FR2802990A1 - Ball bearing for skateboard wheel has inner and outer races with multiple rows of bearing balls of different diameter - Google Patents

Abstract

The ball bearing for a skateboard wheel has an annular exterior race (3) and an annular inner race (3) defining a gap (7) for the bearing balls (17). There are at least three rows of balls in the gap, which is cylindrical or conical. The diameter of the bearing balls can decrease from one row to another. claims include a method of manufacture of the ball bearing assembly

Description

The present invention relates to the technical field of bearings, and more particularly to ball bearings. It also relates to wheels equipped with such bearings, and a method of manufacturing a wheel equipped with a bearing wheel obtained by the method.

Bearings are widely used in the industry, for example in the automotive industry, where they equip many equipment, such as alternators, starters, clutches or servo motors such as those of electric windows, wipers, air conditioners etc. ..., or in other varied fields, such as industrial equipment, for example machine tools.

Another more recent industrial field where the bearings are used that of wheels for roller skates and boards roulettes, also called rollers and skates respectively.

There are many types of bearings, which are designed to meet different operating constraints, and can vary widely in shape, size, and type of components. Ball bearings, spherical roller bearings, cylindrical roller bearings, tapered roller bearings, needle bearings, etc. are known.

The present invention is more particularly concerned with ball bearings.

The ball bearings of the prior art are generally formed of two rings mounted axially, an outer ring and an inner ring, between which are inserted a two rows of spherical balls free to rotate around themselves and / or move. The presence of the balls and possibly additional lubricating means allows the two rings to rotate axially relative to each other minimizing friction, and therefore energy losses. In a manner known per se and according to the desired applications for rolling, the balls may be free and contiguous or free and not contiguous, or otherwise imprisoned in cages that maintain a constant gap between them. A lubricant such as grease may be incorporated in the space formed between the two rings. Gaskets may be provided to close the rings and prevent lubricant leakage and / or penetration of external pollutants such as dust.

In accordance with the bearings of the prior art, when a bearing having an axial dimension larger than the height of two rows of balls is needed, it is necessary to turn to roller or needle bearings, which have always been considered as more resistant and more efficient by the skilled person. The length of said rollers or said needles is then adjusted to the desired axial rolling dimension.

But these types of bearings have the major disadvantage of having a large dimensional space and / or a high starting torque and / or a large weight.

The invention proposes a bearing which overcomes the disadvantages of bearings of the prior art.

Research efforts in the field of rolling have always been to improve the materials chosen, the lubrication of the bearing, the surface conditions of the parts, but did not seek to modify the combination of parts forming the bearing.

The present invention raises the problem in a radically different way, and goes against the old and constant prejudices of the person skilled in the art.

According to the invention, the ball bearing is characterized in that it comprises an outer annular ring and an inner annular ring which define between them an annular space for the balls, and in that it comprises at least three rows of balls. . The rows of balls are superimposed axially. The number of rows is determined according to the desired application and / or the solicitation to which the bearing is to be submitted.

Preferably, the ball bearing according to the invention comprises three rows of balls.

A bearing comprising three rows of balls or more has certain advantages compared to the joining of several bearings comprising a single row of balls. Indeed, the bearing comprising several rows of balls according to the invention has better rolling properties, a better greasing capacity, as well as greater strength and greater robustness. As a result, the life of the bearing is increased. The manufacturing costs of a bearing comprising at least three rows of balls are less than the manufacturing and assembly costs of several bearings comprising a single row of balls, or those of needle roller or roller bearings.

The invention also relates to wheels equipped with such bearings, and more particularly wheels of skates and skateboards, ie rollers and skates.

The wheels for skates and skateboards of the prior art are equipped with conventional ball bearings with one or two rows of balls. They are made of molded plastic, and cover two different plastic materials, one forming the contact part of the wheel with the ground, and characterized by its qualities of adhesion and damping, the other forming the central hub of the wheel, and characterized by its qualities of robustness and rigidity. In a manner known per se, the contact portion and the hub of the wheel are made together by molding in the same mold bi-injection material. Then the bearing is introduced into the central hole of the hub.

The invention also relates to a method of manufacturing a wheel equipped with a bearing according to the invention, and the wheel obtained by said method. According to the invention, the manufacturing process by molding a wheel is carcatérisé in that the bearing is inserted in the mold and that is injected around the bearing one or two plastics to form the wheel, the bearing being thus directly integrated with the wheel.

The invention will be better understood in the following detailed description of preferred but non-limiting embodiments of the bearing and the wheel according to the invention, more particularly provided for ball bearings for wheels of skates and skateboards, and which are illustrated with the aid of the accompanying drawings in which - Figures 1 to 4 show, respectively in perspective cutaway, in top view, in longitudinal section and in side view, a first embodiment of rolling, comprising three rows 10 balls and an outer peripheral shoulder; - Figure 5 shows, in longitudinal section, a second embodiment of rolling, comprising three rows of balls, and having no peripheral shoulder; - Figure 6 shows, in top view, a cage; - Figures 7 to 10 respectively show in longitudinal section four variants of an outer ring, namely cylindrical without shoulder, cylindrical with a shoulder at one end, cylindrical with a shoulder at each end, conical without shoulder; - Figures 11 and 12 respectively show in longitudinal section two variants of an inner ring, namely cylindrical and conical - Figures 13 to 16 show, in longitudinal section, respectively four bearing variants having a cylindrical annular space, namely: Bearing with cylindrical outer ring and tapered inner ring, bearing with tapered outer ring and cylindrical inner ring, bearing with outer ring and inner ring tapered, bearing with outer ring and inner ring tapered, with inverted conicity; - Figures 17 to 20 show, in longitudinal section, respectively four bearing variants having a conical annular space, namely: cylindrical outer and inner ring bearing, cylindrical outer ring bearing and conical inner ring, conical outer ring bearing and cylindrical inner ring, tapered outer and inner ring bearing; - Figure 21 shows another bearing variant having varying ball diameters from one row to another; - Figure 22 shows a wheel for roller skate or skateboard equipped with a bearing having radial outer fins.

Referring to Figures 1 to 4, the bearing 1 comprises a cylindrical outer ring 3 having an outer face 301 and an inner face 303, and a cylindrical inner ring 5 having an outer face 501 and an inner face 503, said rings 3, 5 defining between them a cylindrical annular space 7. The outer ring 3 has at one of its ends a radial shoulder 9 intended to facilitate the insertion of the bearing 1 inside a mounting, for example inside. of a wheel. Thanks to the presence of the shoulder 9, the bearing 1 can be positioned and wedged inside said assembly.

The annular space 7 has raceways 11 embodied by circumferential grooves 13 of the inner face 303 of the outer ring 3 and circumferential grooves 15 of the inner face 503 of the inner ring 5, said grooves 15 being located opposite grooves 13. The grooves 13 and 15 preferably have a profile in the form of a portion of a circle or ellipse. According to the preferred embodiment, the raceways 11 are three in number and equidistant, but one could consider more numerous and / or non-equidistant raceways 1 1.

Balls 17 are disposed inside raceways 11, forming rows 19 of balls 17 which succeed each other axially. According to the embodiment illustrated in Figures 1 to 4, each raceway 11 contains ten balls 17 free and joined. An outer longitudinal groove 21 is formed on the inner face 303 of the outer ring 3 and an inner longitudinal groove 23 is formed facing the preceding on the inner face 503 of the inner ring 5, the two grooves 21, 23 cooperating to form a magazine 25 through which are successively introduced the balls 17 of each row 19 of balls 17. The grooves 21 and 23 preferably have a profile in the form of a portion of a circle or ellipse.

Referring to Figure 5, a second embodiment of the bearing 1 according to the invention is shown, comprising three rows 19 of contiguous beads 17, and without shoulder 9 end. FIG. 5 also shows a lubricating orifice 31 intended in particular to receive a lubricator of the ball-type grease type. The presence of a lubricating orifice 31 is not limited to the embodiment of FIG. 5. Thus, the bearing according to the invention has the advantage, when it is equipped with a lubricator, of having a duration extended life compared to the bearings of the prior art.

The rings may be made of metal, for example steel, or plastic, or sintered material, or synthetic materials or fibers, or ceramic. The balls may be made of metal, for example steel, or plastic, or sintered material, or synthetic materials or fibers, or glass or ceramic. All combinations of rings and balls can be considered, including metal rings and balls, plastic rings and balls, metal rings and glass balls, etc. Other materials than the ones just mentioned can be used, whether for rings or for balls, as soon as they have the required mechanical properties.

According to another embodiment, the bearing may comprise non-contiguous balls set in a cage. According to the cages of the prior art, the cage may be metal or plastic, for example polyamide or polyamide loaded with glass fibers. FIG. 6 illustrates a plastic cage 27 comprising a circular ring 271 on one face of which recesses 273 having walls 275 extending from said face are arranged so as to retain the balls 17. The balls 17 are forced into the dwellings 273. In this example, the dwellings 273 are seven in number.

FIGS. 7 to 10 represent four possible variants of the outer ring 3, and FIGS. 11 and 12 represent two possible variants of the inner ring 5.

FIG. 7 represents an outer cylindrical ring 3 with external faces 301 and internal faces 303 that do not have an end shoulder, comprising on its internal face 303 three circumferential grooves 13 and a longitudinal groove 21 for the introduction of balls 17 .

Figure 8 is similar to Figure 7 for an outer ring 3 having a shoulder 9 at one of its ends. Figure 9 is similar to the previous, for an outer ring 3 having a shoulder 9 at each end.

FIG. 10 represents an outer ring 3 having an inner cylindrical face 303 and an outer conical face 301, comprising on its inner face 303 three circumferential grooves 13 and a longitudinal groove 21.

FIG. 11 shows a cylindrical internal ring 5 with parallel outer faces 501 and inner faces 503, comprising on its internal face 503 three circumferential grooves 15 and a longitudinal groove 23.

FIG. 12 shows an inner ring 5 having a cylindrical outer face 501 and an inner conical face 503, comprising on its internal face 503 three circumferential grooves 15 and a longitudinal groove 23.

Figures 13 to 20 show variants of possible forms of bearings according to the invention. The bearings of FIGS. 13 to 16 comprise rows of balls 17 having all the same diameter from one row to another, whereas the bearings of FIGS. 17 to 20 comprise rows of balls with increasing diameter of a row of balls. end to the other end row. Figures 13 to 20 show bearings having a cylindrical outer ring 3 with parallel faces (Figure 13), or an outer ring 3 having an outer face 301 and a cylindrical inner face 303 (Figures 14, 15, 16), or an outer ring 3 having an outer cylindrical face 301 and an inner conical face 303 (Fig. 17, 18, 19), or an outer ring 3 having two parallel conical faces (Fig. 20). These same figures show bearings having a cylindrical inner ring 5 with parallel faces (FIG 14), or an inner ring 5 having an outer face 501 conical and a inner face 503 cylindrical (FIG 13, 15, 16), or a cylindrical outer face 501 and an inner conical face 503 (Fig. 17, 19), or an inner ring having both parallel conical faces (Fig. 18, 20). It can be seen (FIGS. 15 and 16) that the taper of one ring relative to the other can be reversed. Those skilled in the art will easily extend these examples to other possible combinations of outer rings 3 and inner 5 with cylindrical or conical faces, parallel or otherwise.

Another variant embodiment is illustrated in FIG. 21. The bearing 1 comprises three rows 19 of balls 17, the two end rows having balls 17 with a diameter greater than the diameter of the balls of the row (rows). intermediate (s). The main advantage of the bearing 1 according to this embodiment lies in the fact that the bearing is capable of absorbing the prestressing to which it is subjected, said prestressing being able to be elastic or not.

The invention also relates to a wheel provided with a bearing 1 according to the invention, and in particular a wheel roller wheel or a wheel skateboard.

The invention finally relates to a method of manufacturing a wheel equipped with a bearing according to the invention. The method according to the invention is a method of molding the wheel, which comprises a step of inserting the bearing into the mold, followed by one or two plastic injection steps directly around the bearing. The bearing is thus secured to the wheel at the time of molding. According to a first variant, the bearing is inserted into the mold and a first plastic material, for example polyamide, is injected around the bearing to form a hub, and a second plastic material, for example polyurethane, to form the contact part. of the wheel.

According to a second variant, the bearing is inserted into the mold and a single plastic material, for example polyurethane, is injected around the bearing to form the wheel.

The invention finally relates to the wheel 22 obtained by the method according to the invention, as illustrated in FIG. 22. The bearing 1 is a bearing 1 comprising three rows of balls 17, with outer rings 3 and inner 5 cylindrical faces parallel, defining a cylindrical annular space 7. The bearing 1 is preferably provided with radial fins 29, preferably having an increasing distribution of the edges towards the center of the outer surface of the bearing 1. The fins 29 have the advantage of reinforcing the bearing 1. Their presence increases the surface of the contact between the bearing and the injected plastic material 33, and promotes the adhesion of the plastic material 33 to said bearing 1.

Thus, the wheel according to the invention is not only equipped with a bearing according to the invention having at least three rows of balls, but according to a preferred variant, it has no hub. Indeed, the bearing according to the invention has qualities of strength and rigidity such that when the bearing is integrated with the wheel during the molding operation, the presence of a hub is no longer necessary.

Of course, the invention is not limited to the examples just described, and the skilled person can easily consider many adaptations that are within his reach.

The examples of bearings which have been described comprise three rows of balls, but the invention also relates to the bearings having more than three rows of balls, the number of rows being a function of the desired application and the stresses applied.

We can consider many bearings varying in size, the number and size of the balls they contain on each row, the number of rows of beads, the presence or absence of a shoulder to one and / or at the other of its ends, the cylindrical and / or conical character of the inner and / or outer faces of each ring, ...

One can predict the presence of several loaders of balls, especially for balls having a different diameter from one row to another.

Other materials for the rings, the balls the cages, the materials forming the wheel can be envisaged without departing from the scope of the invention.

The invention is not limited to the applications described, and we can consider many other industrial applications without departing from the scope of the invention.

Claims (1)

<B> <U> CLAIMS </ U> </ B> <B> 1. </ B> Bearing (1) ball (17), characterized in that it comprises an outer annular ring (3) and a annular inner ring (5) which define between them an annular space (7) for the balls (17), and in that it comprises at least three rows (19) of balls (17). 2. Bearing (1) according to claim 1, characterized in that it comprises three rows (19) of balls (17). 3. Bearing (1) according to claim 1 or 2, characterized in that the annular space (7) is cylindrical. <B> 4. </ B> Bearing (1) according to claim 1 or 2, characterized in that the annular space (7) is conical. 5. Bearing (1) according to any one of claims 1 to 4, characterized in that the diameters of the balls (17) are identical from one row (19) of balls (17) to another. 6. Bearing (1) according to any one of claims 1 to 4, characterized in that the diameters of the balls (17) are increasing from one extreme row of balls (17) to the other extreme row of balls (17). ). 7. Bearing (1) according to any one of claims 1 to 4, characterized in that the diameters of the balls (17) are identical in the two extreme rows of balls (17) and the ball diameters (17) are lower. to the precedents on the intermediate row (s) of balls (17). <B> 8. </ B> Bearing (1) according to any one of claims 1 to 7, characterized in that the outer ring (3) has a peripheral shoulder (9) external to at least one of its ends. 9. Bearing (1) according to any one of claims 1 to 8, characterized in that it comprises at least one loader (25) of balls (17). <B> 10. </ B> Bearing (1) according to any one of claims 1 to 9, characterized in that the outer ring (3) has at least one inner longitudinal groove (21) and the inner ring (5). ) has at least one inner longitudinal groove (23), said grooves (21, 23) cooperating in pairs to form a loader (25) of balls (17). <B> 11. </ B> Bearing (1) according to any one of claims 1 to 10, characterized in that it comprises a raceway (11) for each row (19) of balls (17). <B> 12. </ B> Bearing (1) according to any one of claims 1 to 10, characterized in that for each row (19) of balls (17), the outer ring (3) comprises a peripheral groove (13) on its inner face and the inner ring (5) comprises a peripheral groove (15) on its inner face, the two grooves (13, 15) cooperating to form a raceway (11) for the balls (17). of said row (19) of balls (17). <B> 13. </ B> Bearing (1) according to any one of claims 1 to 12, characterized in that on each row (19) the balls (17) are free and contiguous. <B> 14. </ B> Bearing (1) according to any one of claims 1 to 9, characterized in that on each row (19) the balls (17) are free and not contiguous. 15. Bearing (1) according to any one of claims 1 to 9, characterized in that on each row (19) the balls (17) are set in cages (27). <B> 16. </ B> Bearing (1) according to claim 15, characterized in that the cages (27) are made of metal. <B> 17. </ B> Bearing (1) according to claim 15, characterized in that the cages (27) are made of plastic. <B> 18. </ B> Bearing (1) according to any one of claims 1 to 17, characterized in that the rings (3, 5) are metal. 19. Bearing (1) according to any one of claims 1 to 17, characterized in that the rings (3, 5) are plastic. <B> 20. </ B> Bearing (1) according to any one of claims 1 to 19, characterized in that the balls (17) are metal. <B> 21. </ B> Bearing (1) according to any one of claims 1 to 19, characterized in that the balls (17) are plastic. 22. Bearing (1) according to any one of claims 1 to 19, characterized in that the balls (17) are glass or ceramic. <B> 23. </ B> Bearing (1) according to any one of claims 1 to 17, characterized in that the rings (3, 5) and the balls (17) are made of steel. <B> 24. </ B> Bearing (1) according to any one of claims 1 to 23, characterized in that the outer ring (3) is provided on its outer surface with radial fins (29). 25. Use of the bearing (1) according to any one of claims 1 to 24, for equipping a wheel (50) of roller skate or a wheel (50) of skateboard. 26. A method of manufacturing by molding a wheel, characterized in that inserts a bearing (1) according to any one of claims 1 to 24 in the mold and injected around the bearing (1) a first plastic material to form a hub, and a second plastic material to form the contact portion of the wheel (50). 27. A method of manufacturing by molding a wheel (50), characterized in that a bearing (1) according to any one of claims 1 to 24 is inserted in the mold and injected around the bearing (1). ) a single material to form the wheel (50), which then has no hub. 28. Wheel (50), characterized in that it is obtained by the method according to claim 26 or 27. 29. Wheel (50), characterized in that it is equipped with a bearing (1) according to the any one of claims 1 to 24. 30. Wheel (50) according to claim 29, characterized in that the bearing (1) is integrated at the time of molding the wheel (50).