JP2008267452A - Bearing for use in special environment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost bearing for use in special environment capable of accomplishing both grease leakage resistance and space saving. <P>SOLUTION: The cage 4 is equipped with a plurality of pockets 50 on the circumference, each of which contains a ball. The internal surface of each pocket 50 has a concave-curved ring-like form so that the inner diameter side of the ball arranging pitch circle PCD becomes smaller towards the opening fringe on the inner diameter side of the cage. The internal surface of each pocket 50 has a recessed area 54 extending from the opening fringe on the inner diameter side of the cage to the outer diameter side of the cage. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing for a special environment, for example, a technique for solving grease leakage of a bearing used in a transport system including a semiconductor manufacturing apparatus, a liquid crystal panel manufacturing apparatus, and a robot.

Bearings used in semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, and transport systems including robots are required to have many grease leakage resistance, long life, low torque, and the like. In the applications described above, products are manufactured in a clean environment. However, the grease leaking from the bearing is scattered. Further, when a contact seal is used, there is a problem that the wear powder generated by the friction between the seal lip and the seal groove contaminates the clean environment. Therefore, the grease leakage resistance is particularly important.
Therefore, measures such as using a magnetic fluid seal (for example, Patent Document 1) and providing a plurality of non-contact seals have been taken.
JP-A-63-303272

However, the one disclosed in Patent Document 1 requires a space for providing a magnetic fluid seal or a plurality of seals in the axial direction of the bearing, which increases the number of parts and increases the manufacturing cost.
In bearings for special environments such as clean environments and vacuum environments, it is difficult to achieve grease leakage resistance and space saving at the same time and at low cost.

  An object of the present invention is to provide a bearing for special environment that can achieve grease leakage resistance and space saving at the same time and at low cost.

The bearing for special environment according to the present invention is a bearing for special environment in which a plurality of balls interposed between inner and outer rings are held by a cage, and the seal is attached to the outer ring and seals the bearing space. , Pockets for holding a plurality of balls are provided at a plurality of locations in the circumferential direction, and the inner diameter of each pocket becomes smaller as the inner diameter side of the ball arrangement pitch circle approaches the cage inner diameter side opening edge. A ring-shaped cage having a concave curved surface, wherein a concave portion extending from an opening edge on the inner diameter side of the cage to the outer diameter side of the cage is provided on the inner surface of each pocket.
According to the cage of this configuration, the inner surface of each pocket is provided with a recess that extends from the opening edge on the cage inner diameter side to the outer diameter side of the cage, making it difficult for grease to adhere to the seal groove of the inner ring and preventing grease leakage. it can. Therefore, a clean environment can be maintained without polluting the surrounding environment and products.

  In this invention, the concave portion is provided at one position so as to spread from the center in the cage circumferential direction at the opening edge of the pocket to one side, and has a width larger than half of the width in the cage circumferential direction of the pocket. The inner surface shape of the recessed portion is a cylindrical surface shape substantially along the surface of the virtual cylinder centered on the radial straight line of the cage, and the recessed portion extends from the opening edge on the cage inner diameter side to the ball. The shape may extend to the vicinity of the arrangement pitch circle and gradually become shallower and narrower as it approaches the ball arrangement pitch circle from the inner diameter edge of the cage.

  In the present invention, the recesses are provided at a plurality of locations on both sides of the center in the circumferential direction of the cage at the opening edge of the pocket, and the inner surface shape of each recess is a straight line in the radial direction of the cage. It has a cylindrical surface shape that is substantially along the surface of each virtual cylinder as the center, and this recess extends from the opening edge on the inner diameter side of the cage to the vicinity of the ball arrangement pitch circle, and the ball arrangement from the inner diameter edge of the cage The shape may gradually become shallower and narrower as it approaches the pitch circle.

  In this invention, the said recessed part is located in the both sides of the center of the holder circumferential direction in the opening edge of the said pocket, and is provided in two places, It extends to the cage outer diameter edge vicinity, These two recessed parts The inner surface shape of the ring is substantially along the surface of one virtual ring, the virtual ring has a ring outer diameter that fits in a pocket, a circular cross-sectional shape at an arbitrary circumferential position, and the center of the ring is a cage You may make it have inclination with respect to a central axis.

  Further, the bearing for special environment according to the present invention is the bearing for special environment, in which a plurality of balls interposed between the inner and outer rings are held by a cage and have a seal attached to the outer ring and sealing the bearing space. The cage is a ring-shaped cage having pockets for holding the balls of the bearing at a plurality of locations in the circumferential direction, and two annular cage halves are overlapped facing each other in the axial direction. These cage halves each have a spherical shell-shaped plate portion whose inner surface forms half of each pocket, and a flat plate portion that is a portion between adjacent pockets alternately arranged in the circumferential direction, The plate thickness of the portion located on the outer diameter surface portion of the shoulder height on both sides of the raceway surface of the bearing inner ring in the inner diameter side portion from the ball arrangement pitch circle in the spherical shell-shaped plate portion is greater than the plate thickness of the flat plate portion. It is also characterized by being made thinner.

The axial range of the portion where the plate thickness is reduced may be the whole or a part of the spherical shell plate, and at least the outer diameter of the shoulder height on both sides of the raceway surface of the bearing inner ring. The part located on the surface is made thinner.
According to this configuration, since the plate thickness of the portion located at the outer diameter surface portion of the shoulder portion on both sides of the raceway surface of the bearing inner ring is made thinner than the plate thickness of the flat plate portion, no grease adheres to the inner ring shoulder portion. Therefore, it is difficult for grease to adhere to the inner ring seal groove, and grease leakage can be prevented by using either a contact type or non-contact type seal. This particularly appears when the outer ring rotates. Therefore, there is no demerit such as an increase in bearing torque caused by adhering to a seal such as a general iron punching cage. Furthermore, since it is not necessary to add an element for preventing grease leakage to the sealing function, a seal design specialized for muddy water resistance, dust resistance, and low torque is possible.
In addition, the strength of the cage is reduced by making the reference plate thickness that is the plate thickness of the outer diameter side portion of the flat plate portion of the cage half and the ball arrangement pitch circle of the spherical shell plate portion equal to the conventional one. Therefore, only grease leakage can be prevented. Furthermore, since the shape of the pocket part which can contact with the ball is the same as the conventional one, the interference force between the cages does not increase due to the increase of the movable range of the cage.

Further, the bearing for special environment according to the present invention is the bearing for special environment, in which a plurality of balls interposed between the inner and outer rings are held by a cage and have a seal attached to the outer ring and sealing the bearing space. The container has pockets for holding a plurality of balls at a plurality of locations in the circumferential direction, and the radius of the inner diameter of the circumferential portion with the pocket from the center of the cage is set to the inner diameter of the circumferential portion between the pockets. It is characterized by being larger than the radius from the center of the cage.
In this case, the inner ring shoulder is formed by making the radius from the cage center of the inner diameter of the circumferential portion with the pocket of the cage larger than the radius from the cage center of the inner diameter of the circumferential portion between the pockets. And it becomes difficult for grease to adhere to the inner ring seal groove. This appears particularly when the outer ring rotates. Thereby, leakage of grease can be prevented regardless of whether the seal is a contact type or a non-contact type. Further, since it is not necessary to increase the tightening force of the seal lip, the torque does not increase. Each of the above-described actions can be obtained in any case where the inner diameter surface of the circumferential portion having the pocket is a curved surface having a concave curve when viewed from the axial direction, or a polygonal shape having a plurality of corners.

  The cage of the bearing for special environment according to the present invention has pockets for holding a plurality of balls at a plurality of locations in the circumferential direction, and the inner surface of each pocket is held by the inner diameter side of the ball arrangement pitch circle. It is a ring shape with a concave curved surface that becomes smaller in diameter as it approaches the opening edge of the cage inner diameter side, and since the inner surface of each pocket is provided with a recess extending from the opening edge on the cage inner diameter side to the cage outer diameter side, Grease does not easily adhere to the seal groove, preventing grease leakage.

  Therefore, a clean environment can be maintained without polluting the surrounding environment and products. Therefore, the product yield can be improved. Moreover, since grease leakage does not occur by using the cage, it is not necessary to make the seal a contact type, and the torque can be reduced. Further, according to the configuration of the bearing for special environment, it is not necessary to secure a space for providing a magnetic fluid seal or a plurality of seals in the axial direction of the bearing, and the number of parts is less than that described in the above-mentioned patent document, thereby reducing the manufacturing cost. Reduction can be achieved.

Further, the cage of the bearing for special environment according to the present invention is such that the plate thickness of the portion located at the outer diameter surface portion of the shoulder height on both sides of the raceway surface of the bearing inner ring is made thinner than the plate thickness of the flat plate portion. Grease does not adhere to the shoulder. Therefore, it is difficult for grease to adhere to the inner ring seal groove, and grease leakage can be prevented by using either a contact type or non-contact type seal. This particularly appears when the outer ring rotates. Therefore, there is no demerit such as an increase in bearing torque caused by adhering to a seal such as a general iron punching cage. Furthermore, since it is not necessary to add an element for preventing grease leakage to the sealing function, a seal design specialized in dust resistance and low torque is possible.
In addition, the strength of the cage is reduced by making the reference plate thickness that is the plate thickness of the outer diameter side portion of the flat plate portion of the cage half and the ball arrangement pitch circle of the spherical shell plate portion equal to the conventional one. Therefore, only grease leakage can be prevented. Furthermore, since the shape of the pocket part which can contact with the ball is the same as the conventional one, the interference force between the cages does not increase due to the increase of the movable range of the cage.

  Further, the cage of the bearing for special environment according to the present invention has a radius from the cage center of the inner diameter of the circumferential portion with the pocket of the cage from the cage center of the inner diameter of the circumferential portion between the pockets. By making it larger than the radius, it becomes difficult for grease to adhere to the inner ring shoulder and the inner ring seal groove. This appears particularly when the outer ring rotates. Thereby, leakage of grease can be prevented regardless of whether the seal is a contact type or a non-contact type. Further, since it is not necessary to increase the tightening force of the seal lip, the torque does not increase. Each of the above-described actions can be obtained in any case where the inner diameter surface of the circumferential portion having the pocket is a curved surface having a concave curve when viewed from the axial direction, or a polygonal shape having a plurality of corners.

  A first embodiment of the present invention will be described with reference to FIG. The bearing for special environments according to the first embodiment is used for a transport system including a semiconductor manufacturing apparatus, a liquid crystal panel manufacturing apparatus, and a robot, for example. In this bearing, a plurality of rolling elements 3 are interposed between the raceways 1a and 2a of the inner ring 1 and the outer ring 2, a cage 4 for holding the rolling elements 3 is provided, and the bearing space is hermetically sealed on both sides. A seal member 5 having a shape is provided. The rolling element 3 is made of, for example, a ball. In this case, the bearing is a deep groove ball bearing with a seal. The seal member 5 is composed of an annular cored bar 6 and a rubber-like member 7 that is integrally fixed to the cored bar 6, and the outer peripheral part is fitted in a seal mounting groove 8 formed on the inner peripheral surface of the outer ring 2. Fixed to state. The rubber-like member 7 is made of synthetic rubber, and the cored bar 6 is made of a steel plate. The inner ring 1 has a seal groove 9 formed of a circumferential groove at a position corresponding to the inner diameter portion of each seal member 5, and a labyrinth seal gap 10 between the inner diameter side end of the seal member 5 and the seal groove 9 of the inner ring 1. Is formed. The seal mounting groove 8 and the seal groove 9 are turned.

  As shown in an enlarged view in FIG. 1B, the seal groove 9 has a bottom surface 9a formed into a cylindrical flat surface, and the seal groove inner side wall 9b and the seal groove outer wall 9c are both inclined surfaces. ing. The shoulder outer peripheral surface 1c inside the bearing relative to the seal groove 9 of the inner ring 1 is lower than the shoulder outer peripheral surface 1b inside the bearing of the seal groove 9, that is, has a small diameter. The rubber-like member 7 of the seal member 5 has a coreless rubber part 7 a extending from the inner peripheral end of the cored bar 6 to the inner diameter side, and the outer side surface of the cored rubberless part 7 a becomes an annular groove 15. A constricted portion 11 having a cross-sectional shape is provided. The groove side wall surface 15a on the outer diameter side of the annular groove 15 forming the constricted portion 11 is tapered. The inner diameter portion of the coreless rubber portion 7a is formed in two seal lips, a center lip 12a and a dust lip 12b, extending to the inner diameter side and the bearing outer side, respectively. The dust lip 12b extends to the outside of the bearing with the center lip 12a as a base end. The center lip 12a extends to the inside of the bearing and maintains a non-contact state with the seal groove inner wall 9b. In this way, by extending the center lip 12a to the inside of the bearing, the axial position of the center of gravity of the coreless rubber portion 7a is set to the center of the cross section of the constricted portion 11, more specifically, the center of the cross section of the groove bottom portion of the constricted portion 11. Is biased to the inside of the bearing.

  In the labyrinth seal gap 10 formed between the inner diameter end side of the seal member 5 and the outer diameter surface of the inner ring 1, due to the shape of both lips 12a and 12b formed in the inner diameter portion of the coreless rubber portion 7a, Narrowed portions 10a to 10c having gap sizes are formed at a plurality of locations side by side in the inner and outer directions. Specifically, a first narrow portion 10 a is formed between the dust lip 12 b and the outer diameter surface of the inner ring 1, and a second narrow portion is formed between the center lip 12 a and the seal groove outer wall 9 c of the inner ring 1. 10b is formed, and a third narrow portion 10c is formed between the center lip 12a and the seal groove inner wall 9b of the inner ring 1. The outermost narrow portion 10a is narrower than the other narrow portions 10b and 10c. Thereby, in the labyrinth seal gap 10, three wide and narrow change portions are formed with a narrow portion and a wide portion as a set of wide and narrow change portions.

On the inner side surface of the seal member 5, grease reservoirs 13a and 13b each formed of an annular groove are provided at two locations aligned in the radial direction. Of these grease reservoirs 13 a and 13 b, the outer diameter of the grease reservoir 13 a on the outer diameter side is made smaller than the inner diameter of the outer ring 2.
In the labyrinth seal gap 10 formed between the inner diameter end of the seal member and the outer diameter surface of the inner ring 1, the narrowed portions 10a to 10c of the gap dimension are aligned in the inner and outer directions. In the labyrinth seal gap 10, a plurality of (three in this embodiment) wide and narrow change portions are formed with a narrow portion and a wide portion as a set of wide and narrow change portions. As described above, the labyrinth seal gap 10 is repeatedly changed in width and width, so that the prevention of grease leakage from the labyrinth seal gap 10 is enhanced. Therefore, surrounding contamination due to grease leakage is prevented.

  Further, since the axial position of the center of gravity of the coreless rubber portion 7a in the seal member 5 is biased to the inside of the bearing with respect to the center of the cross section of the constricted portion 11, for example, the distal end of the inner diameter portion of the seal member 5 when the outer ring rotates Can be prevented from swinging outside the bearing. Therefore, it is possible to reduce the pump effect caused by the increase or decrease of the gap 10 between the inner diameter end of the seal member 5 and the seal groove 9 due to the vibration, and to suppress the promotion of grease leakage due to the pump effect.

  On the inner side surface of the seal member 5, grease reservoirs 13 a and 13 b each having an annular groove are provided side by side in the radial direction, and the outer diameter dimension of the grease reservoir 13 a on the outer diameter side is made smaller than the inner diameter dimension of the outer ring 2. Therefore, the grease in the grease reservoirs 13a and 13b can be gradually supplied to the raceway surface 2a by the centrifugal force when the outer ring rotates. Therefore, the grease in the grease reservoirs 13a and 13b can contribute to the lubrication of the raceway surfaces 1a and 2a.

  In the special environment bearing according to this embodiment, by using the cage 4 shown below, it is difficult for grease to adhere to the seal groove 9 of the inner ring 1, and grease leakage can be prevented.

The cage 4 will be described with reference to FIGS.
As shown in a perspective view in FIG. 2, the retainer 4 has pockets 50 for holding the balls 3 (FIG. 1A) at a plurality of locations in the circumferential direction, and the inner surface of each pocket 50 is a concave spherical surface. It is a ring-shaped one. The retainer 4 is formed by joining two annular retainer halves 51 shown in a perspective view in FIG. 3 so that they face each other in the axial direction and are joined together by a rivet 53 inserted through a rivet hole 52. Composed. These cage halves 51 have a plurality of spherical shell-shaped plate portions 50A whose inner surfaces form half of the pockets 50, and a flat plate portion 51a serving as a portion between adjacent pockets 50; The spherical shell plate portions 50A are alternately arranged in the circumferential direction. The spherical shell-shaped plate portion 50A is a part that becomes a part of the spherical shell, in other words, a counter-sink-shaped bulged portion in which both the inner and outer surfaces are spherical. The projected shape in the axial direction of the cage half 51 is a ring shape having a constant radial width over the entire circumference.

  A part of the cage half 51 is enlarged and shown in a perspective view in FIG. FIG. 4 is a diagram in the case where the pocket inner surface is a monotonous spherical surface in a portion corresponding to FIG. In FIG. 4, a portion A indicated by a two-dot chain line indicates a circumferential band in which the flat plate portions 51a of the cage half 51 are arranged in the circumferential direction. The spherical shell plate portion 50A, which is a half of the pocket 50, is formed at a portion of the circumferential band A that is not the flat plate portion 51a. One side portion of the spherical shell plate portion 50 </ b> A in the drawing is an inner diameter side portion 50 </ b> Ai of the cage 4, and the other side portion of the spherical shell plate portion 50 </ b> A is an outer diameter side portion 50 </ b> Ao of the cage 4.

  As shown in FIG. 5, the inner surface of the pocket 50 (spherical shell plate portion 50 </ b> A) of the retainer 4 of this embodiment is formed on the inner diameter side portion 50 </ b> Ai of the retainer 4 from the opening edge on the inner diameter side of the retainer. A recess 54 extending toward the outer diameter side is provided, and a cross-sectional shape of the inner surface of the recess 54 along the circumferential direction of the cage (that is, a cross-sectional shape taken along a plane perpendicular to the cage central axis) is defined as the inner surface of the pocket 50. An arc shape having a radius of curvature Rb smaller than the radius of curvature Ra of the concave spherical surface.

  The recessed portion 54 is provided at one location so as to spread from the center OW50 in the cage circumferential direction at the opening edge of the pocket 50 to one side, and the width W54 of the recessed portion 54 is the width W50 in the cage circumferential direction of the pocket 50. The width is almost the whole. The width W54 of the recessed portion 54 is preferably larger than half of the width W50 of the pocket 50, and more preferably 2/3 or more, or 3/4 or more.

  The inner surface shape of the recessed portion 54 is a cylindrical surface shape substantially along the surface of the virtual cylinder V centered on the straight line L in the radial direction of the cage 4 as shown in FIG. The virtual cylinder V may be the surface of a grindstone that processes the recess 54. The concave portion 54 extends from the opening edge on the inner diameter side of the cage to the ball arrangement pitch circle PCD in the radial direction of the cage, and gradually decreases, that is, gradually, from the inner diameter edge of the cage to the ball arrangement pitch circle PCD. The shape is shallow and narrow. In this embodiment, the dent 54 extends to the ball arrangement pitch circle PCD. However, the dent 54 may extend slightly to the outer diameter side of the cage from the ball arrangement pitch circle PCD, or slightly to the ball arrangement pitch circle PCD. You may not reach it. The ball arrangement pitch circle PCD is also called a pocket PCD.

  The depth of the concave portion 54 is such that the distance Rc from the center O50 of the concave spherical surface of the pocket inner surface to the deepest position of the concave portion 54 is 1.05 times or more the radius of the ball 3 (just 1.05 times). Preferably). The radius of curvature Ra of the concave spherical surface serving as the inner surface of the pocket 50 is slightly larger than the radius of the ball 3 and is less than 1.05 of the radius of the ball 3.

  FIG. 6 shows another example of the shape of the inner surface of the pocket 50 (spherical shell plate portion 50A) of the cage 4. In this example, two recessed portions 54A provided in the inner diameter side portion 50Ai of the inner surface of the pocket 50 (spherical shell-shaped plate portion 50A) are positioned on both sides of the center OW50 in the cage circumferential direction at the opening edge of the pocket 50. It is said. The inner surface shape of each recess 54A is such that the cross-sectional shape along the circumferential direction of the cage (that is, the cross-sectional shape taken along the plane perpendicular to the central axis of the cage) is larger than the radius of curvature Ra of the concave spherical surface serving as the inner surface of the pocket 50. It has an arc shape with a small radius of curvature RAb, and in detail, as shown in FIG. 5B, it has a cylindrical surface shape substantially along the surface of each virtual cylinder VA centered on the radial straight line LA of the cage 4. is there. The recessed portion 54A extends from the opening edge on the inner diameter side of the cage to the vicinity of the ball arrangement pitch circle PCD in the radial direction of the cage, and gradually decreases from the inner diameter edge of the cage to the ball arrangement pitch circle PCD. The shape gradually becomes shallower and narrower.

The positions of the two recessed portions 54A are, for example, two symmetrical places where the circumferential orientation angle with respect to the center OW50 in the circumferential direction of the cage at the opening edge of the pocket 50 is 40 ° ± 15 °. Also in this example, the depth of the recessed portion 54A is such that the distance RAc from the center O50 of the concave spherical surface of the pocket inner surface to the deepest position of the recessed portion 54A is 1.05 times or more the radius of the ball 3. Is preferable (it may be just 1.05 times).
In this embodiment, the number of the recessed portions 54A is two, but may be three or more.

  FIG. 7 shows still another example of the shape of the inner surface of the pocket 50 (spherical shell plate portion 50A) of the cage 4 (FIG. 1). In this embodiment, in the embodiment of FIG. 6, the cross-sectional shape of the recess 54A (the cross-sectional shape along the circumferential direction of the cage) is a polygonal shape instead of an arc shape. Specifically, as shown in FIG. 5B, a polygonal shape substantially along the surface of each polygonal column (regular decagonal column in the illustrated example) VC centered on the straight line LA in the radial direction of the cage 4. It is. The recessed portion 54C extends from the opening edge on the cage inner diameter side to the vicinity of the ball arrangement pitch circle PCD in the radial direction of the cage, and gradually decreases from the cage inner edge to the ball arrangement pitch circle PCD. The shape gradually becomes shallower and narrower. Other configurations in this embodiment are the same as those in the example of FIG.

  FIG. 8 shows still another example of the shape of the inner surface of the pocket 50 (spherical shell-like plate portion 50A) of the cage 4. In this example, the recessed portions 54B provided in the inner diameter side portion 50Ai of the inner surface of the pocket 50 (spherical shell-shaped plate portion 50A) are positioned on both sides of the center OW50 in the cage circumferential direction at the opening edge of the pocket 50. Although it is the same as that of embodiment of FIG. 6 by being provided in the location, each recessed part 54B is extended to the cage | basket outer-diameter edge vicinity. The cross-sectional shape along the circumferential direction of the cage of the inner surface of the recessed portion 54B is an arc shape having a curvature radius RBb smaller than the curvature radius Ra of the concave spherical surface serving as the inner surface of the pocket 50. FIG. As shown, the shape is substantially along the surface of one virtual ring VB. The virtual ring VB may be an outer peripheral surface of a grindstone that processes the recess 54B. The virtual ring VB has a ring outer diameter that can be accommodated in the pocket 50, and has a donut shape with a circular cross-sectional shape at an arbitrary circumferential position, and the ring center OVB is placed on the cage center axis O as shown in FIG. It has an inclination to it.

In the present invention, the cross-sectional shape along the circumferential direction of the cage of the recessed portions 54A to 54C is not limited to the shape of each example of FIGS. 6 to 8, but a partial oval shape, a rectangular groove shape, a trapezoidal groove shape, Any other cross-sectional shape may be used. In addition, the cross-sectional shape of the recesses 54A to 54C may be asymmetric with respect to the center of the recess.
The inner surface shape of the pocket 50 is not limited to a spherical shape, and may be any shape as long as the inner diameter side portion of the pocket arrangement pitch circle PCD becomes a smaller diameter as it approaches the cage inner diameter side opening edge, for example, the ball arrangement pitch circle PCD. Further, the outer diameter side portion may be a cylindrical surface shape, and the inner diameter side portion may be a conical surface shape.

  FIG. 10 shows a method for manufacturing the cage 4. This manufacturing method is a method of manufacturing an iron plate punching cage, in which a steel plate is first pressed to punch a ring-shaped metal strip 55. Next, as shown in FIG. 10A, a convex press die 56 for molding the inner surface of the spherical shell plate portion 50A of the cage half 51 and the outer surface of the spherical shell plate portion 50A are molded. A press die set 58 composed of the concave press die 57 is prepared, and the ring-shaped metal strip 55 is sandwiched between the convex press die 56 and the concave press die 57, and FIG. The cage half 51 is press-molded as in B). This press molding may be performed in two stages of rough pressing and finishing pressing, or may be performed once.

Although only one convex press die 56 and one concave press die 57 are shown in the drawing, each of the convex press die 56 and the concave press die 57 is a cage half 51. The same number of the spherical shell plate portions 50A are arranged in the circumferential direction as a single mold, and a plurality of spherical shell plate portions 50A are formed at the same time.
The two retainer halves 51 thus obtained are overlapped as shown in FIG. 10C, and a portion where the flat plate portion 51a of the retainer half 51 is overlapped as shown in FIG. To form a cage 4.

  In FIG. 11, the convex side press die 56 and the concave side press die 57 used for the finishing pressing step in press molding are shown for molding the cage half 51 of FIG. The hemispherical convex surface of the convex side press die 56 is partially formed with a concave portion molding die portion 56a for molding the inner surface of the concave portion 54A in the pocket 50 (spherical shell plate portion 50A). Further, the concave side press mold 57 is partially formed with a concave portion back surface molding die portion 57a for molding the outer surface of the concave portion 54A in the pocket 50 (spherical shell plate portion 50A). Although a convex part will be formed in the outer surface side of a holder | retainer pocket, if it is non-contact with a seal | sticker, there is no functional problem. In this case, the convex-side press die 56 and the concave-side press die 57 are also provided as a single die corresponding to the number of the spherical shell plate portions 50A of the cage half 51, and have a plurality of spherical shell shapes. The plate portion 50A is formed at the same time.

When the cage half 51 shown in FIG. 6 is formed, the inner surface of the spherical shell plate portion 50A has a shape having a concave portion 54A in a part of a simple hemispherical concave surface. If the concave portion 54A is further press-molded into a part of the hemispherical concave surface after forming the concave shape, the manufacturing process is increased by one step as compared with the case of forming a conventional steel punching cage. .
In this embodiment, as described above, for forming a concave portion, the inner surface of the concave portion 54A in the pocket 50 (spherical shell plate portion 50A) is formed on the hemispherical convex surface of the convex press die 56 used in the finishing pressing step. Since the mold portion 56a is partially formed, the recessed portion 54A can be formed at the same time in the finishing pushing process, and the cage 4 can be efficiently manufactured without increasing the manufacturing process.

  Further, the shape and surface roughness of the hemispherical convex surface of the convex press die 56 used in the finishing pressing step are transferred to the inner surface of the cage pocket 50, and the pocket inner surface is inserted into the ball 3 ( In order to come into contact with FIG. 1), it is necessary to reduce the surface roughness of the pocket inner surface. Since the inner surface of the pocket is a simple concave spherical surface in the conventional iron plate punching cage, the surface roughness is reduced by polishing the hemispherical convex surface of the convex press die with a concave grinding stone or the like. However, in the case of this embodiment, as described above, the hemispherical convex surface of the convex-side press die 56 is a part of a simple hemispherical convex surface, and a concave portion molding die portion 56a corresponding to the concave portion 54A of the pocket inner surface. The surface roughness cannot be reduced by polishing with a concave-shaped grindstone or the like as in the conventional example.

  Therefore, in this embodiment, the convex convex spherical surface of the convex press die 56 used in the finishing pressing step is surface-finished by shot blasting, polishing with an electron beam, or lapping by injection of an abrasive. In this case, lapping is generated by obtaining abrasive material having elasticity and adhesiveness by adding moisture to the abrasive grains and sliding the abrasive material on the surface of a mold as a workpiece at high speed. A method of surface finishing by frictional force is preferred. As such wrapping, aero wrapping (Yamashi Towers Co., Ltd.) sold as a mold ultra-mirror finishing device can be employed. As described above, the surface of the convex spherical surface of the convex press die 56 is finished by shot blasting, electron beam, or lapping by jetting an abrasive, so that there is no need for manual polishing, and there is no unevenness and low cost. The surface roughness of the convex convex spherical surface of the side press die 56 can be reduced.

12 to 14 show the test results of confirming the grease adhesion state. In this test, a ball bearing incorporating the cage 4 of this embodiment (the embodiment of FIG. 5 and the embodiment of FIG. 6) and a ball bearing incorporating a general iron plate punched cage are shown in the following table. A comparison was made by driving under the condition of 1.
FIGS. 12 and 13 show the grease adhesion state of the ball bearing using the cage 4 of this embodiment (the embodiment of FIG. 5 and the embodiment of FIG. 6 respectively), and FIG. 14 is a general iron plate punching cage. The grease adhesion state of the ball bearing using

From the test results of FIGS. 12 to 14, in the ball bearing (FIG. 14) in which a general steel plate punched cage is incorporated, grease adheres to the inner ring seal groove, but the ball bearing in which the cage 4 of this embodiment is incorporated. (Examples of FIGS. 12 and 13) show that there is no adhesion of grease.
In the special environment bearing retainer 4 according to this embodiment, since the shape of the pocket 50 is different from that of the conventional example as described above, adhesion of grease to the shoulder portion of the inner ring can be eliminated. In other words, since a recess is provided at the opening edge on the inner diameter side of the cage, where the grease adheres most to the ball, scraping of the surface of the ball when grease scraping occurs reduces the inner diameter of the cage. The amount of grease that accumulates on the surface is reduced.

  Therefore, grease does not adhere to the inner ring seal groove, and no grease leakage occurs regardless of whether a contact type or non-contact type seal is used. This effect is characteristic especially when the outer ring rotates. Therefore, there is no problem caused by the grease adhering to the seal unlike a general iron plate punched cage. Furthermore, since it is not necessary to add an element for preventing grease leakage to the sealing function, a seal design specialized in dust resistance and low torque is possible. Further, since the ball bearing retainer 4 of this embodiment can be pressed, a high-strength one can be manufactured at a low cost, and the distance from the seal does not change as compared with a general iron punching retainer.

  In each of the above-described embodiments, an iron plate punched cage is shown, but the present invention can also be applied to a resin cage 59 as shown in FIGS. 15 and 16. The resin cage 59 has two annular bodies 60, 60 made of a resin molded product. A plurality of hemispherical pockets 61A along the outer periphery of the ball are formed at equal intervals in the circumferential direction on one side surface of each annular body 60 that abuts each other. Between the adjacent pockets 61 </ b> A and 61 </ b> A, an engagement hole 62 and an engagement claw 63 serving as a coupling portion are provided, and the engagement claw 63 of one annular body 60 is connected to the engagement hole 62 of the other annular body 60. By inserting, both annular bodies 60 are joined together to form a cage 59.

  According to the configuration of the bearing for special environment described above, the cages 4 and 59 have pockets 50 that respectively hold a plurality of balls 3 at a plurality of locations in the circumferential direction, and the inner surfaces of the pockets 50 are arranged in a ball arrangement. The portion on the inner diameter side of the pitch circle PCD is a ring-shaped ring having a concave curved surface that becomes smaller in diameter as it approaches the opening diameter on the inner diameter side of the cage. Since the recessed portion 54 (54A, 54B, 54C) extending to the outer diameter side is provided, it is difficult for grease to adhere to the seal groove 9 of the inner ring 1, and grease leakage can be prevented.

  Further, since grease leakage does not occur by using the cage, it is not necessary to make the seal a contact type. In other words, the seal member 5 can be made a non-contact type and the torque can be reduced. Further, according to the configuration of the bearing for special environment, it is not necessary to secure a space for providing a magnetic fluid seal or a plurality of seals in the axial direction of the bearing, and the number of parts is less than that described in the above-mentioned patent document, thereby reducing the manufacturing cost. Reduction can be achieved.

  For example, as shown in FIG. 5, the recessed portion 54 is provided at one position so as to spread from the center in the circumferential direction of the cage at the opening edge of the pocket 50 to a width W50 in the circumferential direction of the cage 50. The inner surface shape of the recess 54 is a cylindrical surface shape substantially along the surface of the virtual cylinder V centered on the straight line L in the radial direction of the cage 4. The recess 54 extends from the opening edge on the inner diameter side of the cage to the vicinity of the ball arrangement pitch circle PCD, and gradually becomes shallower and narrower as it approaches the ball arrangement pitch circle PCD from the inner diameter edge of the cage. Thus, the above-described actions and effects are achieved.

  In addition, as shown in FIG. 6, for example, as shown in FIG. 6, the recessed portions 54 </ b> A are provided at a plurality of locations on both sides of the center OW <b> 50 in the cage circumferential direction at the opening edge of the pocket 50. The concave portion 54A extends from the opening edge on the inner diameter side of the cage to the ball arrangement pitch circle PCD. The cylindrical surface shape is substantially along the surface of each virtual cylinder VA around the straight line LA in the radial direction of the cage 4. The shape is gradually shallower and narrower as it approaches the ball arrangement pitch circle PCD from the inner diameter edge of the cage, thereby providing the above-described operations and effects.

  Further, as shown in FIGS. 8 and 9, for example, as shown in FIGS. 8 and 9, the recessed portions 54 </ b> B are provided at two locations on both sides of the center OW50 in the circumferential direction of the cage at the opening edge of the pocket 50. The inner surface shape of these two recessed portions 54B extends to the vicinity of the edge, and is substantially along the surface of one virtual ring VB. The virtual ring VB has a ring outer diameter that fits in the pocket 50, and has an arbitrary circumference. The cross-sectional shape of the directional position is circular, and the ring center OVB has an inclination with respect to the cage center axis O, so that the above-described operations and effects are achieved.

17 to 19 show an embodiment corresponding to the second invention. The cage 4A for a special environment bearing according to this embodiment is the same as the cage 4 described above with reference to FIGS.
The retainer 4A is a retainer used for the special environment bearing described above with reference to FIG. 1, and is a ring shape having pockets 50 for retaining the balls 3 at a plurality of locations in the circumferential direction. The cage halves 51 are overlapped facing each other in the axial direction. Each of these cage halves 51 has a shape in which spherical shell-shaped plate portions 50A whose inner surfaces form half of the respective pockets and flat plate portions 51a that are portions between adjacent pockets 50 are alternately arranged in the circumferential direction. Is done. Each cage half 51 is a press-formed product of a metal plate (for example, an iron plate punched product), and the two cage halves 51 are mutually connected by a rivet 53 inserted into a rivet hole 52 provided in the flat plate portion 51a. Joined and constructed integrally. The above configuration is the same as that of the embodiment shown in FIGS.

  As shown in FIGS. 17 and 19, the retainer 4 </ b> A has a range that overlaps the outer diameter surface portion 1 b that is the shoulder height on both sides of the raceway surface 1 a of the inner ring 1 in the axial direction.

  The cage 4A of this embodiment has a thin portion 50Aa in the inner diameter side portion of the ball arrangement pitch circle PCD which is the ball arrangement pitch in the spherical shell plate portion 50A in the above configuration. The thin portion 50Aa is obtained by making the plate thickness t1 of the portion located on the outer diameter surface portion 1b, which is the shoulder height on both sides of the raceway surface 1a of the inner ring 1, smaller than the plate thickness t0 of the flat plate portion 51a. The outer diameter surface portion 1b serving as the shoulder height is an outer diameter surface portion continuing at the height of the shoulder portion of the raceway surface 1a of the inner ring 1, and when the seal groove 9 is provided, the raceway surface 1a and the seal groove are provided. 9 is an outer diameter surface portion between 9. The spherical shell plate portion 50A reduces the thickness t1 of the portion located in the axial range W of the outer diameter surface portion 1b. In FIG. 17, the cross-sectional shape when the spherical shell-shaped plate portion 50A is not thinned is indicated by an imaginary line.

  The plate material t1 may be thinned by thinning the entire range from the portion corresponding to the ball arrangement pitch circle PCD to the inner diameter side in the radial direction of the cage, and between the ball arrangement pitch circle PCD and the cage inner edge. The range from the midway point to the inner diameter edge may be made thinner. In these cases, the plate thickness t1 may gradually become thinner toward the inner diameter side in the radial direction of the cage so that the inner diameter edge becomes the minimum plate thickness. You may do it. Furthermore, while maintaining the shape of the inner surface of the pocket of the spherical shell-shaped plate portion 50A, even if the plate thickness is reduced so that the shape of the outer surface changes, or while maintaining the shape of the outer surface of the spherical shell-shaped plate portion 50A, The plate thickness may be reduced so that the shape on the inner surface side of the pocket changes.

  Further, in this embodiment, as shown in FIG. 18, both ends are left thin in the arc-shaped range along the inner diameter edge of the spherical shell-like plate portion 50 </ b> A. Depending on the relationship between the outer diameter surface portion 1b and the width of the retainer 4A, as shown in FIG. 20, the thin portion 50Aa with a reduced plate thickness is on both sides except the center of the arc of the inner diameter edge of the spherical shell plate portion 50A. It may be divided into two places.

  In this cage 4A, a thin-walled portion 50Aa is formed on the inner diameter portion of the spherical shell-shaped plate portion 50A constituting the pocket 50 in this way, and this thin-walled portion 50Aa is the outer-diameter surface portion of the inner ring 1 at the height of the shoulder portion. It is a part which overlaps with 1b in an axial direction, Comprising: It is a part from which the grease adhering to the surface of the ball | bowl 3 is scraped off with the holder | retainer 4A, or the scraped grease moves. If the plate thickness t1 of the portion 50Aa is thin, the amount of grease that can be deposited here decreases, so the frequency and amount that can reach the outer diameter surface portion 1b of the inner ring 1 is reduced, and as a result, the grease flows to the outside of the bearing. Leakage can be prevented. That is, the grease easily moves to the outer diameter side of the cage 4A, and the amount of grease that can stay on the inner diameter side decreases.

However, reducing the overall plate thickness of the cage reduces the strength of the cage alone, so that the cage may be damaged when repeated stress is applied to the cage under misalignment or external vibration. It is difficult to occur.
Therefore, in the inner diameter portion of the cage 4A, the plate thickness is reduced only in the range W that overlaps the outer diameter surface portion 1b serving as the shoulder portion of the inner ring 1 in the axial direction, thereby substantially increasing the strength of the cage 4A. A ball bearing retainer 4A that does not drop and can prevent grease leakage is established.

  Further, since grease leakage does not occur by using the cage, it is not necessary to make the seal a contact type. In other words, the seal member 5 can be made a non-contact type and the torque can be reduced. Further, according to the configuration of the bearing for special environment, it is not necessary to secure a space for providing a magnetic fluid seal or a plurality of seals in the axial direction of the bearing, and the number of parts is less than that described in the above-mentioned patent document, thereby reducing the manufacturing cost. Reduction can be achieved.

  In order to reduce the plate thickness t1, only the inner diameter side of the flat plate initially punched into the ring may be thinned and press molded. Further, in a press mold when a cage is formed by pressing from an annular flat plate having a uniform thickness, the clearance distribution between a pair of molds is reduced so that only the thickness of the region shown in FIGS. 18 and 20 decreases. It may be changed. Further, in this embodiment, the case of a deep groove ball bearing punch made of iron plate is shown, but the second invention can also be applied to the two-part resin cage described above with reference to FIGS. .

  21 to 23 show an embodiment of the present invention. The special environment bearing retainer 4B according to this embodiment is a retainer used for the special environment bearing described above with reference to FIG. The retainer 4B is a ring-shaped member, and the same number of window-like pockets 4Ba for accommodating and holding the ball 3 (FIG. 1) as the balls 3 are formed at equal intervals in the circumferential direction. The inner circumferential surface 4Bb of the circumferential portion with the pocket 4Ba is inclined so as to be recessed toward the outer diameter side, and the radius Rp from the cage center of the inner diameter of the circumferential portion with the pocket 4Ba is between the pockets 4Ba. Is larger than the radius Ri from the center of the cage (Rp> Ri). In this embodiment, the inner peripheral surface 4Bb has a curved surface shape that is a concave curve when viewed from the axial direction, specifically, an arcuate surface.

  The cage 4B is composed of, for example, two annular members 64 manufactured by punching and forming an iron plate by pressing. Each annular member 64 is arranged in the circumferential direction at equal intervals, and a plurality of hemispherical pocket wall portions 64a each constituting the inner wall surface of the pocket 4Ba and a flat plate-like coupling plate that connects adjacent pocket wall portions 64a to each other. The portions 64b are alternately formed. A rivet hole 64c is formed in the coupling plate portion 64b of the annular member 64 made of iron plate. The two annular members 64 are joined by overlapping the respective coupling plate portions 64b with each other, inserting a rivet 65 into the rivet hole 64c, and crimping both ends of the rivet 65. In this way, if the two annular members 64 are coupled to each other to form one cage 4B, the radius from the cage center having the inner diameter as described above is different in each part, but is retained. The processing of the vessel 4B is easy.

  The cage 4B of this embodiment has a shape in which the inner peripheral surface 4Bb of the circumferential direction portion with the pocket 4Ba is recessed toward the outer diameter side, so there is a concern that the overall strength may be lowered. However, most of the damage of the conventional standard shape cage Hr (Rp = Ri) as shown in FIG. 27 is the R portion from the circumferential portion between the pockets Hra to the circumferential portion with the pockets Hra. It is empirically known to occur with Hr7. Since the cage 4B of this embodiment does not change the shape of this portion, it can be said that the overall strength does not decrease.

  In order to investigate the state of grease during operation in this special environmental bearing, a test was conducted under the conditions shown in Table 2. FIG. 23 shows the state of the grease adhering to each part of the bearing after the operation was stopped. For comparison, the bearing incorporating the conventional cage Hr shown in FIG. 27 was also tested under the same conditions. The state of adhesion of grease to each part of the bearing after the operation was stopped was as shown in FIG.

  According to this test, the grease G adheres to the inner ring seal groove Hr1a in the case of the bearing incorporating the conventional cage Hr. However, in the special environment bearing incorporating the cage 4 of the present invention, the grease is applied to the inner ring seal groove Hr1a. It was found that it did not adhere. For this reason, it is inferred that in a special environment bearing provided with a seal, leakage of grease G from the inner ring seal groove Hr1a due to breathing can be prevented.

  Next, a grease leakage frequency confirmation test was performed using a bearing assembled with a contact-type seal (LU seal manufactured by NTN Corporation). The test conditions were changed from the conditions shown in Table 2 to 15 minutes. When it was confirmed by visual inspection that grease of an amount of about 30 to 100 mg had jumped out of the bearing, grease leakage was assumed. The test results are shown in Table 3.

  Nine out of 10 grease leaks were found in the bearings incorporating the conventional cage Hr, but none of the bearings incorporating the cage 4 of the present invention produced any grease leaks. This proved that the reasoning was correct.

In the above embodiment, the two annular members 64 constituting the cage 4B are made of iron plate, but the annular member 64 may be made of resin. In this case, as in the cage 4C shown in FIGS. 24 and 25, the coupling plate portion 64b is provided with the engagement claw 66 and the engagement hole 67, and the two 66 and 67 are fitted to each other, thereby providing two sheets. It can be set as the structure which couple | bonds the annular member 64. FIG. Also in this case, the radius Rp from the cage center at the inner diameter of the circumferential portion with the pocket 4Ca is made larger than the radius Ri from the cage center at the inner diameter of the circumferential portion between the pockets 4Ca (Rp> Ri). . Further, two annular members 64 made of resin may be joined with an adhesive or the like.
As the synthetic resin material used for the cage, for example, polyamide resins such as PA66 and PA46 and polyphenyl sulfide resins are suitable, and a reinforcing fiber material such as glass fiber may be mixed as necessary.
Further, the structure is not limited to a structure in which the two annular members 64 are joined to form a single retainer, but may be a machined retainer that cuts out a steel material into a predetermined shape, or a molded retainer that is integrally molded with a resin material. It is good also as a vessel.

  FIG. 26 shows a different embodiment. In the retainer 4D, the shape of the inner peripheral surface 4Db in the circumferential portion with the pocket 4Da is a polygonal shape when viewed from the axial direction. Specifically, the inner peripheral surface 4Db includes a pair of inclined surface portions 4Dba that are inclined toward the outer diameter side with respect to the inner peripheral surface 4Dc in the circumferential portion between the pockets 4Da, and both ends of the outer peripheral surfaces 4Dba are outside the pair of inclined surface portions 4Dba. It has a trapezoidal shape composed of a constant-diameter surface portion 4Dbb that is connected to the radial end and has a constant inner diameter. Similarly to the cages 4B and 4C of the above-described embodiment, the cage 4D is inclined so that the inner circumferential surface 4Db of the circumferential portion with the pocket 4Da is recessed in the outer diameter side, and the pocket 4Da The radius Rp from the cage center of the inner diameter of a certain circumferential portion is larger than the radius Ri from the cage center of the inner diameter of the circumferential portion between the pockets 4Da (Rp> Ri).

  In this way, the cage 4D having a polygonal shape when viewed from the axial direction in the inner circumferential surface 4Db of the circumferential portion having the pocket 4Da is also reduced in overall strength, like the cages 4B and 4C of the above embodiment. When it is incorporated in a bearing for special environment as shown in FIG. 1, leakage of grease from the inner ring seal groove portion of the bearing can be prevented.

  In addition, when making inner peripheral surface 4Db of the circumferential direction part with pocket 4Da into the polygonal shape which has a some corner | angular part, the number of the corner | angular part is not specifically limited. Further, the shape may be asymmetric with respect to a straight line in the radial direction. Furthermore, the inner peripheral surface 4Db of the circumferential direction portion with the pocket 4Da may be a combination of a flat surface and a curved surface.

In short, regardless of the material and processing method of the present invention, the radius from the cage center of the inner diameter of the circumferential portion with the pocket is larger than the radius from the cage center of the inner diameter of the circumferential portion between the pockets. It can be applied to a cage having a shape that satisfies the condition of large.
As described above, in the special environment bearing, the cage incorporated in the bearing has a radius from the cage center of the inner diameter of the circumferential portion with the pocket, and the inner diameter of the circumferential portion between the pockets. By making it larger than the radius from the cage center, it becomes difficult for grease to adhere to the inner ring shoulder and the inner ring seal groove. This appears particularly when the outer ring rotates. Thereby, leakage of grease can be prevented regardless of whether the seal is a contact type or a non-contact type. That is, it is possible to apply a non-contact type seal, and it is possible to reduce the torque. Further, since it is not necessary to increase the tightening force of the seal lip, the torque does not increase. Each of the above-described actions can be obtained in any case where the inner diameter surface of the circumferential portion having the pocket is a curved surface having a concave curve when viewed from the axial direction, or a polygonal shape having a plurality of corners.

  Here, FIG. 29 is a cross-sectional view in which a bearing according to an embodiment of the present invention is provided in a transport system such as a semiconductor manufacturing apparatus. In this apparatus, a pair of bearings are fitted to one end and the other end in the axial direction of the transfer part HB for transferring the work of the apparatus, and the transfer part HB is configured to be movable on the transfer table HTb. Yes. In this semiconductor manufacturing apparatus or the like, a predetermined clean environment must be maintained. However, by using the above-described cage, grease leakage does not occur, and thus the clean environment can be maintained. Further, since the bearing provided in the transport unit HB is an outer ring rotating type, it is difficult for grease to adhere to the inner ring seal groove.

FIG. 1A is a sectional view of the special environment bearing according to an embodiment of the present invention, and FIG. 1B is a partially enlarged sectional view of a seal and an inner ring. It is a perspective view of the holder | retainer of this embodiment. It is a perspective view of the retainer half which is a structural member of the retainer. It is a partial expansion perspective view which simplifies and shows a pocket shape about a part of the cage half. (A) is a partial enlarged perspective view highlighting an example of the inner surface of the spherical shell plate portion in the cage half, and (B) is a perspective view showing a state in which a virtual cylinder is added to the perspective view. (A) is a partial enlarged perspective view highlighting another example of the inner surface of the spherical shell plate in the cage half, (B) is a perspective view showing a state in which a virtual cylinder is added to the perspective view. is there. (A) is a partial enlarged perspective view highlighting still another example of the inner surface of the spherical shell plate portion in the cage half, and (B) is a perspective view showing a state in which a virtual polygonal column is added to the perspective view. FIG. (A) is a partial enlarged perspective view highlighting still another example of the inner surface of the spherical shell plate portion in the cage half, (B) is a perspective view showing a state in which a virtual cylinder is added to the perspective view It is. It is explanatory drawing which shows the relationship between the spherical shell-shaped board part and a virtual ring in a cross section. It is explanatory drawing which shows the manufacturing process of the holder | retainer of this embodiment. It is a perspective view of the press die set used for the manufacturing process. It is explanatory drawing of the result of the grease leak test of the bearing for special environments incorporating the holder | retainer of the structure shown in FIG. It is explanatory drawing of the result of the grease leak test of the bearing for special environments incorporating the holder | retainer of the structure shown in FIG. It is explanatory drawing of the result of the grease leak test of the ball bearing incorporating the general iron plate punching cage. It is a disassembled perspective view of the resin-made cage to which the cage of this embodiment is applicable. It is sectional drawing of the resin cage. It is a partially broken perspective view of the bearing for special environments incorporating the retainer concerning other embodiments of this invention. It is a partial expansion perspective view which shows the spherical shell-shaped board part in the cage half body of the same cage. It is a top view which shows the assembly which integrated the holder | retainer of the embodiment in the inner ring | wheel. It is a partial expansion perspective view which shows the modification of the spherical shell-shaped board part in the cage half body of the same cage. It is a front view of the holder | retainer integrated in the bearing for special environments concerning one Embodiment of this invention. It is AA sectional drawing of FIG. It is a figure which shows the test result performed with respect to the ball bearing incorporating the said holder | retainer. It is a front view of a different holder. It is a disassembled perspective view which shows the principal part of the annular member of the holder. It is a front view of the holder | retainer concerning different embodiment of this invention. It is a front view of the conventional cage | basket. It is a figure which shows the test result performed with respect to the ball bearing incorporating the said holder | retainer. It is sectional drawing which provided the bearing concerning one Embodiment of this invention in conveyance systems, such as a semiconductor manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 3 ... Ball | bowl 4, 4A, 4B ... Cage 4Ba ... Pocket 5 ... Seal member 50 ... Pocket 50A ... Spherical shell-shaped board part 51 ... Cage half body 51A ... Flat plate part 54, 54A, 54B ... Recess O ... Cage center axis OVB ... Ring center PCD ... Ball arrangement pitch circle Ri, Rp ... Radius t0, t1 ... Plate thickness V, VA ... Virtual cylinder VB ... Virtual ring

Claims (6)

In a special environment bearing having a seal that holds a plurality of balls interposed between inner and outer rings by a cage and is attached to the outer ring and seals the bearing space.
The cage has pockets for holding a plurality of balls at a plurality of locations in the circumferential direction, and the inner surface of each pocket is closer to the inner diameter side opening edge of the cage than the ball arrangement pitch circle. A ring-shaped cage having a concave curved surface having a small diameter according to the above, characterized in that a concave portion extending from the opening edge on the inner diameter side of the cage to the outer diameter side of the cage is provided on the inner surface of each pocket. Environmental bearing.   In Claim 1, the said recessed part spreads in both sides from the center of the holder circumferential direction in the opening edge of the said pocket, and is provided in one place, and has a width | variety larger than the half of the width | variety of the pocket holder circumferential direction. An inner surface shape of the recessed portion is a cylindrical surface shape substantially along a surface of a virtual cylinder centered on a radial straight line of the cage, and the recessed portion is formed from an opening edge on the inner diameter side of the cage. A special environment bearing that extends to the vicinity of the ball arrangement pitch circle and gradually becomes shallower and narrower as it approaches the ball arrangement pitch circle from the inner diameter edge of the cage.   In Claim 1 or Claim 2, the said dent part is located in the both sides of the center of the cage circumferential direction in the opening edge of the pocket, and is provided in a plurality of places, and the inner surface shape of each dent part is It has a cylindrical surface shape that substantially follows the surface of each virtual cylinder centered on a straight line in the radial direction, and this recess extends from the opening edge on the inner diameter side of the cage to the vicinity of the ball arrangement pitch circle. A bearing for special environments that is gradually shallower and narrower as it approaches the ball arrangement pitch circle from the inner edge.   In Claim 1 or Claim 2, the said recessed part is provided in two places located in the both sides of the center of the cage circumferential direction in the opening edge of the pocket, and extends to the vicinity of the outer diameter edge of the cage. The inner surface shape of the two recessed portions is a shape substantially along the surface of one virtual ring, the virtual ring is a ring outer diameter that fits in a pocket, and a cross-sectional shape at an arbitrary circumferential position is circular, Bearings for special environments where the ring center is inclined with respect to the cage center axis. In a special environment bearing having a seal that holds a plurality of balls interposed between inner and outer rings by a cage and is attached to the outer ring and seals the bearing space.
The cage is a ring-shaped cage having pockets for holding balls of the bearings at a plurality of locations in the circumferential direction, and two annular half-body cages are faced and overlapped in the axial direction. Each of these cage halves has a shape in which a spherical shell plate portion whose inner surface forms half of each pocket and a flat plate portion that is a portion between adjacent pockets are alternately arranged in the circumferential direction. The plate thickness of the flat plate portion is the plate thickness of the portion located at the outer diameter surface portion of the shoulder height on both sides of the raceway surface of the bearing inner ring in the inner diameter side portion of the ball arrangement pitch circle in the spherical shell plate portion. Special environment bearing characterized by being thinner than the thickness. In a special environment bearing having a seal that holds a plurality of balls interposed between inner and outer rings by a cage and is attached to the outer ring and seals the bearing space.
The cage has pockets for holding a plurality of balls at a plurality of locations in the circumferential direction, and the radius from the cage center of the inner diameter of the circumferential portion with the pockets is set to the circumferential portion between the pockets. A bearing for special environment, characterized in that its inner diameter is larger than the radius from the cage center.

Images