DE10311566B4 - Roller bearing cage and roller bearing - Google Patents

Abstract

Roller bearing cage (9) made of synthetic resin, having a plurality of pockets defined by two circular ring portions (11) in the axial direction and support portions (19) in the circumferential direction, the two annular ring portions (11) having different diameters and wherein the cage is at least a material portion (21) provided with a hollow portion (12a, 13a, 12b, 13b, 22, 23) for giving the material portion a uniform thickness, the hollow portion (12a, 13a) on the inner side (20) a circular ring portion (11), opposite to an end surface of a roller (3) to be inserted into the cage, is formed to form the material portion of uniform thickness in the circular ring portion.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a roller bearing cage for roller bearings, such as. As a tapered roller bearing, a cylindrical roller bearing, etc., as used mainly in the field of general industrial machinery, such as railway vehicles, iron and steel machines, machine tools and construction machinery.

2. Description of the Related Art

6 shows the construction of a tapered roller bearing as a typical example of conventional roller bearings. The tapered roller bearing 5 has an outer ring 1 with its own, conically shaped track groove 1a , an inner ring 2 with a conical shaped groove 2a and a small rib area 2 B on its side of smaller diameter and a large rib area 2c on its side of large diameter, as well as a variety of tapered rollers 3 , which rotates between the track groove 1a of the outer ring 1 and the track groove 2a of the inner ring 2 is arranged, and a sheet metal cage 4 to the tapered rollers 3 keep evenly spaced. When loads in the axial direction respectively on the inner ring 2 and on the outer ring 1 act and thus on the tapered rollers 3 cause a relative rotational movement of the same, are the large end face 3a the tapered roller 3 and the big rib area 2c of the inner ring 2 designed so that they are in sliding contact with each other. Therefore, great attention must be paid to the lubrication conditions in such an area.

As in 7 shown, the sheet metal cage 4 formed by a cold-rolled steel plate such. SPB2, a cold-pressed tire for bearings or the like is subjected to press-forming treatment. In other words, the above-mentioned steel plate in the form of a perforated disc is formed into a circular truncated cone, and then each of the pockets 8th is punched out of the plate to support areas 7 to build.

For ball bearings to be used under low load conditions, cages made of resin are generally widely used because the strength of the material for the cage need not be so high. On the other hand, the sheet cages which are generally used for tapered roller bearings (roller bearings) have the drawback that they can be mass-produced poorly and thus incur high costs compared to resin cages. In addition, there is the disadvantage of insufficient dimensional accuracy. In addition, the weight of the sheet cage is higher than that of the resin cage, and repeated collision of the cage with the rollers often results in vibration, noise, wear of the cage, etc. under difficult conditions involving high load at high speed, etc. In particular, if the repeated collision of the cage with the rollers clearly occurs, a change in the shape of the pocket area and the intermixing of abraded metal powder from the cage with the lubricating oil is frequently noticed as the wear of the pocket area of the cage progresses over time. This causes deterioration of the lubricating oil. If the lubricating oil deteriorates, depending on the degree of deterioration, the properties of the bearing may also deteriorate. On the other hand, in a resin cage, no metallic powder or the like is generated by wear, which then advantageously can not harm it.

Considering the cost and performance of the bearing, as described above, it is necessary to apply a synthetic resin cage to a tapered roller bearing (roller bearing) as well as a ball bearing. In general, however, the taper roller bearing (roller bearing) should be used under high load conditions, and therefore, the sheet metal cage formed by pressing a steel plate is used. The cage made of synthetic resin, such. As a glass fiber reinforced polyamide resin or the like, has me low stiffness and breaking strength, which has the disadvantage that it has a lower strength than the sheet metal cage. Therefore, in order to improve the rigidity and the breaking strength as much as possible when the resin cage is used in a tapered roller bearing (roller bearing), it is necessary to increase the size of the product (increase the thickness) and the product having a complicated shape to increase the stiffness compared to the sheet metal cage.

The resin cage is usually formed by injecting a resin heated to a melting temperature into a mold cavity (injection molding method). After injecting the resin into the mold cavity, the cage is cooled and cured from the surface of the mold side to the center of the material. In this case, if the cooling rate is evenly distributed and the temperature distribution in the material is uniform, the pressure in the material generated by the temperature difference in each area is also uniformly distributed. Consequently, the material density of the molded cage is evenly distributed. However, if the dimensions of the product are increased (increasing the thickness) or the shape of the product is made more complicated in order to increase the rigidity and strength, undesirable phenomena occur, in which the Internal pressure of the material is distributed unevenly, since the cooling rate at the time of cooling and curing of the cage material from the surface of the mold side to the center of the material varies in each area, so that a temperature difference is generated in each area of the material. This has the consequence that gaps (gaps), such. Cavities and air bubbles in which cage material can form, which in turn causes the problem that the strength of the cage decreases.

From DE 00 I 000774 6 MAZ a needle bearing with pockets and holding projections for receiving the needles is known. Webs are formed with Materialausnehmungen between the pockets in order to increase the elasticity of the retaining projections.

The DE 3701 705 A1 describes a cage for a rolling bearing for particular cylindrical rolling elements, wherein formed between pockets of the bearing cage webs are penetrated by recesses, which lead to a substantially constant, the wall thickness of the end rings of the cage corresponding wall thickness.

SUMMARY OF THE INVENTION

In order to solve the aforementioned problems, the present invention is based on the object to provide a resin cage, which can be applied to a roller bearing.

To solve the foregoing problems, a roller bearing retainer according to the present invention for holding rollers disposed between races of a roller bearing is made of a resin and has a material portion provided with a hollow portion to give the material portion a uniform thickness. The material portion to be formed on a circular ring portion of the cage is formed by creating hollow portions formed in the respective inner surfaces of the circular ring portion facing the end surfaces of the rollers. Moreover, the material portion to be formed on a support portion may be formed by providing hollow portions formed in the respective inner and outer peripheral surfaces of the support portion.

The hollow area is in the circular ring area, if necessary. also formed in the carrier area. That is, a hollow portion is formed in a part of one side of the circular ring portion or in addition also of the support portion, while another hollow portion is formed in a part of the opposite side of the annular annular portion or the support portion to form the material portion which is substantially one having uniform small thickness.

Consequently, by forming the aforesaid material portion, an appropriate cooling speed of each region at the time of molding the cage can be achieved, so that it becomes possible to prevent the generation of voids inside. The hollow portion formed in the inner surface of the circular ring portion also functions as a grease reservoir for enclosing and storing a lubricant such as grease, which enables an improvement in the lubricating properties of the bearing.

BRIEF DESCRIPTION OF THE DRAWING

In the attached drawing show:

1 a plan view of a cage made of a synthetic resin according to an embodiment of the present invention from the perspective of the large diameter thereof;

2 a cross section along the line AA in 1 according to an embodiment of the present invention for illustrating the formation of a pocket portion;

3 an explanatory view of the housing according to the embodiment of the present invention, from which it is apparent that the hollow area in 2 acts as a grease reservoir;

4 a cross section along the line BB in 1 according to the embodiment of the present invention for illustrating the formation of a support portion;

5A and 5B 3-dimensional schematic drawings of the cage according to the embodiment of the present invention, wherein 5A the inner peripheral surface of the cage and 5B show the outer peripheral surface of the cage;

6 a vertical section through a conventional tapered roller bearing; and

7 a perspective view of the sheet metal cage.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of the invention will be described. 1 shows a plan view of a cage for a tapered roller bearing, seen from the outer diameter side, according to the present invention. The cage 9 out a synthetic resin has two circular ring areas 11 on, which are separated from each other in the axial direction, and a plurality of carrier areas 19 that provides a bridge between the circular ring areas 11 form. These areas are integrally connected by injection molding. As shown in the figure, the circular ring areas divide 11 the cage 9 in the axial direction, while the carrier areas 19 the cage 9 split in the circumferential direction. Therefore, along the circumference in several places pockets 10 Are defined. The bags 10 Hold the respective tapered rollers 3 evenly spaced, with each tapered roller 3 between an outer ring 1 and an inner ring 2 can rotate (see 6 ).

The inner surface 20 each circular ring area 11 , the end face of the tapered roller 3 opposite, has a hollow area 12a or 13a on which is formed by part of the inner surface 20 is thinned out. In addition, the outer surface indicates 14 of the circular ring area 11 that the inner surface 20 opposite, a hollow area 12b or 13b on top of the hollow area 12a or 13a is aligned opposite. The hollow areas 12a and 12b of the circular ring area 11 are arranged offset and are thus positioned so that they do not overlap in the axial direction. These hollow areas 12a . 12b reduce the thickness of the circular ring area 11 so that a material section 21 is created, which (in particular in the axial direction) has a substantially uniform thickness. In the same way is in the other circular ring area 11 a material section 21 formed, which has a substantially uniform thickness and thereby has partially hollow areas. The radial thickness of the area in which each of the hollow areas 12a . 12b . 13a and 13b is formed, can be even.

As with the circular ring area 11 can also be at any of the carrier areas 19 a material section 21 be educated. As in 1 and 4 shown, the material section 21 formed by the outer and inner peripheral surfaces of the support area 19 with hollow areas 22 and 23 be provided. As in 4 shown, the hollow areas 22 and 23 be formed overlapping or offset from each other. Depending on the cross-sectional shape of the support area 19 For example, a hollow portion may be formed either only in the outer peripheral surface or only in the inner peripheral surface to form a material portion. In addition, in the hollow areas 22 and 23 Include grease, leaving the hollow areas 22 and 23 serve as a grease reservoir for the supply of grease, thus the tapered roller 3 can be in smooth rolling contact with the surface.

The thickness of a recessed area (area indicated by dashed line) of the circular ring area 11 is provided as a region of substantially uniform thickness. The cooling rate of the cage material at the time of cooling and curing of the cage material from the surface of the cage (ie from one side of the surface of the mold) to the center of the cage material varies within a smaller range such that the internal pressure of the cage material affected by the temperature differential in Regions in the material is also varied within a smaller range. This has the consequence that the formation of gaps (gaps), such. As cavities and air bubbles, can be limited in the cage material, so that the problem of a caused decreasing strength can be avoided. At the same time a weight reduction of the cage can be achieved. Therefore, the generation of a centrifugal force acting on the cage can be suppressed, and it becomes possible to avoid damages such as the deformation of the cage caused by the centrifugal force. In addition, the resin cage does not form a wear-generated metal powder or the like, as can be found in a sheet metal cage, so that this advantageously the cage can not harm.

2 is a cross section through the support area along the line AA in 1 , At a large end face 15 the tapered roller 2 (indicated in the figure by a dot-dash line) there is a grinding undercut 16 for performing the steps of grinding and finishing the large end surface 15 , From the big end face 15 Seen from, is the abrasive undercut 16 shaped like a circle concentric with the outer peripheral surface of the tapered roller 3 is. In particular, the dimension of the area indicated by the arrow C extends from the center of the tapered roller 3 to the outside diameter of the grinding section 16 , The dimension of the area indicated by the arrow D extends from the center of the tapered roller 3 to the inner end surface in the radial direction of the hollow area (recessed area) 12a , the big end face of the tapered roller 3 is facing. The ratio between these dimensions may preferably be represented by D> C for the reasons given below. As in 3 have shown the hollow areas (recessed areas) 12a and 13a in the inner surface of the bag 10 are formed, also the function of grease reservoirs for receiving grease 18 , Because the grease 18 in each of the hollow areas (recessed areas) 12a and 13a is included, the grease can 18 gradually the big end face 15 the tapered roller 3 be supplied so that it contributes to the lubrication of the Reibkontaktbereichs of the bearing. In particular, the restricted area 17 the big endface 15 with the exception of the abrasive undercut 16 is provided as a mechanism to frictional contact (sliding friction) with the large rib area 2c of the inner ring 2 ( 6 ) so that the grease 18 Such an area can be supplied to contribute to the lubrication. In this case, when the above ratio is represented by D ≦ C, the grease moves 18 in the hollow area (recessed area) 12a in the grinding undercut 16 the tapered roller 3 so that the grease gets 18 can accumulate in it. As a result, the grease 18 can hardly contribute to the lubrication of the Reibkontaktbereichs. Therefore, the ratio between the dimensions described above is preferably represented by D> C.

4 is a section through the support area along the line BB in FIG 1 , As shown, hollow areas (recessed areas) 22 and 23 each at the outer and inner peripheral surfaces of the carrier area 19 educated. Therefore, the cross section of the support region has a 19 substantially uniform thickness. Such an embodiment of the carrier area 19 allows the cooling rate of the cage material at the time of cooling and curing of the cage material to vary from the surface of the cage (ie, from a surface of the mold) to the center of the cage material in a smaller range. Thus, the variations in the internal pressure of the cage material caused by the temperature difference of regions in the material can also be reduced. This has the consequence that the formation of gaps (gaps), such. As cavities and air bubbles can be prevented in the cage material, so that the problem of a caused decreasing strength can be avoided. At the same time a weight reduction of the cage can be achieved. Therefore, the generation of a centrifugal force acting on the cage can be suppressed, and it becomes possible to avoid damages such as the deformation of the cage caused by the centrifugal force. In addition, the resin cage does not form a wear-generated metal powder or the like, as can be found in a sheet metal cage, so that this advantageously the cage can not harm.

The present invention is not limited to the tapered roller bearing described in the aforementioned embodiment; It can also be found in roller bearings application that operate under high load conditions, such. B. a cylindrical roller bearing and a spherical roller bearing. In addition, the raw material of the cage is not limited to a polyamide resin (nylon), etc., and also the bonding ratio of glass cloths or the like. is not limited to a specific value.

• i) Der aus einem Harz bestehende Käfig ist mit einem Hohlbereich versehen, der in der Innenfläche eines kreisförmigen Ringbereichs ausgebildet ist, und mit einem Hohlbereich, der in dessen Außenfläche in umgekehrter Richtung ausgebildet ist, mit Ausnahme des Bereichs, der bereits mit dem Hohlbereich versehen ist, wodurch die Dicke des kreisförmigen Ringbereichs gleichmäßig gemacht wird. Folglich kann eine angemessene Kühlgeschwindigkeit jedes Bereichs zum Zeitpunkt der Formgebung des Käfigs erzielt werden, so dass es möglich wird, die Entstehung von Fehlstellen im Inneren zu verhindern.
• ii) Da in dem Hohlbereich, der in der Innenfläche des kreisförmigen Ringbereichs ausgebildet ist und der großen Endfläche der Kegelrolle gegenüberliegt, ein Schmiermittel, wie z. B. Schmierfett, eingeschlossen und aufbewahrt werden kann, können die Schmiereigenschaften der großen Endfläche der Kegelrolle verbessert werden.
• iii) Der Harzkäfig erzeugt kein durch Verschleiß gebildetes Metallpulver oder Ähnliches, wie es im Fall des Blechkäfigs zu finden ist, so dass dieses vorteilhafterweise dem Käfig auch nicht schaden kann.
• iv) Das Gewicht des Käfigs kann verringert werden, so dass die auf den Käfig wirkende Zentrifugalkraft unterdrückt werden kann. Damit wird es möglich, jeglichen Schaden, wie z. B. die Verformung des Käfigs, durch die Zentrifugalkraft zu vermeiden.

In summary, the present invention has the following advantages:

• i) The resinous cage is provided with a hollow portion formed in the inner surface of a circular ring portion and a hollow portion formed in the outer surface thereof in the reverse direction except for the portion already provided with the hollow portion is, whereby the thickness of the circular ring portion is made uniform. Consequently, an appropriate cooling rate of each region at the time of molding the cage can be achieved, so that it becomes possible to prevent the generation of voids inside.
• ii) Since in the hollow portion formed in the inner surface of the circular ring portion and facing the large end face of the tapered roller, a lubricant such. As grease, can be enclosed and stored, the lubricating properties of the large end face of the tapered roller can be improved.
• iii) The resin cage does not generate metal powder or the like formed by wear, as it is found in the case of the sheet metal cage, so that it can advantageously not harm the cage either.
• iv) The weight of the cage can be reduced so that the centrifugal force acting on the cage can be suppressed. This makes it possible, any damage, such. As the deformation of the cage to avoid by the centrifugal force.

Claims (8)

Roller bearing cage ( 9 ) made of synthetic resin, with a plurality of pockets formed by two circular ring areas ( 11 ) in the axial direction and support areas ( 19 ) are defined in the circumferential direction, wherein the two circular ring areas ( 11 ) have different diameters and wherein the cage at least one material section ( 21 ) having a hollow area ( 12a . 13a . 12b . 13b . 22 . 23 ) in order to give the material portion a uniform thickness, wherein the hollow region ( 12a . 13a ) on the inside ( 20 ) of a circular ring area ( 11 ), an end surface of a roll to be inserted into the cage ( 3 ) is formed to form the material portion of uniform thickness in the circular ring portion. Roller bearing cage according to claim 1, wherein the end surface ( 15 ) of the tapered roller to be inserted into the cage ( 3 ) with a grinding undercut ( 16 ), which concentric with the outer peripheral surface of the tapered roller ( 3 ), and wherein the condition D> C holds with the assumption that C is a from the center of the roll to an outer diameter of the abrasive section ( 16 D) is a dimension extending from the center of the roll to a radially inner end surface of the hollow region (FIG. 12a ) extending dimension. Roller bearing cage according to claim 1, wherein additionally at least one hollow region ( 12b . 13b ) is formed in an outer surface of the circular ring portion. Roller bearing cage according to claim 3, wherein the hollow area ( 12a . 13a ) located in the inner surface of the circular ring area ( 11 ) is formed and the end face of the roller opposite and the hollow region ( 12b . 13b ) formed in the outer end surface are circumferentially offset from each other. Roller bearing cage according to claim 1, wherein a further material portion with hollow area ( 22 . 23 ) is formed in the carrier area. Roller bearing cage according to claim 5, wherein the material portion of the support area ( 19 ) through a hollow area ( 22 . 23 ) is formed, which in both an inner peripheral surface and in an outer peripheral surface of the support area ( 19 ) is trained. Roller bearing cage according to claim 6, wherein the hollow region ( 23 ) of the inner peripheral surface of the support area ( 19 ) and the hollow area ( 22 ) of the outer peripheral surface are offset from each other in the axial direction. Roller bearing, with the following elements: an outer ring ( 1 ) with a running groove ( 1a ) on an inner circumference thereof; an inner ring ( 2 ) with a running groove ( 2a on an outer periphery thereof; a roll ( 3 ) disposed between the raceway groove of the inner race and the raceway groove of the outer race; and the roller bearing cage according to any one of claims 1 to 7.

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