JP5560816B2 - Bearing unit - Google Patents

Description

  The present invention includes a virtual circle diameter PCD (diameter) configured by mutually connecting rolling centers of a plurality of rolling elements arranged on the outboard side, and a plurality of rolling elements arranged on the inboard side. The present invention relates to a bearing unit in which the diameter dimension PCD (diameter) of a virtual circle formed by connecting rolling centers to each other is set to a different diameter dimension, and more particularly, to a bearing unit in which the rows between rolling elements are narrowed. .

  Conventionally, various bearing units for supporting a wheel of an automobile or the like (for example, a disc wheel) with respect to a vehicle body (for example, a suspension device (suspension)) are known (see Patent Document 1). As an example, the bearing unit shown in FIG. 4 includes an annular outer ring 2 (for example, a stationary wheel) that is fixed to a component on the inboard (vehicle body) side and is always kept in a non-rotating state, and an inner side of the outer ring 2 An annular inner ring 4 (for example, a rotating wheel) that is provided oppositely and is connected to a component on the outboard (wheel) side and rotates together with the wheel is provided.

  On the inner peripheral surface 2m of the outer ring 2, outer ring raceway surfaces 2s and 2t are formed in double rows (for example, two rows), while each of the outer peripheral surfaces 4m of the inner ring 4 facing the inner peripheral surface 2m Inner ring raceway surfaces 4s and 4t are formed in double rows (for example, two rows) at positions facing the outer ring raceway surfaces 2s and 2t, respectively. Then, a plurality of rolling elements 6 and 8 are rotatably incorporated between the outer ring raceway surface and the inner ring raceway surface (between 2 s and 4 s, between 2 t and 4 t), respectively. A bearing unit is configured in which the inner ring 4 is opposed to the inner ring 4 via the rolling elements 6 and 8 so as to be relatively rotatable.

  In the outer ring 2, the inner diameter dimension of the outer ring raceway surface 2s formed on the outboard side is set larger than the inner diameter dimension of the outer ring raceway surface 2t formed on the inboard side. On the other hand, in the inner ring 4, the outer diameter dimension of the inner ring raceway surface 4s formed on the outboard side is set larger than the outer diameter dimension of the inner ring raceway surface 4t formed on the inboard side.

  In this case, a plurality of rolling elements 6 and 8 are assembled between the outer ring raceway surface and the inner ring raceway surface (between 2 s and 4 s, between 2 t and 4 t). The diameter (diameter: PCD) 6D of a virtual circle formed by mutually connecting the rolling (rotating) centers 6g of the rolling elements 6 is the rolling (rotating) of the rolling elements 8 arranged in a plurality on the inboard side. ) The diameter (6D> 8D) is set larger than the diameter (diameter: PCD) 8D of the virtual circle formed by connecting the centers 8g to each other. The number (total number) of the rolling elements 6 arranged on the outboard side is set larger than the number (total number) of the rolling elements 8 arranged on the inboard side.

  The outer ring 2 has a hollow cylindrical shape and is disposed so as to cover the outer periphery of the inner ring 4. Between the outer ring 2 and the inner ring 4, an annular ring formed between the outer and inner rings 2, 4 is provided. Sealing members (outboard lip seal 10a and inboard pack seal 10b) for sealing the bearing internal space H are provided. Moreover, although the ball | bowl is illustrated in drawing as the rolling elements 6 and 8, a roller may be applied according to the structure and kind of bearing.

  The outer ring 2 (stationary ring) is integrally formed with a fixing flange 2a that protrudes radially outward from the outer peripheral surface 2r, and a fixing bolt (not shown) is provided in the fixing hole 2b of the fixing flange 2a. The outer ring 2 can be fixed to the suspension device (knuckle) by inserting and fastening it to a component on the inboard side (for example, suspension device (knuckle)). As a method for fixing the outer ring 2 and the suspension device (knuckle), for example, a combination of a stud bolt and a nut press-fitted into the fixing flange 2a may be used.

  On the other hand, the inner ring 4 is provided with a substantially cylindrical hub 12 that supports components on the outboard side (for example, a disc wheel of an automobile) and rotates together with the wheels. A hub flange 12a to which a side component (for example, a disc wheel) is fixed is provided.

  The hub flange 12a extends outward (outward in the radial direction of the hub 12) beyond the outer ring 2, and a plurality of hub bolts 14 are provided in the vicinity of the extended edge at predetermined intervals along the circumferential direction. It has been. In this case, the disc wheel can be positioned and fixed with respect to the hub flange 12a by inserting a plurality of hub bolts 14 into bolt holes (not shown) formed in the disc wheel and tightening with hub nuts (not shown). it can. Further, the hub flange 12a side may be formed as a female screw hole and fixed by tightening with a bolt.

  The hub 12 is fitted (externally fitted) with an annular inner ring structure 16 (a member constituting the inner ring 4 together with the hub 12) on the inboard side. In this case, for example, with the plurality of rolling elements 6 and 8 held between the outer ring 2 and the inner ring 4 by the cages 18a and 18b, the inner ring constituting body 16 is fitted to the step 12b formed on the hub 12 ( After the outer fitting), the caulking region 12c at the end of the inboard side of the hub 12 is plastically deformed, and the caulking region 12c is caulked (closely adhered) along the peripheral end 16s of the inner ring constituting body 16. Thus, the inner ring structure 16 can be fixed to the inner ring 4 (hub 12).

  At this time, a predetermined preload is applied to the bearing unit, and in this state, the double-row rolling elements 6 and 8 form predetermined contact angles α and β, respectively, with the outer ring 2 and the inner ring. 4 is installed rotatably in contact with each other between the raceway surfaces (between 2s and 4s, and between 2t and 4t). In this case, the contact angle directions α and β of the rolling elements 6 and 8 are orthogonal to the raceway surfaces 2s, 2t, 4s and 4t, and the rolling (rotation) centers of the rolling elements 6 and 8 are on one side. It passes through 6g and 8g and intersects at one point (action point) on the center line (rotating shaft) of the bearing unit. This constitutes a rear combination (DB) bearing. The other of the contact angle directions α and β intersects at one point that has passed through the outer ring 2.

  In such a configuration, for example, all of the force acting on the wheel while the vehicle is running is transmitted from the disc wheel to the suspension device through the bearing unit. At this time, various loads (radial load, axial load) are applied to the bearing unit. Load, moment load, etc.). However, since the bearing unit is a back combination (DB) bearing as described above, high rigidity is maintained against various loads.

  The annular bearing inner space H configured in the bearing unit described above extends in an annular shape from the inboard side to the outboard side. Specifically, the bearing inner space H is expanded in a divergent shape from the inboard side to the outboard side between the rows of both rolling elements 6 and 8 incorporated in double rows (another view). In other words, the bearing inner space H is filled (enclosed) with a lubricant (for example, grease or oil). ing.

  In such a bearing unit, when the bearing (inner ring 4) rotates, centrifugal force acts on the lubricant, and the lubricant flows (moves) toward the outboard side of the bearing inner space H, and there (Specifically, on the outer diameter side of the bearing inner space H). Then, the amount of lubricant existing around each rolling element 8 arranged on the inboard side (hereinafter referred to as the inboard side rolling element 8) becomes equal to each rolling element 6 arranged on the outboard side (hereinafter referred to as “out”). The amount of lubricant present around the board side row rolling elements 6) may be smaller.

  In this case, depending on the amount of lubricant transferred from the inboard side to the outboard side, the lubrication performance around the inboard side rolling element 8 which is severe in terms of life is deteriorated. As a result, the durability of the bearing unit is reduced. May deteriorate at an early stage. In terms of life, it is not as strict as the inboard side row, but the PCD is large and the number of the rolling elements 6 is large. In other words, the area around the outboard side rolling element 6 where the generation of torque is large is a lubricant (grease). Therefore, the stirring resistance of the lubricant is increased, and torque and heat generation are further increased. Furthermore, in order to avoid lubricant leakage from the outer seal (outboard lip seal 10a) due to the lubricant discharging effect by the rolling elements 6, it is necessary to increase the distance between the outboard side rolling elements 6 and the outer seal 10a. This increases the axial dimension and weight of the bearing unit. Therefore, in the bearing unit, an annular slinger F extends in a direction crossing the bearing inner space H between the rows of the rolling elements 6 and 8. The slinger F has a hollow disk shape extending toward the outer peripheral surface 4m of the inner ring 4 (hub 12) in a state of being fixed to the inner peripheral surface 2m of the outer ring 2, and its extending tip Is positioned in a non-contact state spaced from the outer peripheral surface 4m of the inner ring 4 (hub 12).

  According to this, since the lubricant that flows (moves) toward the outboard side during the rotation of the bearing (inner ring 4) is blocked by the slinger F, the lubricant that exists around the inboard side row rolling element 8 It is possible to avoid a situation in which the amount of water is insufficient. As a result, the lubricating performance around the inboard side row rolling elements 8 can be kept constant. Further, since the amount of lubricant around the outboard side rolling elements 6 can be prevented from increasing, torque increase, heat generation, lubricant leakage, and weight increase can be prevented.

  By the way, the above-described bearing unit assumes a type in which the row between the rolling elements 6 and 8 is relatively wide. For example, depending on the purpose of use and the usage environment, the space between the rolling elements 6 and 8 is narrowed. Some types of bearing units may be required. In this case, the bearing internal space H is sharply expanded from the inboard side toward the outboard side between the rolling elements 6 and 8, and the diameter of the bearing inner space H is sharply expanded. From the side to the inboard side, the taper is reduced and the diameter is sharply reduced). Further, as the space between the rolling elements 6 and 8 is narrowed, the space of the bearing internal space H is also reduced.

  Then, when the bearing (inner ring 4) rotates, the lubricant easily flows (moves) from the inboard side to the outboard side, and it becomes difficult to secure the installation space for the slinger F described above. End up. Therefore, in the narrow-diameter bearing unit of the above-described narrow type, it is desired to control the flow state of the lubricant without using the slinger F.

  Further, in such a narrow-diameter bearing unit of a narrow type between rows, the position of the fixed flange 2a protruding from the outer ring 2 (stationary wheel) as the distance between the rolling elements 6 and 8 narrows, and the inboard The position of the shoulder K continuous with the outer ring raceway surface 2t on the side overlaps each other. The outer ring 2 (stationary ring) is usually formed by hot forging, and after machining, the outer ring raceway surfaces 2s and 2t are induction-hardened. In this case, the outer ring 2 (stationary ring) in the overlapping part is used. If the thickness difference between the wall thickness and the wall thickness of the other part becomes large, it becomes difficult to improve the bearing life by making the fiber flow as parallel as possible to the outer ring raceway surface 2t. Further, as a result of the material surface being wound around the flange portion (fixed flange 2a portion), a so-called wrapping failure phenomenon may occur in which a crack-like defect occurs in the outer ring raceway surface 2t. Furthermore, since the heat capacities greatly differ between the portion with and without the fixed flange 2a, induction hardening is difficult. Specifically, the hardened layer becomes thinner in the part with a large heat capacity, and the hardened layer becomes thick in the part with a small heat capacity, and in the case of remarkable, there is a risk of occurrence of burning cracks and overheating (coarse quenching structure or partial dissolution). .

  Furthermore, in such a case, since it is necessary to design the fixing flange 2a based on the outer diameter of the outer ring 2 on the outboard side, the mass of the outer ring 2 increases. Therefore, development of a bearing unit having an outer ring 2 in which the existing fixed flange 2a is reduced in size or removed is desired.

JP 2008-75748 A

  Therefore, an object of the present invention is to make it possible to control the flow state of the lubricant filled (enclosed) in the bearing internal space regardless of the width between rows of rolling elements incorporated in double rows, It is an object of the present invention to provide a bearing unit having a stationary ring in which a fixed flange is downsized or removed to improve a bearing life and solve problems such as wrapping, cracking, and overheating.

In order to achieve such an object, the present invention is an annular stationary ring that is fixed to a component on the inboard side and is always maintained in a non-rotating state, and a double-row outer ring raceway surface is formed on the inner circumferential surface. and the outer ring is provided to be opposed to the outer wheel, and is connected to the outboard side of the components rotate together, the inner ring is a rotating ring of annular inner raceway surfaces of the double row is formed on the outer peripheral surface And a plurality of rolling elements that are rotatably incorporated in a double row between the outer ring raceway surface and the inner ring raceway surface in an annular bearing inner space configured between the outer ring and the inner ring , and a inboard and outboard of the resin respectively provided side retainer for rotatably holding the rolling elements in each row, the rolling center of the rolling elements on the outboard side one another rotation of the connecting diameter of an imaginary circle formed by the inboard rolling elements Mainly a bearing unit which is set larger than the diameter of the virtual circle formed by connecting each other, the said retainer inboard, circumferentially continuous along the bearing inner space, and with hollow inboard cylindrical portion extending toward the outboard side is provided, the said retainer on the outboard side, circumferentially continuous along the bearing inner space, and inboard hollow outboard cylindrical portion extending toward the side is provided, the said inboard cylindrical portion and the outboard side cylindrical portion, in each of the extending region of the rotary wheel An annular labyrinth is configured by overlapping each other while maintaining a predetermined gap along a direction orthogonal to the rotation axis , and both the inboard side tubular portion and the outboard side tubular portion are Of the rotating wheel The inboard side tubular portion extends in a direction along the axis of rotation, and the inboard side cylindrical portion has a substantially trapezoidal cross section, and becomes smaller in diameter toward the outboard side. The outboard side cylindrical portion has a substantially trapezoidal cross section and becomes larger in diameter toward the inboard side, and its tip portion is in contact with the outer ring raceway surface on the inboard side. Close to continuous shoulders .

  According to the present invention, it is possible to control the flow state of the lubricant filled (enclosed) in the bearing internal space regardless of the width between the rows of rolling elements incorporated in a double row, and an existing fixed flange. Can be reduced in size or removed to improve the bearing life, and a bearing unit having a stationary ring that solves the problems of wrapping, cracking, and overheating can be realized.

Sectional drawing which shows the structure of the bearing unit which concerns on one Embodiment of this invention. Sectional drawing which shows the structure of the bearing unit which concerns on the modification of this invention. Sectional drawing which shows the structure of the bearing unit which concerns on the modification of this invention. Sectional drawing which shows the whole structure of the different diameter bearing unit of a type with a wide space | interval.

Hereinafter, a bearing unit according to an embodiment of the present invention will be described with reference to FIG.
Since the present embodiment is a partial improvement of the different-diameter bearing unit of the type in which the space between rows shown in FIG. 4 is wide, only the improved portion will be described below. In this case, about the same structure as an above-mentioned bearing unit (FIG. 4), the code | symbol same as the reference mark attached | subjected to the structure is attached | subjected on drawing used for this embodiment, and the description is abbreviate | omitted. In the present embodiment, an inter-diameter narrow-diameter bearing unit in which the inter-roller rows of the bearing unit in FIG. 4 are narrowed is assumed.

  As shown in FIG. 1, in the bearing unit of the present embodiment, the inboard retainer 18a is continuous in the circumferential direction along the bearing internal space H and toward the outboard side (rotation of the rotating wheel). A hollow cylindrical inboard side cylindrical portion Ta extending in the direction along the axis) is provided, while the outboard side cage 18b is continuous in the circumferential direction along the bearing internal space H, Further, a hollow cylindrical outboard side tubular portion Tb extending toward the inboard side (in a direction along the rotation axis of the rotating wheel) is provided. The rotating shaft of the rotating wheel indicates the center axis of the bearing unit (the rotating shaft of the inner ring 4 which is a rotating wheel) configured when the outer inner rings 2 and 4 rotate relative to each other.

  Then, the inboard side tubular portion Ta and the outboard side tubular portion Tb are overlapped with each other while maintaining a predetermined gap along the direction orthogonal to the rotation axis of the rotating wheel in each extending region. Thus, an annular labyrinth is configured. In this case, the extension lengths of both the cylindrical portions Ta and Tb (the length dimension in the direction along the rotation axis of the rotating wheel) are the same between the rolling elements 6 and 8 incorporated in a double row in the bearing internal space H. Since it is arbitrarily set according to the distance (length dimension) between the columns, the numerical value is not particularly limited here. In short, what is necessary is just to set to the extent that the extension area | region of both cylindrical part Ta and Tb mutually overlaps.

  Further, the thickness (thickness dimension) of both the cylindrical portions Ta and Tb is, for example, a rigidity that is not easily deformed by a centrifugal force during rotation of the bearing (inner ring 4) (that is, while maintaining a predetermined gap) The rigidity is set such that the superimposed positional relationship is always maintained. For this reason, since the thickness (thickness dimension) of the said cylindrical part Ta and Tb is set to an optimal value according to the use environment and use purpose of a bearing unit, it does not specifically limit a numerical value here.

  Moreover, both cylindrical part Ta and Tb can be integrally shape | molded by the shaping | molding process of the holder | retainers 18a and 18b. For example, assuming that the cages 18a and 18b are molded by an axial draw mold, the axial draw mold is composed of a pair of molding dies that move relative to each other in the axial direction of the cages 18a and 18b. Then, a cavity corresponding to the contour of the cage is formed inside, and after filling a molding material (for example, thermoplastic resin), the cage 18a, which is a molded product, is pulled out in the axial direction and separated from each other. 18b can be completed.

  Here, both the cylindrical parts Ta and Tb are formed into a part having no hindrance (that is, a part having no hindrance to pulling out the mold) and a shape (orientation) having no hindrance when forming by the axial draw mold. It is preferable.

  In the bearing unit of the present embodiment, as an example of a portion without any trouble, the cylindrical portions Ta and Tb are located on the bottoms of the cages 18a and 18b (specifically, on the side opposite to each pocket of the crown type cage). An annular portion that is continuous in the circumferential direction). In addition, as an example of a shape (orientation) that does not hinder, the cylindrical portions Ta and Tb are formed in a hollow cylindrical shape that extends in a direction along the rotation axis of the rotating wheel.

  More specifically, the inboard side cylindrical portion Ta is formed into a hollow cylindrical shape extending in the direction along the rotation axis of the rotating wheel from the bottom outer diameter side of the cage 18a, while the outboard The side cylindrical portion Tb is formed into a hollow cylindrical shape extending from the bottom inner diameter side of the cage 18b in a direction along the rotation axis of the rotating wheel. According to this, in a state where a plurality of rolling elements 6 and 8 are held by the inboard side and outboard side cages 18a and 18b between the outer ring 2 (stationary wheel) and the inner ring 4 (rotating wheel), the outboard The side tubular portions Tb are positioned on the outer diameter side of the inboard side tubular portion Ta so as to overlap each other while maintaining a predetermined gap.

In this case, the gap (labyrinth) between the cylindrical portion Ta and the cylindrical portion Tb is such that the rolling elements 6 and 8 of the outboard side row and the inboard side row are arranged at predetermined positions, and the cages 18a, One that has a larger amount of movement or inclination of the cage 18a, 18b in the radial direction (direction perpendicular to the rotation axis of the rotating wheel) that can be generated from the difference between the pocket diameter (inner diameter) of 18b and the diameter of the rolling elements 6, 8 You can decide from the value of.
Further, a draft is given to the cylindrical portions Ta and Tb so that the radial cross section (the cross section perpendicular to the rotation axis of the rotating wheel) has a substantially trapezoidal shape, and can be forcibly removed. If the outer diameter of the cylindrical portion Tb is a conical shape whose diameter increases toward the inboard side, and the outer diameter of the cylindrical portion Ta of the inboard side retainer 18a becomes a conical shape whose diameter decreases toward the outboard side, The flow around the rolling elements 6 and 8 in each row can be made to flow back to the row, and between the outboard side tubular portion Tb and the shoulder K continuous to the outer ring raceway surface 2t, And it becomes easy to shape | assemble a labyrinth between the inboard side cylindrical part Ta and the hub 12. FIG.

  Moreover, in this embodiment, the bearing life is improved, and the narrow-row inter-diameter bearing unit is realized in which the rows between the rolling elements 6 and 8 are narrowed while solving problems such as wrapping, cracking, and overheating. Therefore, the outer ring 2 (stationary ring) from which the existing fixing flange 2a (FIG. 4) is removed is applied, and the outer ring 2 has an inboard side of the outer peripheral surface 2r in the circumferential direction more than the other parts. An annular step portion is formed that is continuously recessed along. Note that the step portion is provided in place of the fixing flange 2a in order to fix the outer ring 2 (stationary wheel) to the inboard component.

  The step portion includes an annular contact surface 2d formed continuously in a circumferential direction along a direction orthogonal to the rotation axis of the rotating wheel, and an outer ring in a direction along the rotation shaft from the inner diameter side of the contact surface 2d. 2 (stationary wheel) extends to the inboard side end surface 2e and has a cylindrical fitting surface 2f formed continuously along the circumferential direction. Here, the contact surface 2d is formed at a position where the contact angle α of each rolling element 6 on the outboard side passes, and the fitting surface 2f has a contact angle β of each rolling element 8 on the inboard side. It is formed at a passing position.

  In addition, the fitting surface 2f of the outer ring 2 is formed with an attachment portion 2g for attaching a predetermined fixture 20 on the inboard side. In the present embodiment, a disc spring-shaped retaining ring 20 is applied as the fixture 20. Further, on the inboard side of the fitting surface 2f, an annular recess 2g that is continuously depressed along the circumferential direction is formed as the attachment portion 2g. The retaining ring (fixing tool) 20 can be attached to the recess (mounting part) 2g by fitting the inner diameter side of the retaining ring (fixing tool) 20 into the recess (mounting part) 2g.

  Here, the fitting surface 2f is fitted into the cylindrical hole 22h formed in the inboard side component (for example, the knuckle) 22, and the knuckle 22 is brought into contact with the contact surface 2d, and then stopped. The ring 20 is attached to the recess 2g. At this time, the spring force of the retaining ring 20 acts on the knuckle 22 and presses the knuckle 22 against the contact surface 2d. Thereby, the outer ring 2 (stationary wheel) can be fixed to the knuckle 22 on the inboard side by sandwiching the knuckle 22 between the contact surface 2d and the retaining ring (fixing tool) 20.

  As described above, according to the present embodiment, both the cylindrical portions Ta and Tb extended from the two cages 18a and 18b holding the rolling elements 6 and 8 in the double row are predetermined in the extension region. The labyrinth is formed by superimposing each other while maintaining the clearance of the bearing, so that the lubricant that flows (moves) toward the outboard side of the bearing inner space H during the rotation of the bearing (inner ring 4) is caused by the labyrinth. The flow state is controlled. Thereby, it is possible to avoid a situation in which excess lubricant flows (moves) to the outboard side and the amount of lubricant existing around the inboard side rolling element 8 is insufficient. As a result, the lubricating performance around the outboard side row and inboard side row rolling elements 6 and 8 can always be kept constant.

  Further, according to the present embodiment, in the narrow-diameter type different-diameter bearing unit in which the rows of the rolling elements 6 and 8 are narrowed, the installation space for the slinger F (FIG. 4) described above is provided in the bearing internal space H. Even if it cannot be secured, the labyrinth can be configured by extending the cylindrical portions Ta and Tb from the two cages 18a and 18b in accordance with the limited space of the bearing inner space H. The flow state of the lubricant can be controlled without using.

  By the way, when the existing fixed flange 2a (FIG. 4) remains on the outer ring 2 and the row between the rolling elements 6 and 8 is narrowed, the fixed flange 2a and the outer ring raceway surface 2t on the inboard side are continuous. The thickness difference between the thickness of the portion where the shoulder K overlaps with the thickness of the other portion and the thickness of the other portion becomes large, so that the fiber flow is made as parallel as possible to the outer ring raceway surface 2t and the bearing life is improved. It becomes difficult. Further, as a result of the material surface being wound around the flange portion (fixed flange 2a portion), a so-called wrapping failure phenomenon may occur in which a crack-like defect occurs in the outer ring raceway surface 2t. Furthermore, since the heat capacities greatly differ between the portion with and without the fixed flange 2a, induction hardening is difficult. Specifically, the hardened layer becomes thinner in the part with a large heat capacity, and the hardened layer becomes thick in the part with a small heat capacity, and in the case of remarkable, there is a risk of occurrence of burning cracks and overheating (coarse quenching structure or partial dissolution). . Further, along with this, there is a possibility that the mass of the outer ring 2 increases due to the need to design the fixing flange 2a based on the outer diameter dimension of the outer ring 2 on the outboard side.

  However, according to the present embodiment, since it is not necessary to project the fixing flange 2a, the outer ring 2 does not need to be formed by hot forging the medium carbon steel, and is turned from a hollow or solid bearing steel. It can be manufactured by grinding, etc. The heat treatment is a general heat treatment, that is, sub-firing (a method in which the entire product (up to the deep part) is raised to the required temperature in a gas furnace, etc., and rapidly cooled to a hard structure) Is possible.

  Further, according to the present embodiment, the knuckle (inboard side component) 22 is fitted and brought into contact with the step portion (contact surface 2d, fitting surface 2f) of the outer ring 2 (outer peripheral surface 2r). Thus, the outer ring 2 (stationary ring) can be firmly fixed to the knuckle 22 simply by attaching the fixture (retaining ring) 20 to the attaching part (recessed part) 2g. In this case, since the turning outer load acting on the bearing unit when the vehicle turns is directly supported by the knuckle 22, the fixing device (retaining ring) 20 has a load resistance and strength enough to support a normal turning inner load ( (Rigidity) is sufficient. Therefore, since the fixture (retaining ring) 20 can be configured very simply, it can be easily attached to the attachment portion (concave portion) 2g. In the present embodiment, since the outer ring 2 is a stationary ring, a clearance fit is possible with respect to the knuckle 22, but the phase of the outer ring 2 is fixed because a sensor is attached to the outer ring 2 or the like. If necessary, for example, a phase determining means 24 (for example, a detent pin or a key) as shown in FIG. 2 can be used in combination.

  Further, according to the present embodiment, in the stepped portion described above, the contact surface 2d is formed at a position where the contact angle α of each rolling element 6 on the outboard side passes, and the fitting surface 2f is formed on each inboard side. By forming at a position where the contact angle β of the rolling element 8 passes, the moment stiffness against various loads (radial load, axial load, moment load, etc.) applied to the bearing unit during vehicle travel is further improved (increased). Can do.

Note that the present invention is not limited to the above-described embodiment, and the following modifications are also included in the technical scope of the present invention.
As shown in FIG. 2, in the bearing unit according to the present modification, one of the cylindrical portions Ta and Tb extending from the two cages 18a and 18b is annular so as to cross the labyrinth (gap). The convex portion Tp may be extended. In the drawing, as an example, a convex portion Tp is extended from the outboard side tubular portion Tb. In such a case, if the tip of the convex portion Tp is smoothly curved toward the cylindrical portion Ta, and if it is tapered to give a draft, it can be forcibly removed when forming with an axial draw mold. Become.

  The convex portion Tp can be formed by bending the outer peripheral end of the outboard side tubular portion Tb continuously in the circumferential direction in the inboard side tubular portion Ta direction. In this case, the convex portion Tp is formed so as to be maintained in a non-contact state separated from the inboard side tubular portion Ta serving as the counterpart side. Further, it is preferable that a plurality of slits are provided in the convex portion Tp so that the convex portion Tp can be forcibly removed from the mold during the molding with the axial draw mold described above. In addition, since the length dimension of convex-shaped part Tp is arbitrarily set according to the magnitude | size of the labyrinth (gap) between cylindrical part Ta and Tb, it does not specifically limit here.

  According to this modification, the labyrinth (gap) between the cylindrical portions Ta and Tb can be further narrowed, so that the bearing (inner ring 4) flows (moves) toward the outboard side of the bearing inner space H when rotating. The flow state of the lubricant to be attempted can be controlled more efficiently. Since other configurations and effects are the same as those of the above-described embodiment, the description thereof is omitted.

  In this modification, the cylindrical hole 22h of the knuckle 22 is formed in a tapered cone shape toward the inboard side, and the outer peripheral surface 2r on the inboard side of the outer ring 2 is the same as the above-described conical cylindrical hole 22h. A conical fitting surface 2f having a contour shape (outer diameter shape) is formed. In this case, at least one phasing means 24 (in the drawing, as an example, a detent pin 24) is provided near the inboard of the fitting surface 2f.

  The non-rotating pin 24 has, for example, a cylindrical shape having a circular cross section or a rectangular shape, and a proximal end side thereof is embedded in the fitting surface 2f, and a distal end side thereof is positioned so as to protrude from the fitting surface 2f. On the other hand, in the conical cylindrical hole 22h of the knuckle 22, a groove portion 22g having a dimension matching the outer contour (width dimension, thickness dimension, diameter dimension) of the pin 24 is formed to penetrate to the inboard side.

  Here, when the outer ring 2 is fixed to the knuckle 22, if the pin 24 is inserted along the groove portion 22g, the outer ring 2 can be inserted into the cylindrical hole 22h with its phase fixed. Further, after inserting the outer ring 2 into the cylindrical hole 22h and fitting the fitting surface 2f into the cylindrical hole 22h, the retaining ring 20 is attached to the recess 2g. At this time, the spring force of the retaining ring 20 acts on the knuckle 22, so that the cylindrical hole 22h and the contact surface 2d are kept in pressure contact with each other (fitted without a gap). Thereby, the outer ring 2 (stationary wheel) can be fixed to the knuckle 22 in a state where the outer ring 2 (stationary wheel) is prevented from rotating by the pin 24 (a state where the phase is fixed).

  As described above, according to this modification, the cylindrical hole 22h of the knuckle 22 is formed in a tapered conical shape toward the inboard side, and the outer peripheral surface 2r on the inboard side of the outer ring 2 has the same contour shape as the cylindrical hole 22h. By forming the formed conical fitting surface 2f, the machining surfaces of both the outer ring 2 and the knuckle 22 can be reduced compared to the embodiment of FIG. 1 (when the knuckle 22 is fixed to the stepped portion). Therefore, the processing becomes easy. Further, the above contact angles α and β are made to intersect (contact) the cylindrical hole 22h and the contact surface 2d, thereby being equivalent to the embodiment of FIG. 1 (when the knuckle 22 is fixed to the stepped portion). Therefore, the outer ring 2 (stationary ring) can be fixed to the knuckle 22. In this case, instead of the retaining ring (fixing tool) 20 and the recess (mounting part) 2g, for example, as shown in FIG. 3, by attaching the nut (fixing tool) 20 to the screw part (mounting part) 2g, The outer ring 2 (stationary wheel) may be fixed to the knuckle 22.

  Further, as shown in FIG. 3, in the bearing unit according to this modification, a small flange 2p is raised outward from the outer ring 2 (outer peripheral surface 2r) adjacent to the outboard side of the stepped portion, This may be provided continuously or intermittently in the circumferential direction. In this case, the inboard side surface of the flange 2p is positioned on the same plane as the contact surface 2d. And while applying the nut 20 as the fixture 20, the screw part 2g is formed in the inboard side of the fitting surface 2f as the attaching part 2g.

  In this case, after the knuckle (component on the inboard side) 22 is fitted and brought into contact with the step portion (contact surface 2d, fitting surface 2f) of the outer ring 2 (outer peripheral surface 2r), the nut 20 is screwed. By attaching to 2g, the outer ring 2 (stationary ring) can be fixed to the knuckle 22 more firmly than the retaining ring (fixing tool) 20 described above. In this case, in order to prevent delayed fracture of the screw part 2g, the outer ring raceway surfaces 2s and 2t are induction-hardened, and the screw part 2g is not heat-treated, or is subjected to a tempering treatment (high-temperature tempering treatment after quenching). It is preferable to do.

  According to this modification, the inboard side surface of the flange 2p can be used as the abutment surface 2d. Therefore, in another way, the abutment surface 2d is extended over the inboard side surface of the flange 2p. Therefore, the degree of freedom of the position through which the contact angle α of each rolling element 6 on the outboard side with respect to the contact surface 2d passes can be improved. Thereby, it is possible to further improve (increase) the moment rigidity against various loads (radial load, axial load, moment load, etc.) applied to the bearing unit during traveling of the vehicle. Since other configurations and effects are the same as those of the above-described embodiment, the description thereof is omitted.

  In the above-described embodiment and each modified example, it is assumed that the cylindrical portions Ta and Tb are integrally formed with the cages 18a and 18b by the axial draw mold, but each cylindrical portion Ta is replaced with this. , Tb may be formed separately and retrofitted (for example, adhesion, welding, etc.) to each of the cages 18a, 18b. In this case, the freedom degree of arrangement | positioning of each cylindrical part Ta and Tb with respect to each holder | retainer 18a and 18b can be improved. For example, the cylindrical portions Ta and Tb can be arranged in arbitrary directions at portions other than the bottom outer diameter side and the bottom inner diameter side of the cages 18a and 18b. Further, the position of the convex portion Tp (FIG. 2) can also be extended to a portion other than the outer peripheral end of each cylindrical portion Tb.

6,8 Rolling body 18a Inboard side cage 18b Outboard side cage Ta Inboard side cylindrical portion Tb Outboard side cylindrical portion

Claims (1)

It is maintained in a non-rotational state at all times and is fixed to the inboard side components, and the outer ring is a stationary ring of the annular outer ring raceway surface of the double row is formed on the inner peripheral surface, provided opposite to the outer wheel And an inner ring that is an annular rotating wheel that is connected to a component on the outboard side and rotates together , and a double-row inner ring raceway surface is formed on the outer circumferential surface, and the outer ring and the inner ring . an annular bearing internal space, and a plurality of rolling elements incorporated in rollably in double rows between the outer ring raceway surface and the inner ring raceway surface, to hold rotatably said rolling elements in each row With resin cages provided on the inboard side and the outboard side,
Out of the board side the diameter of an imaginary circle formed by connecting mutually the rolling center of each rolling element, of the virtual circle formed by connecting the rolling center of the rolling elements on the inboard side to each other in diameter A bearing unit set larger than
The said retainer inboard, the circumferentially continuous along the bearing inner space, and with the inboard side cylindrical portion of the hollow extending toward the outboard side is provided,
The said retainer on the outboard side, said bearing internal space continuously in the circumferential direction along, and and outboard side cylindrical portion of the hollow extending toward the inboard side is provided,
And said inboard cylindrical portion and the outboard side cylindrical portion, with the respective extension regions, along a direction perpendicular to the rotation axis of the rotary wheel, mutually superimposed while maintaining a predetermined gap An annular labyrinth is constructed ,
Both the inboard side cylindrical part and the outboard side cylindrical part are extended in a direction along the rotation axis of the rotating wheel,
The inboard side cylindrical portion has a substantially trapezoidal cross section, and becomes smaller in diameter toward the outboard side, and its tip is close to the shoulder continuous with the inner ring raceway surface on the outboard side,
The tubular portion on the outboard side has a substantially trapezoidal cross section, the diameter increases toward the inboard side, and the tip portion thereof is close to the shoulder portion continuous with the outer ring raceway surface on the inboard side. Features bearing unit.

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