RU2162173C1 - Roller bearing solid cage - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: invention relates to construction of solid cage of roller bearing manufactured from plastic by casting under pressure. Solid cage of roller bearing has two races coupled to each other by jumpers which form sockets for rollers. Jumpers have middle section with surfaces intended for interaction with conjugated surfaces of rollers and sections adjacent to races and carrying the middle section. Cage also includes facilities for damping of roller impacts. Jumper sections carrying middle section are made elastic-pliable and may be manufactured as channel-section bar or in the form of two parallel rectangular-section bars or as box-section bar. EFFECT: reduced mass of cage, extended service life. 4 cl, 4 dwg

Description

 The invention relates to mechanical engineering, and in particular to the design of an integral cage of a roller bearing made by injection molding of plastic, and can be used for its intended purpose in roller bearings, mainly for railway transport.

 It is known that the cage of a roller bearing performs several functions, of which the first is actually separation (separation); the second is to ensure the movement of rollers in a free, unloaded state outside the loading zone due to the radial clearance and relative displacement of the rings under load; the third - forcibly pushing the rollers initially in a free, unloaded state into the loading zone, the entrance to which is, as you know, a tapering cavity, until they come into frictional contact with both rings and receive forced rotation from them, as well as translational motion; the fourth - work in tension and bending during the transfer of force from those rolling bodies that leave the loading zone, being in the second half of the loading zone, in its expanding cavity, to those rolling bodies that are forced to push into the loading zone from the side of the first half of the loading zone , i.e. from the tapering cavity of the loading zone; fifth, work as sliding bearings conjugated by respective surfaces with each roller.

 When the rollers are pushed into the loading zone mentioned above, there is always a shock that, if not cushioned by the separator, causes the roller to brake, which inevitably results in an increased rate of abrasion of the surfaces of both the rollers and the raceways, and the undamped impacts themselves cyclically load into very a high degree of the separator itself, causing fatigue (brittle) fracture - rupture of the annular base of the separator. Note that damping is almost impossible when the separator is made of metal, due to the very high modulus of elasticity of the latter. Highly effective damping of these shocks is possible only when the separator is made of plastics, mainly thermoplastics, having an elastic modulus 50-100 times smaller than that of a metal. Due to the possibility of damping, plastic separators can have a material stress (with a correctly designed design) and are tens and hundreds of times less than that of a metal separator and much less than the fatigue limit of a plastic. Therefore, solid plastic cages can, unlike metal ones, be made openwork with a minimized mass, and with a separator's own service life that is many times greater than the life of rolling elements, raceways (thus, the very possibility of bearing failure is excluded for reasons related with a breakdown of the separator). However, in our opinion, the potential advantages of plastic separators in the field of damping of roller impacts and, correspondingly, lower loads are rather far from being realized in known constructions, as evidenced by the following review.

 A one-piece plastic roller bearing cage is known (see ed. Certificate of the USSR N 1665121, class F 16 C 19/22, publ. 07/23/91, bull. N 27) in the form of jumpers connected by a ring along only one of the ends, thus , each jumper is a cantilever beam pinched in a ring.

 A disadvantage of the known one-piece separator is that the damping properties of the plastic, themselves very high, are used to a very small extent, essentially the material is loaded only in the transition zone of the ring into the jumper, therefore, the separator has an unreasonably large mass with insufficient reliability due to the simultaneous the action of stresses from forces both stretching the ring and bending the jumper in the place of stress concentration - in the transition zone of the jumper into the ring.

 Known integral plastic roller bearing cage (see ed. Certificate of the USSR N 1732044, class F 16 C 33/46, publ. 07.05.92, bull. N 17), containing two annular bases connected by jumpers forming nests for rolling elements with V-cuts made on each annular base from the inside, located in the middle of each seat under the rolling body, thus forming peculiar “hinges” using the damping properties of the plastic in the “hinges” zone (meaning compliance within the limits of elastic deformation), what about espechivaet slight damping shock and thus to some extent prevent the braking of rolling bodies with a corresponding slight decrease in the wear bodies and the raceways.

 A disadvantage of the known one-piece plastic roller bearing cage is that the damping properties of the material - plastic - are used very locally - only in places of "hinges", which obviously determines the limited damping effect. In addition, it is obvious that the effect of damping, due to insignificance, does not overlap with the obvious negative consequences arising from the well-known position on the very negative influence of stresses as sharp concentrator of section attenuation (in this case, V-shaped notches) in the case of material operation under cyclic loads for rolling bearing cages.

 A known one-piece plastic roller bearing cage, selected as the prototype as the closest in technical essence (see ed. Certificate of the USSR N 1733750, class F 16 C 33/46, publ. 05/15/92, bull. N 18), containing two rings connected by forming bridges with the middle section having surfaces intended for interaction with the mating surfaces of the rollers and sections adjacent to the rings and bearing said middle section, as well as means for damping the impacts of the rollers, and as means For damping, protrusion elements were used in the middle section of the jumper intended for direct interaction with the roller, and at the beginning of interaction only with the edge of the protrusion element intended for damping. The jumpers as a whole and the rings are made very rigid, thus, the elastic properties necessary for damping are endowed with only protruding elements in the middle section of the bridge.

 A disadvantage of the known separator is the small damping effect due to the very small size of the structural elements specially designed for damping and imperfections in the middle part of the bridge and the function of the sliding bearing (due to the fact that when performing one function - damping - the other function is not performed - the sliding bearing, since the continuity of the separating oil layer is violated in the area of too high contact pressures when the roller is hit, it is certainly about the edge of the damping element Designed to interact with it). These disadvantages do not significantly reduce the braking of the rollers at the entrance to the loading zone, i.e. they do not significantly reduce the wear of both rollers and raceways, nor do they minimize the mass of the separator, since insufficient damping of the impacts of the rollers greatly increases the forces acting on the separator rings, which forces them to deliberately increase the cross-sectional area of the separator rings several times.

 The problem to which the claimed invention is directed, is the creation of such a design of an integral plastic roller bearing cage obtained by injection molding of thermoplastics, which has a close to the maximum possible level of damping of roller impacts, which allows to achieve the following technical result: to prevent braking of the rollers at their entrance into the loading zone and practically eliminate the accompanying abrasion of the surfaces of the rollers and raceways, as well as the construction Ia separator that provides the most efficient shock damping rollers minimizes the weight of the separator due to the fact that there is a repeated reduction of the forces acting on the cage ring. The same circumstance guarantees with a minimized mass such a service life of the separator, which obviously exceeds the service life of any other bearing element (i.e., it is guaranteed that failure of the bearing will never occur due to breakdown of the separator).

 The problem is solved as follows.

 A one-piece cage of a roller bearing, comprising two rings connected by bridges forming nests for the rolling elements with a middle section having surfaces intended to interact with the mating surfaces of the rollers and sections adjacent to the rings and bearing said middle section, as well as means for damping the impacts of the rollers, according to the invention has the following distinctive essential features: as the means for damping the impacts of the rollers, the sections of the front tags made resiliently. In addition, the sections of the jumper made by the elastically flexible supporting middle section are each made in the form of a channel beam or in the form of a box-shaped beam, or in the form of two parallel beams of rectangular cross-section.

 The implementation of the middle sections of the web of the jumper bearing the elastic part is a solution to the problem, since it provides the maximum possible degree of damping of the roller impacts due to the maximum possible increase in the time interval for pushing the roller and the loading zone, i.e., the impact is replaced by a smoothly increasing pressure on the roller, which, according to known natural laws leads to a reduction in hundreds of times the values of the stresses of the material of the separator, and this minimizes the mass of se operators for maximum growth of guaranteed service life and reduces almost no tormozhenie rolling elements and the related attrition of bodies and the raceways. In addition, the possibility of braking the roller is also reduced by the fact that in the proposed design at the same time the jumper performs the function of the sliding bearing with respect to the roller almost perfectly, and this follows from the execution of the middle part of the jumper very rigid with the shape of the surfaces in contact with the roller, which ensures continuity of the lubricant separation layer with a known uniform distribution of insignificant due to the pressure distribution in the contact zone of the roller - the corresponding surface the middle of the bridge.

 In FIG. 1 shows a separator with a cut along the axis of symmetry; in FIG. 2 is a view A in FIG. 1 and section BB, illustrating an embodiment of damping means in the form of bridge sections made resiliently in the form of a channel beam section; in FIG. 3 is a view A and a section B-B illustrating an embodiment of damping means in the form of bridge sections made resiliently in the form of a beam and a box section; in FIG. 4 is a view A in FIG. 1 and a section DD illustrating an embodiment of damping means in the form of sections of jumpers made elastically flexible, each section in the form of two parallel beams of rectangular cross section.

 The integral roller bearing cage is manufactured by injection molding from a thermoplastic selected from a number of thermoplastics commonly used for the manufacture of rolling bearing cages, for example, thermocouple Polyamide 66KS glass-filled according to TU 2224-001-13239004-98.

 The separator contains two rings 1 connected by jumpers 2, forming nests 3. The rings 1 have rectangular protrusions 4, made on the inner side of the rings 1, intended for contacting the ends of the rollers (not shown). Each jumper 2 has a middle section 5 (62-66% of the length of the jumper) with surfaces 6 designed to interact with the mating cylindrical surfaces of the rollers (not shown). Each jumper 2 has sections 7 carrying the middle section 5, adjacent to the rings 1 (each section 7 occupies 16-18% of the length of the bridge), made resilient for use as a means of damping the impacts of rollers, for which section 7 is made either in the form of a channel beam section 8 (see Fig. 2), either in the form of a box-shaped beam 9 (see Fig. 3), or in the form of two parallel beams 10 of rectangular cross-section (see Fig. 4). Moreover, with what degree of elasticity section 7 should be performed, it can only be determined empirically for a particular rolling bearing, which follows from the experts' recognition of the impossibility of taking into account theoretically the action of dozens of variable components that affect the magnitude of the forces arising from impacts of rollers (this is also radial the clearance, and the accuracy of parts, and the accuracy of mounting the bearing assembly as a whole, and operating conditions, etc.), According to the author’s research (conclusions from which cannot be claimed comprehensiveness), the flexibility of sections 7, in this case defined as the ratio of the displacement of the middle section of the jumper under the action of the last force to the magnitude of the applied force, acting through the roller used in these experiments, and in the same direction as and the real roller in the bearing should be 3-5 times more than the compliance (determined in the same way) when performing section 7 of the maximum possible stiffness, i.e. with a continuous maximum possible cross-sectional area.

 The cage in the bearing operates as follows.

 In dynamics, each roller is pushed by the separator into the loading zone without impact, because instead of an instantaneous shock, there is a smooth pushing of the roller over a much longer period of time, starting with the fact that the middle section of the jumper abuts the roller and begins to move backward (against the separator) from the original lagging behind the separator, and the sections of the bridge 7 that carry the middle section damping, being resilient and undergoing bending and stretching within the elastic deformation ation, the separator does not experience shock loads, which reduces the stresses in the hundreds of times, and also due to lack of bumps does not occur braking rollers. In the first half of the loading zone, the middle section 5 of the jumper smoothly “catches up” the separator after the roller forcibly driven in the loading zone by the rings, returning to its original position, while the sections 7 carrying the middle section 5 are unloaded, returning to their original position. In the second half of the loading zone, the middle section 5 gradually begins to move forward (along the separator) from its initial position, “ahead” of the separator, drawn by a roller resting on it, forcibly pushed out of the loading zone, while the sections 7 carrying the middle section 5 are carried out, being resilient , damping, undergoing bending and stretching within the limits of elastic deformation, and again, the separator does not experience shock loads, which ensures stress reduction of hundreds of times. Shock-free input and output of the rollers eliminates the braking of the rollers, which, on the one hand, guarantees the termination of the abrasion of bodies and raceways for this reason, on the other hand, allows to minimize the mass of the separator while maximizing the guaranteed service life. For example, the mass of a really manufactured cage for railway bearings was 125 g and now it has successfully passed all stages of testing, unlike cages of the previous design from the same thermoplastic and weighing 250-300 g, which showed poor test results and are not approved for use in railway bearings.

Claims (4)

 1. A one-piece cage of a roller bearing, comprising two rings connected by forming jumpers for the rolling elements with bridges with a middle section having surfaces designed to interact with the mating surfaces of the rollers and sections adjacent to the rings and bearing said middle section, as well as means for damping impacts rollers, characterized in that, as a means for damping the impacts of the rollers, middle section bearing sections made of elastically flexible are used.  2. The one-piece cage of a roller bearing according to claim 1, characterized in that the cross-section of the jumper made by the elastic-bearing medium section is each made in the form of a channel beam.  3. The one-piece cage of a roller bearing according to claim 1, characterized in that the cross-section of the jumper made by the elastic-bearing medium section is each made in the form of two parallel beams of rectangular cross section.  4. The one-piece cage of a roller bearing according to claim 1, characterized in that the cross-section of the jumper made by the elastic-bearing medium section is each made in the form of a box section beam.

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