as seizure of the bearing occur.

In order to solve these problems, a method of increasing the oil content has recently been considered and has been successfully implemented by installing an oil sump device externally in contact with the bearing, but if this oil sump device is used, the configuration is complex and the device However, this method had the problem of being expensive.

The present invention was made in order to solve the above-mentioned conventional problems, and the holes in the surface and shallow parts of the bearing through which the lubricating medium flows out are made small, and the holes in the deep part are made large. As a result, the objective is to provide an inexpensive oil-impregnated bearing that can increase the oil retention amount (oil content) and maintain the oil retention time.

1. Structure of the Invention (Means for Solving Problems) The oil-impregnated bearing according to the first invention for achieving the above-mentioned object has a porous oil-impregnated bearing 1 in which a lubricating medium is used as shown in the embodiment. The lubricating medium 2 is impregnated into the porous parts such that the holes 5 in the bearing surface part 3 and the shallow part 4 are small holes, and the holes 8 in the deep part 7 are made large holes.

Further, the method for manufacturing an oil-impregnated bearing, which is the second invention of the present application, consists of the following steps shown in Examples.

That is, in a porous oil-impregnated bearing, after the firing process C, a process d of masking the bearing surface part 3 and the small hole wall part of the shallow layer part 4 is performed.
After the masking step d, there is a step e of etching the bearing deep layer 7, and a step i of impregnating the etched pores with the lubricating medium 2.

(Function) When using the oil-impregnated bearing according to the present invention, for example, it can be used for sounds such as audio! It is used in micro motors, etc. in 7 equipment, and receives the rotating shaft of such equipment.When the shaft rotates, the oil of the lubricating medium 2 impregnated in the porous part of the bearing flows out, causing a gap between the bearing and the shaft. Creates an oil film to lubricate.

At this time, the oil film is initially formed by the oil accumulated in the holes 5 of the bearing surface part 3 and the shallow part 4, and is later formed by the oil 2 deposited in the holes 8 of the bearing deep part 7, where the oil content has been increased. , a long-life oil-impregnated bearing can be obtained by providing a constant and stable supply of oil.

(Example) Next, an example of the oil-impregnated bearing according to the present invention will be described based on FIGS. 1 to 3. FIG. 1 is a sectional view showing a porous oil-impregnated bearing 1 in the example. In the oil-impregnated bearing 1, the holes 5 in the bearing surface part 3 and the shallow part 4 through which the lubricating medium 2 made of oil flows out are made into small holes during pressure molding, and the deep part 7 of the formed bearing 6 is made into a small hole as described below. A large hole 8 is formed by an etching step of vacuum impregnation with an etching solution such as ferric chloride, and the porous portion consisting of the bearing surface portion 3, the hole 5 in the shallow layer 4, and the hole 8 in the deep layer 7 is formed. , impregnated with a lubricating medium 2 made of oil such as Amprol oil.

The oil-impregnated bearing having the above structure can be manufactured by the following manufacturing methods of the first and second embodiments, and the first embodiment will be explained based on FIG. 4.

(a) Mixing process: Fine particles of copper powder, lead powder, tin powder, and graphite powder are mixed in a mixer, or bearing forming materials made of iron powder, copper powder, lead powder, and graphite powder are mixed in a mixer.

(b) Molding process: The mixed bearing forming material is compression molded in a mold to form the bearing 6.
to form. At this time, a powder compact is obtained in which holes 5 consisting of a large number of small holes are formed in the surface portion 3 and shallow layer portion 4 of the bearing 6.

(c) Firing process: The compacted compact in the shape of a bearing is placed in a firing furnace with a high temperature inside and sintered.

(d) Masking step: The surface of the metal powder in the hole 5 of the surface portion 3 and the shallow layer 4 near the surface of the fired bearing 6 is vacuum impregnated with a water-soluble acrylic resin liquid and dried. is evaporated to form a resin film 9 of about lum, so that the surface of the metal powder is not affected by the etching described later.

As a means for this masking, for example, an oxide film may be formed by surface treatment such as black dyeing, or a film may be formed on the surface of the metal powder by electrolytic plating of nickel or the like. All of these materials must be made of materials that cannot be corroded by the etching solution.

(e) Etching step: impregnating the inside of the bearing 6 with an etching solution from the hole 5 of the bearing surface portion 3 covered with the resin film 9 in the masking step;
The unmasked iron or copper metal part is corroded to form a large hole 8 in the deep part 7 of the bearing 5.

This etching solution uses ferric chloride and is vacuum impregnated. The amount of etching is controlled by the time and concentration of the solution.

In some cases, a gas that corrodes metal is used as the etching means.

<fp cleaning step; The etched bearing 6 is washed with a cleaning solvent to wash away the etching solution and remove it.

(g) Masking film removal step: After removing the etching solution, the surface portion 3 of the bearing 6 was impregnated with a film removal solution, and the holes 5 in the surface portion 3 and shallow layer portion 4 of the bearing 6 were impregnated with the film removal liquid. The resin film 9 is peeled off. If the resin film 9 is formed using an acrylic resin at this time, the film 9 can be removed using an alkaline solution.

(h) Cleaning process: After removing the resin film 9, the adhering film removal liquid is washed away again with a cleaning solution to remove it.

(1) Oil impregnation process; The holes 5 in the bearing 6 are porous, with the holes 5 in the surface part 3 and the shallow part 4 being small holes, and the holes 8 in the deep part 7 being large holes.
In this impregnation, the bearing 6 is placed in an impregnation tank, the tank is vacuum degassed, Amprol oil is injected into the tank, and the tank is held for a certain period of time. Then, it is impregnated with oil.

Next, a second embodiment of the manufacturing method according to the present invention will be explained based on FIG. 5. The manufacturing method of the second embodiment includes a mixing step,
It consists of a forming process, a firing process, a masking process, an etching process, a cleaning process, and an oil impregnation process, especially the mixing process,
The molding process and firing process are the same as in the first embodiment, and in the next masking process, a fluorine-based resin with a low friction coefficient is used, and fluorine is added to the bearing surface and the holes in the shallow layer near the surface. It is impregnated with a resin solution, dried, and further evaporated to form a resin film for masking.

This masked bearing is vacuum impregnated with an etching solution made of ferric chloride to erase the unmasked metal parts and form holes for oil reservoirs in the deep part of the bearing (etching process). After washing the liquid with a cleaning solution (washing step), the porous areas formed are impregnated with amprol oil (oil impregnation step).
This forms a predetermined oil-impregnated bearing.

Furthermore, if fluororesin is used for this masking,
Even after the etching process, it may be left as is without washing for the purpose of adding a friction coefficient.

Effects of the Invention As described above, the oil-impregnated bearing according to the present invention is a porous oil-impregnated bearing in which the holes in the bearing surface and the shallow layer through which the lubricating medium flows out are made small holes, and the holes in the deep layer are made into small holes. As a courtesy, since the porous parts are impregnated with a lubricating medium, oil, which is a lubricating medium, can be stored in the holes formed in the deep part of the bearing, so compared to conventional oil-impregnated bearings, The oil content is greatly increased, and at the same time, the outflow of this impregnated oil can be kept at an optimal value, which has the unique effect of making it possible to obtain a bearing that is always stable and has a long life. During assembly, when a housing case, etc. is press-fitted when attaching to a bearing device, the hole formed in the deep part of the bearing also absorbs the press-fit strain, making it difficult for the press-fit strain to be transmitted to the inner diameter part. When the sizing pin press-fitting method, which has been generally adopted and used in the past, is used, it is possible to suppress the variation in the inner diameter dimension to a small extent, and it has the unique effect of being able to assemble the bearing with high precision. .

Furthermore, the method for manufacturing an oil-impregnated bearing according to the present invention includes, in a porous oil-impregnated bearing, a process of masking the surface of the bearing and the walls of the small holes in the shallow layer after the baking process, and a process of masking the surface of the bearing and the walls of the small holes in the shallow layer after the masking process. This is due to the process of etching the porous part and the process of impregnating the etched porous part with a lubricating medium.
It is possible to easily form holes for oil storage or for absorbing press-fit strain in the deep layer without affecting the holes on the surface of the bearing and in the shallow layer, and in the etching process, the concentration of the etching liquid and the etching time can be easily formed. By adjusting the diameter of the hole, the thick hole in the deep layer can be made to the optimum hole size, making it possible to constantly supply an appropriate lubricating medium during use, and to provide a high-performance bearing at a low cost. It has a unique effect.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an embodiment of the oil-impregnated bearing according to the present invention, Figure 2 is an enlarged cross-sectional view of the main part in a masked state during the manufacturing process, and Figure 3 is a cross-sectional view of the oil-impregnated bearing after it has been impregnated with oil. An enlarged sectional view of the main parts, the fourth factor is a block diagram showing the first embodiment of the manufacturing method, FIG. 5 is a block diagram showing the second embodiment, and FIG. 6 shows the conventional manufacturing process. It is a block diagram. In the figure, 1 is an oil-impregnated bearing, 2 is a lubricating medium, 3 is a bearing surface,
4 is a shallow seven-layer portion, 5 is a hole, 6 is a bearing, 7 is a deep layer, 8 is a hole, 9 is a resin film C, a baking process d is a masking process, e is an etching process, and i is an oil impregnation process. July 21, 1985 29 Name of invention −′−″′ □−′2−2:
') -, '+ Oil-impregnated bearings and their manufacturing method 3, relationship with the case of the person making the amendment Patent application Person name 11, 2346 Sena, Shizuoka City, Shizuoka Prefecture Name Yo Shige Mori 2 Part 4, Agent's mail No. Box ■ - Rollo 5, Date of notice of reasons for refusal Showa Year Month Day Specification as attached Document 1 Name of the invention Oil-impregnated bearing and its manufacturing method 2 Scope of claims (1) In porous oil-impregnated bearing An oil-impregnated bearing characterized in that the holes on the surface of the bearing and the shallow layer through which the lubricating medium flows out are small holes, and the holes in the A layer are made large and the porous portions are impregnated with a lubricating medium. (In porous oil-impregnated bearings, after the baking process, there is a process of masking the surface of the bearing and the walls of the small holes in the shallow part, and after the masking process, a process of etching the deep part of the bearing. A method for manufacturing an oil-impregnated bearing comprising a step of impregnating a lubricating medium into a porous portion. 3. Detailed Description of the Invention Related to an oil-impregnated bearing and its manufacturing method. (Prior art) Conventionally, metal powder is pressure-formed in a mold, sintered to form a porous sintered body, and the pores are further lubricated with oil or the like. A sintered oil-impregnated bearing impregnated with a medium is already known. As shown in FIG. A mixing step for uniformly mixing the materials, a pressure forming step for compression molding the mixed material in a mold, and a sintering step for sintering the pressure formed material at high temperature in a sintering furnace. It can be manufactured through a manufacturing process consisting of a straightening and machining process in which the dimensions of the sintered product are straightened and partial machining is carried out, and an oil impregnation process in which oil is impregnated into the porous parts of the bearing to be formed. (Invention However, when the conventional oil-impregnated bearing is in use and the shaft rotates while the bearing is in contact with the shaft, the oil impregnated in the hole in the bearing flows out and creates a gap between the bearing and the shaft. It forms an oil film, and this oil film lubricates and enables smooth rotation of the shaft.For this reason, it is important to impregnate as much lubricant into the porous part, and at the same time, this lubricant In order to ensure that the appropriate amount of oil always flows out, it is important to consider how large the holes in the porous section should be.For example, if the holes are too large, a large amount of oil, which is a lubricating medium, will leak out. splatters, and the oil disappears quickly. Also, if the holes are too small, the lubricating medium oil will not flow out as expected, making it difficult to form the oil film and causing problems such as seizure of the bearing. Recently, as a method to increase the oil content in order to solve this problem, a method of installing an oil sump device externally in contact with the bearing has been considered and has been successfully implemented. However, using this oil sump device requires a complicated structure and is expensive. The present invention was made in order to solve the above-mentioned problems of the conventional technology, and it is possible to reduce the size of the holes in the surface and shallow parts of the bearing through which the lubricating medium flows out. The purpose of this invention is to provide an inexpensive oil-impregnated bearing that can increase the amount of oil retained (oil content) by forming large holes in the deep layer, and can maintain the oil retention time. 1. Structure of the Invention (Means for Solving Problems) The oil-impregnated bearing according to the first invention for achieving the above-mentioned object has a porous oil-impregnated bearing 1 in which a lubricating medium is used as shown in the embodiment. The lubricating medium 2 is impregnated into the porous portions, with holes 5 in the bearing surface portion 3 and shallow layer portion 4 serving as small holes, and holes 8 in the deep drinking portion 7 serving as large holes. Further, the method for manufacturing an oil-impregnated bearing, which is the second invention of the present application, consists of the following steps shown in Examples. That is, in a porous oil-impregnated bearing, after the firing step C, there is a step d of masking the bearing surface portion 3 and the small hole wall portion of the shallow layer portion 4.
After the masking step d, the process includes a step e of etching the bearing deep layer 7, and a step i of impregnating the etched pores with the lubricating medium 2. (Function) When using the oil-impregnated bearing according to the present invention, it is used, for example, in a micromotor in audio equipment such as an audio device, and receives a rotating shaft of the same, so that when the shaft rotates, the porous holes in the bearing The oil of the lubricating medium 2 impregnated in the bearing flows out and forms an oil film between the bearing and the shaft to provide lubrication. At this time, the oil film is initially formed by the oil accumulated in the holes 5 of the bearing surface part 3 and the shallow part 4, and later is formed by the oil 2 accumulated in the holes 8 of the bearing deep part 7, whose oil content has been increased. A long-life oil-impregnated bearing can be obtained with a constant and stable supply of oil. (Example) Next, an example of the oil-impregnated bearing according to the present invention will be described based on FIGS. 1 to 3. FIG. 1 is a sectional view showing a porous oil-impregnated bearing 1 in the example. In the oil-impregnated bearing 1, the holes 5 in the bearing surface part 3 and the shallow part 4 through which the lubricating medium 2 made of oil flows out are made into small holes during pressure molding, and the deep part 7 of the formed bearing 6 is made into a small hole as described below. A large hole 8 is formed by an etching process of vacuum impregnation with an etching solution such as ferric chloride, and the porous portion consisting of the bearing surface portion 3, the hole 5 in the shallow layer 4, and the hole 8 in the deep layer 7 is formed. , impregnated with a lubricating medium 2 made of oil such as Amprol oil. The oil-impregnated bearing having the above structure can be manufactured by the manufacturing methods of the first and second embodiments described below, and the first embodiment will be explained based on FIG. 4. (a) Mixing step: Either fine particles of copper powder, lead powder, tin powder, and graphite powder are mixed in a mixer, or bearing forming materials made of iron powder, copper powder, lead powder, and graphite powder are mixed in a mixer. (b) Molding process: The mixed bearing forming material is compression molded in a mold to form the bearing 6.
to form. At this time, a powder compact is obtained in which holes 5 consisting of a large number of small holes are formed in the surface portion 3 and shallow layer portion 4 of the bearing 6. (c) Firing step: The compacted powder body in the shape of a bearing is placed in a firing furnace whose interior is heated to a high temperature and sintered. (d) Masking step: The surface of the metal powder in the holes 5 in the surface portion 3 and the shallow layer 4 near the surface of the fired bearing 6 is vacuum impregnated with a water-soluble acrylic resin liquid and allowed to dry. is evaporated to form a resin film 9 of about 1 lum, so that the surface of the metal powder is not affected by the etching described later. As a means for this masking, for example, an oxide film may be formed by surface treatment such as black dyeing, or a film may be formed on the surface of the metal powder by electrolytic plating of nickel or the like. All of these materials must be made of materials that are not corroded by the etching solution. (e) Etching step; impregnating the inside of the bearing 6 with an etching solution from the hole 5 of the bearing surface portion 3 covered with the resin film 9 in the masking step;
The iron or copper metal parts that have not been completely masked are corroded to form a large hole 8 in the deep part 7 of the bearing 5. This etching solution uses ferric chloride and is vacuum impregnated. The amount of etching is controlled by the time and concentration of the solution. In some cases, a gas that corrodes metal is used as the etching means. (f) Cleaning step: The etched bearing 6 is washed with a cleaning solvent to wash away the etching solution and remove it. (g) Masking film removal step: After removing the etching solution, a film removal solution was impregnated from the surface portion 3 of the bearing 6 and applied to the holes 5 in the surface portion 3 and shallow layer portion 4 of the bearing 6. The resin film 9 is peeled off. If the resin film 9 is formed using an acrylic resin at this time, the film 9 can be removed using an alkaline solution. (h) Washing step: After removing the resin film 9, the adhering film removal liquid is washed away again with a cleaning solution to remove it. (i) Oil impregnation step; The holes 5 in the porous bearing 6 have the holes 5 in the surface part 3 and the shallow part 4 of the bearing 6 as small holes, and the holes 8 in the deep part 7 as large holes.
, the lubricating medium 2, Amprol oil, can be impregnated into the tank.This impregnation is carried out by placing the bearing 6 in an impregnating tank, vacuum degassing the tank, then injecting Amprol oil into the tank and leaving it for a certain period of time. It is held and impregnated with oil. Next, a second embodiment of the manufacturing method according to the present invention will be explained based on FIG. 5. The manufacturing method of this second embodiment includes a mixing step,
It consists of a molding process, a firing process, a masking process, an etching process, a cleaning process, and an oil impregnation process, especially the mixing process,
The molding process and firing process are the same as in the first embodiment, and in the next masking process, a fluororesin with a low friction coefficient is used, and fluorine is added to the bearing surface and the holes in the shallow layer near the surface. It is impregnated with a resin solution, dried, and further prevented from evaporating to form a resin film for masking. This masked bearing is vacuum impregnated with an etching solution made of ferric chloride to etch the unmasked metal parts to form holes for oil reservoirs in the deep part of the bearing (etching process). After washing away the liquid with a cleaning solution (cleaning step), the formed porous portions are impregnated with amprol oil (oil impregnation step) to form a predetermined oil-impregnated bearing. Furthermore, if fluororesin is used for this masking,
Even after the etching process, it may be left as is without washing for the purpose of adding a friction coefficient. Effects of the Invention As described above, the oil-impregnated bearing according to the present invention is a porous oil-impregnated bearing in which the holes in the bearing surface and the shallow layer through which the lubricating medium flows out are made small holes, and the holes in the deep layer are made into small holes. As a courtesy, since the porous parts are impregnated with a lubricating medium, the lubricating medium, oil, can be stored in the holes formed in the deep layer of the bearing, so compared to conventional oil-impregnated bearings, The oil content is greatly increased, and at the same time, the outflow of this impregnated oil can be kept at an optimal value, which has the unique effect of making it possible to obtain a bearing that is always stable and has a long life. During assembly, when a housing case, etc. is press-fitted when attaching to a bearing device, the hole formed in the deep part of the bearing also absorbs the press-fit strain, making it difficult for the press-fit strain to be transmitted to the inner diameter part. When the sizing pin press-fitting method, which has been generally adopted and used in the past, is used, it is possible to suppress the variation in the inner diameter dimension to a small extent, and it has the unique effect of being able to assemble the bearing with high precision. . Furthermore, the method for producing an oil-impregnated bearing according to the present invention includes, in a porous oil-impregnated bearing, a step of masking the surface of the bearing and the walls of the small holes in the shallow layer after the baking step, and a step of masking the surface of the bearing and the walls of the small holes in the shallow layer after the masking step. This is due to the process of etching the porous parts and impregnating the etched porous parts with a lubricating medium.
It is possible to easily form holes for oil storage or for absorbing press-fit strain in the deep layer without affecting the holes on the surface of the bearing and in the shallow layer. By adjusting the time, the size of the hole in the deep layer can be set to the optimal hole diameter, making it possible to constantly supply an appropriate lubricating medium during use, and providing high-performance bearings at low cost. There are unique effects that can be achieved. 4. Brief description of the drawings Drawings Fig. 1 is a sectional view showing an embodiment of the oil-impregnated bearing according to the present invention, Fig. 2 is an enlarged sectional view of main parts in a masked state during the manufacturing process, and Fig. 3 FIG. 4 is a block diagram showing the first embodiment of the manufacturing method, FIG. 5 is a block diagram showing the second practical example, and FIG. The figure is a block diagram showing a conventional manufacturing process. In the figure, 1 is an oil-impregnated bearing, 2 is a lubricating medium, 3 is a bearing surface,
4 is a shallow part, 5 is a hole, 6 is a bearing, 7 is a deep part, 8 is a hole,
9 is a baking process for the resin film C, d is a masking process, e is an etching process, and i is an oil impregnation process. As shown in the attached sheet, Figures 4 to 6 of the drawings will be corrected. (May 14, 1986)

Claims (2)

[Claims] (1) In porous oil-impregnated bearings, the pores on the bearing surface and shallow layer where the lubricant flows out are small holes, and the holes in the deep layer are treated as large holes, and the porous portions are impregnated with the lubricant. Features: Oil-impregnated bearings. (2) In a porous oil-impregnated bearing, after the baking process, there is a process of masking the surface of the bearing and the walls of the small holes in the shallow part, and after the masking process, a process of etching the deep part of the bearing, and an etching process. A method for manufacturing an oil-impregnated bearing, which comprises a step of impregnating a lubricating medium into the porous portions formed in the oil-impregnated bearing.