JP2865036B2 - Dry bearing manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dry bearing which exhibits good lubrication for a long period without lubrication.

[0002]

2. Description of the Related Art A dry bearing is a bearing in which a metal plate having high mechanical strength is used as a backing metal, and a multilayer material in which a sliding material is adhered to the backing metal has a cylindrical shape.

[0003] Generally, a dry bearing uses an iron plate as a backing metal and a polymer resin such as a polytetrafluoroethylene resin as a sliding material, and is excellent in the sliding material itself without lubrication. Equipment, machinery, and equipment that cannot be refueled due to lubricity, such as OA equipment such as copiers, computers, facsimile machines, printers, hydraulic machines such as axial piston pumps and gear pumps, automatic adjustment mirrors for automobiles, power windows, wipers, etc. Are used for rotating parts and sliding parts.

[0004] In order to make the backing metal of the dry bearing and the sliding material into a multi-layer, they may be bonded together using an adhesive. However, those bonded with the adhesive require a shaft rotating at high speed and high load. It was not enough to support the shaft, and the backing metal and the sliding material were sometimes peeled off. For this reason, conventionally, when a back metal and a sliding material are formed into multiple layers, a reliable impregnation method is used.

In the impregnation method, a metal powder is sprayed on one surface of a back metal and sintered to form a porous metal layer. Then, a sliding material is placed on the porous metal layer, and the sliding material is pressed on the porous metal layer with a roller or a press to impregnate the sliding material into the porous metal layer. The dry bearing manufactured by rolling the multilayer material obtained by the impregnation method has a sliding material anchored in the porous metal layer, so it peels off even if it supports a high-speed and high-load shaft. It has an excellent feature that it does not occur.

Here, a method of manufacturing a conventional dry bearing will be described. As the material of this dry bearing, an iron plate is used for the back metal, a bronze alloy is used for the powder metal sintered on the back metal, and a mixture of polytetrafluoroethylene resin, polyphenylene sulfide resin, and powder lead is used for the sliding material. .

[0007] A bronze alloy powder is sprinkled thinly on the surface of a wide strip-shaped iron plate and sintered in a sintering furnace in an active atmosphere composed of a mixture of hydrogen and nitrogen to form a porous metal layer on the iron plate. Make it a sintered material. Place the dispersion of the sliding material on the porous metal layer of the wide sintered material, impregnate it with a roller, bake the resin, then adjust the thickness with a roller to form a wide multilayer material I do. The wide multilayer material is slit into a predetermined width in the longitudinal direction to form a narrow multilayer material (hereinafter, referred to as a narrow material). Chamfer by cutting corners of narrow material. The chamfered narrow material is cut into strips, and the strips are rolled into a cylinder by a press. Electroplating of tin is performed on the iron part of the cylinder.

In general, when a dry bearing is mounted on an apparatus or a machine, a hole is formed in a mounting portion, and the dry bearing is mounted in the hole. After the dry bearing is installed in the hole, it must not rotate together with the rotating shaft. Therefore, the outer diameter of the dry bearing is slightly smaller than the inner diameter of the hole, for example, about 40 to 50 μm, so that the dry bearing adheres to the hole. It is made large. Therefore,
Since the dry bearing cannot be easily mounted in a slightly small hole, it is mounted by press-fitting with a hydraulic machine or a press.

Recent devices and machines for mounting dry bearings are often made of aluminum having a low specific gravity in order to reduce the weight. However, since aluminum is softer than iron, if a dry bearing is press-fitted into a mounting hole, a hard back metal will damage the mounting hole, causing "galling". If galling occurs at the time of press-fitting, the galled pieces will enter the inside of the dry bearing, causing damage to the sliding material and the shaft. Therefore, a lubricating metal such as tin or lead is plated on the back metal of the dry bearing so that the press-fitting can be performed smoothly without causing galling when the dry bearing is attached. The lubricating metal acts as a lubricant between the hole and the dry bearing, making it easier to press-fit the dry bearing into the hole. The plating on the back metal is necessary not only for preventing galling but also for preventing rust.

In a conventional method for manufacturing a dry bearing,
Plating was performed in the final step. The reason is that it was thought that rust would occur on the unplated part unless plating was performed on all the parts where the iron as the back metal was exposed.

Therefore, conventional dry bearing plating is performed by suspending one dry bearing at a time on a suspending jig serving as one electrode. A large number of dry bearings suspended on this hanging jig are immersed in a plating tank filled with plating solution to perform plating, but plating a large amount of dry bearings in a single plating operation increases productivity. it is possible, the plating bath was used a relatively large even for.

[0012]

In a conventional dry bearing to be attached to a device or a machine having a rotating part, strict dimensional accuracy is not required, and a general tolerance, for example, ± 50 μm is required.
m was enough, but dry bearings attached to precision equipment such as OA equipment have a tolerance of ± 10μ.
Very strict dimensional accuracy of less than m is required. However, for such strict dimensional accuracy, the tolerance after plating is ± 10μ regardless of the precision of the dry bearing manufactured by the conventional manufacturing method.
m.

Further, many dry bearings have different widths, thicknesses and outer diameters, and there are very many types combining these. Therefore, in order to keep the product as a stock, a wide variety of products must be prepared, and a large warehouse and a laborious management are required for stocking the various kinds of products.
However, the width of the intermediate material with the sliding material attached to the iron plate is different only in width and thickness, and the type is less than the type of dry bearing that is the product. It would have been possible to stock up on narrow strips because it would take up less space. However, there is a problem that rust is generated on the back metal when the narrow material manufactured by the conventional manufacturing method is stocked as an intermediate material.

Further, in the conventional manufacturing method, since a large number of dry bearings are suspended one by one on the suspension jig, a great deal of labor is required for the suspension operation. In order to plate a large number of dry bearings at one time, a large plating tank had to be installed. Since a large amount of plating solution is supplied to a large plating tank, a large amount of expensive plating solution is required.Moreover, it is costly to process a large amount of plating solution that has deteriorated and cannot be used. It was problematic.

Further, when there is no stock of the product, the conventional method of manufacturing a dry bearing has to go through the time-consuming steps (1) to (2) after the order is received and before the product is completed. Long days were needed.

The present invention can be used satisfactorily in applications requiring strict dimensional tolerances, such as OA equipment, and does not generate rust even if it is stocked as an intermediate material. Another object of the present invention is to provide a dry bearing manufacturing method which is advantageous in terms of location because it requires only a small amount of plating solution, and can complete a product in a short time after receiving an order.

[0017]

The present inventors have found that the plating on the outside of the dry bearing is necessary for press-fitting into the hole at the time of mounting, but the plating on the joint of the dry bearing is completely unrelated at the time of press-fitting. The present invention was completed by noting that there is no rust, and that rust is hardly generated because the seam is closely adhered, and even if rust is generated at the seam, it hardly affects the bearing performance.

According to the present invention, there is provided a flat metal plate having one wide surface.
Sprinkle the powdered metal evenly on the top and sinter it in a sintering furnace.
A porous metal layer on the one plane of the metal strip.
A sintering step of obtaining a wide sintered material by forming
Resin is added to the porous metal layer formed on the wide sintered material.
Impregnated with a sliding material consisting of
Impregnation step, and the wide multi-layer material is elongated to a predetermined width.
Slitting into narrow material by cutting in the direction
Chamfering process to cut the corner of the material to make it a chamfered narrow material,
Part where the sliding material does not exist in the chamfered narrow material
Plating with lubricating metal on the surface
And adjust the thickness of the plating narrow material to a precise width.
Plate thickness adjustment step, and cutting the precision narrow material into strips,
A rounding process for rounding the cut strips
This is a manufacturing method of the ring .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An iron plate is suitable as the wide band-shaped metal plate used in the present invention, and a copper powder such as a bronze alloy, a phosphor bronze alloy, a lead bronze alloy is used as a metal powder for forming the porous metal layer. Alloys and pure copper are suitable. Using iron plate as backing metal,
When a copper alloy or pure copper is used for forming the porous metal layer, the sintering temperature is lower than the melting temperature of the copper alloy, for example, 800 to 900 ° C., in order to adhere the powder metals to each other, the powder metal and the iron plate by solid diffusion. To

The sliding material to be impregnated into the porous metal layer is mainly composed of a polymer resin such as polytetrafluoroethylene resin, polyamide resin, polyacetal resin, polyphenylene sulfide resin. And a solid lubricant such as molybdenum disulfide. The porous metal layer is impregnated with the sliding material by pressing with a roller or a press. After the sliding material is impregnated into the porous metal layer, firing is performed in a firing furnace. By the firing, the sliding material is fused to be anchored to the porous metal layer, thereby strengthening the adhesion to the porous metal layer and improving the lubricity. After baking, it is passed through a roller to adjust the thickness. The thickness tolerance here is ± 15 μm.

A wide multilayer material in which a porous metal layer is impregnated with a sliding material is cut in the longitudinal direction into a narrow material. The width of the narrow material is the same as the width of the dry bearing.

In the transverse section of the thin material, the corners are at right angles, and in the case of a dry bearing as it is, the inner end contacts the rotating shaft and damages the shaft, and the outer end uses the dry bearing. When press-fitting into the hole to be mounted, galling that damages the hole will occur. Therefore, chamfering is performed by slightly cutting the corners of the narrow material diagonally.

The metal used for plating in the present invention has lubricity and is tin, lead, or an alloy thereof.
Tin is suitable for dry bearing plating. The plating is applied to the outside of the dry bearing in order to improve the lubricity with the hole and eliminate galling when the dry bearing is pressed into the hole. As a plating method, there are electroplating, hot-dip plating, chemical plating and the like, but the electroplating is most suitable in terms of uniformity and thickness control.

Even in the case of electroplating in which uniform plating is obtained, the thickness is precisely adjusted because the electroplating is not always uniform due to the positional relationship with the electrodes and changes in the concentration of the electrolytic solution.
The plate thickness adjusting device used here is a precision roller.

The fine narrow material whose thickness has been adjusted is cut into a strip shape in accordance with the circumference of the dry bearing, and the strip material is rolled to finish the dry bearing. In this rounding step, the outer diameter accuracy must be within ± 10 μm.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
FIG. 2 is a view for explaining each step of the present invention, and FIG. 2 is a front enlarged sectional view of a material in each step and a front view of a dry bearing obtained by the present invention.

(A) Sintering step A wide band-shaped iron plate 1 having a thickness of 1.5 mm and a width of 200 mm
Are wound in a coil shape. The wide strip-shaped iron plate is rewound and fed horizontally as shown by the arrow, and the bronze powder 3 is uniformly spread from the hopper 2 thereon. The strip-shaped iron plate on which the bronze powder has been sprayed is sent to the sintering furnace 4, where the bronze powder and the bronze powder and the iron plate are sintered to form the porous metal layer 5 on the strip-shaped iron plate 1, and the wide sintering is performed. It becomes material 6. The wide sintered material 6 is wound in a coil shape.

(B) Impregnation Step The wide sintered material 6 wound in a coil shape is unwound and sent horizontally as indicated by an arrow, and slides 8 on the porous metal layer 5 from a syringe 7. Is placed. The sliding material is obtained by mixing a polyphenylene sulfide resin, a lead powder and the like with a dispersion of a polytetrafluoroethylene resin. The sliding material 8 on the wide sintered material is pressed by the impregnating roller 9, and a part of the sliding material is impregnated in the porous metal layer 5. The wide sintered material 6 impregnated with the sliding material is sent to a firing furnace 10 and fired. After that, the wide sintered material 6 is
The thickness is adjusted within the allowable range of 15 μm, and the wide multilayer material 1
2 and wound in a coil shape.

(C) Slit Step The wide multilayer material 12 wound in a coil shape is unwound as shown by an arrow and sent to a slitter 13. In the slitter 13, the wide multilayer material is cut into a predetermined width, for example, a width of 20 mm, which is the width of the dry bearing, in the longitudinal direction to form a plurality of narrow materials 14. The narrow material 14 is wound in a coil shape.

(D) Chamfering Step The coiled narrow material 14 is unwound as shown by an arrow and sent to a chamfering device 15. In the chamfering device 15, the narrow material 1
The upper and lower portions 16 on both sides of 4 are chamfered and cut obliquely to form a chamfered thin material 17. The chamfered narrow material 17 is wound into a coil shape.

(E) Plating Step The coil-shaped chamfered thin material 17 is rewound as shown by the arrow and introduced into an electroplating tank 18 where the iron portion is electroplated with tin. Become. Plating tank 18
Is charged with a plating solution 20 made of sulfuric acid, stannous sulfate, water, etc., and a tin anode plate 21 is provided below. The anode plate 21 is connected to the anode (+) of the DC power supply, and the chamfered narrow material 17 is connected to the cathode (−) by the conducting portion 22. The thickness of the plating 23 on the iron plate 1 is about 3 μm. The plating thin material 19 is wound in a coil shape.

(F) Plate Thickness Adjusting Step The plating thin material 19 has a state in which the plating 23 on the iron plate portion has unevenness and uneven plating thickness as shown in FIG. Since the thickness is not sufficiently accurate in the thickness adjustment after firing, precise thickness adjustment must be performed. Then, the coiled plating thin material 19 is rewound as shown by the arrow, and the thickness is accurately adjusted through the precision rolling roller 24. The precision narrow material 25 whose thickness has been adjusted is wound in a coil shape.

(G) Rounding Step The coil-shaped precision narrow material 25 is unwound as shown by an arrow.
The strip material 27 is cut by the cutter 26. The strip material 27 is sent to a rounding device, where it is first U-shaped by a cored bar 28 and a female mold 29, and then rounded by an upper and lower rounded molds 30, 30 to form a perfect circle. Although the dry bearing 31 is formed in this manner, the seam 32 is in close contact with the joint, so that rust hardly occurs.

The dimensional accuracy of the dry bearing obtained by the method of the present invention was extremely high within ± 5 μm with respect to the outer diameter of 20 mm. In addition, no rust was generated even when it was kept in stock for a long period of time as a precision thin material which was an intermediate material in the production method of the present invention, and no rust was generated from the joint in the finished product. It took only one day from the time when the intermediate precision narrow material was stocked to the time it was completed as a dry bearing.

[0035]

According to the present invention, since the plating of the lubricating metal is performed after the thin material is formed, the plating tank needs to be small enough to allow the thin material to pass through. Therefore, the amount of the plating solution input is small. Since the thin material is coil-shaped, plating can be performed continuously, and plating productivity is improved. Also, even when stocked with plated thin material or precision thin material, rust does not occur because the iron part is plated. If the thickness adjustment is performed in the state of the thin plating material, the uneven plating is flattened to achieve accurate thickness adjustment.

The two combinations of thickness and width are as follows:
Less than three combinations of outer diameters. In other words, the plated thin material and precision thin material, which are the intermediate materials of dry bearings, are a combination of only the thickness and width, and the finished dry bearing is a combination of the thickness, width, and outer diameter. There are more types of finished products. The type of dry bearings is ten times as large as the type of thin materials, and cylindrical dry bearings have more cavities, so one type of thin material wound in a coil shape
The volume becomes 00 times. Therefore, if the stock is made in the form of an intermediate material of a plated thin material or a precision thin material, the intermediate material needs to be placed in a much smaller area than the product. In addition, since there are few kinds of narrow wood, the management becomes easy.

At the time of receiving an order for a dry bearing, if production is started from a wide band-shaped metal plate, it is necessary to go through the time-consuming steps described above, and it takes a long time to complete. If you start with fine materials and fine width materials, only simple processes are required, so that it can be finished in a short time of only one day and can be easily produced even after the order is confirmed.

When electroplating is performed on a plate material, the plating thickness may not be uniform or the surface may have irregularities depending on the positional relationship with the anode plate and the energized state. Plating variations can be corrected.

When a wide plate is rolled, the overall thickness, particularly the dimensional accuracy of both sides of the plate, is not improved. This is because if the distance between the pair of rolling rollers is not very parallel, the thickness will be different on both sides of the plate. However, in the case of a thin sheet material, even if the rolling rollers are not somewhat parallel, they do not appear as a large difference on both sides of the sheet. Therefore, if precision rolling is performed with a thin plating material, the accuracy of the thickness of the sheet becomes good.

As described above, the present invention is significantly superior to conventional manufacturing methods in plating, stock economy, precision in thickness adjustment, production period from order to product completion, and the like. It has.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating each step of the present invention.

FIG. 2 is an enlarged front sectional view of a material in each step of the present invention and a front view of a dry bearing obtained by the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wide band-shaped iron plate 3 Bronze powder 4 Sintering furnace 6 Wide sintering material 8 Sliding material 9 Impregnation roller 10 Firing furnace 11 Roller 12 Wide multilayer material 13 Slitter 14 Wide thin material 15 Chamfering device 17 Chamfering thin material 18 Plating tank 19 Plating narrow material 24 Precision rolling roller 25 Precision narrow material 27 Strip material 31 Dry bearing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-16603 (JP, A) JP-B-38-17553 (JP, B1) JP-B-42-18747 (JP, B1) (58) Field (Int.Cl. ⁶ , DB name) F16C 33/14 F16C 33/10

Claims (2)

(57) [Claims] 1. A (a) the powder metal was uniformly sprayed on one of the plane of the strip metal plate wide width, before it was sintered in the sintering furnace
A sintering step to obtain a sintered material of the wide width by forming a porous metal layer on said one plane of serial metal band plate, and the porous formed sintered material of (b) the wide width Quality metal layer
To a sliding member made of a resin impregnated, it impregnation step of the multi-layer material of the wide width and fired, and cut longitudinally a multilayer material (c) the wide width to the predetermined width width a slitting step to Hosozai, (d) and chamfering step for chamfering width fine material by cutting a corner portion of the width fine material, Do exists the sliding member in (e) the chamfered width fine material
A plating process have been plated lubricity metal portion to a plating width fine material, and the plate thickness adjustment step of the fine width fine material established a thickness of (f) the plating width fine material, (g) the A method for manufacturing a dry bearing, comprising: a step of cutting a precision narrow material into strips and a rounding process of rounding the cut strips. 2. The method according to claim 1, wherein the plating of the lubricating metal is plating of tin, lead, or an alloy thereof.