JP5223440B2 - Wheel bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing for a wheel superior in sealability for maintaining a fitting state of a fitting surface of a cover member constant over a long period, without being influenced by a temperature change in a use environment of the bearing. <P>SOLUTION: This bearing for the wheel includes a resin sealing member (a cover member 20) for sealing the bearing inside partitioned between bearing rings oppositely arranged to as to be relatively rotatable. The sealing member includes the fitting surface 20m fittable to the bearing ring (an outer ring 2). Metallic core metal (an annular member) 22 is arranged along the fitting surface. In the positional relationship between the core metal and the fitting surface, the core metal is positioned while making its part approach the fitting surface more than the other part. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a wheel bearing that rotatably supports wheels of various vehicles including automobiles.

Conventionally, for example, various wheel bearings as shown in Patent Document 1 and Patent Document 2 are known.
As an example, the bearing shown in FIG. 2 (a) is opposed to an annular 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 stationary wheel 2 inside. And an annular rotating wheel (for example, an inner ring) 4 connected to the wheel side and rotating together with the wheel (not shown). Further, double-row (for example, two rows) raceway grooves 2 s are formed on the inner peripheral surface 2 m of the stationary wheel 2, and each raceway groove 2 s of the stationary wheel 2 is formed on the outer peripheral surface 4 m of the rotating wheel 4. Oppositely, double-row (for example, two-row) raceway grooves 4s are formed. A plurality of rolling elements 6 and 8 are rotatably incorporated between the raceway grooves 2s and 4s, so that the stationary wheel 2 and the rotating wheel 4 can be rotated relative to each other.

  The stationary wheel 2 has a hollow cylindrical shape and is arranged so as to cover the outer periphery of the rotating wheel 4. In this case, a sealing member (for example, a lip seal 10 on the wheel side and a cover member 20 on the vehicle body side) for sealing the inside of the bearing from the outside of the bearing is provided between the stationary wheel 2 and the rotating wheel 4. . In addition, 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. Further, the stationary wheel 2 and the rotating wheel 4 described above may be referred to as track rings, respectively.

  The stationary 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. By fastening to the vehicle body side, the stationary wheel 2 can be fixed to a suspension device (knuckle) (not shown). The rotating wheel 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 hub 12 has a hub flange 12a to which the disc wheel is fixed. Is protruding.

  The hub flange 12a extends outward (radially outward of the hub 12) beyond the stationary ring 2, and a plurality of hub flanges 12a are arranged at predetermined intervals along the circumferential direction in the vicinity of the extended edge. 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). .

  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 cage 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, the above-described bearing is in a state where a predetermined preload is applied, 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). ) It is rotatably assembled while being in contact with the four raceway grooves 2s and 4s. In this case, an action line (not shown) connecting the two contact points is orthogonal to the raceway grooves 2s and 4s and passes through the centers of the rolling elements 6 and 8, and is on one point (action point) on the center line of the bearing. ) This constitutes a rear combination (DB) bearing.

  In such a configuration, all of the force acting on the wheel while the vehicle is running is transmitted from the disk wheel to the suspension device through the bearing described above. In this case, the bearing has various loads (radial). Load, axial load, moment load, etc.). However, since such a bearing is a back combination (DB) bearing as described above, high rigidity is maintained with respect to various loads.

  Further, in the above-described bearing, the cover member 20 has a resin-like annular structure that covers and seals the end of the stationary wheel (outer ring) 2 on the vehicle body side (portion opened in the bearing outer direction). And can be attached to the end of the stationary wheel 2 on the vehicle body side. Specifically, the cover member 20 is provided with an annular fitting surface 20m continuous in the circumferential direction along its outer periphery on the wheel side (the side attached to the stationary wheel 2), and on the vehicle body side. A sensor mounting portion 20p for mounting a sensor (not shown) for detecting the rotation state of the bearing (for example, the rotational speed of the rotating wheel (inner ring) 4 rotating with the wheel) on the side opposite to the fitting surface 20m is provided. Is provided. On the other hand, the end (opening) on the vehicle body side of the stationary wheel 2 is an annular attachment that is continuous in the circumferential direction along the inner periphery of the opening and that can be fitted with the fitting surface 20m of the cover member 20. A surface 2f is provided.

  Here, when the fitting surface 20m of the cover member 20 is inserted along the mounting surface 2f of the stationary ring 2, the fitting surface 20m is fitted (internally fitted) to the mounting surface 2f without a gap. As a result, the stationary ring ( The entire vehicle body side (opening) of the outer ring 2 can be covered. Thereby, the inside of the bearing defined between the stationary wheel (outer ring) 2 and the rotating wheel (inner ring) 4 can be sealed from the outside of the bearing.

  Further, the resin cover member 20 is provided with a metal annular member (core metal) 22 continuous in the circumferential direction along its inner periphery on the wheel side (position facing the fitting surface 20m). ing. Accordingly, the fitting state of the fitting surface 20m of the cover member 20 (specifically, the fitting surface 20m and the mounting surface 2f of the stationary ring 2) without being affected by the temperature change in the usage environment of the bearing. The effect of maintaining the (fitted state) in a constant state is achieved.

In this case, in the above-described bearing (FIG. 2A), as an example, a configuration example in which the annular member (core metal) 22 is exposed on the inner periphery of the cover member 20 is assumed. As an example, in the bearing shown in FIG. 2B, the annular member (core metal) 22 is configured to be embedded (embedded) on the wheel side of the cover member 20 (position facing the fitting surface 20m). ing. 2B is the same as the above-described bearing (FIG. 2A), the same reference numerals as those in FIG. 2A are used. A description of the configuration is omitted by attaching it to FIG.
JP 2006-112582 A JP 2006-144867 A

  By the way, the cover member 20 is generally molded using a thermoplastic resin such as polyamide (PA), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), for example. It has a predetermined glass transition point (Tg: temperature at which crystals are lost). Here, the glass transition point refers to a temperature at which a solid, which is hard like a crystal at a low temperature (high rigidity) and has no fluidity, rapidly decreases in rigidity and viscosity and increases fluidity in a narrow temperature range. In this case, the glass transition point of the thermoplastic resin as described above is about 50 ° C., and the glass transition points of many other resins are not so high.

  In this case, assuming the use environment of the above-mentioned bearing, for example, during running of an automobile to which the bearing is applied, the temperature around the rotating bearing tends to rise above the glass transition point of the thermoplastic resin as described above. It is in. Further, it is known that the thermoplastic resin as described above loses its crystal at a temperature higher than the glass transition point, and its fluidity increases at the same time as its volume increases.

  Here, considering the above-described bearing, as shown in FIGS. 2A and 2B, the cover member 20 is coated with a resin with a uniform thickness on the outer peripheral side of the annular member 22. The fitted surface 20m is configured. Specifically, the fitting surface 20 m of the cover member 20 is configured by covering a uniform thickness of resin between the fitting surface 20 m and the annular member 22.

  However, in such a cover member 20, when the temperature around the bearing rises above the glass transition point, the volume of the resin constituting the fitting surface 20 m increases and the fluidity increases, and as a result, the resin flows out. Resin flow "occurs. The resin flow at this time is a rheologically slow flow caused by complicated mechanical behavior of the material such as resin viscosity, elasticity, plasticity, etc., but after such resin flow occurs, the temperature around the bearing changes to the glass transition. When it falls to a point, the thickness of the resin which comprises the fitting surface 20m becomes thin. That is, the squeeze (tightening margin) of the fitting surface 20m of the cover member 20 is reduced. When the temperature change around the bearing as described above is repeated, and the resin flow is repeated accordingly, the squeeze (tightening margin) of the fitting surface 20m of the cover member 20 gradually decreases.

  In this case, when the outer diameter size of the fitting surface 20m of the cover member 20 becomes smaller than the inner diameter size of the mounting surface 2f of the stationary wheel 2 due to the reduction of the shimoshiro (tightening allowance), the fitting surface 20m is fitted. The combined state (specifically, the fitting state between the fitting surface 20m and the mounting surface 2f of the stationary wheel 2) cannot be maintained constant. As a result, the inside of the bearing defined between the stationary ring (outer ring) 2 and the rotating ring (inner ring) 4 cannot be sealed from the outside of the bearing. As a result, foreign matter (for example, dust, water) easily enters the bearing from the outside of the bearing, and it becomes difficult to continue to use the bearing continuously for a long time.

  The present invention has been made to solve such a problem, and the object thereof is to maintain the fitting state of the fitting surface of the cover member over a long period of time without being affected by the temperature change in the usage environment of the bearing. Another object of the present invention is to provide a wheel bearing excellent in sealing performance that can be maintained constant.

In order to achieve such an object, the present invention is a wheel bearing provided with a resin sealing member for sealing the inside of a bearing defined between bearing rings opposed to each other so as to be relatively rotatable. The sealing member is provided with an annular fitting surface that can be fitted to the race, and a metal annular metal core is provided along the fitting surface. Since the peripheral ends of both sides are positioned in a state closer to the fitting surface than the other parts , the sealing member between the peripheral ends of the core metal is fitted to the raceway over the entire surface. Maintained in a state .
Further, the wheel bearing of the present invention includes one bearing ring that is maintained in a non-rotating state and the other bearing ring that is provided so as to be opposed to the wheel and rotates together with the wheel, and the sealing member includes An annular structure is formed that covers and seals the entire portion of the end of the ring that is open toward the outside of the bearing, and its fitting surface is an annular shape that can be fitted to the end of the one raceway ring. The sealing member core has a continuous annular shape along the annular mating surface, and one of the peripheral ends of the sealing member is closer to the mating surface than the other part. The positioning is performed, and the other of the peripheral ends on both sides is positioned in a state of being closer to the outside of the end of one of the race rings than the other part.

  According to the present invention, a wheel excellent in hermeticity capable of maintaining the fitting state of the fitting surface of the cover member constant over a long period of time without being affected by the temperature change in the usage environment of the bearing. Bearings can be realized.

Hereinafter, a wheel bearing according to an embodiment of the present invention will be described with reference to FIG.
Since the present embodiment is an improvement of the wheel bearing shown in FIG. 2, only the improved portion will be described below. In this case, in the following description, with respect to the same configuration as the above-described wheel bearing (FIG. 2), the same reference numerals as those used for the configuration are used in the present embodiment (FIG. 1). The description is omitted by adding the above.

  As shown in FIG. 1 (a), in the wheel bearing of the present embodiment, the cover member 20 as the sealing member described above has a metal annular member (core metal) along the annular fitting surface 20m. ) 22 is provided. And in the positional relationship between the said annular member (core metal) 22 and the fitting surface 20m, the annular member (core metal) 22 is in a state where a part thereof is closer to the fitting surface 20m than the other parts. It is positioned.

  More specifically, the annular member (core metal) 22 shown in FIG. 1 (a) has a continuous annular shape (circular shape) along the annular fitting surface 20m, and both circumferential edges 22a thereof. , 22b are formed in a shape protruding in an annular shape toward the outside along the radial direction. In this case, the protrusion amount (protrusion length) of each of the side peripheral ends 22a and 22b may be set so as not to penetrate from the fitting surface 20m, but the protruding end and the fitting surface of the side peripheral ends 22a and 22b. It is preferable that the predetermined thickness W (thickness of the thermoplastic resin) be set between 20 m. Note that the predetermined thickness W is set in consideration of, for example, an increase in volume of the resin and a degree of increase in fluidity when the temperature around the bearing rises above the glass transition point. do not do. In short, it is only necessary to secure a thickness W that can keep the fitting state of the fitting surface 20m constant over a long period of time.

  Further, the protrusion amounts (protrusion lengths) of the side peripheral ends 22a and 22b may be set to be the same with each other, or may be set with a difference in height. In the drawing, as an example, a configuration example of the side peripheral ends 22a and 22b set to the same protrusion amount (protrusion length) is shown. In this case, between the peripheral peripheral ends 22a and 22b and the fitting surface 20m. Have the same thickness W. Thereby, the annular member (core metal) 22 is realized in which both side peripheral ends 22a and 22b are closer to the fitting surface 20m than the other portions.

  Further, the direction (angle) at which these side peripheral ends 22a and 22b are brought close to the fitting surface 20m is not particularly limited as long as the above-described thickness W can be secured. In the drawing, as an example, a configuration example of the side peripheral ends 22a and 22b set in directions (angles) that are parallel to each other and orthogonal to the fitting surface 20m is shown, but may have an appropriate inclination. . In this case, both side peripheral ends 22a and 22b may be inclined in the same direction, or in different directions.

  As described above, according to the present embodiment, part of the annular member (core metal) 22 (both side peripheral ends 22a and 22b) is positioned in a state closer to the fitting surface 20m than the other parts, thereby fitting. The thermoplastic resin around the surface 20m is maintained in the state (squeezed state) held by the peripheral edges 22a and 22b. At this time, even when the temperature around the bearing rises above the glass transition point and a rheological “resin flow” occurs, the thermoplastic resin around the fitting surface 20 m is surely secured by the peripheral edges 22 a and 22 b. Retained. And even when the temperature around the bearing is lowered to the glass transition point, the thickness of the resin constituting the fitting surface 20m does not become thin, and the squeezing (tightening margin) of the fitting surface 20m of the cover member 20 is reduced. There is no.

  Thereby, the fitting state of the fitting surface 20m (specifically, the fitting state of the fitting surface 20m and the mounting surface 2f of the stationary wheel 2) can be maintained constant. As a result, the inside of the bearing defined between the stationary ring (outer ring) 2 and the rotating ring (inner ring) 4 can be reliably sealed from the outside of the bearing. For this reason, it is possible to prevent foreign matters (for example, dust and water) from entering the bearing from the outside of the bearing, and the bearing can be used continuously for a long period of time.

  Furthermore, according to the present embodiment, by positioning a part (both side peripheral ends 22a, 22b) of the annular member (core metal) 22 closer to the fitting surface 20m than the other parts, The expansion force resulting from the increase in the volume of the resin when the temperature rises above the glass transition point can be efficiently converted into a fitting force (fitting surface pressure) on the fitting surface 20m of the cover member 20. . Thereby, the fitting force (fitting surface pressure) between the fitting surface 20m and the mounting surface 2f of the stationary wheel 2 can be improved. As a result, it becomes possible to improve the sealing performance (water resistance) between the fitting surface 20m and the mounting surface 2f. For this reason, since other water-resistant parts, such as an O-ring, are unnecessary, the manufacturing cost of the bearing can be reduced.

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 a first modification, as shown in FIG. 1 (b), the entire annular member (core metal) 22 is curved in an arc shape in a sectional view toward the outside along the radial direction. You may make it make 22a and 22b approach the fitting surface 20m rather than another part. Thereby, the effect similar to embodiment mentioned above is realizable.

  As a second modification, as shown in FIG. 1 (c), a side peripheral end 22a on the outer side of the bearing among the peripheral peripheral ends 22a and 22b (FIG. 1 (a)) of the annular member (core metal) 22 is changed. The stationary wheel (outer ring) 2 may be extended and protruded so as to go around the outside of the end of the vehicle body side. In this case, the thickness W between the side peripheral end 22a and the end of the stationary wheel (outer ring) 2 on the vehicle body side is between the protruding end of the side peripheral end 22b on the bearing inner side and the fitting surface 20m. It is preferable to set similarly to the thickness W. Thereby, since the part (both peripheral end 22a, 22b) used as thickness W can be brought closer to the fitting surface 20m rather than another part, the effect similar to embodiment mentioned above is realizable. .

  As a third modified example, as shown in FIG. 1 (d), the side peripheral end 22a on the outer side of the bearing among the peripheral peripheral ends 22a and 22b (FIG. 1 (a)) of the annular member (core metal) 22 is changed. The stationary wheel (outer ring) 2 may be extended so as to wrap around the vehicle body side end, and the extended end may be folded back toward the stationary wheel (outer ring) 2 to protrude. In this case, the thickness W between the extending end of the side peripheral end 22a and the end of the stationary ring (outer ring) 2 on the vehicle body side is such that the protruding end of the side peripheral end 22b on the bearing inner side and the fitting surface 20m. It is preferable to set similarly to the thickness W between the two. Thereby, since the part (both peripheral end 22a, 22b) used as thickness W can be brought closer to the fitting surface 20m rather than another part, the effect similar to embodiment mentioned above is realizable. .

  Here, in the above-described embodiment (FIG. 1A) and the first to third modifications (FIGS. 1B to 1D), the annular member (core metal) 22 is pressed on a metal plate. Since it is formed by processing, in consideration of the ease of processing and labor, the two circumferential ends 22a and 22b of the annular member (core metal) 22 are folded back. However, the present invention is not limited to this, and three or more places may be folded, or only one place may be folded.

  As a fourth modified example, FIG. 1 (e) shows a configuration example of an annular member (core metal) 22 that is formed by folding back at only one place, and the annular member (core metal) 22 is shown in FIG. It is substantially L-shaped in cross-sectional view. At this time, of the both side peripheral ends 22 a and 22 b of the substantially L-shaped annular member (core metal) 22, the side peripheral end 22 a on the bearing outer side is placed outside the end of the stationary ring (outer ring) 2 on the vehicle body side. While extending and projecting so as to wrap around, the side peripheral end 22b on the bearing inner side is projected in parallel along the fitting surface 20m. In this case, the thickness W between the extended end of the side peripheral end 22a and the end of the stationary ring (outer ring) 2 on the vehicle body side is such that the protruding end of the side peripheral end 22b on the bearing inner side and the fitting surface 20m It is preferable to set it similarly to the thickness W between the two. As a result, although the thickness between the side peripheral end 22b on the bearing inner side and the fitting surface 20m is relatively wide, the portion having the thickness W (both side peripheral ends 22a, 22b) is fitted more than the other portions. Since it can be brought close to the surface 20m, the same effect as the above-described embodiment can be realized. Furthermore, since the annular member (core metal) 22 of the fourth modified example is folded only once by press working, the working cost can be reduced, and as a result, the manufacturing cost of the bearing can be reduced. Can do.

(a) is sectional drawing which partially expands and shows the structure of the wheel bearing which concerns on one embodiment of this invention, (b) is the structure of the wheel bearing which concerns on the 1st modification of this invention. A partially enlarged cross-sectional view, (c) is a partially enlarged cross-sectional view showing the configuration of a wheel bearing according to a second modification of the present invention, and (d) is a third view of the present invention. Sectional drawing which expands and partially shows the structure of the wheel bearing which concerns on a modification, (e) is sectional drawing which expands partially and shows the structure of the wheel bearing which concerns on the 4th modification of this invention. (a) is sectional drawing which shows schematically one structural example of the conventional wheel bearing, (b) is sectional drawing which shows schematically the other structural example of the conventional wheel bearing.

Explanation of symbols

2 Outer ring (stationary ring)
20 Cover member (sealing member)
20m mating surface 22 cored bar (annular member)

Claims (2)

A wheel bearing provided with a resin sealing member for sealing the inside of the bearing defined between the bearing rings arranged to face each other so as to be relatively rotatable,
The sealing member is provided with an annular fitting surface that can be fitted to the race, and a metal annular cored bar is provided along the fitting surface.
The core metal is positioned with its peripheral edges closer to the fitting surface than the other parts, so that the sealing member between the peripheral edges of the core metal is tracked over the entire surface. A wheel bearing characterized by being maintained in a state of being fitted to a wheel. One bearing ring maintained in a non-rotating state, and the other bearing ring provided opposite to this and rotating together with the wheel,
The sealing member covers the entire portion opened at the end of one bearing ring in the bearing external direction and forms a sealable annular body structure, and its fitting surface is the end of the one bearing ring. An annular shape that can be fitted to the part,
The metal core of the sealing member forms a continuous ring along the ring-shaped fitting surface, and is positioned with one of the peripheral edges of the both sides being closer to the fitting surface than the other part, and The wheel bearing is characterized in that the other circumferential end of the both sides is positioned in a state of being closer to the outside of the end of one of the bearing rings than the other part.

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