Storage device for vehicle wheel and vehicle

Abstract

A wheel bearing device is provided that makes it possible to prevent weight increase while suppressing the generation of abnormal noise. In a wheel bearing device 1, a ratio of an axial length C of a depressed portion 3h formed in a through hole 3e of a hub ring 3 to a pitch diameter A of the depressed portion 3h formed in an inner peripheral surface of the hub ring 3 is 0.7 ≤ (C / A) ≤ 1.07; a ratio of an axial distance E between a flange surface 3j of a wheel mounting flange 3b and an inner end surface 4b of an inner ring 4 to a ball pitch F between an inner ball row 5 and an outer ball row 6 is 2.85 ≤ (E / F); and a ratio of the axial distance E to a pitch diameter D of balls 8 is 0.8 ≤ (E / D) ≤ 0.94.

Description

Technical FieldThe present invention relates to a bearing device for a vehicle wheel and a vehicle.Prior ArtConventionally, as disclosed in Patent Literature 1, a bearing device for a vehicle wheel is known, which includes a bearing for a vehicle wheel rotatably supporting a vehicle wheel in a suspension of an automobile or the like, and a constant velocity joint coupled to the bearing for a vehicle wheel to be able to transmit torque. In such a bearing device for a vehicle wheel, an outer joint member of the constant velocity joint is fixed to an inner diameter portion of a hub ring constituting the bearing for a vehicle wheel with spline connection, whereby the bearing for a vehicle wheel and the constant velocity joint are coupled.The driving force from a driving source of a vehicle is input to the constant velocity joint. In recent years, there are more and more electric vehicles with electric motors besides vehicles with internal combustion engines.Since the driving torque of the motor in the electric vehicle is immediately input to the constant velocity joint compared to the driving torque of the internal combustion engine, relative slip occurs rapidly between the inner ring of the bearing for a vehicle wheel and the abutting surface of the constant velocity joint with respect to the inner ring, and unusual noise may occur due to slidebacks, which are generally referred to as quieting noise or justification noise.List of Citer ListsPatent LiteraturePatent Literature 1: JP-B 3650746 GazetteSUMMARY OF THE INVENTIONTechnical ProblemsIn order to suppress the occurrence of unusual noises due to slip between the bearing for a vehicle wheel and the above-described constant velocity joint, grease is applied between the inner ring of the bearing for a vehicle wheel and the contact surface of the constant velocity joint with respect to the inner ring, a lubricant is applied to the contact surface of the constant velocity joint with respect to the inner ring, or a plate coated with a low friction coating agent is interposed between the inner ring of the bearing for a vehicle wheel and the contact surface of the constant velocity joint with respect to the inner ring. However, it has been difficult to sufficiently suppress the occurrence of unusual noises due to the driving torque momentarily applied from the motor.In order to suppress the occurrence of unusual noises due to slippage between the bearing for a vehicle wheel and the constant velocity joint, it is also conceivable to increase the fitting diameter of the spline fit between the bearing for a vehicle wheel and the constant velocity joint according to the magnitude of the driving torque applied to the constant velocity joint. However, there is a problem that simply increasing the fitting diameter between the bearing for a vehicle wheel and the constant velocity joint results in an increase in the weight of the bearing for a vehicle wheel and the constant velocity joint.The present invention has been made in view of the above-mentioned circumstances. The present invention provides a bearing device for a vehicle wheel and a vehicle, which is capable of suppressing weight increase while suppressing the occurrence of unusual sounds.Solution of the ProblemsA bearing device for a vehicle wheel, comprising a bearing for a vehicle wheel comprising an outer member, an inner member, and double row rolling elements, the outer member comprising double row outer raceway surfaces on an inner periphery, the inner member comprising a hub ring and at least one inner ring, the hub ring comprising a vehicle wheel mounting flange for mounting a vehicle wheel on an end portion in an axial direction, comprising a small diameter step portion extending in the axial direction on an outer periphery, and comprising a through hole penetrating in the axial direction into an inner diameter portion, wherein at least one inner ring is press-fitted into the small diameter step portion of the hub ring, wherein the inner member has double row inner raceway surfaces facing the double row outer raceway surfaces, wherein the double-row rolling elements are rollably received between the outer raceway surfaces of the outer member and the inner raceway surfaces of the inner member; and a constant velocity joint having a fitting portion fittable into the through hole of the hub ring, wherein an inner circumferential surface of the through hole of the hub ring is provided with recesses extending along the axial direction, an outer circumferential surface of the fitting portion in the constant velocity joint is provided with protrusions extending along the axial direction and spline-fitted into the recesses, a ratio of an axial length C of the recesses to a pitch circle diameter A of the recesses satisfies 0.7≤(C / A)≤1.07, a ratio of an axial distance E between a flange surface of the vehicle wheel mounting flange and the other axial end surface of the inner ring to a rolling element distance F between a rolling element of the double row rolling elements on one axial side and a rolling element of the double row rolling elements on the other axial side in the double row rolling elements satisfies 2.85≤(E / F), and a ratio of the axial distance E to a pitch circle diameter D of the double row rolling elements satisfies 0.8≤(E / D)≤0.94.Advantageous Effects of the InventionThe present invention can suppress weight increase and at the same time suppress the occurrence of unusual sounds.Brief Description of the DrawingsFIG. 1 is a side sectional view showing a bearing device for a vehicle wheel. FIG. 2 is a side sectional view showing a shaft hole of a hub ring and a shaft portion of an outer joint member. FIG. 3 is an axial sectional view showing recesses in the shaft hole of the hub ring and protrusions of the shaft portion. FIG. 4 is a side sectional view showing a bearing device for a vehicle wheel in a state where a shaft is pivoted by a maximum angle. FIG. 5 is a side sectional view showing a bearing device for a vehicle wheel according to a second embodiment. FIG. 6 is a side sectional view showing a bearing device for a vehicle wheel according to a third embodiment. FIG. 7 is a side sectional view showing a bearing device for a vehicle wheel according to a fourth embodiment.DESCRIPTION OF THE EMBODIMENTSHereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.[Bearing Device for Vehicle Wheel]A bearing device for a vehicle wheel 1 illustrated in FIG. 1 is an embodiment of a bearing device for a vehicle wheel according to the present invention, which includes a bearing for a vehicle wheel 10 and a constant velocity joint 20.In the following description, an axial direction refers to a direction along a rotation axis X of the bearing for a vehicle wheel 10. an outer side refers to one side in the axial direction and the vehicle wheel side of the bearing device for a vehicle wheel 1 when the bearing device for a vehicle wheel is mounted on a vehicle body, and an inner side refers to the other side in the axial direction and the vehicle body side of the bearing device for a vehicle wheel 1 when the bearing device for a vehicle wheel is mounted on a vehicle body.(Bearing for Vehicle Wheel)The bearing for a vehicle wheel 10 rotatably supports a vehicle wheel in a suspension of a vehicle, for example, a car. The bearing for a vehicle wheel 10 includes an outer ring 2 that is an outer member, a hub ring 3 and an inner ring 4 that are inner members, two rows of an inner-side ball row 5 and an outer-side ball row 6 that are rolling rows, an inner-side seal member 9A, and an outer-side seal member 9B.An inner side end portion of the outer ring 2 is provided with an inner side opening 2 ainto which the inner side seal member 9A can be inserted. An outer side end portion of the outer ring 2 is provided with an outer side opening 2 binto which the outer side seal member 9B can be inserted.An opening end on the inside of an annular space 15 formed by the outer ring 2 and the inner member is closed by the inside seal member 9A inserted into the inside opening 2 a. An opening end on the outside of the annular space 15 is closed by the outside seal member 9B inserted into the outside opening 2 b.The inner circumferential surface of the outer ring 2 is formed with an outer raceway surface 2 con the inner side and an outer raceway surface 2 don the outer side. An outer peripheral surface 20 of the outer ring 2 is integrally formed with a vehicle body mounting flange 2 efor mounting the outer ring 2 to a vehicle body side member (knuckle). The vehicle body mounting flange 2 eis provided with a bolt hole 2 fthrough which a fastening member for fastening the vehicle body side member and the outer ring 2 is to be inserted.At an inner side end portion of the outer circumferential surface 30 of the hub ring 3, a small diameter step portion 3a, whose diameter decreases from the outer side end portion and which extends in the axial direction, is formed. An outer side end portion of the hub ring 3 is integrally formed with a vehicle wheel mounting flange 3 bto mount a vehicle wheel. The vehicle wheel mounting flange 3 bis provided with a bolt hole 3 finto which a boss bolt 3 gis to be press-fitted.The vehicle wheel mounting flange 3 bhas a flange surface 3 j, against which a brake disc to be mounted on the vehicle wheel mounting flange 3 b abuts.The flange surface 3 jis a surface on the outside of the vehicle wheel mounting flange 3 b.The hub ring 3 is provided with an inner raceway surface 3 con the outer side so as to be opposed to the outer raceway surface 2 don the outer side of the outer ring 2. In the hub ring 3, a lip sliding surface 3 dis formed on a base side of the vehicle wheel mounting flange 3 bto which the outside seal member 9B is in sliding contact.An inner diameter portion of the hub ring 3 is provided with a shaft hole 3 eformed along the axial direction and to which the constant velocity joint 20 is coupled. The shaft hole 3 efiltrates through the hub ring 3 in the axial direction. The shaft hole 3 eis an example of a through hole. The inner ring 4 is press-fitted into the small-diameter step portion 3 aof the hub ring 3. The inner ring 4 has an inner-side end surface 4 bat its inner end portion. The inner-side end surface 4 bis an example of the other axial end surface of the inner ring.An outer circumferential surface of the inner ring 4 is formed with an inner raceway surface 4 a. That is, the inner ring 4 forms the inner raceway surface 4 aon the inner side of the hub ring 3.The inside ball row 5 and the outside ball row 6, which are rolling rows, are constituted by a plurality of balls 7, which are rolling elements and are held by a cage 8. The inner-side ball row 5 is rollably sandwiched between the inner raceway surface 4 aof the inner ring 4 and the outer raceway surface 2 con the inner side of the outer ring 2. The outer-side ball row 6 is rollably clamped between the inner raceway surface 3 cof the hub ring 3 and the outer raceway surface 2 don the outer side of the outer ring 2. The inner ring 4 applies a preload to the inner-side ball row 5 and the outer-side ball row 6, which are rolling rows.The outer ring 2, the hub ring 3, and the inner ring 4, the inner-side ball row 5, and the outer-side ball row 6 form a double-row angular contact ball bearing in the bearing for a vehicle wheel 10.(Constant Velocity Constant Velocity Constant Velocity Universal Joint)The constant velocity constant velocity constant velocity joint 20 includes an outer joint member 21 in which a track groove 25 is formed on the inner circumferential surface, an inner joint member 22 in which a track groove 22 afacing the track groove 25 is formed on the outer circumferential surface, a ball 23 installed between the track groove 25 and the track groove 22 a, and a cage 24 disposed between the inner circumferential surface of the outer joint member 21 and the outer circumferential surface of the inner joint member 22 to hold the ball 23.The outer joint member 21 includes a mouth portion 26 that receives internal components including the inner joint member 22, the ball 23, and the cage 24, and a shaft portion 27 that integrally extends from the mouth portion 26 in the axial direction toward the outside. The mouth portion 26 has a contact surface 26 athat abuts on the inner-side end surface 4 bof the inner ring 4 at the outer-side end portion.An axial end of the shaft 31 to which a driving force from a driving source such as a motor or an engine is to be transmitted is press-fitted into the inner joint member 22. The inner joint member 22 and the shaft 31 are coupled so as to be able to transmit torque through spline fitting.The mouth portion 26 of the outer joint member 21 supports the shaft 31 via the inner joint member 22, the ball 23, and the cage 24 swingably with respect to the rotation axis X.[Fitting Structure Between Hub Ring and Shaft Portion]As shown in FIGS. 2 and 3, the inner circumferential surface of the shaft hole 3 eof the hub ring 3 is provided with a recess 3 hextending along the axial direction. A plurality of recesses 3h are formed along a circumferential direction. The outer circumferential surface of the shaft portion 27 of the outer joint member 21 is provided with a protrusion 28 extending along the axial direction and splined to the recess 3 h. A plurality of protrusions 28 are formed along the circumferential direction. The plurality of recesses 3h formed along the circumferential direction form female spline, and the plurality of protrusions 28 formed along the circumferential direction form male spline. The shaft portion 27 of the outer joint member 21 is an example of a fitting portion that can be inserted into the through hole of the hub ring.The recess 3 hof the shaft hole 3 emay be formed to have a smaller diameter than the protrusion 28 of the shaft portion 27. in this case, the recess 3 hhas a fastening tolerance n with respect to the protrusion 28, and the protrusion 28 is press-fitted.The shaft portion 27 has an externally threaded portion 27 aon the outside of the protrusion 28, and the hub ring 3 and the outer joint member 21 are fixed in a state where the shaft portion 27 is inserted into the shaft hole 3 eby screwing a nut 41 onto the externally threaded portion 27 a. By screwing the nut 41 onto the male threaded portion 27 a, the inner ring 4 can be pressed in the axial direction against the abutment surface 26 aof the outer joint member 21, and a preload can be applied to the inner-side ball row 5 and the outer-side ball row 6.When the shaft portion 27 is moved from the inside to the outside of the shaft hole 3 ewhen the shaft portion 27 is inserted into the shaft hole 3 e, the protrusion 28 is press-fitted into the recess 3 hbecause the recess 3 his smaller diameter than the protrusion 28 and has the fitting tolerance n for the protrusion 28.When the protrusion 28 is press-fitted into the recess 3 h, the inner circumferential surface of the recess 3 his easily cut by the protrusion 28, and the shape of the protrusion 28 is transferred to the inner circumferential surface of the recess 3 h, which is accompanied with easy plastic and elastic deformation.In a state where the protrusion 28 is press-fitted into the recess 3 h, a fitting contact portion Y (see FIG. 1 ) is formed between the spline-fitted recess 3 hand the protrusion 28. In the fitting contact portion Y, the outer circumferential surface of the protrusion 28 and the inner circumferential surface of the recess 3 hare in close contact with each other as a whole.In this way, the recess 3 his spline-fitted to the protrusion 28 with the fitting tolerance n, and the spline-fitted recess 3 hand the protrusion 28 are in close contact with each other in the axial direction as a whole. Since the protrusion 28 and the recess 3 htogether are in close contact with each other at the fitting contact portion Y, the allowable torque at the fitting contact portion Y can be increased and the axial length of the fitting contact portion Y can be shortened to reduce the weight of the bearing for a vehicle wheel 10.[Relationship between Dimensions of Each Portion in Bearing Device for Vehicle Wheels]In the bearing device for a vehicle wheel 1, the pitch diameter of the spline shaft formed by the recesses 3 hand the protrusions 28 matched with each other is A. The pitch diameter A of the spline shaft is also the pitch diameter A of the recesses 3 hand the pitch diameter A of the protrusions 28.The axial length of the protrusions 28 in the shaft portion 27 is B, and the axial length of the recesses 3 hin the axial hole 3 eis C. The axial distance between the flange surface 3 jof the vehicle wheel mounting flange 3 band the inner side end surface 4 bof the inner ring 4 is E.The pitch circle diameter of the balls 8 constituting the inner side ball row 5 and the pitch circle diameter of the balls 8 constituting the outer side ball row 6 are the same, and the pitch circle diameter of the balls 8 constituting the inner side ball row 5 and the outer side ball row 6 is D. The pitch circle diameter D is the diameter of a circle whose center is the rotation axis X and which passes through the centers P of the balls 8 in the inner side ball rows 5 and 6. The pitch circle diameter D of the balls 8 is an example of the pitch circle diameter D of a rolling element.The balls 8 constituting the inner side ball row 5 and the balls 8 constituting the outer side ball row 6 are arranged so that the distance between the balls in the axial direction is F. The ball pitch F is a pitch in the axial direction between the center P of the balls 8 in the inner side ball row 5 and the center P of the balls 8 in the outer side ball row 6.In the bearing device for a vehicle wheel 1, the ratio of the axial length C of the recesses 3 hto the pitch circle diameter A of the recesses 3 his set so as to satisfy 0.7≤(C / A)≤1.07.In the conventional bearing device for a vehicle wheel, the ratio of the axial length B of the protrusions 28 to the pitch diameter A of the recesses 3 his about 1.1≤(B / A)≤1.9, and the ratio of the axial length C of the recesses 3 hto the pitch diameter A of the recesses 3 his about 1.25≤(C / A)≤1.8.On the other hand, in the bearing device for a vehicle wheel 1 in which the ratio of the axial length C of the recesses 3 hto the pitch circle diameter A of the recesses 3 his 0.7≤(C / A)≤1.07 as in the present embodiment, the diameters of the shaft hole 3 ehaving the recesses 3 hand the shaft portion 27 having the protrusions 28 are formed larger, and the axial length C of the recesses 3 hand the axial length B of the protrusions 28 are formed smaller than in the conventional bearing device for a vehicle wheel.The protrusions 28 of the shaft portion 27 are twisted in the rotational direction when the driving torque is applied to the constant velocity joint 20, but the degree of twist of the protrusions 28 increases as the length of the shaft portion 27 increases, and thus the degree of twist is proportional to the axial length B of the protrusions 28.When the driving torque is applied to the constant velocity joint 20, relative slip occurs in the rotational direction between the inner side end surface 4 bof the inner ring 4 in the bearing for a vehicle wheel 10 and the abutment surface 26 aof the mouth portion 26 in the constant velocity joint 20. In this case, the amount of relative slip between the inner side end surface 4 bof the inner ring 4 and the abutment surface 26 aof the mouth portion 26 decreases as the degree of rotation of the protrusions 28 in the shaft portion 27 decreases.By making the diameter of the shaft portion 27 large and making the axial length C of the recesses 3 h small and setting the ratio of the axial length C of the recesses 3 hto the pitch circle diameter A of the recesses 3 hin the range of 0.7≤(C / A)≤1.07, the amount of relative slip between the inner-side end surface 4 band the abutment surface 26 aof the orifice portion 26 can be reduced and the occurrence of unusual sounds due to slide jerks can be suppressed.At this time, a rotation angle of about 10 to 30 minutes with respect to the axial direction is normally applied to the protrusions 28 of the shaft portion 27 to prevent rattle upon spline fitting into the recesses 3h of the hub ring 3. Thus, in the conventional bearing device for a vehicle wheel, there is a portion having a gap between the spline fitting protrusions 28 and the recesses 3 h. For example, when the surface on one rotational side at one axial end portion of the protrusion 28 is in contact with the recess 3 h, there is a gap between the surface on one rotational side and the recess 3 hat the other axial end portion of the protrusion 28.In addition, since the rotational direction of the protrusions 28 is unified in the same type of bearing device for a vehicle wheel 1, when the bearing device for a vehicle wheel 1 is used for left and right vehicle wheels in a vehicle, the rotational direction of the protrusions 28 and the direction of the driving torque to be applied to the shaft portion 27 are different between the left and right vehicle wheels.As a result, the amount of relative slip in the rotational direction between the inner side end surface 4 bof the inner ring 4 and the abutment surface 26 aof the mouth portion 26 when the driving torque is applied to the shaft portion 27 is greatly different between the left and right vehicle wheels, and the possibility that the unusual sound due to the slip occurs in the vehicle wheel on the side where the amount of slip is large increases.However, in the bearing device for a vehicle wheel 1, the ratio of the axial length C of the recesses 3 hto the pitch diameter A of the recesses 3 his set in the range of 0.7≤(C / A)≤1.07, and the amount of relative slip in the rotational direction between the inner-side end surface 4 band the abutment surface 26 aof the orifice portion 26 is suppressed to a small value. Thus, it is possible to suppress the occurrence of unusual noises due to slip even in a vehicle wheel having a large slip.In addition, when the diameter of the shaft portion 27 is increased to make the pitch circle diameter A of the protrusions 28 large, the stress applied to the tooth surfaces of the protrusions 28 and the recesses 3 hwhen the driving torque is applied to the shaft portion 27 is reduced. Thus, the axial length B of the protrusions 28 and the axial length C of the recesses 3 hcan be made small to reduce the axial length of the bearing for a vehicle wheel 10.Thus, in the bearing device for a vehicle wheel 1, the ball clearance F is made small, so that the ratio of an axial clearance E between the flange surface 3 jand the inner-side end surface 4 bto the ball clearance F SATISFIES 2.85≤(E / F), and the axial length of the bearing for a vehicle wheel 10 is reduced. The weight of the bearing for a vehicle wheel 10 can be reduced by reducing the axial length of the bearing for a vehicle wheel 10 in this way.In addition, in the bearing device for a vehicle wheel 1, the axial distance E is made small, so that the ratio of the axial distance E between the flange surface 3 jand the inner-side end surface 4 bto the pitch circle diameter D of the balls 8 satisfies 0.8≤(E / D)≤0.94, and the axial length of the bearing for a vehicle wheel 10 is reduced. By thus reducing the axial length of the vehicle wheel bearing 10, the weight of the vehicle wheel bearing 10 can be reduced.In this way, in the bearing device for a vehicle wheel 1, weight gain can be suppressed while suppressing the occurrence of unusual noises due to slide-backs by setting the ratio of the axial length C of the recesses 3 hto the pitch diameter A of the recesses 3 hin the range of 0.7≤(C / A)≤1.07, setting the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the ball distance F in the range of 2.85≤(E / F), and setting the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the pitch diameter D of the balls 8 in the range of 0.8≤(E / D)≤0.94.Further, in the bearing device for a vehicle wheel 1, the recesses 3 hand the protrusions 28 spline-connected to each other are connected to each other in a state having the fastening allowance n, and they are closely contacted to each other as a whole in the axial direction. Thus, the bearing device for a vehicle wheel has improved withstanding voltage against the driving torque to be applied to the shaft portion 27, as compared with a case where the recesses and the protrusions are spline-connected to each other in a state of not being in close contact with each other as a whole.Thus, it is possible to reduce the axial length of the bearing for a vehicle wheel 10 by making the axial length B of the protrusions 28 so small that the ratio of the axial length B of the protrusions 28 to the pitch circle diameter A of the recesses 3 his 0.32≤(B / A)≤0.6. The weight of the bearing for a vehicle wheel 10 can be reduced by reducing the axial length of the bearing for a vehicle wheel 10 in this way.In the bearing device for a vehicle wheel 1, even when the spline recesses 3 hand protrusions 28 are not in close contact with each other as a whole, weight increase can be suppressed while the occurrence of unusual noises due to slideback is suppressed by setting the ratio of the axial length C of the recesses 3 hto the pitch circle diameter A of the recesses 3 hin the range of 0.7≤(C / A)≤1.07, the ratio of the axial distance E between the flange surface 3 jand the inside end surface 4 bto the ball distance F is set in the range of 2.85≤(E / F), and the ratio of the axial distance E between the flange surface 3 jand the inside end surface 4 bto the pitch circle diameter D of the ball 8 is set in the range of 0.8≤(E / D)≤0.94.In the bearing device for a vehicle wheel 1, the shaft diameter of the shaft 31 in the constant velocity joint 20 is G. As illustrated in FIG. 4, the shaft 31 can pivot with respect to the mouth portion 26 within a range R in which the shaft 31 comes into contact with the mouth portion 26, and when the shaft 31 is pivoted by a maximum angle with respect to the mouth portion 26, a contact point 31 aof the shaft 31 comes into contact with the mouth portion 26. The shaft diameter G is a shaft diameter of a portion including the contact point 31 aof the shaft 31, and is a minimum shaft diameter of the shaft 31.The size of the shaft portion 27 of the constant velocity joint 20 and the shaft diameter G of the shaft 31 are preferably determined according to the size of the driving torque to be applied from the driving source such as a motor, but in the constant velocity joint 20 spline-fitted to the bearing for a vehicle wheel 10, the pitch diameter A of the protrusions 28 in the shaft portion 27 and the shaft diameter G of the shaft 31 are set so that the ratio of the pitch diameter A of the protrusions 28 to the shaft diameter G satisfies the condition 1.1≤(A / G)≤1.41.Thereby, it is possible to secure the shaft diameter G of the shaft 31 required in the bearing device for a vehicle wheel 1, and it is possible to secure a safety factor with respect to the driving torque to be applied to the constant velocity joint 20 and secure the torsional rigidity of the shaft 31.[Second Embodiment of Bearing Device for Vehicle Wheel]The bearing device for a vehicle wheel 1 may also be configured like a bearing device for a vehicle wheel 1A according to a second embodiment. As illustrated in FIG. 5, the bearing device for a vehicle wheel 1A is different from the bearing device for a vehicle wheel 1 in that a bearing for a vehicle wheel 10A having a hub ring 3A is provided instead of the bearing for a vehicle wheel 10 having the hub ring 3.In the bearing for a vehicle wheel 10A, the inner ring 4 press-fitted into the small-diameter step portion 3 aof the hub ring 3A is fixed by crimping with the hub ring 3A, and the hub ring 3A has a crimping portion 3 kfor crimping the inner-side end surface 4 bof the inner ring 4. The inner ring 4 is crimped by the crimping portion 3 k, thereby applying a preload to the inner-side ball row 5 and the outer-side ball row 6.In the bearing for a vehicle wheel 10A, the crimping portion 3 kof the hub ring 3A and the abutting surface 26 aof the mouth portion 26 are in contact with each other. Since the other configurations of the bearing for a vehicle wheel 10A and the hub ring 3A are the same as those of the bearing for a vehicle wheel 10 and the hub ring 3, the same reference numerals are given, and description thereof is omitted.In the configuration in which the inner ring 4 is crimped by the crimping portion 3 kas in the bearing for a vehicle wheel 10A, it is not necessary to apply a preload by pressing the inner ring 4 with the axial force generated when the nut 41 is screwed onto the male threaded portion 27 aof the shaft portion 27 because a preload is applied by crimping the inner ring 4.Therefore, it is not necessary to generate a large axial force when the nut 41 is screwed on the male threaded portion 27 a, and the abutting pressure between the crimping portion 3 kof the hub ring 3A and the abutting surface 26 aof the mouth portion 26 can be reduced. By reducing the abutting pressure between the crimping portion 3 kand the abutting surface 26 a, occurrence of slideback between the crimping portion 3 kand the abutting surface 26 ais suppressed, and occurrence of abnormal noise due to slideback can be suppressed.Also in the bearing device for a vehicle wheel 1A, the ratio of the axial length C of the recesses 3 hto the pitch diameter A of the recesses 3 hmay be set in the range of 0.7≤(C / A)≤1.07, the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the ball distance F may be set in the range of 2.85≤(E / F), and the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the pitch diameter D of the balls 8 may be set in the range of 0.8≤(E / D)≤0.94. Thereby, an increase in weight can be suppressed, and at the same time, occurrence of unusual sounds due to slide-back can be further suppressed.Also in the bearing device for a vehicle wheel 1A, the ratio of the axial length B of the protrusions 28 to the pitch circle diameter A of the recesses 3 hmay be set to satisfy 0.32≤(B / A)≤0.6. Thereby, an increase in the weight of the bearing for a vehicle wheel 10 can be avoided while avoiding the occurrence of unusual noises due to slide jerks.In addition, also in the bearing device for a vehicle wheel 1A, the ratio of the pitch diameter A of the protrusions 28 to the shaft diameter G may be set so as to satisfy 1.1≤(A / G)≤1.41. This can ensure a safety factor regarding the driving torque to be applied to the constant velocity joint 20 and ensure the torsional rigidity of the shaft 31, while further suppressing the occurrence of unusual noises due to slide-backs in the bearing device for a vehicle wheel 1A.[Third Embodiment of Bearing Device for Vehicle Wheel]The bearing device for a vehicle wheel 1A may also be configured like a bearing device for a vehicle wheel 1B according to a third embodiment. As seen in FIG. 6, the bearing device for a vehicle wheel 1B is different from the bearing device for a vehicle wheel 1A in that, instead of the bearing for a vehicle wheel 10A having the hub ring 3A, a bearing for a vehicle wheel 10B having a hub ring 3B is disposed.The hub ring 3B is different from the hub ring 3A in that, instead of the vehicle wheel mounting flange 3 bhaving the bolt hole 3 f, a vehicle wheel mounting flange 3 mhaving a bolt hole 3 nis disposed. The screw hole 3 nis a hole into which a wheel bolt for fastening a wheel and a brake disk to be mounted on the vehicle wheel mounting flange 3 mis to be screwed. The thickness of the vehicle wheel mounting flange 3m in the axial direction is H.In the bearing for a vehicle wheel 10B, the hub ring 3B includes the vehicle wheel mounting flange 3 mwith the bolt hole 3 ninto which the wheel bolt is to be screwed, instead of the vehicle wheel mounting flange 3 bwith the bolt hole 3 finto which the hub bolt 3 gis to be press-fitted. Thus, the diameter of the outer ring 2 can be increased. With this configuration, when the axial length of the bearing for a vehicle wheel 10B is reduced, the outer diameter of the outer ring 2 can be increased to ensure durability of the bearing for a vehicle wheel 10B.Since the other configurations of the bearing for a vehicle wheel 10B and the hub ring 3B are the same as those of the bearing for a vehicle wheel 10A and the hub ring 3A, the same reference numerals are given and the description thereof is omitted.In the bearing device for a vehicle wheel 1B, the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the thickness H of the vehicle wheel mounting flange 3 min the axial direction is set so as to satisfy 4.5≤(E / H)≤5.6. With this setting, the thickness H of the vehicle wheel mounting flange 3 mcan be secured even when the axial distance E in the bearing device for a vehicle wheel 1B is set small.Also in the bearing device for a vehicle wheel 1B, the ratio of the axial length C of the recesses 3 hto the pitch diameter A of the recesses 3 hmay be set in the range of 0.7≤(C / A)≤1.07, the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the ball distance F may be set in the range of 2.85≤(E / F), and the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the pitch diameter D of the balls 8 may be set in the range of 0.8≤(E / D)≤0.94. Thereby, an increase in weight can be suppressed, and at the same time, occurrence of unusual sounds due to slide-back can be further suppressed.Also in the bearing device for a vehicle wheel 1B, the ratio of the axial length B of the protrusions 28 to the pitch circle diameter A of the recesses 3 hmay be set to satisfy 0.32≤(B / A)≤0.6. This can suppress an increase in weight of the bearing for a vehicle wheel 10 and at the same time suppress the occurrence of unusual sounds due to slideback.In addition, also in the bearing device for a vehicle wheel 1B, the ratio of the pitch diameter A of the protrusions 28 to the shaft diameter G may be set to satisfy 1.1≤(A / G)≤1.41. This can ensure a safety factor regarding the driving torque to be applied to the constant velocity joint 20 and ensure the torsional rigidity of the shaft 31 while further suppressing the occurrence of unusual noises due to slide-backs in the bearing device for a vehicle wheel 1B.[Fourth Embodiment of Bearing Device for Vehicle Wheel]The bearing device for a vehicle wheel 1B may also be configured like a bearing device for a vehicle wheel 1C according to a fourth embodiment. As illustrated in FIG. 7, the bearing device for a vehicle wheel 1C is different from the bearing device for a vehicle wheel 1B in that a constant velocity joint 20A having a shaft portion 27A is disposed instead of the constant velocity joint 20 having the shaft portion 27.The shaft portion 27A includes an internally threaded portion 27 bformed from the outer side toward the inner side, and the hub ring 3B and the constant velocity joint 20A are fixed in a state where the shaft portion 27A is fitted into the shaft hole 3 eby screwing a bolt 42 into the internally threaded portion 27 b. Thereby, the bearing for a vehicle wheel 10B and the constant velocity joint 20A are fixed.A locking surface 3 p, which is a surface perpendicular to the rotation axis X serving as an axis of the shaft hole 3 e, is formed at the outer end portion of the shaft hole 3 eof the hub ring 3B. In the present embodiment, the bolt 42 is locked to the locking surface 3 pof the hub ring 3B via a washer 43, but the bolt 42 may be directly locked to the locking surface 3 pwithout interposing the washer 43 as long as the necessary axial force is obtained when the bolt 42 is screwed into the female threaded portion 27 b.In the present embodiment, since the locking surface 3 pis formed on a surface perpendicular to the axis of the shaft hole 3 e, it is possible to obtain the required axial force when the bolt 42 is screwed into the female threaded portion 27 b, and it is possible to stably maintain the fixed state between the bearing for a vehicle wheel 10B and the constant velocity joint 20A.Since other configurations of the constant velocity joint 20A and the shaft portion 27A are the same as those of the constant velocity joint 20 and the shaft portion 27, the same reference numerals are given and the description thereof is omitted.In the bearing device for a vehicle wheel 1C, the ratio of the axial distance E between the flange surface 3 jand the inner end surface 4 bto the thickness H of the vehicle wheel mounting flange 3 min the axial direction is set to be 4.5≤(E / H)≤5.6. With this configuration, the thickness H of the vehicle wheel mounting flange 3 mcan be secured even when the axial distance E in the bearing device for a vehicle wheel 1C is set small.Also in the bearing device for a vehicle wheel 1C, the ratio of the axial length C of the recesses 3 hto the pitch diameter A of the recesses 3 hmay be set in the range of 0.7≤(C / A)≤1.07, the ratio of the axial distance E between the flange surface 3 jand the inner-side end surface 4 bto the ball distance F may be set in the range of 2.85≤(E / F), and the ratio of the axial distance E between the flange surface 3 jand the inner-side end surface 4 bto the pitch diameter D of the balls 8 may be set in the range of 0.8≤(E / D)≤0.94. Thereby, an increase in weight can be suppressed while further suppressing the occurrence of abnormal noise due to slide jerks.Also in the bearing device for a vehicle wheel 1C, the ratio of the axial length B of the protrusions 28 to the pitch circle diameter A of the recesses 3 hmay be set to satisfy 0.32≤(B / A)≤0.6. This can suppress an increase in weight of the bearing for a vehicle wheel 10 and at the same time suppress the occurrence of abnormal noise due to slideback.In addition, also in the bearing device for a vehicle wheel 1C, the ratio of the pitch diameter A of the protrusions 28 to the shaft diameter G may be set to satisfy 1.1≤(A / G)≤1.41. This can ensure a safety factor regarding the driving torque to be applied to the constant velocity joint 20A and ensure the torsional rigidity of the shaft 31 while further suppressing the occurrence of unusual noises due to slide-backs in the bearing device for a vehicle wheel 1C.[Vehicle with Bearing Device for Vehicle Wheel]The bearing device for a vehicle wheel 1, 1A, 1B, or 1C can be used for a vehicle using an internal combustion engine, an engine, or the like as a drive source. In particular, the use of the bearing device for a vehicle wheel 1, 1A, 1B, or 1C in a vehicle in which a driving torque is immediately transmitted to the constant velocity joint 20 or 20A, such as an electric vehicle using a motor as a driving source, makes it possible to effectively suppress the occurrence of unusual sounds due to slide jerks, and at the same time, to suppress the weight increase of the bearing device for a vehicle wheel 1, 1A, 1B, or 1C.Moreover, as in the bearing device for a vehicle wheel 1, 1A, 1B, or 1C, by making the axial length of the bearing for a vehicle wheel 10, 10A, or 10B small, in the case of a front drive (FF) vehicle, for example, the pivot center of the constant velocity joint 20 or 20A on the vehicle wheel side is shifted further to the vehicle wheel side than in a conventional bearing device for a vehicle wheel, and it is possible to suppress the maximum angle of the constant velocity joint 20 or 20A in steering and suppress an increase in the minimum rotational radius of the vehicle.Although the embodiments of the present invention have been described above, the present invention is in no way limited to such embodiments, and the embodiments are merely examples. Needless to say, the present invention can be implemented in various forms without departing from the gist of the present invention. The scope of the present invention is indicated by the description of the claims and further includes the equivalent meaning and all changes within the scope of the claims.Industrial applicabilityThe present invention is applicable to a bearing device for a vehicle wheel.Reference Character List1, 1A, 1B, 1C Bearing device for vehicle wheel 2 Outer ring 2 c Äußere raceway surface (on the inner side) 2 d Äußere raceway surface (on the outer side) 3, 3A, 3B Hub ring 3 a Kleinem small diameter portion 3 b, 3 m Fahrzeugrad wheel mounting flange 3 c Innere raceway surface 3 e Shank hole 3 h Aussparung 3 j Flansch surface 3 k Crimp portion 3 nScrew hole 4 Inner ring 4 a Innere raceway surface 4 b Innere end surface 5 Innere ball row 6 Äußere ball row 7Ball 8 Cage 10, 10A, 10B Bearing for vehicle wheel 20, 20A constant velocity joint 27 Adhesion portion 28 Projection 31 Shaft A Pitch diameter B Axial length of projection C Axial length of recess D Pitch diameter of ball E Axial distance between flange surface and inner side end surface of inner ring F Pitch between balls G Shaft diameter of shaft H Thickness of flange in axial direction n Mounting toleranceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP-B 3650746

[0005]

Claims

A bearing device for a vehicle wheel, comprising: a bearing for a vehicle wheel comprising an outer member, an inner member, and double-row rolling elements, the outer member comprising double-row outer raceway surfaces on an inner periphery, the inner member comprising a hub ring and at least one inner ring, the hub ring comprising a vehicle wheel mounting flange for mounting a vehicle wheel on an end portion in an axial direction, comprising a small-diameter step portion extending in the axial direction on an outer periphery, and comprising a through hole penetrating in the axial direction into an inner diameter portion, wherein at least one inner ring is press-fitted into the small-diameter step portion of the hub ring, wherein the inner member has double-row inner raceway surfaces facing the double-row outer raceway surfaces, wherein the double-row rolling elements are rollably received between the outer raceway surfaces of the outer member and the inner raceway surfaces of the inner member; and a constant velocity joint having a fitting portion fittable into the through hole of the hub ring, wherein an inner circumferential surface of the through hole of the hub ring is provided with recesses extending along the axial direction, an outer circumferential surface of the fitting portion in the constant velocity joint is provided with protrusions extending along the axial direction and spline-fitted into the recesses, a ratio of an axial length C of the recesses to a pitch circle diameter A of the recesses satisfies 0.7≤(C / A)≤1.07, a ratio of an axial distance E between a flange surface of the vehicle wheel mounting flange and the other axial end surface of the inner ring to a rolling element distance F between a rolling element of the double row rolling elements on one axial side and a rolling element of the double row rolling elements on the other axial side in the double row rolling elements satisfies 2.85≤(E / F), and a ratio of the axial distance E to a pitch circle diameter D of the double row rolling elements satisfies 0.8≤(E / D)≤0.94.The bearing device for a vehicle wheel according to claim 1, wherein the hub ring includes a crimping portion for crimping the inner ring to the hub ring.The bearing device for a vehicle wheel according to claim 1, wherein the recesses and protrusions spline-connected to each other are in close contact with each other as a whole in the axial direction, and the ratio of an axial length B of the protrusions to the pitch diameter A of the recesses satisfies 0.32 ≤ (B / A) ≤ 0.6.The bearing device for a vehicle wheel according to claim 1, wherein the constant velocity joint includes a shaft to which a driving force is transmitted, the shaft being coupled to the fitting portion and capable of transmitting torque, and a ratio of the pitch diameter A of the protrusions to a shaft diameter G of the shaft satisfies 1.1≤(A / G)≤1.41.The bearing device for a vehicle wheel according to claim 1, wherein the vehicle wheel mounting flange has a plurality of bolt holes into which wheel bolts are to be screwed for fastening a wheel and a brake disk, and a ratio of the axial distance E to a thickness H of the vehicle wheel mounting flange in the axial direction satisfies 4.5≤(E / H)≤5.6.A vehicle, comprising: the bearing device for a vehicle wheel according to any one of claims 1 to 5; and a motor that generates a driving force, wherein the constant velocity joint includes a shaft to which the driving force from the motor is to be input, the shaft being coupled to the fitting portion and capable of transmitting torque.

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