JP2007232150A - Seal with encoder and bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive technique which allows the positioning of a positional relation between a sensor and encoder within a detection permissible range without changing an existing bearing composition. <P>SOLUTION: A seal 24 with an encoder is assembled in a bearing unit equipped with: a static wheel 2 and rotating wheel 4 arranged to face each other so as to be relatively rotatable; and a sensor 1 for detecting a rotation state of the rotary wheel with respect to the static wheel, and seals an annular space between the static wheel and rotating wheel. The seal 24 with the encoder is equipped with: an annular slinger 26 which is fixed to the rotating wheel; an annular seal body 28 which is fixed to the static wheel in a state of coming into a slide contact with the slinger; and an encoder 22 which records encoded information detectable by a sensor in the bearing unit. The encoder is mounted in the slinger and a positioning structure (an extended part P1, a seal position adjusting part P2) for positioning the encoder within the detection permissible range W is included. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a seal with an encoder and a bearing unit capable of detecting a rotation state (for example, rotation speed, rotation direction) of a rotating wheel with respect to a stationary wheel.

  In recent years, with the increasing awareness of automobile safety, for example, ABS (Antilock Brake System) is widely used to ensure running stability during braking on slippery roads such as freezing. Various bearing units having sensors capable of detecting a rotation state (for example, a rotation speed or a rotation direction of a wheel) have been proposed. For example, the bearing unit shown in FIG. 2 (a) is provided on a stationary wheel (for example, an outer ring) 2 that is fixed to the vehicle body side and maintained in a non-rotating state at all times, and provided on the inner side of the outer ring 2 A rotating wheel (for example, an inner ring) 4 connected to the side and rotating together with the wheel, and a plurality of rolling elements 6 and 8 rotatably incorporated in a double row (for example, two rows) between the outer ring 2 and the inner ring 4; The sensor 1 is positioned and fixed to a sensor cap 10a attached to a vehicle body side end 2e of a stationary wheel (outer ring) 2.

  In this case, the stationary wheel 2 has a hollow cylindrical shape, and is disposed so as to cover the outer periphery of the inner ring 4. Between the stationary wheel 2 and the rotating wheel 4, the inside of the bearing unit is sealed. A sealing member (wheel side lip seal 10b) is provided. In this case, the sensor cap 10a attached to the vehicle body side end portion 2e is also used as a seal member, and the sensor cap 10a and the lip seal 10b allow the inside of the bearing (the annular space between the stationary wheel 2 and the rotating wheel 4). ) Is kept sealed from the outside. In the drawings, balls are illustrated as the rolling elements 6 and 8, but rollers may be applied depending on the configuration and type of the bearing unit.

  The stationary ring 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, and this is connected 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 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).

  In addition, an annular rotating wheel component 16 (a member constituting the rotating wheel 4 together with the hub 12) is externally fitted to the rotating wheel 4 (hub 12) from an end portion 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 externally fitted to the step portion 12 b formed on the hub 12. Then, the caulking region 12c at the end of the vehicle body side of the rotating wheel 4 is plastically deformed, and the caulking region 12c is caulked (adhered) along the peripheral end surface 16s of the rotating wheel constituting body 16, thereby The rotating wheel component 16 can be fixed to the rotating wheel 4.

  At this time, a predetermined preload is applied to the bearing unit, and in this state, the rolling elements 6 and 8 form a predetermined contact angle with each other and the raceway surfaces of both the stationary wheel 2 and the rotating wheel 4. It is assembled so as to be able to rotate in contact with 2s and 4s respectively. In this case, an action line (not shown) connecting the two contact points is perpendicular to the raceway surfaces 2s and 4s and passes through the centers of the rolling elements 6 and 8, so that one point on the center line of the bearing unit (the action point). ) This constitutes a rear combination (DB) bearing.

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

  In addition, an annular slinger 20 is fixed to the end of the rotating wheel 4 (hub 12) on the vehicle body side to prevent foreign substances (for example, rainwater and muddy water) from entering the inside of the bearing by centrifugal action. 2A, the base end of the slinger 20 is fixed to the outer periphery of the rotating wheel 4 (rotating wheel constituting body 16), and the tip thereof extends in the radial direction toward the stationary wheel 2. ing. An annular encoder 22 in which encoded information that can be detected by the sensor 1 is recorded along the rotation direction of the rotating wheel 4 is fixed to the side surface of the slinger 20 on the vehicle body.

  In this case, when the rotating wheel 4 connected to the wheel side rotates while the vehicle is running, the encoded information is detected by the sensor 1 from the encoder 22 that rotates along with the rotating wheel 4, and a predetermined signal is added to the signal detected at that time. By performing the arithmetic processing, the rotation state of the wheel (for example, the rotation speed and the rotation direction) is detected. Here, as encoded information, for example, when magnetic poles having different N and S poles are alternately magnetized along the circumferential direction of the encoder 22, the sensor 1 is provided with a magnetic that can detect a change in the magnetic poles. A sensor (active sensor, passive sensor) may be applied. According to this, by detecting the change of the magnetic pole per unit time by the magnetic sensor 1 while the encoder 22 is rotating, it is possible to detect the rotation speed and the rotation direction of the wheel. For example, when a barcode or a slit is formed as the encoded information, a photo sensor or the like that can optically detect these is used as the sensor 1.

  By the way, considering the positional relationship between the sensor 1 and the encoder 22, in order to detect the encoded information from the encoder 22 with high accuracy, the encoder 22 is set within the detection allowable range W of the sensor 1 (see FIG. 2B). Need to be positioned accurately. For this reason, for example, in the technique proposed in Patent Document 1, the sensor 1 is extended in the direction of the encoder 22 (FIG. 2A), and the sensor 1 and the encoder 22 are moved closer to the encoder 22. Is set within the detection allowable range W. For example, in the technique proposed in Patent Document 2, the rotating wheel 4 (the rotating wheel component 16) is extended in the direction of the sensor 1 (FIG. 2B), and the encoder 22 fixed to the rotating wheel 4 is used. By approaching the sensor 1 to the sensor 1, the positional relationship between the sensor 1 and the encoder 22 is set within the detection allowable range W.

  However, in the technique for extending the sensor 1 in the direction of the encoder 22 (Patent Document 1), since the sensor 1 is increased in size, it is necessary to increase the strength (rigidity) of the sensor cap 10a for positioning and fixing the sensor 1. In this case, the existing sensor cap 10a cannot be used as it is, and a new sensor cap 10a must be manufactured. Since the manufacturing cost of the high-strength (rigid) sensor cap 10a is high, the manufacturing cost of a bearing unit using the same may increase. Further, in the technology for extending the rotating wheel 4 (the rotating wheel component 16) in the direction of the sensor 1 (Patent Document 2), a separate process for extending the rotating wheel 4 is required, and the rotating wheel 4 is extended. The weight of the entire bearing unit is increased by the amount of the protrusion, and it may be assumed that the design of other bearing configurations needs to be changed accordingly. Thereby, there exists a possibility that the manufacturing cost of a bearing unit may rise.

Therefore, there is a demand for a low-cost technology that can be used as it is without changing the existing bearing configuration and that the positional relationship between the sensor 1 and the encoder 22 can be positioned within the allowable detection range. Such techniques are not known.
Japanese Patent No. 3663866 (FIG. 6) Japanese Patent No. 3440800 (FIG. 1)

  The present invention has been made to meet such demands, and its purpose is to use the existing bearing configuration as it is without changing the positional relationship between the sensor and the encoder within the detection allowable range. It is to provide a low-cost technology that is possible.

  In order to achieve such an object, the present invention is incorporated in a bearing unit including stationary wheels and rotating wheels that are opposed to each other so as to be relatively rotatable, and a sensor that detects a rotation state of the rotating wheels with respect to the stationary wheel. , A seal with an encoder that can seal the annular space between the stationary wheel and the rotating wheel, and can be fixed to the stationary wheel while being in sliding contact with the annular slinger that can be fixed to the rotating wheel An annular seal body and an encoder in which encoded information that can be detected by the sensor of the bearing unit is recorded. The encoder can be attached to the slinger, and the encoder is positioned within the detection allowable range of the sensor. A positioning structure is provided for this purpose.

  In the present invention, the positioning structure is provided with an extending portion that can extend in the sensor direction of the bearing unit, and the encoder is attached to a slinger that is extended in the sensor direction by the extending portion. Positioned within the detection tolerance of the sensor. In this case, the slinger includes an annular fixed portion fixed to the rotating wheel and slidably contacted with the seal body, and an annular wall portion folded back from the fixed portion toward the stationary wheel and slidably contacted with the seal body. At the same time, the extending portion is configured to be adjacent to the wall portion and extend in the sensor direction, and the encoder is attached to the extending portion adjacent to the wall portion. The slinger includes an annular fixed portion fixed to the rotating wheel and slidably contacted with the seal body, and an annular wall portion folded back from the fixed portion toward the stationary wheel and slidably contacted with the seal body. The extending portion is configured such that the wall portion can be extended in the same direction by extending the fixing portion in the sensor direction, and the encoder is attached to the wall portion extended in the sensor direction by the extending portion. It is attached.

  Furthermore, the positioning structure adjusts the position of the seal body in the sensor direction according to the extension state of the wall portion extended in the sensor direction by the extension portion, and positions the seal body in a state of sliding contact with the slinger. A seal position adjustment unit is provided. In this case, the seal main body is configured by adding a sealing material to the core metal, and the core metal is an annular main body fixed portion fixed to the stationary wheel, and an annular main body folded from the main body fixed portion toward the rotating wheel. The seal material is integrally formed with a seal lip that is slidably contacted with the slinger, and the seal position adjusting portion is fixed to the stationary ring and is in an extended state of the slinger wall portion. Accordingly, the seal main body is positioned in a state where the seal lip is slidably contacted with the slinger by fixing the cored bar to the seal position adjusting portion extended in the sensor direction.

  Further, the present invention is a bearing unit incorporating a seal with an encoder as described above, which is fixed to the vehicle body side and is always kept in a non-rotating state, and is provided facing the stationary wheel and A rotating wheel connected to the wheel side and rotating together with the wheel, a plurality of rolling elements rotatably incorporated between the stationary wheel and the rotating wheel, and a sensor for detecting a rotation state of the rotating wheel with respect to the stationary wheel A seal member is incorporated between the stationary wheel and the rotating wheel on the vehicle body side, and a seal with an encoder is incorporated between the stationary wheel and the rotating wheel on the wheel side, so that the stationary wheel and the rotating wheel are And the encoder is positioned within the detection tolerance of the sensor by the positioning structure of the seal with the encoder.

  According to the present invention, it is possible to realize a low-cost technology capable of positioning the positional relationship between the sensor and the encoder within the detection allowable range by using the existing bearing configuration without any change. .

  Hereinafter, a seal with an encoder and a bearing unit according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the present embodiment, since the configuration other than the seal with the encoder is the same as that of the bearing unit (FIG. 2) described above, the description thereof is omitted by giving the same reference numerals on the drawing, and is different in the following. The description is limited to the configuration.

  As shown in FIG. 1A, the encoder-equipped seal 24 of the present embodiment is incorporated between the stationary ring (outer ring) 2 and the rotating ring (inner ring) 4 in the above-described bearing unit (FIG. 2). Thus, the annular space between the outer and inner rings can be sealed. Specifically, an annular slinger 26 that can be fixed to the rotating wheel 4, an annular seal body 28 that can be fixed to the stationary wheel 2 while being in sliding contact with the slinger 26, and a sensor 1 of the bearing unit can be detected. And an encoder 22 in which encoded information is recorded. In this case, the encoder 22 can be attached to the slinger 26, and a positioning structure for positioning the encoder 22 within the detection allowable range W of the sensor 1 is provided.

  The slinger 26 is fixed to the rotating wheel 4 and has an annular fixed portion 26a to which the seal body 28 is slidably contacted, and an annular wall that is folded back from the fixed portion 26a toward the stationary wheel 2 and is slidably contacted to the seal body 28. Part 26b. The seal body 28 is configured by adding a sealing material 32 to a core metal 30, and the core metal 30 includes an annular main body fixing portion 30 a fixed to the stationary wheel 2, and the main body fixing portion 30 a to the rotating wheel 4. The sealing material 32 is integrally formed with a seal lip 32a slidably contacting the slinger 26 (fixed portion 26a, wall portion 26b). Although the three seal lips 32a are illustrated in the drawings, the present invention is not limited to this, and one, two, or three or more seal lips 32a may be configured.

  Further, the positioning structure is provided with an extending portion P1 that can extend in the direction of the sensor 1 of the bearing unit, and the encoder 22 is attached to the slinger 26 that is extended in the direction of the sensor 1 by the extending portion P1. The encoder 22 is positioned within the detection allowable range W of the sensor 1. In this case, the extending portion P1 is configured to be adjacent to the wall portion 26b and extend in the direction of the sensor 1, and the encoder 22 is provided on the side surface of the vehicle body of the extending portion P1 adjacent to the wall portion 26b ( The surface facing the sensor 1 is attached to Ps.

  In the present embodiment, the extension portion P1 has a substantially U-shaped cross section as an example, and one surface (surface on the wheel side) of the U-shaped tip is adjacent to the wall portion 26b of the slinger 26. And fixed. In this case, the extension part P1 and the wall part 26b may be fixed by, for example, integrally forming the extension part P1 and the wall part 26b, or separately forming the extension part P1 and the wall part 26b. It may be retrofitted (for example, welding, welding, adhesion). In addition, the extension part P1 may be formed of the same material as the slinger 26, or may be formed of a different material (a material having high rigidity) in order to increase the rigidity of the extension part P1. In any case, the material of the extending portion P1 is not particularly limited here because it is arbitrarily set according to, for example, the usage environment and purpose of the bearing unit.

  Further, the extension amount (extension length) L of the extension portion P1 having a substantially U-shaped cross section can be arbitrarily increased or decreased according to the distance between the encoder 22 and the sensor 1, thereby the encoder. 22 can be positioned within the detection allowable range W of the sensor 1. Further, the extending direction of the extending portion P1 can be arbitrarily changed according to the positional relationship between the encoder 22 and the sensor 1, and thus the encoder 22 is accurately set within the detection allowable range W of the sensor 1. Can be positioned. Furthermore, the extension angle θ of the vehicle body side surface (surface facing the sensor 1) Ps of the extension part P1 can be arbitrarily adjusted according to the direction of the sensor 1, and thus the encoder 22 is connected to the sensor 1. Can be positioned so as to face each other accurately. Note that the extension amount (extension length) L, the extension direction, and the extension angle θ are arbitrarily set according to the distance to the sensor 1, the positional relationship with the sensor 1, and the orientation of the sensor 1. Here, numerical values are not particularly limited.

  As described above, according to the present embodiment, the positioning structure (extending portion P1) is provided in the slinger 26, so that the existing bearing configuration can be used as it is without any change, and within the detection allowable range W of the sensor 1. It is possible to position the encoder 22. This eliminates the need for an increase in the weight of the bearing and a change in the design of the bearing structure associated therewith, as in the prior art, so that the manufacturing cost of the bearing unit can be greatly reduced as compared with the prior art.

  Further, according to the present embodiment, even if the extension amount (extension length) L, the extension direction, and the extension angle θ of the slinger 26 are arbitrarily set by the positioning structure (extension part P1), the stationary Since the sliding contact state between the seal body 28 and the slinger 26 is maintained as it is during the rotation of the rotating wheel 4 with respect to the wheel 2, the sealing performance of the seal 24 is not deteriorated. As a result, it is possible to reliably prevent foreign matter (for example, rainwater or muddy water) from entering the bearing.

The present invention is not limited to the above-described embodiment. For example, the encoder-equipped seal 24 according to another embodiment shown in FIG. 2B is similar to the above-described embodiment. The effect can be realized.
That is, as shown in FIG. 2B, in the positioning structure of the seal 24 with an encoder according to another embodiment, the extending portion P1 applied to the slinger 26 extends the annular fixing portion 26a in the sensor direction. By doing so, the annular wall portion 26b can be extended in the same direction. In this case, the encoder 22 is attached to the vehicle body side surface (surface facing the sensor 1) 26s of the wall portion 26b extended in the direction of the sensor 1 by the extending portion P1.

  The positioning structure has a seal according to the extension state (extension amount (extension length) N2 and extension direction and extension angle) of the wall part 26b extended in the sensor 1 direction by the extension part P1. There is further provided a seal position adjusting portion P2 that adjusts the position of the main body 28 in the direction of the sensor 1 and positions the seal main body 28 in a state of sliding contact with the slinger 26. Here, the extension angle is not particularly shown in the drawing, but can be defined as an angle formed by the fixing portion 26a and the wall portion 26b. In addition, the extension state (extension amount (extension length) N2, extension direction, and extension angle) of the extension part P1 depends on the distance to the sensor 1, the positional relationship with the sensor 1, and the direction of the sensor 1. Since it is arbitrarily set according to this, there is no particular numerical limitation here.

  The seal position adjusting portion P2 includes an annular adjustment fixing portion 34a fixed to the stationary wheel 2, and an annular connecting portion 34b extending from the adjustment fixing portion 34a in the direction of the rotating wheel 4. In this case, the adjustment fixing portion 34a can extend in the direction of the sensor 1 according to the extending state of the wall portion 26b of the slinger 26, and the core metal 30 is folded back to the connecting portion 34b extended in the direction of the sensor 1. By fixing the portion 30b, the seal body 28 can be positioned in a state where the sealing material 32 (seal lip 32a) is in sliding contact with the slinger 26 (fixing portion 26a, wall portion 26b). In addition, as for the fixing method of the connection part 34b and the folding | returning part 30b, you may form the connection part 34b and the folding | returning part 30b integrally, for example, respectively, it forms separately and attaches the folding | returning part 30b to the connection part 34b (for example, , Welding, welding, bonding). Further, the seal position adjusting portion P2 may be formed of the same material as the core metal 30, or may be formed of a different material (a material having high rigidity) in order to increase the rigidity of the seal position adjusting portion P2. . In any case, since the material of the seal position adjusting portion P2 is arbitrarily set according to, for example, the usage environment or usage purpose of the bearing unit, it is not particularly limited here.

  According to such a configuration, for example, the wall portion 26b of the slinger 26 is extended in the direction of the sensor 1 by the extension portion P1 by the extension amount (extension length) N2, and the extension state (extension) The seal body 28 is brought into sliding contact with the slinger 26 only by extending the adjustment fixing portion 34a in the direction of the sensor 1 by the seal position adjustment portion P2 according to the amount (extension length) N2). At the same time, the encoder 22 attached to the wall portion 26b can be positioned within the detection allowable range W of the sensor 1. Since other effects are the same as those of the above-described embodiment (FIG. 1A), description thereof is omitted.

  In each of the embodiments described above, the outer ring 2 is a stationary wheel and the inner ring 4 is a rotating wheel. Conversely, the same effect can be obtained if the outer ring 2 is a rotating wheel and the inner ring 4 is a stationary wheel. Can be realized. In this case, the assembly direction of the seal 24 with the encoder between the outer and inner rings may be reversed upside down. 1 and 2 show a bearing unit for a driven wheel, but the same can be achieved by incorporating a seal 24 with an encoder similar to each of the above-described embodiments into a bearing unit for a driving wheel. The effect of can be realized.

(a) is sectional drawing which expands and shows a part of structure by which the seal | sticker with an encoder which concerns on one embodiment of this invention was integrated in the bearing unit, (b) is other embodiment of this invention. Sectional drawing which expands and shows a part of structure by which the seal | sticker with an encoder which concerns was integrated in the bearing unit. (a) is sectional drawing which shows the structure of the conventional bearing unit, Comprising: The figure which shows the structural example extended to the encoder direction, (b) is by extending a rotating wheel to a sensor direction. FIG. 3 is a partially enlarged cross-sectional view illustrating a configuration example in which an encoder is positioned within a detection allowable range of a sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor 2 Stationary wheel 4 Rotating wheel 22 Encoder 24 Seal 26 with an encoder 26 Slinger 28 Seal main body P1 Extension part P2 Seal position adjustment part

Claims (7)

It is built into a bearing unit that has stationary and rotating wheels that face each other so that they can rotate relative to each other, and a sensor that detects the rotational state of the rotating wheel with respect to the stationary wheel, and seals the annular space between the stationary wheel and the rotating wheel. A seal with an encoder capable of
An annular slinger that can be fixed to a rotating wheel;
An annular seal body that can be fixed to a stationary ring in sliding contact with the slinger;
An encoder in which encoded information that can be detected by the sensor of the bearing unit is recorded,
An encoder-attached seal, wherein an encoder can be attached to the slinger, and a positioning structure for positioning the encoder within a detection allowable range of the sensor is provided.   The positioning structure is provided with an extension that can be extended in the sensor direction of the bearing unit. By attaching the encoder to the slinger that is extended in the sensor direction by the extension, the encoder can detect the sensor. The seal with an encoder according to claim 1, wherein the seal is positioned within a range.   The slinger includes an annular fixed portion that is fixed to the rotating wheel and to which the seal body is slidably contacted, and an annular wall portion that is folded back from the fixed portion toward the stationary wheel and that is slidably contacted to the seal body. The extending portion is configured to be adjacent to the wall portion and extend in the sensor direction, and the encoder is attached to the extending portion adjacent to the wall portion. The seal with an encoder according to 2.   The slinger includes an annular fixed portion that is fixed to the rotating wheel and that is slidably contacted with the seal body, and an annular wall portion that is folded back from the fixed portion toward the stationary wheel and is slidably contacted with the seal body. The extension part is configured such that the wall part can be extended in the same direction by extending the fixing part in the sensor direction, and the encoder is attached to the wall part extended in the sensor direction by the extension part. The seal with an encoder according to claim 2, wherein the seal has an encoder.   The positioning structure has a seal position that adjusts the position of the seal body in the sensor direction according to the extension state of the wall portion extended in the sensor direction by the extension portion, and positions the seal body in sliding contact with the slinger. The seal with an encoder according to claim 4, further comprising an adjusting portion. The seal body is configured by adding a sealing material to a core metal, and the core metal includes an annular body fixing portion fixed to the stationary ring, and an annular folding portion folded back from the body fixing portion toward the rotating wheel. In addition, the seal material is integrally formed with a seal lip that is slidably contacted with the slinger.
The seal position adjusting unit is fixed to the stationary wheel and can extend in the sensor direction according to the extending state of the slinger wall, and fixes the cored bar to the seal position adjusting unit extended in the sensor direction. The seal body with an encoder according to claim 5, wherein the seal body is positioned in a state where the seal lip is in sliding contact with the slinger. A bearing unit in which the seal with an encoder according to any one of claims 1 to 6 is incorporated,
Between the stationary wheel and the rotating wheel, a stationary wheel that is fixed to the vehicle body and is maintained in a non-rotating state at all times, a rotating wheel that is provided opposite to the stationary wheel and that is connected to the wheel side and rotates together with the wheel. A plurality of rolling elements incorporated in a freely rotatable manner, and a sensor for detecting a rotation state of the rotating wheel with respect to the stationary wheel,
A seal member is incorporated between the stationary wheel on the vehicle body side and the rotating wheel, and a seal with an encoder is incorporated between the stationary wheel on the wheel side and the rotating wheel so that an annular shape between the stationary wheel and the rotating wheel is obtained. A bearing unit, wherein a space is sealed and an encoder is positioned within a detection allowable range of a sensor by a positioning structure of a seal with an encoder.

Images