JP2018179167A - Spherical slide bearing and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a spherical slide bearing that is excellent in bearing life at low cost.SOLUTION: A spherical slide bearing 1 includes an outer ring 2 and an inner ring 3. An inner peripheral surface 4 of the outer ring 2 and an outer peripheral surface 5 of the inner ring 3 become a partially spherical-shaped bearing surface of the spherical slide bearing 1. The inner ring 3 is formed of a sintered metal and holds lubricant in the internal hole 6 thereof, while the outer ring 2 is formed of ceramic.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a spherical plain bearing and a method of manufacturing the same.

  Heretofore, spherical slide bearings in which the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring both have a partial spherical shape are suitably used under a rocking movement environment or a centering movement environment. Also, if regular oiling is difficult, oil-free spherical plain bearings, in which a resin liner showing self-lubricity is placed between the inner ring and the outer ring, are preferably used. (See, for example, Patent Document 1).

JP, 2011-247408, A

  On the other hand, when using the above-mentioned oil-free spherical plain bearing under high load and high speed swing environment, the wear of the liner progresses and the liner finally disappears at least partially. It is necessary to assume. As described above, even if the resin liner partially disappears, the surface (for example, the inner peripheral surface of the outer ring) to which the liner is fixed is exposed, and there is a possibility of metal contact with the opposing surface (for example, the outer peripheral surface of the inner ring) . As a result, if an increase in torque or seizing between sliding surfaces occurs, there is a risk of losing the function as a sliding bearing.

  Further, in the spherical slide bearing, both the inner peripheral surface of the outer ring as the bearing surface and the outer peripheral surface of the inner ring have a partial spherical shape, so when assembling the spherical slide bearing, the inner ring is manufactured after the inner ring and outer ring are manufactured. It is necessary to press-fit the inner periphery of the outer ring. Alternatively, after the inner ring is introduced to the inner periphery of the cylindrical outer ring material, means may be subjected to plastic working on the outer ring material to form the inner peripheral surface of the outer ring into a partial spherical shape. However, in any case, not only assembly takes time but also plastic deformation, which may affect the shape accuracy of the bearing surface. If there is a problem in the shape accuracy of the bearing surface, the sliding state may not be stable (locally strong contact may occur), and as a result, the bearing life may be reduced.

  In view of the above situation, in the present invention, manufacturing a spherical plain bearing excellent in bearing life at low cost is a technical problem to be solved.

  The solution to the problem is achieved by the spherical plain bearing according to the invention. That is, this slide bearing is a spherical slide bearing having an outer ring and an inner ring and the inner circumferential surface of the outer ring and the outer circumferential surface of the inner ring being a partially spherical bearing surface, the inner ring being formed of sintered metal The lubricant is held in the holes, and the outer ring is characterized by being formed of a ceramic.

  As described above, in the present invention, the inner ring is formed of a sintered metal and the lubricant is held in the inner holes thereof, so that the outer peripheral surface of the inner ring can be provided with self-lubricity. . As a result, the lubricant is supplied to the bearing surface (the outer peripheral surface), so that a good sliding lubrication state can be maintained with the outer peripheral surface of the outer ring. Therefore, it is possible to improve the bearing life by improving the wear resistance and the seizure resistance as compared with the conventional oil-free spherical slide bearing.

  Further, in the present invention, the inner ring having the above-described function is formed of a sintered metal, and the outer ring is formed of a ceramic. Ceramics exhibit high hardness and excellent wear resistance as compared to common metal materials (such as stainless steel). In addition, even when the oil film is broken, it exhibits the characteristic that adhesion is not easily caused. Furthermore, since the heat resistance temperature of the ceramic is very high, for example, when the inner ring is formed of a sintered metal, the inner ring can be subjected to a sintering process in a state where the inner ring is disposed on the inner periphery of the outer ring. Therefore, it becomes possible to assemble a spherical plain bearing simply by omitting the process of manufacturing and assembling the outer ring and the inner ring respectively. Further, by making the outer ring of ceramic, dimensional changes and structural changes after the sintering process can be minimized, so that the shape accuracy of the bearing surface having a partial spherical shape can be maintained. If the shape accuracy of the bearing surface is good, the sliding state is also stable, which also makes it possible to improve the bearing life.

  In the spherical slide bearing according to the present invention, the outer peripheral surface of the inner ring may be a molding surface formed of the inner peripheral surface of the outer ring.

  By thus forming the outer peripheral surface of the inner ring as a molded surface formed by the inner peripheral surface of the outer ring, the sintered metal inner ring can be formed on the inner peripheral surface of the outer ring. That is, when the inner ring is formed of a sintered metal, first, metal powder as a raw material is filled into the inside of a molding die, and compression molding is performed to form a green compact of the inner ring. By forming the molded surface on the inner peripheral surface of the outer ring, it is possible to use the outer ring as a part of the molding die to form a green compact of the inner ring. Therefore, after compacting, by carrying out a sintering process while the green compact of the inner ring is disposed on the inner circumference of the outer ring, the inner ring can be incorporated into the inner ring of the outer ring simultaneously with the preparation of the inner ring. it can. Therefore, the assembly process can be further simplified to further reduce the manufacturing cost.

  In the spherical slide bearing according to the present invention, the linear expansion coefficient of the ceramic may be larger than the linear expansion coefficient of the sintered metal.

  Ceramics have high hardness and one surface showing brittle properties. Therefore, for example, when the inner ring material is subjected to a sintering process in a state where the outer ring made of ceramics is disposed on the outer periphery of the inner ring material as described above, the outer ring receives a compressive force directed radially outward due to expansion of the inner ring material. is assumed. In this case, if the compression force is too large, the outer ring may be cracked. In this respect, by setting the linear expansion coefficient of the ceramic that is the material of the outer ring to be larger than the linear expansion coefficient of the sintered metal that is the material of the inner ring, it is possible to relieve the compressive force from the inside in the radial direction to the outer ring. Therefore, while the inner ring is heated to a predetermined temperature and subjected to a sufficient sintering process, it is possible to reduce the pressing force acting on the outer ring and to prevent the outer ring from cracking.

  Further, in the spherical plain bearing according to the present invention, the area of the surface of the inner ring excluding the outer peripheral surface may be sealed.

  By partially sealing the surface of the inner ring in this manner, the lubricant is made to exude only from the outer peripheral surface of the inner ring to be the bearing surface, and unnecessary from other regions (for example, axial end surfaces) Lubricant can be prevented from leaking out. Therefore, the lubricant can be used without loss for the sliding lubrication of the bearing surface, which makes it possible to further improve the bearing life.

  Further, the solution of the above problems is also achieved by the method of manufacturing a spherical plain bearing according to the present invention. That is, this manufacturing method is a manufacturing method of a spherical plain bearing having an outer ring and an inner ring, and an inner peripheral surface of the outer ring and an outer peripheral surface of the inner ring having a partial spherically shaped bearing surface. And a sintering step of sintering the green compact obtained by compression molding to produce an inner ring, wherein the outer ring is used as part of a molding die in the compression molding step. It is characterized in that it is used and sintered in the sintering step while holding the outer ring on the outer periphery of the green compact.

  As described above, in the method of manufacturing a spherical plain bearing according to the present invention, the outer ring is used as part of a molding die in the compression molding step of molding the green compact of the inner ring, and the outer ring is pressed in the sintering step. It was made to sinter in the state hold | maintained on the outer periphery of powder. In this way, the green compact of the inner ring can be molded using the outer ring as a part of the molding die, that is, as the molding surface. Then, after compacting, by performing the sintering process while holding the outer ring on the outer periphery of the green compact, the inner ring can be incorporated into the inner ring of the outer ring simultaneously with the preparation of the inner ring. Therefore, it is possible to reduce the manufacturing cost by omitting the step of incorporating the inner ring into the outer ring. In addition, by forming the inner ring of sintered metal, it becomes possible to take a form in which the lubricant is held in the internal pores. Thereby, since self-lubricity can be provided to the outer peripheral surface of an inner ring | wheel, a favorable sliding lubrication state can be maintained between outer ring | wheel inner peripheral surfaces. Therefore, it is possible to improve the bearing life by improving the wear resistance and the seizure resistance as compared with the conventional oil-free spherical slide bearing.

  As mentioned above, according to this invention, it becomes possible to manufacture the spherical plain bearing excellent in bearing life at low cost.

It is a sectional view of a spherical slide bearing concerning one embodiment of the present invention. It is a figure for demonstrating an example of the manufacturing process of the spherical plain bearing shown in FIG. 1, Comprising: It is an outer ring sectional view for explaining an outer ring production process. It is a figure for demonstrating an example of the manufacturing process of the spherical plain bearing shown in FIG. 1, Comprising: (a) and (b) are principal part sectional drawings for demonstrating a compression molding process. It is a figure for demonstrating an example of the manufacturing process of the spherical plain bearing shown in FIG. 1, Comprising: It is principal part sectional drawing for demonstrating a sintering process.

  Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 4. First, the configuration of the spherical plain bearing 1 according to the present embodiment will be described based on FIG.

  FIG. 1 shows a cross-sectional view of a spherical plain bearing 1 according to the present embodiment. The spherical plain bearing 1 includes an outer ring 2 and an inner ring 3 as shown in FIG.

  The outer ring 2 is formed of a ceramic. Therefore, the inner circumferential surface 4 of the outer ring 2 which is the bearing surface is also formed of the ceramic. In this case, the inner circumferential surface 4 has a partial spherical shape. As ceramics, so-called fine ceramics which can be mainly used as nonmetallic inorganic materials which can be used for industrial use can be used. For example, metal oxides such as alumina, forsterite, zirconia, zircon, steatite, cordierite and the like can be used. Or non-metal oxides such as silicon nitride and silicon oxide can be used.

  The inner ring 3 is formed of sintered metal. Therefore, the outer peripheral surface 5 of the inner ring 3 is also formed of sintered metal. In this case, the outer peripheral surface 5 of the inner ring 3 has a partial spherical shape. In addition, a predetermined lubricant is impregnated in the internal holes 6 (portions shown by the dotted pattern in FIG. 1) of the sintered metal, whereby the lubricant is held inside the inner ring 3 . Of the outer surface of the inner ring 3, the region excluding the outer peripheral surface 5 having a partial spherical shape, that is, the axial end faces 7 and 7, and the cylindrical inner peripheral surface 8 are sealed. A sealing portion 9 is formed in the surface layer portion including the direction end surfaces 7 and the surface layer portion including the inner peripheral surface 8.

  The material of the sintered metal constituting the inner ring 3 is optional, for example, mainly iron-based powder (including not only pure iron powder but also iron alloy powder) or copper-based powder (including not only pure copper powder but also copper alloy powder) It is possible to use a metal powder as a component. For example, in the case where priority is given to strength and hardness, it is preferable to form a sintered metal of the inner ring 3 with metal powder containing iron-based powder as a main component. Of course, in consideration of not only strength and hardness but also good slidability, iron-based powder and copper-based powder are main components (one of iron-based powder and copper-based powder is the most, the other is the second most It is also possible to use metal powders.

  The lubricant to be held in the internal pores of the inner ring 3 can be used without particular limitation, for example, liquid lubricants such as lubricating oil, semi-solid lubricants such as grease, or powdery solid such as molybdenum disulfide powder or graphite As long as the lubricant can flow from the inner cavity of the inner ring 3 to the sliding surface (between the inner peripheral surface 4 of the outer ring 2 and the outer peripheral surface 5 of the inner ring 3) as the outer ring 2 and the inner ring 3 rotate relative to each other. In, it is possible to use any lubricant. Of course, it is desirable to select an appropriate type of lubricant, taking into consideration the actual use conditions. For example, in the use environment where the sliding region between the outer ring 2 and the inner ring 3 is expected to be very high temperature, a solid lubricant is more preferable than a lubricating oil which has a concern such as deterioration or volatilization.

  Next, an example of the manufacturing method of the spherical plain bearing 1 of the said structure is demonstrated based on FIGS.

  The method of manufacturing the spherical plain bearing 1 according to the present embodiment includes an outer ring manufacturing step (a), a compression molding step (b), a sintering step (c), and a sealing treatment step (d). Hereinafter, the details of each step will be described in order.

(A) Outer ring manufacturing process First, as shown in FIG. 2, the ceramic outer ring 2 is manufactured. A partially spherical inner circumferential surface 4 is formed on the inner periphery of the outer ring 2 as a bearing surface of the spherical slide bearing 1. At this time, the inner ring 3 is not introduced to the inner periphery of the outer ring 2.

(B) Compression molding step Next, the sintered metal inner ring 3 is manufactured. FIG. 3 is a cross-sectional view of the compression molding apparatus 10 used in the compression molding process. As shown in this figure, the compression molding apparatus 10 includes an upper die 11, a lower die 12, a core rod 13, a spacer 14, a filling space 15, and an outer ring 2. The outer ring 2 is installed at a predetermined position on the lower mold 12, and the spacer 14 is installed on the outer ring 2 and the lower mold 12. By arranging in this way, the filling space 15 is defined by the lower die 12, the outer ring 2, the core rod 13 and the spacer 14.

  The filling space 15 is filled with a predetermined metal powder P as a raw material of the sintered metal forming the inner ring 3. The filling space 15 has a shape according to the inner ring 3 to be formed. In the present embodiment, the push-in portion 11a is provided in the lower portion of the upper mold 11, and the push-in margin 15a corresponding to the push-in portion 11a is provided in the upper portion of the filling space 15 (see FIG. 3A). The portion excluding the pressing allowance 15a has a shape similar to the inner ring 3 to be molded.

  After the metal powder P is filled in the filling space 15 described above, the upper mold 11 is brought close to the lower mold 12 and clamping is performed to apply a pressing force to the metal powder P in the filling space 15, thereby compressing the metal powder P. Perform molding. In the present embodiment, the pressing allowance 15a is provided in the upper part of the filling space 15, and the metal powder P is filled up to the pressing allowance 15a (see FIG. 3A). The pressing force is applied to the metal powder in the filling space 15 by pressing the pressing portion 11 a of 11. In this case, as shown in FIG. 3B, the lower surface of the push-in portion 11a, the upper end surface 12a and the inner peripheral surface 12b of the lower mold 12, the outer peripheral surface 13a of the core rod 13, the inner peripheral surface 4 of the outer ring 2, and the spacer 14 The inner peripheral surface 14a of the second embodiment compresses the metal powder P as a molding surface, and the inner ring green compact 16 having a shape conforming to these surfaces is molded. Since the inner ring green compact 16 is formed by including the inner circumferential surface 4 of the outer ring 2 in the molding surface, the inner ring green compact 16 is already formed on the inner periphery of the outer ring 2 when the inner ring green compact 16 is molded. It has been introduced. Therefore, at the end of the compression molding process, a temporary assembly 17 in which the inner ring green compact 16 is disposed on the inner circumference of the outer ring 2 is formed.

(C) Sintering step After that, the temporary assembly 17 is carried into the heating device 20, and a predetermined heating process is performed by the heating unit 21 (see FIG. 4). Specifically, the inner ring green compact 16 is heated to the sintering temperature of the metal that is the main component of the inner ring green compact 16 and the inner ring green compact 16 is sintered. The sintering temperature varies depending on the type of metal that is the main component of the inner ring compact 16; for example, approximately 900 ° C. to 1100 ° C. for iron-based components, and approximately 800 ° C. to 1000 ° C. for copper-based components. Be done. Under the present circumstances, since the outer ring 2 is formed with ceramics, it is excellent in the surface of heat-resistant temperature compared with the material of the conventional outer rings 2 such as stainless steel. Therefore, even if the inner ring green compact 16 is heated to the above temperature, the dimensional change can be minimized, and the shape accuracy of the inner circumferential surface 4 to be the bearing surface can be secured.

(D) Sealing treatment step After sintering, the outer surface of the sintered body is subjected to sealing treatment in the region corresponding to the axial end faces 7 and 7 and the inner circumferential surface 8 (see FIG. 1), Sealing portion 9 is formed. Finally, the inner hole 6 is impregnated with a lubricant to complete the inner ring 3 shown in FIG. At the same time when the inner ring 3 is completed, the spherical plain bearing 1 including the outer ring 2 and the inner ring 3 is completed. The order of the impregnation treatment and the sealing treatment is not particularly limited. If possible, the lubricant may be impregnated into the internal pores 6 of the sintered body and then sealing treatment may be performed.

  As described above, the spherical plain bearing 1 according to the present invention is provided with the inner ring 3 made of sintered metal, and the lubricant is held in the inner holes 6 of the inner ring 3. According to this configuration, since the lubricant is supplied to the outer peripheral surface 5 of the inner ring 3, a good sliding lubrication state can be maintained with the inner peripheral surface 4 of the outer ring 2. Therefore, it is possible to improve the bearing life by improving the wear resistance and the seizure resistance as compared with the conventional oil-free spherical slide bearing.

  Further, in the present embodiment, of the outer surface of the inner ring 3, a region excluding the outer peripheral surface 5 having a partial spherical shape, that is, a surface layer including the axial end faces 7 and 7 and a surface layer including the cylindrical inner peripheral surface 8. The sealing portion 9 was formed in the portion. According to this configuration, the lubricant is made to exude only from the outer peripheral surface 5 of the inner ring 3 to be the bearing surface, and unnecessary lubricant leaks from the other regions (axial end surfaces 7 and 7 and the inner peripheral surface 8). It is possible to prevent the delivery. Therefore, the lubricant can be used without loss for the sliding lubrication of the bearing surface, which makes it possible to further improve the bearing life.

  Further, in the spherical plain bearing 1 according to the present invention, the inner ring 3 having the above-described function is formed of a sintered metal, and the outer ring 2 is formed of a ceramic. Ceramics exhibit high hardness and excellent wear resistance as compared to common metal materials (such as stainless steel). Furthermore, since the heat resistance temperature of the ceramic is very high, when the inner ring 3 is formed of a sintered metal, the inner ring 3 (inner ring compact 16) is disposed on the inner periphery of the outer ring 2 as shown in FIG. The inner ring green compact 16 can be sintered. Therefore, it becomes possible to simplify the spherical slide bearing 1 simply by omitting the process of manufacturing and assembling the outer ring 2 and the inner ring 3 respectively. Further, by making the outer ring 2 made of ceramic, dimensional change and structure change after the sintering process can be minimized, so that the shape accuracy of the bearing surface (inner circumferential surface 4) having a partial spherical shape can be maintained. Can. If the shape accuracy of the bearing surface is good, the sliding state is also stable, which also makes it possible to improve the bearing life.

  Further, in the present embodiment, the outer peripheral surface 5 of the inner ring 3 is a molding surface formed by the inner peripheral surface 4 of the outer ring 2. That is, as shown in FIG. 2, by molding the inner ring green compact 16 using the outer ring 2 as a part of the compression molding apparatus 10, the outer peripheral surface 5 of a shape similar to the inner peripheral surface 4 of the outer ring 2 is It can be molded into the inner ring 3. In addition, after compacting, by performing sintering processing while the inner ring green compact 16 is disposed on the inner periphery of the outer ring 2, the inner ring 3 is incorporated into the outer ring 2 simultaneously with the preparation of the inner ring 3. It can be performed. Therefore, the assembly process can be further simplified to further reduce the manufacturing cost.

  As mentioned above, although one Embodiment of this invention was described, the spherical plain bearing concerning this invention and its manufacturing method are not limited to the form of the said illustration, It is possible to take arbitrary forms within the scope of the present invention Of course.

  For example, in the above embodiment, the pressing allowance 15a is provided in the upper part of the filling space 15, and the metal powder P is additionally filled, and the pressing allowance 15a is pressed by the pressing part 11a provided in the upper mold 11. This is just an example. The form of the compression molding apparatus 10 and the compression mode of the metal powder P using this apparatus 10 are optional as long as sufficient compression force can be applied to the metal powder in the filling space 15.

  Moreover, although the case where sealing treatment was given to the predetermined area | region (axial direction end surfaces 7 and 7 and inner peripheral surface 8) except the outer peripheral surface 5 among the outer surfaces of the inner ring 3 was illustrated in the said embodiment, of course Pore treatment is not essential. Depending on the type of lubricant and the use environment, the inner ring 3 may be completed without being subjected to sealing treatment after sintering.

  In the above embodiment, the inner ring 3 is formed of sintered metal and the outer ring 2 is formed of ceramic. However, the material of the outer ring 2 is not limited to ceramic. Depending on the sintering temperature of the inner ring 3, in other words, as long as the material exhibits a heat resistance temperature higher than the sintering temperature, it can be adopted as the material of the outer ring 2.

DESCRIPTION OF SYMBOLS 1 spherical slide bearing 2 outer ring 3 inner ring 4 inner circumferential surface 5 outer circumferential surface 6 inner hole 9 sealing portion 10 compression molding device 11 upper die 11 a push-in portion 12 lower die 13 core rod 14 spacer 15 filling space 15 a push-in margin 16 inner ring pressed powder Body 17 Temporary assembly 20 Heating device 21 Heating part P Metal powder

Claims (5)

A spherical plain bearing comprising an outer ring and an inner ring, wherein an inner circumferential surface of the outer ring and an outer circumferential surface of the inner ring are partially spherically shaped bearing surfaces,
The inner ring is formed of a sintered metal, and a lubricant is held in its inner cavity,
The spherical slide bearing characterized in that the outer ring is formed of a ceramic.   The spherical plain bearing according to claim 1, wherein the outer peripheral surface of the inner ring is a molding surface formed by the inner peripheral surface of the outer ring.   The spherical plain bearing according to claim 1 or 2, wherein a linear expansion coefficient of the ceramic is larger than a linear expansion coefficient of the sintered metal.   The spherical plain bearing according to any one of claims 1 to 3, wherein a region of the surface of the inner ring excluding the outer peripheral surface is sealed. A manufacturing method of a spherical slide bearing comprising an outer ring and an inner ring, wherein an inner peripheral surface of the outer ring and an outer peripheral surface of the inner ring are bearing surfaces of partial spherical shape,
An outer ring manufacturing step of manufacturing the outer ring;
A compression molding step of compression molding a predetermined metal powder;
And sintering the green compact obtained by the compression molding to produce the inner ring,
In the compression molding step, the outer ring is used as a part of a molding die, and in the sintering step, the outer ring is sintered while being held on the outer periphery of the green compact, a spherical surface Method of manufacturing a sliding bearing.

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