JP2002372056A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing having excellent characteristics such as low torque, high moment rigidity and high spin wear resistance, capable of receiving radial load, bidirectional axial load and moment load and usable in a corrosion resistant atmosphere. SOLUTION: Rolling elements 6 are built in between an outer ring 1 and an inner ring 2. The outer ring and the inner ring have two raceway surfaces 4a, 4b and 5a, 5b larger than the radius of each rolling element. Each rolling element is arranged in the alternately intersecting manner on the circumference while an outer diameter 6a used as a rolling contact surface has a curvature also in the axial direction. The outer diameter of each rolling element comes in contact at two points in total, one point each on the constantly facing raceway surfaces of the outer and inner rings. According to the operating environment, stainless steel, ceramics, resin, or the like is used for all of the inner ring, outer ring and rolling elements, or at least the material of one of three elements, and corrosion-resistant coating is applied to the surface of at least one of the inner ring, outer ring and rolling elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing capable of receiving a radial load, an axial load in both directions, and a moment load, and more particularly to a robot, a transport device, a food machine, a washing device, a fishing machine, a chemical facility, Medical equipment,
High humidity, splash, underwater,
The present invention relates to a rolling bearing that can be used in a corrosive atmosphere environment such as an acid, an alkali, and a reactive gas.

[0002]

2. Description of the Related Art Conventionally, as a bearing capable of receiving a radial load, an axial load and a moment load in both directions, a cross roller bearing shown in FIG. 7, a four-point contact ball bearing shown in FIG. 8, and a bearing shown in FIG. Three point contact ball bearings are known. In the cross roller bearing shown in FIG. 7, the rolling element 300 is a roller, and the rolling element 300 and the race rings 100 and 200 are in line contact with each other at two points, and thus have an advantage of high moment rigidity. In the four-point contact ball bearing shown in FIG. 8 or the three-point contact ball bearing shown in FIG. 9, the rolling element 400 is a ball.
And four or three points of contact with the bearing rings 100 and 200, so that it has the advantages of low torque and smooth operation. However, the cross roller bearing has the advantage of high moment rigidity, while the rolling element 300 and the races 100 and 200 have the advantage.
However, there is also a disadvantage that torque and torque fluctuation are large because of the line contact. Four-point contact ball bearings or three-point contact ball bearings
Since the rolling element 400 is a ball, it has the advantage that the torque is smaller than that of a cross roller of the same size, but has the disadvantage that the moment rigidity is small. When the radial load is dominant over the axial load or when a pure radial load is applied,
Since 00 is in contact with the races 100 and 200 at four or three points, the ball 400 has a large spin and small spin wear performance cannot be obtained. Further, the gap between the bearings is set to be positive in order to improve the spin wear performance even slightly, so that the moment rigidity of the bearings is reduced as a result.

[0003]

In order to solve these problems, the present inventor has proposed a radial load having a lower torque except for a large spin in the case of a four-point contact ball bearing, an axial load in both directions, and a moment load. A new and useful rolling bearing (Japanese Unexamined Patent Application Publication No. 2001-50264) was invented earlier. That is, a plurality of rolling elements are incorporated between a pair of races, and each of the races has a raceway groove having a raceway surface having a diameter larger than the radius of the rolling body, and at least one raceway ring therein. Consists of two raceway surfaces, and each rolling element has an outer diameter serving as a rolling contact surface also having a curvature in the axial direction, and is alternately arranged on the circumference in an intersecting manner. The rolling bearing has a configuration in which the diameter is always in contact at two points, one point each on the raceway surface of one of the raceways and the raceway surface of the other raceway, which has the following new and useful effects. Offered. Since the rolling elements are arranged alternately on the circumference between the outer and inner rings, a single bearing can receive a radial load, an axial load in both directions, and a moment load. Since each rolling element is always in contact with the outer and inner races only at two places, slippage due to large spin in the conventional four-point contact ball bearing or three-point contact ball bearing is small, and the spin wear resistance can be improved. Also, since the bearing clearance can be set small or negative as required, high moment rigidity can be realized. Further, since the rolling elements and the races are in point contact, the rolling resistance is lower and the torque can be reduced as compared with the cross rollers.

However, this novel rolling bearing invented earlier by the present inventor has been used in robots, transportation equipment, food machinery, washing equipment, fishing machinery, chemical equipment, medical equipment, semiconductor / liquid crystal manufacturing equipment, and the like. High humidity, splashing, underwater,
It is often used in a corrosive atmosphere environment such as an acid, an alkali, and a reactive gas, and the bearing is required to have corrosion resistance.

The present invention has been made in view of the above-mentioned problems of the prior art.
An object of the present invention is to provide a rolling bearing that has excellent characteristics such as low torque, high moment rigidity, and high spin resistance, can receive a radial load, an axial load and a moment load in both directions, and can be used in a corrosion-resistant atmosphere.

[0006]

In order to achieve the above object, the present invention provides a technical means in which a plurality of rolling elements are incorporated between a pair of races, and each of the races has a radius of the rolling race. Each has a raceway groove having a larger diameter raceway surface, in which at least one raceway ring has two raceway surfaces, and each of the rolling elements has an outer diameter that becomes a rolling contact surface also in the axial direction. It has a curvature and is arranged alternately in an intersecting manner on the circumference, and the outer diameter of each rolling element is always one point on the raceway surface of one raceway and the raceway surface of the other raceway that are always opposed. Rolling bearings in contact at a total of two points have technical means characteristic of adopting the following configuration.
That is, depending on the use environment, the inner ring and the outer ring that constitute the pair of races, all of the rolling elements or at least one of the three elements, stainless steel, ceramics,
The use of resin or the like, or the execution of a corrosion-resistant coating on at least one surface of the inner ring, outer ring, and rolling elements of the bearing.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rolling bearing according to an embodiment of the present invention. Note that the present embodiment is merely an embodiment disclosed in the description of the rolling bearing of the present invention, and is not to be construed as limiting at all. The design can be freely changed within the scope of the present invention.

The rolling bearing of the present invention can be used for, for example, high humidity, splashing water, water, acid, alkali, etc. of robots, transport equipment, food machinery, washing equipment, fishing equipment, chemical equipment, medical equipment, semiconductor / liquid crystal manufacturing equipment and the like. Used under corrosive atmosphere environment such as reactive gas. The rolling bearing has a plurality of rolling elements 6, 6... Incorporated in a raceway groove 3 formed between an inner diameter of a raceway (outer ring) 1 and an outer diameter of a raceway (inner race) 2. The races 1 and 2 may be integrally or one or both of them may be axially divided at an arbitrary position in the width direction and may be integrally assembled with bolts and rivets. In the case of splitting into two parts, if there is a flange part, the fixing of the flange part may also serve as the fixing action of the two orbital rings. In this case, the shape and structure of the flange are not particularly interpreted, and the axial dimension of the flange may be symmetric or asymmetric, and is not particularly limited, and the design can be changed within the scope of the present invention. Also,
A spigot or the like may be formed on the flange in order to improve the mounting position accuracy between the flange and the mating part.

The raceway groove 3 is formed by raceway surfaces 4 and 5 having a radius larger than the radius of the rolling element 6. The raceway surfaces 4 and 5 of the raceway grooves 3 of at least one of the raceways 1 and 2 are each composed of two raceway surfaces 4 a, 4 b or 5 a, 5 b having a radius larger than the radius of the rolling element 6. ing. The shape of each raceway surface 4 (or 4a or 4b) or 5 (or 5a or 5b) may be any shape such as an arched cross section or a V-shape as long as it has a shape suitable for rolling of the rolling element 6. However, the shape may be any of a curved shape and a straight shape, and is not particularly limited. For example, a Gothic arch formed by both arcs in which the center of the circle is arranged in a cross is applied. In this embodiment, the grinding relief is formed at the intersection of the raceway surfaces to facilitate the grinding process. However, it is also possible to form a continuous elliptical raceway groove without forming the grinding relief. It is.

The rolling element 6 has an outer diameter 6a serving as a rolling contact surface.
Has a curvature in the axial direction, and the raceway surfaces 4 (4a and 4b),
5 (5a, 5b), the rolling elements 6 have an arbitrary shape having a radius smaller than the radius of each of the rolling elements 6, and the adjacent rolling elements 6 are alternately arranged in an intersecting manner. Diameter 6a
Are always in contact with the raceway surface 4 (4a, 4b) of one raceway ring 1 and the raceway surface 5 (5a, 5b) of the other raceway ring 2 at one point each. For example, the rolling element 6 shown in FIG. 2 has a vertically-cut ball having a pair of planes (relative surfaces) 6b, 6b (having a structure in which the upper and lower portions of the ball are cut to form the relative surfaces 6b, 6b). The same applies hereinafter.)
The rolling elements 6, 6... are assembled so that the rotation center axes 6c perpendicular to b and 6b intersect with each other, and the outer diameter 6a of each rolling element 6 is always the raceway surface of one race 1 4
(4a ・ 4b) and the raceway surface 5 (5a ・ 5
In b), contact is made at two points, one point each. The upper and lower cutting widths of the rolling elements 6 are not particularly limited, and the upper and lower cutting ratios may be equal or unequal, and can be arbitrarily selected within the scope of the present invention. That is, the relative surfaces 6b, 6b of the rolling elements 6 may be symmetric or asymmetric, and both are within the scope of the present invention.

FIG. 3 shows an embodiment of a rolling element in which two planes are asymmetric, and this embodiment is used particularly in the case of high-speed rotation. The rolling element 6 of the present embodiment has an asymmetric flat surface (relative surface).
6b, 6d, and the large end 6 of the plane (relative surface) 6b, 6d
By arranging d to face the inner ring 2 of the bearing, the rolling elements 6
Is more stable, and a lower torque can be realized. 6a indicates an outer diameter, and 6c indicates a rotation center axis. The other configuration and effects are the same as those of the rolling element 6 shown in FIG. 2, and the description thereof is omitted. Further, as shown in FIG. 4, the rolling element 6 may have a ball shape formed by cutting one of the upper and lower sides to form one plane. Note that the overall shape of the rolling element 6, the presence or absence of the relative surfaces 6b, 6b (6d), the magnitude of the curvature in the axial direction at the outer diameter 6a, and the like are not limited to the above-described specific shape. It can be arbitrarily changed within the range. That is, for example, in place of the relative surfaces 6b, 6b, non-parallel surfaces may be provided, and a rotation center axis 6c perpendicular to the both surfaces may be provided.

The rolling elements 6, 6... Are assembled by the relative surfaces 6b, 6b, 6b, 6 of the adjacent rolling elements 6, 6.
The rotation center axes 6c, 6c perpendicular to b are alternately crossed, but the crossing state may be orthogonal or non-orthogonal. The method of arranging the rolling elements 6 in an intersecting manner is not particularly limited as long as the numbers are the same in both cases, that is, the rolling elements 6 may intersect one by one, and do not intersect one by one. If both have the same number, they may intersect two by two or intersect one by one or two, and both are within the scope of the present invention.

The movement of each rolling element 6, 6 is guided by a cage 7 or a separator (spacer) 9. Retainer 7,
The separator (spacer) 9 is not particularly limited as long as it has pockets 8 for holding and guiding the rolling elements 6 or grooves 10, respectively, and is arbitrarily selected and changed within the scope of the present invention. It is possible. The guide system of the retainer 7 is not particularly limited, and may be inner ring guide, outer ring guide, or rolling element guide. Further, the configuration and shape of the retainer 7 are not particularly limited, and may be, for example, an integral type or formed from several parts. Further, the material of the retainer is not particularly limited, and a retainer, a press retainer, a resin retainer, and the like are appropriately selected. For example, metals such as brass, iron, and stainless steel, and polyethylene (PE) Resin, polypropylene (PP) resin,
Polyarylene sulfide resin represented by polyacetal (POM) resin, polyferylene sulfide (PPS) resin, polyetheretherketone (PEE)
K), polyether nitrile (PEN), aromatic polyimide (PI), thermoplastic polyimide (TPI), polyamide imide (PAI), aromatic polyester (LCP)
And synthetic resins such as various fluorine-containing resins are selected within the scope of the present invention. For example, the cage 7 shown in FIG. 5 includes pockets 8... Which can alternately incorporate the adjacent rolling elements 6, 6 such that the rotation center axes 6 c, 6 c intersect, respectively. This is an embodiment in which the rolling elements 6 are arranged at equal intervals and alternately in an intersecting manner with the same number as the quantity. Both side surfaces 8a, 8b in the axial direction of each pocket 8 ...
Are parallel to each other alternately and neither perpendicular nor parallel to the rotation axis of the bearing, and have a constant angle (inclined) at the same level as the contact angle of the rolling element 6. The distance between both side surfaces 8 a and 8 b in the axial direction of each pocket 8 is slightly larger than the width of the rolling element 6. The pocket 8 has slanted parallel side surfaces 8a and 8b, and has both side surfaces 8a and 8b.
As long as the distance between them is slightly larger than the width of the rolling element 6, the overall shape of the pocket is not particularly limited and can be changed within the scope of the present invention.
In the present embodiment, the same number of pockets 8 as the number of rolling elements 6 are arranged at equal intervals and alternately in an intersecting manner on the circumference. However, the present invention is not particularly limited. If they are the same, they may intersect with each other, such as two by two or two by one, two or more, which is within the scope of the present invention. Due to the influence of various factors, there is a possibility that spin or skew may occur in the rolling element during rotation, and if the attitude of the rolling element can not be controlled well, the rotational resistance of the bearing may increase or the rotation may not be performed smoothly. there's a possibility that. Therefore,
According to the present embodiment, the pocket 8 of the retainer 7 is
And the parallel side surfaces 8a and 8b which are substantially the same as a constant angle of the same level as the contact angle of the pocket.
With b, a change in the attitude of the rolling element 6 due to spin, skew, or the like of the rolling element 6 is suppressed, and the attitude of the bearing can be maintained, so that a lower torque of the bearing can be realized.

The separator 9 shown in FIG. 6 has a smaller diameter than the diameter of the rolling element 6 so that the rotating central axes 6c, 6c of the adjacent rolling elements 6, 6 cross each other as described above. The concave arc grooves 10, 10 held on the
1 is formed in a cross shape. The radius of curvature of the arc groove 10 may be substantially the same as or larger than the radius of curvature of the rolling element outer diameter 6a, and is arbitrary. By using the separator 9 in this manner, the entire bearing can be made compact.

The state in which the preload is applied between the rolling element and the raceway surface is not particularly limited. That is, the preload may or may not be applied in the manufacturing stage, and both are within the scope of the present invention. . Also, the internal clearance of the bearing is set to be small or negative as necessary. Thereby, higher moment rigidity of the bearing can be realized.

In FIG. 1, reference numeral 14 denotes a sealing plate.
Corresponds to either a contact type seal or a non-contact type seal, or a non-contact type shield, and the shape is not particularly limited, and a well-known shape is appropriately selected within the scope of the present invention. . In the drawing, reference numeral 14a denotes a sealing surface of the sealing plate 14 which is in close contact with the inner bottom of the inner ring sealing groove and serves as a sealing surface. The material of the seal or shield is not particularly limited, but is preferably nitrile rubber or stainless steel. The method of arranging the sealing plate 14 is not particularly limited, and may be arranged on both sides or on one side as necessary, and both are within the scope of the present invention. Both the outer ring side and the inner ring side of the sealing surface are within the scope of the present invention. The shape of the seal, for example, the lip shape, is not particularly limited, and any line contact or surface contact with the sealing surface is within the scope of the present invention. Further, the presence or absence of the core metal is free, and the type having the core metal and the type without the core metal may be properly used as needed, and are not particularly limited. Also, the seal groove structure of the outer ring 1 and the inner ring 2 is not particularly limited, and can be appropriately changed within the scope of the present invention. Seal plate 1
The presence or absence of 4 is not particularly limited, and it is within the scope of the present invention whether or not it is installed as necessary.

These races (outer race) 1 and races (inner race)
According to the present invention, the materials of the outer ring 1, the inner ring 2, and the rolling element 6 or at least one of the three elements may be used as materials of the rolling element 6 and the rolling element 6, depending on the use environment (corrosive atmosphere environment). A stainless steel, ceramics, resin, or the like is used, or a corrosion-resistant coating treatment is performed on the surface of at least one of the outer ring 1, the inner ring 2, and the rolling element 6 or at least one of the three elements.

The components of "stainless steel" are not particularly limited, and may be ostenite stainless steel, martensite stainless steel, or precipitation hardening stainless steel, and can be changed within the scope of the present invention. The type of the "ceramic material" is not particularly limited, and a structural ceramic material such as an alumina-based, zirconia-based, silicon nitride-based, or silicon carbide-based material can be selected. As a base material of "corrosion resistant coating",
There is no particular limitation, and for example, bearing steel, carburized steel, stainless steel, ceramics, and the like are appropriately selected. The “corrosion-resistant coating” is not particularly limited, and may be, for example, soft metals such as gold, silver, and lead, layered compounds such as molybdenum disulfide and tungsten disulfide, graphite, fluorine resins such as polytetrafluoroethylene, and hard chromium. Plating, electroless nickel plating, low-temperature fluorinated chromium coating, ceramic coating and the like are appropriately selected. Further, the corrosion resistant coating may be a single coating or a composite coating, both of which are within the scope of the present invention. Although the component of the “resin material” is not particularly limited, polyethylene (P
E) resin, polypropylene (PP) resin, polyacetal (POM) resin, polyphenylene sulfide (PP
S) polyarylene sulfide resin represented by resin,
Polyetheretherketone (PEEK), polyethernitrile (PEN), aromatic polyimide (PI), thermoplastic polyimide (TPI), polyamideimide (PA
I), aromatic polyester (LCP) and various fluorine-containing resins are preferred. The fluorinated resin is not particularly limited, but may be a tetrafluoroethylene / perfluoroalkylvinyl ether copolymer (hereinafter abbreviated as PFA) or a tetrafluoroethylene / ethylene copolymer (hereinafter ETFE).
Abbreviation), polyvinylidene fluoride (hereinafter, PVD)
F), tetrafluoroethylene / hexafluoropropylene copolymer (hereinafter abbreviated as FEP), polychlorotrifluoroethylene (hereinafter abbreviated as PCTFE),
Examples thereof include chlorotrifluoroethylene / ethylene copolymer (hereinafter abbreviated as ECTFE). The resin used in the present invention may contain a fibrous filler in order to improve mechanical strength, heat resistance, dimensional stability and the like.
The fibrous filler is not particularly limited, but includes aluminum borate whiskers, potassium titanate whiskers,
Examples include carbon whiskers, aramid fibers, aromatic polyimide fibers, liquid crystal polyester fibers, graphite whiskers, glass fibers, carbon fibers, boron fibers, silicon whiskers, silicon nitride whiskers, alumina whiskers, aluminum nitride whiskers, wollastonite, and the like. Various additives may be blended within a range that does not impair the object of the present invention. For example, antioxidants, heat stabilizers, ultraviolet absorbers, light protectants, flame retardants, antistatic agents, flow improvers, non-tackifiers, crystallization accelerators, nucleating agents, pigments, dyes, etc. Examples can be given.

Next, based on the specific form shown in FIG.
Each embodiment will be described. The bearings shown in the first to ninth embodiments have the same basic bearing configuration as the following configuration. First, the basic configuration of the bearing of this embodiment includes a race (outer race) 1, a race (inner race) 2, and a rolling element (vertical cut ball) 6. The raceway ring (outer race) 1 has a raceway groove 3 composed of two raceway surfaces 4a and 4b each having a radius larger than the radius of the rolling element 6, as shown in FIG. The (inner ring) 2 has a raceway groove 3 composed of two raceway surfaces 5a and 5b having a radius larger than the radius of the rolling element 6 as shown in FIG. Upper and lower cut ball) 6
Adopted the form shown in FIG. 2 in which the planes (relative surfaces) 6b, 6b were symmetrical. Also, planes (relative surfaces) 6b, 6b
Are arranged so that the rotation center axes 6c, 6c of the rolling elements 6, 6 perpendicular to each other intersect alternately, and the movement of the rolling elements 6, 6 is guided by the pockets 8, 8 of the retainer 7 shown in FIG. You. The cage 7 rolls pockets 8... On which the adjacent rolling elements 6, 6 can be alternately assembled so that the rotation center axes 6 c, 6 c respectively cross each other as described above, on the circumference of the annular body. The moving bodies 6 are arranged at equal intervals and alternately in an intersecting manner with the same quantity as the quantity.

Embodiment 1 In this embodiment, the outer ring 1, the inner ring 2, and the rolling elements 6 are all made of stainless steel. Outer / Inner ring: Martensitic stainless steel Rolling element: Martensitic stainless steel Cage: Resin Lubricant: Lithium grease Sealing plate: Contact type rubber seal made of nitrile rubber Applicable corrosion environment: Used in high humidity environment. Features: According to the present embodiment, better corrosion resistance than a bearing using bearing steel is obtained.

Embodiment 2 In this embodiment, the outer race 1 and the inner race 2 are made of stainless steel, and the rolling elements 6 are made of ceramics. Outer / Inner ring: Martensitic stainless steel Rolling element: Silicon nitride ceramics Cage: Fluororesin Lubricant: Water-resistant grease Sealing plate: Stainless steel shield (non-contact sealing plate) Applicable corrosion environment: High humidity, splash, underwater environment Used in Features: According to the present embodiment, the bearing has a longer life in a water environment than the bearing of the first embodiment, while having corrosion resistance.

Embodiment 3 In this embodiment, the outer ring 1 and the inner ring 2 are made of ceramics, and the rolling elements 6 are made of stainless steel. Outer / Inner ring: Silicon nitride ceramics Rolling element: Martensitic stainless steel Cage: Fluororesin Lubricant: Water-resistant grease Sealing plate: Stainless steel shield (non-contact sealing plate) Applicable corrosion environment: High humidity, splash, underwater environment Used in Features: According to the present embodiment, the service life is longer than the bearing of the first embodiment in a water environment while having corrosion resistance.

[Embodiment 4] In this embodiment, an outer ring 1 and an inner ring 2 are provided.
And the rolling element 6 was made of a ceramic material. Outer / Inner ring: Precipitation hardened stainless steel Rolling element: Silicon nitride ceramics Cage: Fluororesin Lubricant: Solid lubrication Sealing plate: Stainless steel shield (non-contact sealing plate) Applicable corrosion environment: High humidity, splashing, water, weak acid environment Used below. Features: According to the present embodiment, it has higher corrosion resistance than when using martensitic stainless steel. Although not particularly limited, the present embodiment is preferably used for light loads.

[Embodiment 5] In this embodiment, an outer ring 1 and an inner ring 2
Has a corrosion-resistant coating, and the rolling element is a corrosion-resistant bearing made of stainless steel. Outer / Inner ring: Stainless steel + low-temperature fluorinated chrome coating Rolling element: stainless steel Cage: Fluororesin Lubricant: Water-resistant grease Seal plate: Nitrile rubber seal (contact type seal plate) Applicable corrosion environment: High humidity, splash, underwater Used in a weak acid environment. Features: According to the present embodiment, it has higher corrosion resistance and superior durability than the bearing of the first embodiment in an environment such as water and weak acid.

[Embodiment 6] In this embodiment, an outer ring 1 and an inner ring 2 are provided.
In addition, all of the rolling elements 6 were formed as corrosion-resistant bearings subjected to a corrosion-resistant coating treatment. Outer / Inner ring: Martensitic stainless steel + nickel alloy coating Rolling element: martensitic stainless steel + nickel alloy coating Cage: Fluororesin Lubricant: Water-resistant grease Seal plate: Stainless steel shield (non-contact seal plate) Applicable corrosion environment : High humidity, splash, underwater, weak acid, chemical,
Used in an alkaline environment. Features: According to this embodiment, higher corrosion resistance than bearings using martensitic stainless steel or hard chrome plating,
High hardness.

Embodiment 7 In this embodiment, the outer ring 1, the inner ring 2, and the rolling elements 6 are all made of a ceramic material. In this embodiment, no sealing plate is used. Outer / Inner ring: Alumina ceramics Rolling element: Silicon nitride ceramics Cage: Fluororesin Lubricant: Solid lubrication Applicable corrosion environment: Used in high humidity, splashing water, underwater, weak acid, and alkaline environment. Features: According to this embodiment, the bearing of the first embodiment and the second embodiment
Longer life than bearings. Alumina ceramics also has the advantage of lower cost than other ceramics.

[Embodiment 8] In this embodiment, an outer ring 1 and an inner ring 2
And all of the rolling elements 6 were made of a ceramic material. In this embodiment, no sealing plate is used. Outer / Inner ring: Silicon carbide ceramics Rolling element: Silicon carbide ceramics Cage: Fluororesin Lubricants: Solid lubrication Applicable corrosion environment: High humidity, water splash, water, weak acid, strong acid,
Used under strong alkali and reactive gas environment. Features: The ceramics used for the outer and inner races and rolling elements in this example have higher corrosion resistance than other ceramics, and therefore have a long life even in a strong acid environment.

[Embodiment 9] In this embodiment, an outer ring 1 and an inner ring 2 are provided.
Are made of a resin material, and the rolling elements are made of ceramics. Outer / Inner ring: Fluororesin Rolling element: Ceramics Retainer: Fluororesin Lubricant: Solid lubrication Applicable corrosion environment: High humidity, water splash, water, weak acid, strong acid,
Used under strong alkali and reactive gas environment. Features: According to this embodiment, it has higher durability than the bearing of the first embodiment under a light load. It also has the same corrosion resistance as a bearing using ceramics for the outer and inner rings. It is also low cost.

Therefore, according to each of the above-described embodiments, the outer diameter 6a of the rolling element 6 contacts the raceway surface 4a of the outer race 1 and the raceway surface 5b of the inner race 2 which are opposed to each other at a total of two points (one point in total).
2 and 12), and the adjacent rolling elements 6 contact the raceway surface 4b of the outer race 1 and the raceway surface 5a of the inner race 2 at one point each, for a total of two points (contact points are indicated by 13 and 13). Rolling element 6,6
Since the contact angles intersect alternately, a single bearing can receive a radial load, an axial load in both directions, and a moment load. The rolling element 6 is at one point on each of the raceway surfaces 4a and 5b, and the other rolling element 6 is on the raceway surfaces 4b and 5a.
Point contact, and only two points (two points) are in point contact (1
Since 2, 12, 13 and 13) are not performed, slippage due to large spin in a conventional four-point contact ball bearing or three-point contact ball bearing is small, and spin wear resistance can be improved. Furthermore, since the rolling elements 6, 6 and the outer and inner rings 1, 2 are in point contact, rolling resistance is lower than that of the cross roller, and low torque can be realized. As a result, it is possible to reduce the size, weight, and durability of the entire apparatus, and to reduce the cost. The use of stainless steel, ceramics, resin, etc. for the inner ring, outer ring, and rolling elements of the bearing improves the corrosion resistance of the bearing.Corrosion substances cannot directly corrode the base material of the bearing material by performing the corrosion-resistant coating treatment. , Long life of the bearing can be realized.

[0030]

According to the present invention, the rolling elements are arranged alternately on the circumference between the outer and inner rings, so that a single bearing can reduce the radial load and the axial load and the moment load in both directions. Can be received. Since each rolling element is always in contact with the outer and inner races only at two places, slippage due to large spin in the conventional four-point contact ball bearing or three-point contact ball bearing is small, and the spin wear resistance can be improved. Also, since the bearing clearance can be set small or negative as required, high moment rigidity can be realized. Further, since the rolling elements and the races are in point contact, the rolling resistance is lower and the torque can be reduced as compared with the cross rollers. as a result,
The overall device can be made compact, light, and durable, and the cost can be reduced.

The use of stainless steel, ceramics, resin, etc. for the inner ring, outer ring, and rolling elements of the bearing improves the corrosion resistance of the bearing.
Corrosive substances cannot directly corrode the base material of the bearing material, so that a long life of the bearing can be realized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing one embodiment of a rolling element.

FIG. 3 is an enlarged perspective view showing another embodiment of a rolling element.

FIG. 4 is an enlarged perspective view showing another embodiment of a rolling element.

FIG. 5 is a perspective view showing one embodiment of a retainer.

FIG. 6 is a perspective view showing one embodiment of a separator.

FIG. 7 is a longitudinal sectional view of a cross roller bearing according to an example of the related art.

FIG. 8 is a longitudinal sectional view of a four-point contact ball bearing as an example of the prior art.

FIG. 9 is a vertical sectional view of a three-point contact ball bearing as an example of the prior art.

[Explanation of symbols]

 1: outer ring 2: inner ring 3: track groove 6: rolling element 6a: outer diameter 6b: flat surface 6c: rotation center axis

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J101 AA12 AA15 AA25 AA26 AA32 AA42 AA54 AA62 BA10 BA50 BA55 BA70 CA34 DA09 DA14 DA16 EA06 EA13 EA31 EA32 EA33 EA34 EA35 EA36 EA37 EA41 EA42 EA41 GA32 FA08

Claims (4)

[Claims] A plurality of rolling elements are incorporated between a pair of bearing rings, each of which has a raceway groove having a raceway surface having a diameter larger than the radius of the rolling element, and at least one raceway groove therein. One race is composed of two raceways, and each rolling element is
The outer diameter serving as a rolling contact surface also has a curvature in the axial direction, and is alternately arranged on the circumference in a crossing manner, and the outer diameter of each rolling element is always in contact with the raceway surface of one of the opposed raceways. In a rolling bearing contacting at a total of two points, one point each on the raceway surface of the other race, at least one of the three elements of the pair of races and the rolling element is made of stainless steel. bearing. 2. A plurality of rolling elements are incorporated between a pair of bearing rings, each of which has a raceway groove having a raceway surface having a diameter larger than the radius of the rolling elements, and at least one raceway groove therein. One race is composed of two raceways, and each rolling element is
The outer diameter serving as a rolling contact surface also has a curvature in the axial direction, and is alternately arranged on the circumference in a crossing manner, and the outer diameter of each rolling element is always in contact with the raceway surface of one of the opposed raceways. A rolling bearing contacting at two points, one point each on the raceway surface of the other race, wherein at least one of the three elements of the pair of races and the rolling element is made of ceramics. . 3. A plurality of rolling elements are incorporated between a pair of races, each of the races having a raceway groove having a raceway surface having a diameter larger than the radius of the rolling body. One race is composed of two raceways, and each rolling element is
The outer diameter serving as a rolling contact surface also has a curvature in the axial direction, and is alternately arranged on the circumference in a crossing manner, and the outer diameter of each rolling element is always in contact with the raceway surface of one of the opposed raceways. In a rolling bearing contacting at a total of two points, one point each on the raceway surface of the other raceway, at least one of the three elements of the pair of raceways and the rolling element has a corrosion-resistant coating. And rolling bearing. 4. A plurality of rolling elements are incorporated between a pair of races, and each of the races has a raceway groove having a raceway surface having a diameter larger than the radius of the rolling body. One race is composed of two raceways, and each rolling element is
The outer diameter serving as a rolling contact surface also has a curvature in the axial direction, and is alternately arranged on the circumference in a crossing manner, and the outer diameter of each rolling element is always in contact with the raceway surface of one of the opposed raceways. In a rolling bearing contacting at a total of two points, one point each on the raceway surface of the other race, at least one of the three elements of the pair of races and the rolling element is made of resin. .