JP2007232176A - Bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive bearing unit which achieves a weight reduction while constantly maintaining rigidity of the whole bearing. <P>SOLUTION: The bearing unit is equipped with: an outer ring 2 containing double row raceway grooves 2s in an inner peripheral surface 2m; an inner ring 4 containing double row raceway grooves 4s in an outer peripheral surface 4m opposed to respective raceway grooves in the outer ring; and a plurality of rolling elements 6, 8 rollably installed between the raceway grooves of the outer and inner rings. One of the outer and inner rings is fixed to the vehicle body side to be normally maintained in a non-rotation condition and the other is connected to the wheel side to rotate together with the wheel. A recess 20 in which at least one part of the surface is recessed below the other part between the double row raceway grooves is formed in the inner peripheral surface of the outer ring. In this case, when the diameter of the recess in the outer ring is ϕX, the diameter of the raceway groove in the outer ring is ϕD, and the diameter of the inner peripheral surface in the outer ring is ϕY, the recess satisfies the relationship of ϕY<ϕX≤ϕD. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bearing unit capable of reducing the weight while maintaining the rigidity of the entire bearing constant.

  For example, in various vehicles including automobiles, various components are reduced in weight while maintaining the rigidity of the entire bearing constant in order to improve traveling performance and fuel consumption. As an example, Patent Document 1 proposes a technique for reducing the weight of a bearing unit that rotatably supports a wheel of an automobile. In this technique, a plurality of notch-shaped recesses are formed on the outer periphery of a wheel mounting flange. As a result, the entire bearing unit is reduced in weight.

  By the way, a plurality of hub bolts for mounting wheel side components such as a disc wheel and a brake rotor are arranged at predetermined intervals along the circumferential direction on the wheel mounting flange. In this case, in order to maintain running stability and safety, it is necessary to ensure a high mounting strength between each hub bolt and the wheel-side component. And in order to satisfy this, it is necessary to maintain the rigidity of the flange at least in the peripheral region of each hub bolt at a constant level.

Therefore, in the conventional weight reduction technology as described above, when a plurality of notched recesses are formed on the outer periphery of the flange, it is necessary to form each recess at a position avoiding the peripheral region of each hub bolt. However, it is troublesome and troublesome to form each recess in accordance with such a requirement, so that the cost required for weight reduction increases, and as a result, the manufacturing cost of the bearing unit significantly increases.
JP 2005-349982 A

  The present invention has been made to solve such problems, and an object of the present invention is to provide a low-cost bearing unit capable of reducing the weight while maintaining the rigidity of the entire bearing constant. is there.

  In order to achieve such an object, the present invention has an outer ring in which double row raceway grooves are formed on the inner peripheral surface, and a double row raceway groove is formed on the outer peripheral surface facing each raceway groove in the outer ring. The inner ring and a plurality of rolling elements that are rotatably incorporated between the raceway grooves of the outer inner ring that are opposed to each other so that they can rotate relative to each other. A bearing unit that is maintained in a rotating state and the other is connected to the wheel side and rotates together with the wheel. Of the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, at least the inner peripheral surface of the outer ring has a double-row track. A recess having at least a part of the surface recessed from the surface of the other part is formed between the grooves.

  In such an invention, assuming that the diameter of the recess of the outer ring is φX, the diameter of the raceway groove of the outer ring is φD, and the diameter of the inner peripheral surface of the outer ring is φY, the recess satisfies the relationship of φY <φX ≦ φD. Is formed. In this case, the concave portion may be formed continuously along the inner peripheral surface of the outer ring, or may be formed intermittently along the inner peripheral surface of the outer ring.

  ADVANTAGE OF THE INVENTION According to this invention, the low-cost bearing unit which can achieve weight reduction can be implement | achieved, maintaining the rigidity as the whole bearing constant.

Hereinafter, a bearing unit according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1 (a), the bearing unit of the present embodiment is opposed to a stationary wheel (for example, an outer ring) 2 that is fixed to the vehicle body side and is maintained in a non-rotating state at all times, and the inner side of the stationary wheel 2. And a rotating wheel (for example, an inner ring) 4 that is connected to the wheel side and rotates together with the wheel, and the inner circumferential surface 2m of the stationary wheel 2 has a double row (for example, two rows) of raceway grooves. 2s are formed, and on the outer peripheral surface 4m of the rotating wheel 4, double-row (for example, two-row) track grooves 4s are formed to face the track grooves 2s of the stationary wheel 2. In a state where the stationary wheel 2 and the rotating wheel 4 are opposed to each other so as to be relatively rotatable, a plurality of rolling elements 6 and 8 are incorporated between the raceway grooves 2s and 4s so as to freely roll.

  In this case, the stationary wheel 2 has a hollow cylindrical shape and is disposed so as to cover the outer periphery of the rotating wheel 4, so that the inside of the bearing unit is sealed between the stationary wheel 2 and the rotating wheel 4. Sealing members (wheel side lip seal 10a, vehicle body side cover 10b) are provided. In the drawings, balls are illustrated as the rolling elements 6 and 8, but rollers may be applied depending on the configuration and type of the bearing unit.

  The stationary ring (outer ring) 2 is integrally formed with a fixing flange 2a protruding outward from the outer peripheral surface thereof, and a fixing bolt (not shown) is inserted into the fixing hole 2b of the fixing flange 2a. The stationary wheel 2 can be fixed to a suspension device (knuckle) (not shown). The rotating wheel (inner ring) 4 is provided with a substantially cylindrical hub 12 that rotates together with, for example, a disc wheel (not shown) of an automobile, and the disc wheel is fixed to the hub 12. A hub flange 12a is projected.

  The hub flange 12a extends outward (outward in the radial direction of the hub 12) beyond the stationary ring (outer ring) 2, and is arranged at predetermined intervals along the circumferential direction in the vicinity of the extended edge. A plurality of hub bolts 14 are provided. 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.

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

  At this time, a predetermined preload is applied to the bearing unit, and in this state, the rolling elements 6 and 8 form a predetermined contact angle with each other to form a stationary wheel (outer ring) 2 and a rotating wheel (inner ring). The four raceways 2s and 4s are rotatably assembled while being in contact with each other. In this case, an action line (not shown) connecting the two contact points is perpendicular to each raceway groove 2s, 4s and passes through the center of each rolling element 6, 8 to one point (action point) on the center line of the bearing unit. ) This constitutes a rear combination (DB) bearing.

  In such a configuration, all of the force acting on the wheel during traveling of the vehicle is transmitted from the disk wheel to the suspension device through the bearing unit. At that time, various loads (radial loads) are applied to the bearing unit. , Axial load, moment load, etc.). However, since the bearing unit is a back combination (DB) bearing as described above, high rigidity is maintained with respect to various loads.

  Further, in the bearing unit of the present embodiment, at least a part of the inner peripheral surface 2m of the stationary ring (outer ring) 2 is recessed between the two rows of raceway grooves 2s than the other parts. A recess 20 is formed. As shown in FIG. 1 (b), the recess 20 of the present embodiment has a substantially rectangular cross section, and is continuously extended along the inner peripheral surface 2 m of the stationary ring (outer ring) 2. Has been. In this case, when the diameter of the recess 20 is φX, the diameter of the raceway groove 2s is φD, and the diameter of the inner peripheral surface 2m is φY, the recess 20 is preferably formed so as to satisfy the relationship φY <φX ≦ φD. .

  Here, as the forming direction of the recess 20, it may be formed by extending linearly along the circumferential direction of the inner peripheral surface 2 m (alternatively, along the rotating direction of the rotating wheel 4). Alternatively, it may be formed by meandering. In any case, the recess 20 is preferably formed within a range in which a certain thickness W (FIG. 1B) is secured in the vicinity of the double row raceway groove 2s. As a result, the rigidity of the region in the vicinity of each raceway groove 2s can be maintained constant, so that it is possible to prevent a decrease in the rigidity of the entire stationary ring (outer ring) 2. In addition, since the thickness W is arbitrarily set according to the shape and size of the bearing unit, the purpose of use, and the use environment, there is no particular numerical limitation here.

  Moreover, as a formation method of the recessed part 20, it is possible to apply various formation methods currently known, such as forging and turning, for example. In addition, after forming the recessed part 20 with this formation method, it is preferable to heat-process (for example, induction hardening) to the said recessed part 20 and its peripheral region. As a result, the strength of the concave portion 20 and its peripheral region can be improved, so that the static strength of the entire stationary ring (outer ring) 2 can be improved by forming the concave portion 20.

  As described above, according to the present embodiment, the recess 20 having a part of the inner ring 2m of the stationary ring (outer ring) 2 that is recessed from the other part is formed. The (outer ring) 2 can be reduced in weight, and as a result, the entire bearing unit can be reduced in weight. In addition to this, the recess 20 is set so as to satisfy the relationship of “diameter φY of the inner peripheral surface 2 m <diameter φX of the recess 20 ≦ diameter φD of the raceway groove 2 s”, thereby making the rigidity of the entire bearing constant. The weight can be reduced while maintaining. As a result, the axle rigidity can be maintained while reducing the unsprung weight of the vehicle, so that the running performance of the vehicle can be improved. In addition, the vehicle weight is reduced, which can contribute to lower fuel consumption.

  Furthermore, as a method for forming the recess 20, since a currently known method such as forging or turning can be used as it is, it does not require time and labor as compared with the conventional method. Cost can be reduced. As a result, an increase in manufacturing cost of the entire bearing unit can be suppressed.

  Further, since the outer diameter shape of the stationary ring (outer ring) 2 is determined by the restriction due to the parts to be assembled thereto, it is desired to avoid changing the shape arbitrarily. However, according to the present embodiment, the concave portion 20 for reducing the weight can be formed on the inner peripheral surface 2m of the stationary ring (outer ring) 2, so that the outer diameter shape of the stationary ring (outer ring) 2 is changed. Therefore, the weight of the bearing unit can be reduced.

  In the above-described embodiment, the concave portion 20 (FIG. 1) having a substantially rectangular cross section is illustrated, but the present invention is not limited to this. For example, the concave portion 20 having a substantially circular cross section (FIG. 2 (a)), Alternatively, a recess 20 having a substantially elliptical cross section (FIG. 2B), a recess 20 having a substantially triangular cross section (FIG. 3A), and a recess 20 having a substantially dovetail cross section (FIG. 3B). Even if it is applied, the same effect can be realized.

  Moreover, although the recessed part 20 in the structural example (FIGS. 1-3) mentioned above was comprised as one recessed part 20 continued along the inner peripheral surface 2m of the stationary ring (outer ring) 2, it is limited to this. For example, a plurality of recesses 20 may be formed between the two rows of raceway grooves 2s. In this case, the respective concave portions 20 may be formed in parallel, or may be formed so as to cross each other.

  Further, instead of continuously forming the recess 20, it may be formed intermittently at predetermined intervals along the inner peripheral surface 2 m of the stationary ring (outer ring) 2. In this case, the shape of each recess 20 can be arbitrarily set, such as a circle, an ellipse, a triangle, and a rectangle, and the size of each recess 20 can also be set arbitrarily. In this case, as arrangement | positioning of each recessed part 20, you may align along 2 m of inner peripheral surfaces, and may arrange | position so that it may cross | intersect. Moreover, you may arrange irregularly.

  In the above-described configuration example (FIGS. 1 to 3), the outer ring 2 is a stationary wheel and the inner ring 4 is a rotating wheel. Conversely, the outer ring 2 is a rotating wheel and the inner ring 4 is a stationary wheel. Even if configured, the same effect as that of the above-described embodiment can be realized by forming the same recess 20. In this case, FIGS. 1 to 3 show the bearing unit for the driven wheel, but the same effect can be obtained by applying the same configuration as that of the above-described embodiment to the bearing unit for the driving wheel. Can be realized.

  In the above-described configuration example (FIGS. 1 to 3), it is assumed that the recess 20 is formed on the inner peripheral surface 2m of the stationary wheel (outer ring) 2, but the present invention is not limited to this. A similar concave portion may be formed on the outer peripheral surface 4m of the inner ring 4, or concave portions may be formed on the inner peripheral surface 2 m and the outer peripheral surface 4 m of both the outer inner rings 2 and 4. As a result, it is possible to realize a low-cost bearing unit that can be reduced in weight while maintaining the rigidity of the entire bearing constant.

(a) is sectional drawing which shows the structure of the bearing unit which concerns on one embodiment of this invention, (b) expands and shows a part of stationary ring (outer ring) shown to the figure (a). Sectional drawing. (a) is sectional drawing which shows the structure of the bearing unit in which the recessed part of cross-sectional substantially circular shape was formed in the internal peripheral surface of a stationary ring (outer ring), (b) is a cross section in the internal peripheral surface of a stationary ring (outer ring) Sectional drawing which shows the structure of the bearing unit in which the substantially elliptical recessed part was formed. (a) is sectional drawing which shows the structure of the bearing unit in which the recessed part of the substantially triangular cross section was formed in the internal peripheral surface of a stationary ring (outer ring), (b) is a cross section in the internal peripheral surface of a stationary ring (outer ring) Sectional drawing which shows the structure of the bearing unit in which the substantially dovetail-shaped recessed part was formed.

Explanation of symbols

2 Outer ring 2 m Outer ring inner circumferential surface 2 s Outer ring raceway groove 4 Inner ring 4 m Inner ring outer circumferential surface 4 s Inner ring raceway groove
6,8 Rolling element 20 Recess

Claims (4)

An outer ring in which double row raceway grooves are formed on the inner peripheral surface, an inner ring in which double row raceway grooves are formed on the outer peripheral surface so as to face each raceway groove of the outer ring, and an outer inner ring disposed so as to be relatively rotatable. A plurality of rolling elements incorporated in a freely rolling manner between the raceway grooves, and either one of the outer ring and the inner ring is fixed to the vehicle body side and is maintained in a non-rotating state at all times, and the other is connected to the wheel side. A bearing unit that rotates with the wheel,
Of the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, at least the inner peripheral surface of the outer ring is formed with a recess in which at least a part of the surface is recessed from the surface of other parts between the double row raceway grooves. A bearing unit characterized by being made. If the diameter of the recess of the outer ring is φX, the diameter of the raceway groove of the outer ring is φD, and the diameter of the inner peripheral surface of the outer ring is φY,
The recess is φY <φX ≦ φD
The bearing unit according to claim 1, wherein the bearing unit is formed so as to satisfy the following relationship.   The bearing unit according to claim 1, wherein the recess is formed continuously along the inner peripheral surface of the outer ring. The bearing unit according to claim 1, wherein the recess is intermittently formed along the inner peripheral surface of the outer ring.

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