JP4602363B2 - Bearing device for driven wheel - Google Patents

Description

  The present invention relates to a bearing device for a driven wheel that rotatably supports a driven wheel of a vehicle such as an automobile.

  A wheel bearing device that rotatably supports a wheel of an automobile has a structure in which a hub wheel is rotatably supported by a double-row bearing, and the hub wheel is fixed to the wheel and the fixed side of the bearing is fixed to the suspension device of the vehicle body. .

This wheel bearing device is roughly classified into a driven wheel and a driving wheel, and hub wheels having different shapes are used for the driven wheel and the driving wheel in order to satisfy the respective required functions. FIG. 13 shows a conventional example of a hub wheel 22 ′ for a driven wheel. As this type of hub wheel 22 ′, there are many solid wheels having a flange portion 25 ′ for mounting a wheel on the outer periphery of one end. in use.
Japanese Patent Laid-Open No. 9-220904

However, in the hub wheel for driven wheels of FIG. 13, the opening on the outboard side may be forged skin, which causes rusting and further aesthetic deterioration. In addition, since this hub wheel is solid, grinding heat tends to accumulate when grinding the raceway surface, etc., so the workpiece expands due to the influence of grinding heat, and the dimension after grinding is compared to the target dimension. Become smaller. This becomes a factor causing a processing error. In addition, depending on the shape, the temperature distribution of the grinding heat accumulated in the hub wheel may become non-uniform, which may lead to dimensional and shape defects.

  These indications are dealt with by means such as (1) slowing the cutting speed, (2) increasing the flow rate or pressure of the grinding fluid, (3) performing complex cutting control, etc. None of these means is decisive because it leads to longer cycle times and higher costs.

Then, an object of this invention is to prevent the rusting in the outboard side opening part of a hub ring. Another object of the present invention is to increase the processing accuracy by avoiding the influence of grinding heat, and to shorten the cycle time and reduce the cost.

In order to achieve the above object, the present invention provides an outer member having a double-row raceway surface on the inner periphery, a hub wheel, an inner ring press-fitted on the outer periphery of the hub wheel, and a double-row facing each of the raceway surfaces. An inner member having a raceway surface, wherein one of the double row raceway surfaces is formed on the outer periphery of the hub wheel and the other is formed on the outer periphery of the inner wheel, and the hub wheel is provided with a mounting flange of the driven wheel; In a bearing device for a driven wheel comprising a double row rolling element interposed between a raceway surface of a member and a raceway surface of an inner member, the hub wheel is hollow with a through hole opened at both ends thereof. Formed on the outboard side of the through hole with a forged skin opening, and a fitting surface consisting of a turning surface is provided at the end of the opening on the outboard side. The bearing internal space is sealed with a ring-shaped seal member arranged between the inner peripheral surface of both ends and the outer peripheral surface of the inner member. By crimping an end portion of the hub wheel, it is performed and the inner ring of the positioning and preload imparting, further comprising a cover enclosing the opening in the outboard side of the hub wheel, the cover, the mating face A lid-shaped bottom portion that is more closely in contact with the end face of the hub wheel on the outboard side, a protrusion that protrudes from the bottom portion to the inboard side, is fitted to the fitting surface, and has a thinner fitting portion than the bottom portion. It is characterized by.

Thus, by sealing the opening of the hub wheel with the cover on the outboard side of the hub wheel, it is possible to prevent rust on the forged skin exposed surface of the hub wheel opening and to improve the aesthetics viewed from the tire side. . Further , if the inner member is hollowed out, a heat radiating surface is formed on the inner peripheral surface of the inner member, so that the self-radiating power is increased and excessive heat storage during grinding or the like is suppressed. In addition, since the grinding liquid can be supplied to the hollow portion, an improvement in the cooling effect by the grinding liquid can be expected. Further, since the product is reduced in weight, it is effective for reducing the weight of the vehicle, and at the same time, it is possible to reduce the power of processing equipment (for example, a loading device during grinding).

  In order to make the axial dimension of the bearing device compact, the inner member is composed of a hollow hub ring and an inner ring press-fitted into the outer periphery of the hub ring, and one of the double row raceway surfaces of the inner member is formed. It is also possible to form the other on the outer periphery of the hub ring and the other on the outer periphery of the inner ring. In this case, a small-diameter step portion for press-fitting the inner ring is provided on the outer periphery of the hub ring.

  In a bearing device for a driven wheel, a structure is generally used in which the inner ring is positioned in the axial direction by tightening a nut at the end of the hub ring, and a preload is applied to the bearing, but the end of the hub ring is added. By tightening and integrating the inner ring in a non-separable manner, the same effect can be obtained. In this case, a nut is not required, so that cost reduction, axial dimension reduction, and weight reduction are achieved.

  The hollow part of the inward member (or hub wheel) can be a through hole with both ends opened, or a blind hole with one end closed. In the latter case, if the bottom of the hollow portion is disposed on the inner ring side, the rigidity of the inner ring side portion of the inner ring among the hub rings can be increased, and the radial load capacity can be increased. If the rigidity of the inner diameter side portion is low, the portion is elastically deformed by a radial load, creating a gap in the fitting surface between the inner ring and the hub ring, which may cause creep. Since the rigidity of the inner diameter side portion is improved, the generation of a gap is prevented and creep can be avoided.

  By making the hollow part an unequal diameter according to the thickness of the inner member (hub wheel), it is possible to control the heat radiation area and the amount of heat storage according to the thickness, and the heat distribution of the entire inner member can be controlled. It becomes possible to balance. As the unequal diameter hollow portion, for example, a tapered shape in which the inboard side gradually decreases or a stepped shape can be considered.

  The above bearing device is attached to the vehicle body side through a vehicle body attachment flange provided on the outer member. For example, an attachment member (knuckle) extending from the suspension device of the vehicle body is fitted to the outer periphery of the outer member, and this attachment member is fixed to the vehicle body attachment flange.

As described above, according to the present invention, the opening of the hub wheel is sealed with the cover on the outboard side of the hub wheel, so that the forged skin exposed surface of the hub wheel opening is rust-proofed and viewed from the tire side. The aesthetics can be improved. Moreover, since the hollow part is provided in the inward member, the improvement effect of the self-radiation power by the increase in the heat radiation area and the cooling effect by the grinding liquid are obtained. Therefore, it is possible to suppress processing errors in grinding or the like and shorten the cycle time. Further, since heat is radiated from the hollow portion even during use of the bearing device, excessive heat storage in the inner member can be prevented, and the bearing life can be improved. Furthermore, since the entire bearing device is reduced in weight, it is possible to reduce the fuel consumption of the automobile and reduce the processing power, which is effective for energy saving.

  By making the hollow part an unequal diameter according to the thickness of the inner member, it becomes possible to control the heat radiation area and the amount of heat storage according to the thickness, and to balance the heat distribution of the entire inner member. It becomes possible.

  Embodiments of a driven wheel bearing device according to the present invention will be described below with reference to FIGS. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outboard side, and the left side in each of the above figures is the outboard side. On the other hand, the side closer to the center of the vehicle is called the inboard side, and the right side of each figure is the inboard side.

  The bearing device according to the embodiment shown in FIG. 1 includes a cylindrical outer member 10, an inner member 20 disposed on an inner diameter portion of the outer member, and a plurality of members interposed between the outer member 10 and the inner member 20. The rolling elements 30 (for example, balls) and the cage 40 (see FIG. 11) for holding the rolling elements 30 at equal intervals in the circumferential direction are the main components.

  The outer member 10 includes a double-row raceway surface 11 on the inner periphery, and integrally includes a vehicle body attachment flange 12 for attachment to a vehicle body side attachment member, for example, a knuckle extending from a suspension device. Of the openings at both ends of the outer member 10, a ring-shaped seal member 13 is mounted on the outboard side, and a disk-shaped hub cap 14 is mounted on the inboard side, thereby sealing the internal space of the bearing. ing. As a sealing device on the inboard side, a ring-shaped sealing member 14 (see FIG. 11) can be used instead of the hub cap 14.

  The inner member 20 includes a hub wheel 22 and a ring-shaped inner ring 23 fixed to the outer periphery of the hub wheel. A raceway surface 24 is formed at substantially the center in the axial direction of the outer periphery of the hub wheel 22, and a mounting flange 25 for attaching a driven wheel (not shown) to the outer periphery on the outboard side of the raceway surface 24 is integrally formed. Hub bolts 50 are implanted in the circumferentially equidistant positions of the mounting flange 25, and the hub wheel 22 is fixed to the driven wheel together with a brake rotor (not shown) by the hub bolt 50. On the outer periphery of the hub wheel 22 on the inboard side with respect to the raceway surface 24, a small diameter step portion 26 having a smaller diameter than the raceway surface 24 and a cylindrical shape is formed, and the inner ring 23 is press-fitted into the small diameter step portion 26. The inner ring 23 has a raceway surface 27 on the outer periphery thereof, and the raceway surface 27 and the raceway surface 24 formed on the outer periphery of the hub ring 22 are respectively opposed to the double row raceway surface 11 of the outer member 10. A raceway surface is formed.

  A threaded portion 28 is formed at the end of the inner member 20 on the inboard side. When a nut 61 as a pressurizing means 60 is screwed into this screw portion 28 and tightened, the inner ring 23 is clamped between the shoulder portion 29 of the small diameter step portion 26, and the inner ring 23 is positioned in the axial direction. In addition, a predetermined preload is applied to the rolling elements 30. Each of the double row rolling elements 30 has a contact angle, and the above-described preload increases the bearing rigidity and can receive a moment load.

  As shown in the figure, the hub wheel 22 has a through hole-shaped hollow portion 21 having both ends opened in the axial center thereof along the axial direction. By forming the hollow portion 21, a heat radiating surface is formed on the inner peripheral surface of the hub wheel 22, so that the self-heat radiation power is increased and the grinding fluid can be supplied to the hollow portion 21, and cooling by the grinding fluid is performed. Increases effectiveness. Therefore, due to the synergistic effect of both, it is possible to improve the machining accuracy and shorten the cycle time. Further, since the heat dissipation effect of the hub wheel 22 is exhibited even during use of the bearing device, the bearing life is improved. Furthermore, since the entire bearing device is reduced in weight by the presence of the hollow portion 21, fuel consumption can be reduced by reducing the weight of the vehicle, and at the same time, processing equipment such as a loading device used in the grinding process of the hub wheel 22 is simplified. , Compactness, or reduction of processing power (energy saving) is achieved.

  2 to 6 show other embodiments of the hollow portion 21 provided in the hub wheel 22. Except for the points described below, the configuration and function are the same as those of the hollow portion of the bearing device shown in FIG. Have

  FIG. 2 and FIG. 3 are examples of measures when it is difficult to open both ends of the hollow portion 21, and is an embodiment in which the hollow portion 21 is a blind hole with one opening closed. In any case, the hollow portion 21 exists at least on the inboard side of the wheel mounting flange 25. 2 shows the inner ring 23 side (inboard side), and FIG. 3 shows the opposite side (outboard side) as the closed side. In the former case, the inner ring 23 portion of the inner ring 23 in the hub ring 22 is shown. Therefore, it is possible to increase the radial load capacity or to suppress the creeping of the inner ring 23 and the hub ring 22 on the saddle eye surface. In either case, a center hole 71 can be formed at the end of the hub wheel 22 on the closed side.

  FIGS. 4 to 6 are examples in which the inner diameter of the hollow portion 21 is made unequal in accordance with the outer peripheral shape of the hub wheel 22, thereby suppressing the variation in grinding heat and making the temperature distribution uniform. 4 shows the inner periphery of the hollow portion 21 formed in a stepped shape substantially corresponding to the outer peripheral shape of the hub wheel 22, and FIG. 5 shows the inner periphery of the inboard side hollow portion 21 tapered. . FIG. 6 is a combination of FIGS. 4 and 5, and the inner diameter of the hollow portion 21 is reduced to a stepped shape via one or a plurality (two in the illustrated example) of tapered portions 21 a and 21 b. It is an example. In any embodiment, the inner diameter of the hollow portion 21 is also reduced on the inboard side, corresponding to the fact that the outer circumference of the hub wheel 22 is generally reduced in diameter toward the inboard side.

  7 to 10 show a grinding process of the hub wheel 22 according to the present invention. 7 and 8 show an example in which the outer periphery of the hub wheel 22 is supported by the shoe 81 (in this case, the opening 22a on the end surface on the outboard side of the hub wheel 22 is preferably sealed with the packing plate 82). FIG. 7 shows a grinding process for the hub wheel 22 (see FIG. 1) having a hollow portion 21 having a through hole, and FIG. 8 shows a grinding process for the hub wheel 22 having a hollow portion 21 having a blind hole (see FIG. 3). In the through-hole-shaped hollow portion 21 in FIG. 7, the grinding fluid can be supplied from either the main spindle side (left side of the drawing) or the opposite side of the grinding apparatus. Is supplied only from the opening side. FIGS. 9 and 10 show examples in which the same hub wheel 22 as in FIGS. 7 and 8 is supported by a collet chuck 83 attached to the main shaft, and the method of supplying the grinding fluid is the same as in FIGS.

  FIG. 11 eliminates the nut 61 as the pressurizing means 60, and instead of caulking the end portion (inboard side) of the hub wheel 22 having the hollow portion 21, and integrating the inner ring 23 in a non-separable manner, This is an example of further cost reduction and axial dimension reduction. In the case of the illustrated example, the caulking is performed by forming a caulking portion such as a cylindrical shape at one end portion of the hub wheel 22 and expanding it to the outer diameter side. In this case, like the nut 61, the caulking portion 62 serves to position the inner ring 23 and to apply preload to the double row rolling elements 30.

11 and 12 show a structure in which the end portion on the outboard side of the hub wheel 22 is sealed with a cover 90. FIG. This is for the purpose of rust prevention of the exposed surface of the forged skin of the tapered opening 22a that expands on the outboard side of the through hole 21 and the improvement of aesthetics viewed from the tire side. The painting process of the opening part 22a performed conventionally can be omitted, and further cost reduction can be achieved. The cover 90 can be made of resin / rubber (see FIG. 11) or metal (see FIG. 12). For example, the cover 90 is press-fitted into the fitting surface 22b formed in the opening 22a of the hub wheel 22 by turning or the like. Thus, the hub wheel 22 is fixed. The cover 90 has a lid-like bottom portion 90a that is in close contact with the hub wheel end surface 22c on the outboard side from the fitting surface 22b, and a fitting portion 90b that protrudes from the bottom portion 90a to the inboard side and is fitted to the fitting surface 22b. And integrally. In the cover 90 shown in FIG. 11, the fitting part 90b is formed thinner than the bottom part 90a.

It is sectional drawing of the bearing apparatus for driven wheels concerning this invention. It is sectional drawing of the hub ring which shows other embodiment of a hollow part. It is sectional drawing of the hub ring which shows other embodiment of a hollow part. It is sectional drawing of the hub ring which shows other embodiment of a hollow part. It is sectional drawing of the hub ring which shows other embodiment of a hollow part. It is sectional drawing of the hub ring which shows other embodiment of a hollow part. It is sectional drawing which shows the example of a grinding process of a hub ring. It is sectional drawing which shows the example of a grinding process of a hub ring. It is sectional drawing which shows the example of a grinding process of a hub ring. It is sectional drawing which shows the example of a grinding process of a hub ring. It is sectional drawing which shows other embodiment of the bearing apparatus for driven wheels. It is sectional drawing which shows the other example of a cover. It is sectional drawing of the conventional hub ring.

Explanation of symbols

10 Outer member
11 Track surface
12 Body mounting flange
20 Inner member
21 Hollow part
22 Hub wheel
23 Inner ring
24 Track surface
25 Wheel mounting flange
27 Track surface
62 Caulking part

Claims (7)

An outer member having a double-row raceway surface on the inner periphery, a hub wheel, an inner ring press-fitted into the outer periphery of the hub wheel, and a double-row raceway surface facing each of the raceway surfaces. One of them is formed on the outer periphery of the hub ring, the other is formed on the outer periphery of the inner ring, the inner member provided with the mounting flange of the driven wheel of the hub wheel, the raceway surface of the outer member and the raceway surface of the inner member In a bearing device for a driven wheel comprising a double row rolling element interposed between
The hub wheel is formed in a hollow shape with through holes opening at both ends thereof , and has an opening portion of forging skin that expands in a tapered shape on the outboard side of the through hole, and the end portion on the outboard side of the opening portion Is provided with a mating surface consisting of a turning surface,
Positioning and preloading of the inner ring is achieved by sealing the inner space of the bearing with a ring-shaped seal member disposed between the inner peripheral surface of both ends of the outer member and the outer peripheral surface of the inner member, and crimping the end of the hub ring. Is granted,
Furthermore, a cover for sealing the opening on the outboard side of the hub wheel is provided, and the cover has a lid-like bottom portion that is in close contact with the end surface of the hub wheel on the outboard side with respect to the fitting surface, and the inboard side from the bottom portion The driven wheel bearing device is characterized in that it integrally has a fitting portion that protrudes into the fitting surface and is fitted to the fitting surface and is thinner than the bottom portion . A through hole, the driven wheel bearing apparatus of claim 1, wherein the unequal diameter corresponding to the thickness of the inner member. The bearing device for a driven wheel according to claim 2, further comprising a tapered through hole whose inner diameter on the inboard side gradually decreases. The bearing device for a driven wheel according to claim 2, comprising a stepped through hole. The bearing device for a driven wheel according to any one of claims 1 to 4 , wherein a vehicle body mounting flange is formed on the outer member.   The driven-wheel bearing device according to claim 1, wherein the seal member is brought into contact with the outer peripheral surface of the hub wheel.   The driven-wheel bearing device according to claim 1, wherein the seal member is brought into contact with the outer peripheral surface of the inner ring.

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