JPH02173415A - Ceramic bearing and its manufacture - Google Patents

Abstract

PURPOSE:To improve oil film formation by making, of ceramics, an inner race having a shaft hole and a convex curved surface on its outer circumference, and an outer race having a concave curved surface on its inner circumference, providing an oil supply-and-discharge port on the concave curved surface and having both thrust and radial loads supported on thus formed ceramic bearing. CONSTITUTION:A ceramic bearing A comprises an inner race 1 having a shaft hole 4 and a convex curved surface 1a formed on its outer circumference, and an outer race 2 having a concave curved surface 2c fitted to the convex curved surface 1a, and on which half bodies 5 and 6 are fixed. A groove 7 and a hole 8 are provided on the outer race 2 to provide a means to supply and discharge oil to an from an oil cup 9. The journal B1 of a shaft B is engaged with the shaft hole 4, and an end surface B2 is brought into contact with the contact surface 1c of the inner race. A resultant load F of a thrust load Fs and a radial load Fr is supported by the concave curved surface 2c. As the bearing is made of ceramic, it has high abrasion resistance and heat resistance, and lubricating oil from the hole 8 promotes these effects. As the outer race is divided, grinding in the process of production is easy.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a ceramic 7x bearing comprised of a ceramic outer race and a ceramic inner race, and a manufacturing method for manufacturing the bearing. be.

<Prior Art> Conventionally, when attaching a rotating shaft to a frame, it has been common practice to use a bearing such as a sliding bearing or a rolling bearing.

The rolling bearing is constructed by providing rolling elements such as poles, Ll-ra, and needles between an outer race that fits into a housing formed on a machine frame, etc., and an inner race that fits a rotating shaft. There is. There are various types of rolling bearings depending on the rolling elements used, such as pole hair rings, roller hair rings, and needle hair rings, and there are also types such as radial bearings and thrust bearings depending on how the load is received (Japanese Patent Publication No. 49-1986). 41231, etc.). Among these bearings, bearings such as deep groove ball hair rings, angular pole hair rings, and tapered roller hair rings are used as bearings that can simultaneously support thrust loads and radial loads.

The sliding bearing may be constructed by laminating a white metal layer on a metal support such as steel, cast iron, or copper, and finishing the metal layer to a predetermined diameter by machining, or a bearing made of copper, gunmetal, or the like. Some are constructed by laminating or embedding an oil-impregnated alloy layer on a metal support.

A bearing constructed by forming the metal support in the shape of a sleeve is used as a radial bearing for supporting a radial load (Japanese Patent Publication No. 18885/1985, etc.); Such bearings are used as bearings for supporting thrust loads (e.g., vF Publication No. 49-681).

Each of the above-mentioned rolling bearings and sliding bearings has unique characteristics, and when used, the most suitable bearing is selected in consideration of the characteristics of each bearing.

<Problems that the invention sought to solve> The above-mentioned rolling bearings inevitably have a limited lifespan due to flaking caused by rolling fatigue, low heat resistance, and high cost due to the large number of component parts. There is a problem.

In a sliding bearing, since the shaft and the inner circumferential surface of the sliding bearing come into sliding contact, there is a risk that the shaft may become thin during long-term use.

An object of the present invention is to fit a shaft into a ceramic inner race to prevent slippage between the inner race and the shaft, and to reduce the number of parts by forming the outer race from ceramics. We provide ceramic bearings,
The present invention also provides a method for manufacturing the bearing.

<Means for Solving the Problems> In order to solve the above problems, the ceramic bearing of the present invention has a shaft hole for fitting a shaft formed on the inner peripheral surface and a convex curved surface on the outer peripheral surface. It has an inner race made of ceramics and an outer race made of ceramics having a concave curved surface formed on the inner peripheral surface for fitting the convex curved surface formed on the inner race, and the inner race made of ceramics is attached to the outer race made of ceramics. It is constructed by being stored.

Further, in the ceramic bearing, a plurality of holes are bored in the outer circumferential surface of the ceramic outer race and communicate with the concave curved surface formed on the inner circumferential surface.

In addition, the method for manufacturing a ceramic bearing includes the steps of: enclosing a ceramic inner race with a ceramic outer race formed into a plurality of parts, and fixing the plurality of ceramic outer races to each other; Injecting an abrasive through the hole to polish the contact surface between the outer race and the inner race, then injecting a fluid through the hole to drain the abrasive, and then injecting lubricating oil through the hole. It is characterized by

<Operation> According to the above means, a ceramic bearing is formed with a ceramic inner race (hereinafter referred to as "inner race J ) is housed in an outer race made of Ceramic Nox (hereinafter referred to as "outer race j"), which has a concave curved surface on its inner circumferential surface for fitting the convex curved surface formed on the inner race. A radial load acts on the shaft fitted in the shaft hole formed in the inner race, using the convex curved surface formed on the inner race and the concave curved surface formed on the outer race as sliding contact surfaces,
It is possible to support a thrust load or a combined load of a thrust load and a radial load.

The magnitude and direction of the combined load of the thrust load and radial load acting on the shaft fitted to the inner race are determined by the magnitude of each load. However, when the bearing of the present invention is used as a general-purpose product, since the direction of action of the composite load is unknown, the convex curved surface formed on the outer peripheral surface of the inner race and the aforementioned curved surface formed on the inner peripheral surface of the outer race By making the concave curved surface into which the convex curved surface fits into a sliding contact surface, it is possible to always smoothly support the unknown composite load even if the acting direction of the unknown load changes.

Further, by forming a plurality of holes on the outer circumferential surface of the outer race to communicate with the concave curved surface formed on the inner circumferential surface,
Through the hole, lubricating oil can be supplied to or discharged from the clearance of the sliding contact surface formed by the convex curved surface formed on the inner race and the concave curved surface formed on the outer race. Therefore, the heat generated by sliding friction between the convex curved surface formed on the inner race and the concave curved surface formed on the outer race can be absorbed, and the sliding contact surface can be cooled. The oil film can be formed smoothly.

Further, according to the method for manufacturing a ceramic bearing, the inner race is encapsulated by an outer race formed into a plurality of parts, and the outer races formed into a plurality of parts are fixed to each other by fusing or gluing. The race can be rotatably housed in the outer race. Further, by injecting an abrasive such as diamond powder through a hole formed in the outer peripheral surface of the outer race and polishing the contact surface between the outer race and the inner race, both contact surfaces can be brought into smooth sliding contact. After that, fluid is injected through the hole to cause the abrasive to flow out,
Furthermore, by injecting lubricating oil through the hole, a ceramic bearing can be manufactured.

<Example> Hereinafter, an example of a bearing to which the above means is applied will be described with reference to the drawings.

1A and 1B are cross-sectional explanatory diagrams of a ceramic bearing, FIG. 2 is a cross-sectional explanatory diagram of the ceramic bearing in use, and FIG. 3 is a developed explanatory diagram of the ceramic bearing.

In the figure, a ceramic bearing A is composed of an inner race 1 and an outer race 2. The inner race 1 is formed by filling a mold with an oxide-based ceramic raw material such as alumina or PSZ and press-forming the material to a diameter of about 1,500 to 1,000 yen.
It is formed by firing at 1600°C.

A shaft hole 4 is formed in the inner circumferential surface of the inner race 1 so as to be aligned with the shaft center 3 of the inner race 1 and into which the journal portion B1 of the shaft B is fitted. In addition, on the outer peripheral surface of the inner race 1,
A convex curved surface 1a and linear portions 1b are formed continuously on both sides of the curved surface 1a in the axial direction. Inner race 1
Both end surfaces of are contact surfaces I for abutting end surface B2 of shaft B.
It is formed as C.

The convex curved surface 1a is a curved surface that becomes a sliding surface that slides into contact with a concave curved surface 2C formed on the inner peripheral surface of the outer race 2, which will be described later. For this reason, the convex curved surface 1a is formed as a ring-shaped convex strip on the outer periphery of the inner race 1. The center of the convex curved surface 1a is set on the axis 3. The shape of the convex curved surface 1a can be formed as a spherical surface having a radius R and having a center on the axis 3, but it can also be formed as another curved surface.

The contact surface 1c comes into contact with an end surface B2 formed on the shaft B, and a thrust load acting on the shaft B is transmitted to the contact surface 1c. For this reason, the abutting surface C is formed to have a highly accurate perpendicular surface to the axis 3. Furthermore, the contact surface 1C is set at a position that protrudes from an end surface 2b of the outer race 2, which will be described later, so that when the end surface B2 of the shaft B comes into contact with the core IC,
It is configured so that the end surface B2 does not come into contact with the end surface 2b of the outer race 2. Therefore, the length of the inner race 1 in the 3-axis direction, that is, the distance between the contact surfaces IC, is longer than the length of the outer race 1 in the 3-axis direction.

The journal portion B1 of the shaft B is fitted into the shaft hole 4B, so that the radial load acting on the shaft B is transmitted.

For this reason, the shaft hole 4 is formed with a predetermined tolerance with respect to the diameter of the journal portion B.

In this embodiment, the outer race 2 is provided with the inner race 1 on the inner peripheral surface.
A concave curved surface 2C that matches the convex curved surface 1a formed in the half body 5.6 is formed, and the half body 5.6 is formed symmetrically with the inner race (2) and is fused or adhered to the inner race (2). , 6 are fixed to each other.

The halves 5 and 6 are formed by filling a mold with an oxide-based ceramic raw material such as alumina or PSZ, press molding, and firing at about 1500 to 1600°C.

The outer shape of the outer race (hereinafter simply referred to as "r outer race") 2 formed by fixing the halves 5 and 6 is a cylindrical outer peripheral part 2a,
It is formed by the end surface 2b. The outer circumferential portion 2a is a surface that becomes a fitting surface when attached to the housing H formed on the machine frame as shown in FIG. They are formed parallel to each other and have a predetermined diameter and political and economical tolerances.

A concave curved surface 2c is formed on the inner peripheral surface of the outer race 2. This concave curved surface 2C is a curved surface that becomes a sliding surface that slides into contact with the convex curved surface 1a formed on the outer periphery of the inner race 1 described above.

The concave curved surface 2C may be formed as a curved surface that coincides with the convex curved surface 1a, or may be formed as a curved surface that can come into contact with the convex curved surface 1a at a predetermined position. That is, the concave curved surface 2C does not necessarily have to match the shape of the convex curved surface 1a. At the top of the concave curved surface 2C,
A ring-shaped groove 7 is formed over the entire circumference. This groove 7 is formed on the convex curved surface 1a when manufacturing the bearing of this embodiment.
This is for supplying abrasive or lubricating oil between the concave curved surface 2C and the concave curved surface 2C.

A plurality of holes 8 are formed in the outer peripheral portion 2a of the outer race 2 and communicate with grooves 7 formed at the top of the concave curved surface 2C. This hole 8 is for supplying abrasive and lubricating oil to the groove 7.

Next, a case will be described in which the shaft B, on which thrust load and radial load act simultaneously, is supported by the ceramic bearing constructed as described above.

As shown in FIG. 2, the ceramic bearing A is constructed by housing the inner race 1 in the outer race 2, and the journal portion B+ of the shaft B is fitted into the shaft hole 4 formed in the inner race 1. Housing formed on the machine frame with the end surface B2 of the shaft B in contact with the contact surface IC formed on the inner race 1.
It is housed in 1.

The convex curved surface 1a formed on the outer circumference of the inner race 1 and the concave curved surface 2Ce formed on the inner circumference of the outer race 2 contact each other to form a sliding surface. At this time, a thrust load Fs and a radial load Fr are applied to the shaft B, and a composite load F is applied by these loads.

The thrust load Fs is transmitted to the inner race 1 through the end surface B2 of the shaft B, and the radial load Fr is transmitted to the inner race 1 through the journal portion B1 of the shaft B. Then, at a position corresponding to the direction of action of the composite load F, the inner race 1
The convex curved surface 1a formed on the outer race 2 contacts the concave curved surface 2c formed on the outer race 2, and slides at that position.

At this time, at the contact position between the convex curved surface 1a and the concave curved surface 2c, a component force in the tangential direction of the concave curved surface 2c is generated due to the resultant load F. The component force acts as an aligning force that urges the inner race l in the direction of the axis 3, regardless of the clearance between the concave curved surface 2c formed on the outer race 2 and the concave curved surface 1a formed on the inner race 1. It acts to align the axis B with the axis 3. In other words, when axis B rotates, centrifugal force causes
The shaft B rotates eccentrically in accordance with the clearance between the convex curved surface 1a and the concave curved surface 2c. At this time, inner race 1
Since the centering force acts on the centering force, the centering force overcomes the centrifugal force and always acts to align the inner race and therefore the axis B with the axis 3.

Furthermore, if the shape of the convex curved surface 1a formed on the inner race 1 is formed by a spherical surface centered on the axis 3, the inner race 1 can be It can be rotated in the direction of the arrow shown in Figure (A), and therefore can be configured as a self-aligning type bearing.

Furthermore, due to the sliding contact between the convex curved surface 1a formed on the inner race I and the concave curved surface 2C formed on the outer race 2, heat is generated on the contact surface, but since the inner race 1 and the outer race 2 are made of ceramics, Therefore, the influence of heat on bearing A is small. That is, the coefficient of thermal expansion is approximately 8 to 11
Since the temperature is 10 to 6/°C, the bearing A will not deteriorate due to heat, and will not be subject to excessive thermal stress due to thermal expansion.

Furthermore, when the shaft B is supported by the bearing A, the second
A hole 8 formed in the outer peripheral portion 1a of the outer race 1 supplies lubricating oil by a lubricating oil supply means such as an oil cup or a grease nipple, which is indicated by the reference numeral 9 in the figure.
The convex curved surface 1a formed on the inner race 1 and the concave curved surface 2c formed on the outer race 2 are
It is possible to supply lubricating oil to the clearance between the

Next, a procedure for manufacturing the ceramic bearing A constructed as described above will be explained. FIG. 3 is a developed explanatory diagram of the ceramic bearing A.

The halves 5 and 6 constituting the outer race 2 are symmetrical and have a concave curved surface 2c on the inner peripheral surface and a groove 7 on the top of the curved surface 2c when these halves 5 and 6 are fixed to each other. , and a hole 8 are formed therein. Further, the opposing surfaces of the halves 5 and 6 are formed as adhesive surfaces 5a and 6a. Then, as shown in FIG. 3, the molded half-holes 5.6 are faced so that a concave curved surface 2c is formed, the inner race 1 is sandwiched between them, and the adhesive surfaces 5a and 6a are fused or bonded. So, inner race 1
is rotatably stored in the outer race 2.

Inner race 1 is stored in outer race 2 as described above, but
At this time, the sliding contact surfaces of the convex curved surface 1a of the inner race J and the concave curved surface 2c of the outer race 2 are not familiar with each other. For this purpose, an abrasive such as diamond powder is supplied to the groove 7 through the hole 8, and the inner race 1 and the outer race 2 are rotated relative to each other to blend the curved surfaces 1a and 2c and finish the curved surface smoothly. .

When the polishing is completed, a fluid such as water is injected into the groove 7 through the hole 8 to discharge the abrasive remaining in the clearance between the convex curved surface 1a and the concave curved surface 2c and to clean the clearance.

Next, lubricating oil is injected into the groove 7 through the hole 8 to replace the water in the clearance with the lubricating oil.

The ceramic bearing A can be manufactured by the above procedure.

FIG. 4(A) is an explanatory diagram of another embodiment of the inner race 1, in which a ring-shaped groove 1 is formed on the convex curved surface 1a formed on the inner race 1.
0 is formed.

By forming the ring-shaped 1Jfi 10 on the convex curved surface 1a in this way, it becomes possible to smoothly supply lubricating oil to the sliding contact surface between the convex curved surface 1a and the concave curved surface 2C, and to the sliding contact surface. The sliding friction at the contact surface can be reduced, and the heat generation at the sliding contact surface can be reduced. Further, the groove 10 does not necessarily have to be a semicircular groove as shown in the figure, but may be, for example, conical.

FIG. 4(B) is an explanatory diagram of another embodiment of the outer race 2, in which a ring-shaped groove 1 is formed on the concave curved surface 2C formed on the outer race 2.
1 was formed.

Even if the ring-shaped ring 111 is formed on the concave curved surface 2c formed on the outer race 2 in this way, the same effect as when alo is formed on the convex curved surface 1a can be obtained.

<Effects of the Invention> As explained in detail above, according to the ceramic bearing of the present invention, the ceramic bearing has a shaft hole formed on the inner circumferential surface for fitting the shaft, and a convex curved surface formed on the outer circumferential surface. The manufactured inner race is housed in an outer ceramic race whose inner peripheral surface has a concave curved surface into which the convex curved surface formed on the inner race is inserted, so that the convex curved surface formed on the inner race and the convex curved surface formed on the inner race The concave curved surface formed on the outer race serves as a sliding contact surface to support the radial load, thrust load, or composite load of the thrust load and radial load acting on the shaft fitted in the shaft hole formed on the inner race. Moreover, even if the direction of action of the resultant load changes, it can always be supported smoothly.

Furthermore, since the bearing can be configured with an inner race and an outer race, the number of parts can be reduced compared to conventional rolling bearings, and therefore costs can be reduced.

Furthermore, even shafts on which thrust loads and radial loads act simultaneously, which are difficult to support with conventional sliding bearings, can be supported rationally.

In addition, by forming a plurality of holes on the outer peripheral surface of the outer race that communicate with the concave curved surface formed on the inner peripheral surface of the outer race, a convex shape formed on the inner race through the core portion can be formed. Lubricating oil can be supplied to or discharged from the clearance of the sliding contact surface formed by the curved surface and the concave curved surface formed on the outer race. Therefore, the heat generated by the sliding friction between the convex curved surface formed on the inner race and the concave curved surface formed on the outer race can be absorbed, and the sliding contact surface can be cooled. This allows smooth formation of an oil film.

Further, according to the method for manufacturing a ceramic bearing, the inner race is encapsulated by an outer race formed into a plurality of parts, and the outer races formed into a plurality of parts are fixed to each other by fusing or gluing. The race can be rotatably housed in the outer race. Further, by injecting an abrasive such as diamond powder through a hole formed in the outer circumferential surface of the outer race and polishing the contact surface between the outer race and the inner race, both contact surfaces can be brought into smooth sliding contact. After that, fluid is injected through the hole to cause the abrasive to flow out,
Further, by injecting lubricating oil through the hole, a ceramic bearing can be manufactured.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are cross-sectional explanatory views of ceramic bearings, Figure 2 is cross-sectional explanatory views of ceramic bearings in use, Figure 3 is expanded explanatory views of ceramic bearings, and Figure 4 is an explanatory cross-sectional view of ceramic bearings. Figures (A) and (B) are explanatory diagrams of other embodiments. A is a ceramic bearing, B is a shaft, B1 is a journal part, B2 is an end face, H is a housing, 1 is an inner race, 1a is a convex curved surface, 1c is a contact surface, 2 is an outer race, 2a is an outer peripheral part, 2b is an end surface, 2c is a concave curved surface, 3 is a shaft center, 4 is a shaft hole,
5 and 6 are half holes, 7 is a groove, 8 is a hole, 10. The moon is a ring-shaped groove

Claims (3)

[Claims] (1) A ceramic inner race with a shaft hole formed on the inner circumferential surface for fitting the shaft and a convex curved surface on the outer circumferential surface, and the convex curved surface formed on the inner race formed on the inner circumferential surface is fitted. What is claimed is: 1. A ceramic bearing comprising: a ceramic outer race having a concave curved surface for the purpose of holding the ceramic inner race; and the ceramic inner race is housed in the ceramic outer race. (2) The ceramic bearing according to claim 1, wherein a plurality of holes are bored on the outer peripheral surface of the ceramic outer race and communicate with a concave curved surface formed on the inner peripheral surface. (3) A ceramic inner race is encapsulated by a ceramic outer race formed into a plurality of parts, and the plurality of ceramic outer races are fixed to each other, and an abrasive is injected through holes formed in the outer peripheral surface of the ceramic outer race. A ceramic bearing characterized in that it is produced by polishing the contact surface between the outer race and the inner race, then injecting fluid through the hole to cause the abrasive to flow out, and further injecting lubricating oil through the hole. manufacturing method.