JP2008051277A - Wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device having reduced rotating torque while improving the assembling efficiency of tapered rollers. <P>SOLUTION: Cutouts 6a are formed in columnar portions 5c on the narrow sides of pockets 6 of a cage 5, thus improving the circulation of lubricant, reducing the amount of the lubricant residing in a bearing, and reducing torque resulting from the flowing resistance of the lubricant. A front end 5d of the rib of the cage 5 is bent to the axial inside. Thus, when assembled on the cage 5, the tapered rollers are supported between a small annular portion 5a of the cage 5 and the front end 5d of the rib and held in stable attitude, and they are thereby smoothly assembled thereon without leaning to the circumferential direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like.

  For example, a wheel bearing device shown in Patent Document 1 (hereinafter simply referred to as a bearing device) includes an outer member having a double-row rolling surface on the inner periphery, and a rolling facing the rolling surface. The inner member which has a surface in an outer periphery, and the double row rolling element arrange | positioned so that rolling is possible between these opposing rolling surfaces are provided.

  When such a bearing device is used as, for example, a wheel bearing device having a relatively large load capacity such as a truck or a wagon car, the use of a tapered roller as a rolling element can improve the load capacity of the bearing device ( For example, refer to FIG.

  In a wheel bearing device having a tapered roller bearing, grease is divided into a cage outer diameter side and an inner diameter side from the small diameter side of the tapered roller and flows into the bearing. The grease flowing in from the outer diameter side of the cage passes along the rolling surface (outer race) of the outer member serving as the outer ring to the larger diameter side of the tapered roller. The grease flowing in from the inner diameter side of the cage passes along the rolling surface (inner race) of the inner ring to the larger diameter side of the tapered roller.

  As described above, the tapered roller used for the portion where the lubricant such as grease flows from the outside is provided with a notch in the pocket of the cage, and flows separately into the outer diameter side and the inner diameter side of the cage. There is one in which the lubricant passes through the notch to improve the flow of the lubricant inside the bearing (see Patent Documents 2 and 3). As shown in FIG. 24 (A), in the one described in Patent Document 2, a notch 6d is provided in the central portion of the column portion 5c between the pockets 6 of the cage 5, and foreign matter mixed in the lubricant is caused inside the bearing. So that it does not stay. Moreover, in what was described in patent document 3, as shown to FIG. 24 (B), the notch 6e is provided in the small annular part 5a and the large annular part 5b of the axial direction both ends of the pocket 6 of the holder | retainer 5, and hold | maintained. The lubricant flowing in from the outer diameter side of the vessel is made to flow easily to the inner ring side. In addition, each dimension of the pocket 6 entered in each figure is the value used for the comparative example in the torque measurement test mentioned later.

  By the way, in the bearing device as described above, in recent years, low-viscosity oil tends to be used to reduce fuel consumption. In an environment where low-viscosity oil is used, it is caused by poor lubrication when adverse conditions such as (1) high oil temperature, (2) low oil volume, and (3) preload loss occur. Very short-life surface-origin separation may occur on the inner ring rolling surface with high surface pressure.

  As a measure for short life due to this surface-origin separation, reduction of the maximum surface pressure is a direct and effective solution. In order to reduce the maximum surface pressure, for example, there is a method of increasing the number of tapered rollers of the bearing. In order to increase the number of tapered rollers without reducing the diameter of the tapered rollers, the pocket spacing (columns) of the cage must be narrowed, but the columns of the cage ensure strength to support the sliding contact with the tapered rollers. Therefore, a certain width or more is necessary. Therefore, in order to increase the number of tapered rollers while maintaining the width of the pillar portion of the cage, it is necessary to increase the pitch circle of the cage as close as possible to the outer ring side.

  As the method, for example, in the tapered roller bearing shown in Patent Document 4, a protrusion is provided on the outer diameter surface of the cage. As a result, during the rotation of the tapered roller bearing, a minute gap between the cage and the outer ring is maintained by the dynamic pressure of the wedge-shaped oil film formed between the protrusion and the inner surface of the outer ring, and torque loss due to contact between the two is maintained. In addition, damage to the cage and the outer ring rolling surface is prevented. Accordingly, the outer diameter surface of the cage can be made as close as possible without contacting the inner diameter surface of the outer ring, and the pitch circle of the cage can be enlarged.

JP 2004-345543 A (FIG. 7) JP-A-9-32858 (FIG. 3) JP-A-11-2011149 (FIG. 2) JP 2005-98316 A

  However, by increasing the diameter of the cage and increasing the number of tapered rollers as described above, the flow resistance due to the lubricant inside the bearing is increased, and the rotational torque is increased.

  Further, by expanding the pitch circle of the cage as described above, the following problems occur when the tapered roller is assembled to the cage. Assemble the tapered roller to the cage by placing the cage so that the small annular part is at the bottom, and lowering the tapered roller from above with the small diameter end face down until it is caught in the pocket (small annular part) of the cage And the tapered roller is tilted radially outward. When the small-diameter end surface of the tapered roller is caught in the pocket, the tapered roller is supported only by the small annular portion of the cage, so that it is very unstable. When the pitch surface of the cage is increased in diameter, the portion where the tapered roller is caught in the pocket becomes smaller, which makes the tapered roller more unstable and tilts in the circumferential direction, making assembly difficult.

  An object of this invention is to reduce the rotational torque of the tapered roller in a wheel bearing apparatus, and to improve an assembly | attachment property.

  In order to solve the above problems, the present invention provides an outer member having a double row rolling surface on the inner periphery, an inner member having a rolling surface on the outer periphery facing each of the rolling surfaces, and In a wheel bearing device including a double row rolling element that is arranged to freely roll between opposing double row rolling surfaces, at least one of the rolling elements of the double row rolling element is It is a tapered roller, further comprising a cage having a pocket for accommodating the tapered roller at a predetermined circumferential interval, and the cage is connected to a small annular portion connected on the small diameter side of the tapered roller and a large diameter side of the tapered roller. It consists of a series of large annular portions and a plurality of column portions connecting these annular portions, and the pocket has a narrow side where the small diameter side of the tapered roller is accommodated and a wide side which accommodates the large diameter side It is formed in a trapezoidal shape, and ribs extend radially from the edge of the small annular portion of the cage. The distal end portion of the rib and axially inwardly by bending shape, and is characterized in that a notch bar portion of the narrow side of the cage trapezoidal pockets.

  As described above, in the bearing device of the present invention, the notch is provided in the trapezoidal pocket of the cage. As a result, the circulation of the lubricant becomes good and the amount of the lubricant staying in the bearing can be reduced, so that the torque due to the flow resistance of the lubricant is reduced. Further, according to the verification by the present inventors, when the notch is provided in the column on the narrow side of the pocket of the cage, for example, in the case where it is provided in the center of the column (see FIG. 24A), It has been found that the torque reduction effect is further exhibited as compared with the case where the large annular portion is provided (see FIG. 24B).

  Moreover, in the bearing apparatus of this invention, it is set as the shape which bent the rib front-end | tip part of the holder | retainer in the axial direction inner side. Thus, when the tapered roller is assembled to the cage, the tapered roller is supported by the small annular portion of the cage and the tip of the rib when the small diameter end surface of the tapered roller is caught in the pocket. Thereby, since the tapered roller is held in a stable posture, the tapered roller is smoothly assembled without being inclined in the circumferential direction.

  If such a cage is further provided with a notch in the small annular portion on the narrow side of the trapezoidal pocket, the circulation of the lubricant in the bearing becomes better and the torque reduction effect can be increased.

  Moreover, if a notch is provided in at least the column part on the wide side of the trapezoidal pocket, the tapered roller can be brought into sliding contact with the column part with a good balance.

  Also, by setting the total area of the notches provided on the narrow side of the trapezoidal pocket wider than the total area of the notches provided on the wide side, the amount of lubricant staying inside the bearing can be reduced. Can do.

  In the bearing device as described above, the load applied to the rolling surface on the inboard side and the rolling surface on the outboard side may be different. In this case, for example, by using a tapered roller as the rolling element in the row with the larger load load and a ball as the rolling element in the other row, the load capacity of both rolling surfaces can be balanced. The effect of high rigidity and long life can be expected.

Further, if the PCD of the double row rolling elements is increased, the effect of increasing the rigidity and extending the life of the bearing device can be expected. This is because the expansion of the rolling element PCD increases the bearing span (interval between the line of action of the acting direction of the force applied to both rolling surfaces and the axis) without increasing the axial distance of the rolling elements in each row. The reason is that it can be increased, the number of rolling elements that can be incorporated is increased, and the like. Moreover, an efficient design is attained by enlarging only one rolling element PCD and making rolling element PCD different.

  Also, the same effect as described above can be obtained by making the number of rolling elements in the double row different between the inboard side and the outboard side. Alternatively, the same effect as described above can be obtained by making the sizes of the double row rolling elements different between the inboard side and the outboard side.

  As described above, according to the present invention, the rotational torque of the tapered roller in the wheel bearing device can be reduced, and the assemblability can be improved.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a bearing device 1 according to a first embodiment of the present invention. This bearing device 1 is an example applied to support of driving wheels, and an outer member 2 having double-row rolling surfaces 2a1, 2a2 on the inner periphery, and a double-row facing the rolling surfaces 2a1, 2a2. The inner member 3 having the rolling surfaces 3a1 and 3a2 on the outer periphery thereof, and the double row rolling elements that are interposed between these rolling surfaces and are arranged to roll freely. In the present embodiment, tapered rollers 41 and 42 are used as rolling elements and are held by the cage 5 for each row. Thus, by using the tapered roller as the rolling element, the contact area between the rolling element and the rolling surface is increased, so that the load capacity can be increased. The bearing device 1 of the present embodiment is set so that the tapered rollers 41 and 42 have the same PCD (indicated by D in FIG. 1).

  The inner member 3 includes a hub ring 31 and double-row inner rings 32 and 33 that are fitted to the outer peripheral surface 31 a of the hub ring 31. The hub wheel 31 has an inner peripheral surface 31b into which a shaft portion 7a provided in the constant velocity universal joint 7 is inserted. Splines are formed on the inner peripheral surface 31b of the hub wheel 31 and the outer peripheral surface 7a1 of the shaft portion 7a, respectively, and the hub wheel 31 and the constant velocity universal joint 7 can transmit torque by engaging with each other. Further, the end portion on the outboard side of the shaft portion 7a is fastened with the nut 13, whereby the hub wheel 31 and the constant velocity universal joint 7 are fixed in the axial direction. The hub wheel 31 has a hub flange 31c on the outer periphery near the end on the outboard side, and a disk wheel (not shown) is attached to the hub flange 31c by a hub bolt 8 that passes through the hole of the hub flange 31c.

  Inner rings 32 and 33 are press-fitted into the outer peripheral surface 31 a of the hub ring 31, and the constant velocity universal joint 7 regulates the disconnection. Rolling surfaces 3a1 and 3a2 are formed on the outer peripheral surfaces of the inner rings 32 and 33, respectively.

  The outer member 2 is provided with a flange portion 2b on the outer diameter surface. The outer member 2 is attached to the knuckle 10 in the suspension device on the vehicle body side by the knuckle bolt 9 that passes through the hole of the flange portion 2b. Seals 11 are attached to both ends of the outer member 2. Each seal 11 is in sliding contact with the seal ring 12 provided on each of the inner rings 32 and 33, thereby sealing the space formed between the outer member 2 and the inner member 3.

  The cage 5 is a press-worked product formed by pressing from a steel plate (steel pipe) such as an SPCC steel plate, for example, and includes a small annular portion 5a, a large annular portion 5b, a small annular portion 5a, and a large annular portion 5b. And a plurality of column portions 5c connected in the axial direction (see FIG. 2). A pocket 6 is provided between the column portions 5 c adjacent to each other in the circumferential direction, and the tapered rollers 41 and 42 are accommodated in the pocket 6 so as to roll freely. The pocket 6 is formed in a trapezoidal shape in which the portion for storing the small diameter side of the tapered roller is the narrow side, and the portion for storing the large diameter side is the wide side. The small annular portion 5a is provided with a rib extending from an end portion thereof, and has a shape in which the rib tip portion 5d is bent inward in the axial direction.

  FIG. 3 shows details of the cage 5. On the narrow side and wide side of the pocket 6, two notches 6 a and 6 b are provided in each of the column portions 5 c on both sides and cut from the outer diameter side to the inner diameter side. The notches 6a and 6b have a depth of 1.0 mm and a width of 4.6 mm. The notches 6a and 6b illustrated in the drawings are in the form of grooves cut in the radial direction of the cage 5, but the inner diameter side and the outer diameter side of the cage 5 are connected to each other to smoothly lubricate the lubricant. As long as the passage can be allowed, the shape and dimensions are arbitrary.

  4 and 5 show a modified example of the cage 5. In the modification shown in FIG. 4, a notch 6 c is also provided in the small annular portion 5 a on the narrow side of the pocket 6. The total area of the three notches 6a and 6c on the narrow side is wider than the total area of the two notches 6b on the wide side. The notch 6c has a depth of 1.0 mm and a width of 5.7 mm. In the modification shown in FIG. 5, the depth of each notch 6a of the narrow column portion 5c is 1.5 mm, which is deeper than each notch 6b of the wide column portion 5c, and each notch on the narrow side. The total area of 6a is wider than the total area of the notches 6b on the wide side.

  6 and 7 are sectional views of the inner ring 32 on the outboard side. The outer diameter surface of the pillar portion 5c of the cage 5 is integrally provided with a protruding portion 5e having a convex shape toward the rolling surface formed on the inner periphery of the outer member 2 (hereinafter, outer ring rolling surface 2a1). Is formed. The projecting portion 5e has an arc shape in cross section (see FIG. 6). This arc-shaped curvature radius R2 is formed smaller than the radius R1 of the outer ring rolling surface 2a1 (R1> R2, see FIG. 7). This is so that a good wedge-shaped oil film is formed between the protrusion 5e and the outer ring rolling surface 2a1, and preferably the radius of curvature R2 of the protrusion 5e is 70, which is the radius R1 of the outer ring rolling surface 2a1. It is good to form in about -90%. If it is less than 70%, the opening angle of the wedge-shaped oil film becomes too large, and the dynamic pressure decreases. If it exceeds 90%, the inlet angle of the wedge-shaped oil film becomes too small, and the dynamic pressure similarly decreases. Further, the lateral width W2 of the protruding portion 5e is desirably formed to be 50% or more of the lateral width W1 of the column portion 5c (W2 ≧ 0.5 × W1). This is because if it is less than 50%, a sufficient height of the projection 5e for forming a good wedge-shaped oil film cannot be secured. Further, since the radius R1 of the outer ring rolling surface 2a1 continuously changes from the large diameter side to the small diameter side, the curvature radius R2 of the protruding portion 5e also matches the large curvature radius R2 of the large diameter side annular portion 5b. Continuously to a small radius of curvature R2 of the small-diameter side annular portion 5a. In addition, since the cross section in the inner ring | wheel 33 by the side of an inboard is the same, description is abbreviate | omitted.

  The reason why notches as shown in FIGS. 2 and 3 are provided in the pocket 6 of the cage 5 will be described with reference to FIG. In the bearing device 1, a lubricant such as grease is injected into a space formed by the outer member 2, the inner member 3, and the oil seal 11. At this time, since the tapered roller 41 rotates at a high speed with its lower part immersed in an oil bath, as shown by an arrow in FIG. 8, the lubricant moves from the small diameter end surface 41 a side of the tapered roller 41 to the outer diameter side of the cage 5. It is divided into the inner diameter side and flows into the bearing. The lubricant flowing from the outer diameter side of the cage 5 to the outer member 2 side has no obstacle on the rolling surface 2a1 of the outer member 2, so that the large size of the tapered roller 41 along the rolling surface 2a1. Passes smoothly to the radial end face 41b side and flows out of the bearing. However, the lubricant that flows from the inner diameter side of the cage 5 to the inner ring 32 side is dammed by the large collar portion 32b of the inner ring 32 and tends to stay inside the bearing. This staying lubricant becomes a flow resistance against the bearing rotation and increases the rotational torque.

  A gap δ between the rib tip portion 5d of the cage 5 and the small flange portion 32a of the inner ring 32 is set to be narrow, for example, 2.0% or less of the outer diameter of the small flange portion 32a of the inner ring 32. In this way, by setting the gap δ to be narrow, the lubricant flowing from the inner diameter side of the cage 5 to the inner ring 32 side is much less than the lubricant flowing from the outer diameter side of the cage 5. Further, most of the lubricant flowing in from the gap δ moves to the outer diameter side of the cage 5 through the notch 6 a provided in the column portion 5 c on the narrow side of the pocket 6. Therefore, the amount of the lubricant that reaches the large collar portion 32b along the rolling surface 3a1 of the inner ring 32 is extremely reduced, and the amount of the lubricant staying in the bearing can be reduced, so that the rotational torque can be reduced. . In the present embodiment, since the notch 6c is also provided in the small annular portion 5a on the narrow side of the pocket 6, the lubricant that has flowed into the inner ring 32 side can be further moved to the outer member 2 side, Further reduction of rotational torque can be expected.

  Further, even when the total area of the notches 6a and 6c provided on the narrow side of the pocket 6 is set wider than the total area of the notches 6b provided on the wide side, the large ring portion 32b of the inner ring 32 is reached. The amount of lubricant can be reduced, and the rotational torque can be reduced. Moreover, since the notch 6b is provided also in the column part 5c of the wide side of the pocket 6, the tapered roller 41 can be slidably contacted with the column part 5c with good balance. Since the behavior of the lubricant on the inner ring 33 side is the same, the description thereof is omitted.

The surface of the cage 5, particularly the outer diameter surface of the cage 5, should be as smooth as possible. That is, during the rotation of the bearing device 1, a wedge-shaped oil film is formed between the protrusion 5e on the outer diameter surface of the cage 5 and the outer ring rolling surfaces 2a1 and 2a2. Therefore, the protrusion 5e on the outer diameter surface of the cage 5 does not come into contact with the outer ring rolling surfaces 2a1 and 2a2 due to the dynamic pressure action. When a severe wedge-shaped oil film is not formed and severe lubrication conditions occur, the protrusion 5e on the outer diameter surface of the cage 5 may come into contact with the outer ring rolling surfaces 2a1 and 2a2. In preparation for such a case, the coefficient of friction is reduced as much as possible by, for example, applying a molybdenum disulfide (MOS ₂ ) coating to the outer diameter surface of the cage 5 or performing a barrel polishing finish. It is better to take treatment.

  9 to 12 show the pocket 6 viewed from the inner diameter side of the cage 5, and the contact of the tapered roller with the pocket column surface 5c1 (side surface of the column portion 5c) is indicated by a two-dot chain line. In any case, the contact width of the roller of the pocket column surface 5c1 is secured 10% or more of the pocket length from the axial center position of the pocket 6, that is, the pocket center position. This is because the load acting on the cage 5 from the rollers is concentrated locally or biased so that abnormal wear does not occur and damage due to stress concentration does not occur. 9 to 12, the notch 6a and the like are omitted.

  Specifically, in the case of FIG. 9, the roller contact width is secured over 10% or more of the pocket length from the center position of the pocket to both sides in the axial direction. Therefore, the roller contact width at the pocket center position is 20% or more of the pocket length. In the case of FIG. 10, the roller contact is closer to the left side in the figure, but a roller contact width of 10% or more of the pocket length is also secured from the center of the pocket to the right side. In the case of FIG. 11, the roller contact is closer to the right side in the figure, contrary to FIG. 10, but a roller contact width of 10% or more of the pocket length is secured on the left side from the pocket center position. FIG. 12 shows a case in which the roller contact between the upper pocket column surface 5c1 and the lower pocket column surface 5c1 in the drawing is offset in the opposite direction. In any case, at least the pocket length from the pocket center position is shown. A width per roller of 10% or more is secured.

  The cage 5 may be made of resin other than a steel plate press product. As a type of resin, when it is assumed to be used in automobile transmissions, super engineering plastics such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphthalamide (PPA), or polyamide resin are used in consideration of oil resistance. It is desirable to do. Moreover, you may mix | blend glass fiber or carbon fiber etc. with these resin for intensity | strength reinforcement | strengthening as needed.

  In the case of an iron plate cage, it is necessary to spread the bottom and caulking, but in the case of a resin cage, these are not necessary, so that it is easy to ensure the necessary dimensional accuracy. Here, “bottom opening” means that when the cage 5 incorporating the roller is assembled to the inner ring, the diameter of the column portion on the small diameter side of the cage 5 is greatly expanded so that the roller can get over the small brim of the inner ring. . “Caulking operation” refers to pushing the column portion of the small-diameter portion of the cage 5 greatly expanded as described above by pushing it with a mold from the outside.

  In addition, by using engineering plastics excellent in mechanical strength, oil resistance and heat resistance for the cage, it is possible to reduce the weight, improve the self-lubricity, and reduce the friction coefficient compared to the steel plate. For this reason, combined with the effect of the lubricant interposed in the bearing, it is possible to suppress the occurrence of wear due to contact with the outer ring, and it is possible to reduce torque loss and cage wear at the start of the bearing.

  Although not shown in the drawings, the entire surfaces of the tapered rollers 41 and 42 are provided with an infinite number of minute concave recesses. The surface provided with the indentation has a surface roughness parameter Ryni of 0.4 μm ≦ Ryni ≦ 1.0 μm and a Sk value of −1.6 or less.

  The bearing device 1 of the present invention is configured as described above, and when the bearing device 1 rotates and the cage 5 starts to rotate, the outer ring rolling surfaces 2a1 and 2a2 and the protrusion 5e of the cage 5 are interposed. A wedge-shaped oil film is formed. Since this wedge-shaped oil film generates a dynamic pressure substantially proportional to the rotational speed of the bearing device 1, even if the pitch circle diameter of the cage 5 is increased and brought close to the outer ring rolling surfaces 2a1 and 2a2, the bearing device 1 becomes large. It becomes possible to rotate without causing wear or torque loss, and the number of tapered rollers can be increased without difficulty. Thereby, the maximum surface pressure of a rolling surface is reduced and the malfunction by surface origin peeling can be avoided. If the cage 5 can be sufficiently expanded even without the dynamic pressure action as described above, it is not necessary to provide the protrusion 5e.

  When the number of tapered rollers is increased as described above, the flow resistance due to the lubricant inside the bearing increases, and the rotational torque may increase. As a countermeasure, the notch 6a, 6c is provided in the column portion 5c and the small annular portion 5a on the narrow width side of the pocket 6, whereby the circulation of the lubricant inside the bearing is improved, and the lubricant stays inside the bearing. The amount of agent can be reduced. Therefore, torque due to the flow resistance of the lubricant is reduced.

  Next, the process of assembling the tapered roller 41 (or 42, the same shall apply hereinafter) will be described with reference to FIGS. First, the cage 5 is installed with the small annular portion 5a facing downward, and the tapered roller 41 is lowered from above with the small diameter end surface 41a facing downward as shown in FIG. 13, and inserted into the pocket 6 from the inside. To do. Next, as shown in FIG. 14, the small-diameter end surface 41a of the tapered roller 41 is caught on the edge of the pocket 6, and the tapered roller 41 is tilted radially outward (in the direction indicated by the arrow), as shown in FIG. A tapered roller 41 is installed in the cage 5.

  For example, when the tip 5d of the rib of the cage 5 is formed in parallel with the radial direction, when the small diameter end surface 41a of the tapered roller 41 is caught by the edge of the pocket 6, the tapered roller 41 becomes the edge of the pocket 6. It becomes a very unstable state. In particular, when the diameter of the cage 5 is increased as described above, the portion where the small-diameter end surface 41a of the tapered roller 41 is caught by the end edge of the pocket 6 becomes smaller, which makes the tapered roller 41 circumferential. There is a risk of tilting in the direction.

  As shown in FIGS. 13 to 15, when the tip 5 d of the rib of the cage 5 is bent inward in the axial direction, when the small diameter end surface 41 a of the tapered roller 41 is caught in the pocket 6, the tapered roller 41 is It is supported by the small annular portion 5a of the cage 5 and the tip portion 5d of the rib (see FIG. 14). Thereby, since the tapered roller 41 is held in a stable posture, the above-described problem can be avoided.

  Since the bearing device 1 has the above configuration, the rotational torque can be reduced and the assembly is efficiently performed. The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, a sufficient torque reduction effect can be obtained even without the notch 6c of the small annular portion 5a, or the tapered roller is in sliding contact with the column portion 5c in a well-balanced manner without the notch 6b of the wide column portion 5c. These can be omitted if possible.

  The present invention is not limited to the above embodiment. Hereinafter, other embodiments of the present invention will be described. In addition, the same code | symbol is attached | subjected to the location which has the structure and function similar to said embodiment, and description is abbreviate | omitted.

  FIG. 16 shows a bearing device 201 according to the second embodiment of the present invention. In the bearing device 201, the rolling surface 3 a 1 on the outboard side is formed on the hub wheel 31. The inner ring 33 on the inboard side is press-fitted into the outer peripheral surface 31 a of the hub ring 31 and is prevented from being removed by the constant velocity universal joint 7.

  FIG. 17 shows a bearing device 301 according to the third embodiment of the present invention. This bearing device 301 is mainly used for supporting a driven wheel. The inner rings 32, 33 are press-fitted into the outer peripheral surface 31 a of the hub ring 31, and are prevented from coming off by crimping the end 31 e on the inboard side of the hub ring 31. By the way, depending on the usage mode of the bearing device, the load applied to the rolling surfaces 2a1 and 3a1 on the outboard side may be larger than the load applied to the rolling surfaces 2a2 and 3a2 on the inboard side. In this case, if the ball 43 is used as the rolling element on the outboard side and the tapered roller 42 is used as the rolling element on the inboard side as in this embodiment, the load capacity of both rolling surfaces can be balanced. Therefore, the effect of increasing the rigidity and extending the life of the bearing device 301 can be expected. Of course, conversely, if the load applied to the rolling surfaces 2a2, 3a2 on the inboard side is larger than the load applied to the rolling surfaces 2a1, 3a1 on the outboard side, the rolling elements on the inboard side are A tapered roller may be used, and the rolling element on the outboard side may be a ball.

  FIG. 18 shows a bearing device 401 according to the fourth embodiment of the present invention. In the bearing device 401, the rolling surface 3 a 1 on the outboard side is formed on the hub wheel 31. The inner ring 33 on the inboard side is press-fitted into the outer peripheral surface 31 a of the hub ring 31, and the omission is regulated by crimping the end part 31 e on the inboard side of the hub ring 31.

  FIG. 19 shows a bearing device 501 according to a fifth embodiment of the present invention. In the bearing device 501 shown in FIG. 1, the PCD (D1) of the rolling element on the outboard side is larger than the PCD (D2) of the rolling element on the inboard side (D1> D2). According to this, since the bearing span can be expanded without increasing the axial interval between the rolling elements on the inboard side and the outboard side, it is possible to achieve high rigidity and long life of the bearing device. In this case, it is only necessary to enlarge the PCD on the side that can be enlarged by design. Contrary to the present embodiment, the PCD (D2) of the rolling element on the inboard side is set to be higher than the PCD (D1) of the rolling element on the outboard side It may be increased (D1 <D2).

  The bearing device 601 shown in FIG. 20, the bearing device 701 shown in FIG. 21, and the bearing device 801 shown in FIG. 22 are respectively the bearing device 201 shown in FIG. 16, the bearing device 301 shown in FIG. 17, and the bearing shown in FIG. In the apparatus 401, the PCD (D1) of the rolling element on the outboard side is set to be larger than the PCD (D2) of the rolling element on the inboard side (D1> D2).

  Further, by increasing the number of rolling elements incorporated in the row, or by increasing the size of each rolling element incorporated in the row, it is possible to increase the rigidity and life of the bearing device.

  In addition, the effect of increasing the rigidity and extending the life of the bearing device as described above is obtained by increasing the PCD, increasing the number of rolling elements, or increasing the size of the rolling elements in the inboard side and outboard side columns. This leads to an increase in the size of the bearing device. In this case, an efficient design is possible by performing these operations on the side where higher rigidity is required.

In order to confirm the torque reduction effect of the cage 5 used in the bearing device of the present invention, a torque measurement test was performed using a vertical torque tester. In this test, a tapered roller bearing using the cage shown in FIG. 3 and a tapered roller bearing using the cage shown in FIG. 4 were prepared. These are referred to as Example A and Example B, respectively, for convenience. Moreover, as a comparative example, a tapered roller bearing (Comparative Example A) using a cage without a notch in a pocket and a tapered roller bearing (Comparative Example) using the cage shown in FIGS. 24 (A) and (B). B, C) were prepared. Each tapered roller bearing has an outer diameter of 100 mm, an inner diameter of 45 mm, and a width of 27.25 mm, and the portions other than the pocket notch are the same. The test conditions are as follows.
Axial load: 300kgf
Rotational speed: 300-2000r / min (100r / min pitch)
Lubrication condition: oil bath lubrication (lubricant: 75W-90)

  FIG. 23 shows the test results. The vertical axis of the graph in the figure represents the torque reduction rate with respect to the torque of Comparative Example A using a cage not having a notch in the pocket. Although the comparative example B in which a notch is provided in the central portion of the pocket portion and the comparative example C in which a notch is provided in the small annular portion and the large annular portion of the pocket have a torque reducing effect, the narrow width portion of the pocket Example A, in which a notch is provided in the column on the side, shows a torque reduction effect superior to those of these comparative examples, and a notch on the narrow side is provided with a notch in the small annular portion on the narrow side. In Example B in which the total area of each of these is wider than that on the wide side, a further excellent torque reduction effect is recognized.

  The torque reduction rate at 2000 r / min, which is the maximum rotation speed of the test, is 9.5% in Example A and 11.5% in Example B. Excellent torque reduction effect even under use conditions at high speed rotation Can be obtained. In addition, the torque reduction rate in the rotational speed 2000r / min of the comparative example B and the comparative example C is 8.0% and 6.5%, respectively.

It is sectional drawing of the bearing apparatus 1 which concerns on this invention. It is a fragmentary perspective view of the holder | retainer 5. FIG. 3 is a partially enlarged plan view of the cage 5. FIG. FIG. 6 is a partially enlarged plan view showing another example of the cage 5. FIG. 6 is a partially enlarged plan view showing another example of the cage 5. 2 is a partial cross-sectional view of the bearing device 1. FIG. It is an expanded sectional view of FIG. It is sectional drawing which shows the flow of the lubricant inside a bearing. FIG. 6 is a simplified view of a pocket 6 of the cage 5. FIG. 6 is a simplified view of a pocket 6 of the cage 5. FIG. 6 is a simplified view of a pocket 6 of the cage 5. FIG. 6 is a simplified view of a pocket 6 of the cage 5. FIG. 6 is a cross-sectional view for explaining the point of inserting a tapered roller 41 into the cage 5. FIG. 6 is a cross-sectional view for explaining the point of inserting a tapered roller 41 into the cage 5. FIG. 6 is a cross-sectional view for explaining the point of inserting a tapered roller 41 into the cage 5. It is sectional drawing of the bearing apparatus 201 which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the bearing apparatus 301 which concerns on the 3rd Embodiment of this invention. It is sectional drawing of the bearing apparatus 401 which concerns on the 4th Embodiment of this invention. It is sectional drawing of the bearing apparatus 501 which concerns on the 5th Embodiment of this invention. It is sectional drawing of the bearing apparatus 601 which concerns on the 6th Embodiment of this invention. It is sectional drawing of the bearing apparatus 701 which concerns on the 7th Embodiment of this invention. It is sectional drawing of the bearing apparatus 801 which concerns on the 8th Embodiment of this invention. It is a graph which shows the result of a torque measurement test. (A), (B) is a partial enlarged plan view which shows the conventional holder | retainer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing apparatus 2 Outer member 2a1 Rolling surface 3 Inner member 31 Hub ring 32, 33 Inner ring 3a1 Rolling surface 41, 42 Tapered roller (rolling element)
43 balls (rolling elements)
DESCRIPTION OF SYMBOLS 5 Cage 5a Small annular part 5b Large annular part 5c Column part 5c1 Pocket column surface 5d Rib tip part 5e Projection part 6 Pocket 7 Constant velocity universal joint

Claims (8)

An outer member having a double-row rolling surface on the inner periphery, an inner member having a rolling surface facing each of the rolling surfaces on the outer periphery, and rolling between these opposing double-row rolling surfaces In a wheel bearing device comprising a double row rolling element freely arranged,
Among the double row rolling elements, at least one row of rolling elements is a tapered roller, and includes a cage having a pocket for storing the tapered rollers at predetermined circumferential intervals,
The cage is composed of a small annular portion that is continuous on the small diameter side of the tapered roller, a large annular portion that is continuous on the large diameter side of the tapered roller, and a plurality of column portions that connect these annular portions, and the pocket is The portion that stores the small diameter side of the tapered roller is formed in a trapezoidal shape that the narrow side is the side and the portion that stores the large diameter side is the wide side,
A rib is extended in the radial direction from the edge of the small annular portion of the cage, the tip of the rib is bent inward in the axial direction, and the narrow side of the trapezoidal pocket of the cage A bearing device for a wheel, wherein a notch is provided in a column portion.   The wheel bearing device according to claim 1, wherein a notch is provided also in a small annular portion on a narrow side of the trapezoidal pocket.   The wheel bearing device according to claim 1, wherein a notch is provided in at least a column part on the wide side of the trapezoidal pocket.   The wheel bearing device according to claim 1, wherein a total area of the notches provided on the narrow side of the trapezoidal pocket is wider than a total area of the notches provided on the wide side of the trapezoidal pocket.   The wheel bearing device according to any one of claims 1 to 4, wherein one of the rolling elements in the double row is a ball.   The wheel bearing device according to any one of claims 1 to 5, wherein PCDs of the double-row rolling elements are different between an inboard side and an outboard side.   The wheel bearing device according to any one of claims 1 to 6, wherein the number of rolling elements in the double row is different between the inboard side and the outboard side.   The wheel bearing device according to any one of claims 1 to 4, 6, and 7, wherein the size of the double row rolling elements is different between the inboard side and the outboard side.

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