JP2008107177A - Hub unit for driving wheel with state quantity measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete structure of a hub unit for a driving wheel with a state quantity measuring device aiming at the fourth generation hub unit, which is a structure capable of measuring accurately the state quantity. <P>SOLUTION: A core bar 33 to which an encoder 27a is attached and fixed is fitted and fixed on the second cylindrical surface part 25 existing in a space sealed by a seal ring 15 on a middle part outer circumferential surface of a driving shaft member 11. A pair of sensors 28a, 28b are supported inside a cover 16 constituting the seal ring 15, and each detection part of both sensors 28a, 28b is faced close to the outer circumferential surface of the encoder 27a which is a surface to be detected. An aperture 36 is provided between the encoder 27a and the second step surface 26 of the driving shaft member 11. The problem can be solved by adopting this constitution. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The hub unit for a drive wheel with a state quantity measuring device according to the present invention can rotate a drive wheel of an automobile (front wheel of FF vehicle, rear wheel of FR vehicle and RR vehicle, all wheels of 4WD vehicle) with respect to a suspension device. The load acting on the drive wheel is measured and used to ensure stable operation of the vehicle.

  A wheel-supporting hub unit is used to rotatably support a vehicle wheel with respect to a suspension device. In order to control the anti-lock brake system (ABS) or the traction control system (TCS), it is necessary to detect the rotational speed of the wheel. For this reason, the wheel support hub unit with a rotation speed detection device, in which a rotation speed detection device is incorporated in the wheel support hub unit, supports the wheel rotatably with respect to the suspension device, and the rotation of the wheel. In recent years, the detection of speed has been widely performed.

  On the other hand, among the wheel support hub units, the drive wheel hub unit for supporting the drive wheels is used in a state where the outer ring for constant velocity joint, which is a member for transmitting the rotational force from the transmission, is coupled. . Therefore, in recent years, a so-called fourth-generation hub unit called a fourth-generation hub unit, in which the outer ring for the constant velocity joint is unitized with the above-mentioned hub unit for the drive wheel, has been developed in order to reduce the size and weight and improve the handleability. It is considered. 6 to 8 show, as an example of a conventional structure of a drive wheel hub unit with a rotational speed detection device, in which a rotational speed detection device is incorporated in such a drive wheel hub unit called a fourth generation hub unit. The thing described in the literature 1 is shown.

  A drive wheel hub unit 1 called a fourth generation hub unit, which constitutes an example of this conventional structure, includes an outer ring 2, an inner member 3, and a plurality of rolling elements 4 and 4. Of these, the outer ring 2 has first and second outer ring raceways 5a and 5b on the inner circumferential surface and a coupling flange 6 on the outer circumferential surface for coupling and fixing to a suspension device. Further, the inner member 3 is a portion near the outer end of the outer peripheral surface ("outside in the axial direction" means the outer side in the width direction of the vehicle in the assembled state to the automobile, and the left side of each figure except FIG. The right side of each figure except for FIG. 11, which is the center side in the width direction of the vehicle in the assembled state in the automobile, is referred to as “inside” with respect to the axial direction, and is the same throughout the present specification and claims. The mounting flange 7 for supporting and fixing the wheel is similarly provided with first and second inner ring raceways 8a and 8b at the intermediate part and a constant velocity joint outer ring 9 at the inner end part.

  Such an inner member 3 includes a hollow hub 10 having the mounting flange 7 and the first inner ring raceway 8 on the outer peripheral surface, the second inner ring raceway 8b on the outer peripheral surface, and the constant velocity on the inner end. A drive shaft member 11 having the joint outer ring 9 is coupled and fixed to each other. In order to couple and fix the hub 10 and the drive shaft member 11 to each other, in the example shown in the drawing, the hub 10 is fitted on the hollow shaft portion 12 provided at the outer end portion of the drive shaft member 11 without rattling. In this state, the outer half portion of the shaft portion 12 is expanded with a jig, whereby the outer surface of the outer half portion of the shaft portion 12 is formed on the uneven surface portion (spiral unevenness) formed on the inner peripheral surface of the hub 10. Part, Ayame knurl part, etc.) 13. As for the coupling structure between the hub and the drive shaft member, various structures are conventionally known in addition to the illustrated structure (for example, see Patent Document 1).

  Further, a plurality of each of the rolling elements 4, 4 can freely roll between the first and second outer ring raceways 5a, 5b and the first and second inner ring raceways 8a, 8b. Provided. A preload is applied to each of the rolling elements 4 and 4 together with contact angles that are opposite to each other (in the illustrated case, a rear combination type). In the example shown in the figure, balls are used as the rolling elements 4 and 4. However, in the case of a driving wheel hub unit for automobiles which is heavy in weight, a tapered roller may be used. Further, both end openings of the space where the rolling elements 4 and 4 are provided between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the inner member 3 are sealed rings 14 each being a sealing device. , 15.

  Of these seal rings 14, 15, the seal ring 15 that seals the inner end opening of the space includes a cover 16 and a seal material 17. Of these, the cover 16 is formed in an annular shape with a crank-shaped cross section by pressing a steel plate such as SPCC. That is, the cover 16 includes a large-diameter cylindrical portion 18, a large-diameter annular portion 19 bent at a right angle inward in the radial direction from the axial inner end edge of the large-diameter cylindrical portion 18, and the large-diameter annular portion. A small-diameter cylindrical portion 20 bent at a right angle inward in the axial direction from the radially inner end edge of 19, and a small-diameter ring portion 21 bent at a right angle inward in the radial direction from the axial inner end edge of the small-diameter cylindrical portion 20; Is provided. In such a cover 16, the large-diameter cylindrical portion 18 is externally fitted to the inner end portion of the outer ring 2 by an interference fit, and the large-diameter circular ring portion 19 is in contact with the inner end surface of the outer ring 2. Therefore, the outer ring 2 is supported and fixed. Further, the sealing material 17 is formed in an annular shape by rubber, and its base is fixed to the inner peripheral edge of the small-diameter annular portion 21 over the entire circumference. Then, in this state, the cylindrical surface portion 23 and the step surface formed by forming the leading edges of the plurality of seal lips 22a, 22b and 22c constituting the seal material 17 on the outer peripheral surface of the drive shaft member 11 near the inner end, respectively. 24 is in sliding contact with the entire circumference. Thereby, the inner end opening of the space in which the plurality of rolling elements 4 and 4 are installed is sealed.

  Further, in the outer peripheral surface of the intermediate portion of the drive shaft member 11, a portion between the second inner ring raceway 8 b and the cylindrical surface portion 23 has a second cylindrical surface portion 25 having a smaller diameter than the cylindrical surface portion 23. Is provided. Further, a second step surface 26 is provided between the cylindrical surface portion 23 and the second cylindrical surface portion 25. A cylindrical encoder 27 made of a rubber magnet is fitted and fixed to the second step surface 26. In this state, the encoder 27 is positioned in the axial direction by abutting the inner edge of the encoder 27 against the second step surface 26. On the outer peripheral surface of the encoder 27, which is the detection surface, as shown in FIG. 8, S poles and N poles are alternately arranged at equal intervals in the circumferential direction. The boundaries between these S poles and N poles are parallel to the axial direction of the encoder 27, respectively.

  A sensor 28 is supported and fixed to a part of the cover 16. Specifically, with the tip of the sensor 28 (the lower end in FIGS. 6 to 7) inserted inside the cover 16 through the through hole 29 formed in the small diameter cylindrical portion 20 constituting the cover 16, The sensor 28 is supported and fixed to the cover 16. In this state, the tip of the sensor 28, which is a detection unit, is placed in close proximity to the outer peripheral surface of the encoder 27, which is a detection surface. Note that a magnetic sensing element such as a Hall IC, a Hall element, an MR element, or a GMR element is incorporated in the detection portion of the sensor 28.

  When the drive wheel hub unit with a rotational speed detection device configured as described above is used, when the encoder 27 rotates together with the wheel supported and fixed to the inner member 3, the vicinity of the detection portion of the sensor 28 is placed near the encoder. S poles and N poles provided on the outer peripheral surface of 27 pass alternately. As a result, the direction of the magnetic flux penetrating the detection unit of the sensor 28 is alternately changed, and the output of the sensor 28 is periodically changed accordingly. The frequency at which the output of the sensor 28 changes in this way is proportional to the rotational speed of the wheel. Therefore, based on the output signal of the sensor 28, the rotational speed of the wheel can be obtained. Further, in the case of the drive wheel hub unit with the rotational speed detection device configured as described above, the encoder 27 and the sensor 28 are disposed in the radial direction between the outer ring 2 and the drive shaft member 11. It arrange | positions inside the recessed part opened outside. For this reason, the hub unit for a drive wheel with a rotational speed detection device including the encoder 27 and the sensor 28 can be configured in a small size.

  By the way, the above-mentioned ABS, TCS, and various vehicle travel stabilization devices such as an electronically controlled vehicle stability control system (ESC) as described in Non-Patent Document 1, for example, are more highly controlled. In order to do this, it may be preferable to know the magnitude of the load (for example, one or both of the radial load and the axial load) applied to the wheel supporting hub unit via the wheel in addition to the rotational speed of the wheel described above. is there. In view of such circumstances, Patent Documents 2 to 3 describe inventions that measure the magnitude of the load applied to the wheel supporting hub unit using a special encoder.

  9 to 11 show what is described in Patent Document 2 as a first example of a conventional structure of a wheel support hub unit with a state quantity measuring device capable of measuring the load. The wheel support hub unit 30 constituting the first example of this conventional structure is a so-called third generation hub unit, and is used on the inner diameter side of the outer ring 2 that does not rotate in a state of being coupled and fixed to a suspension device during use. A hub 10a that rotates together with the wheel in a state where the wheel is supported and fixed during use is rotatably supported via a plurality of rolling elements 4 and 4. A preload is applied to each of the rolling elements 4 and 4 together with contact angles that are opposite to each other (in the illustrated case, a rear combination type). The third-generation hub unit shown in the figure is for a driven wheel (rear wheel of FF vehicle, front wheel of FR vehicle and RR vehicle), and therefore, the outer ring for constant velocity joint is not coupled to the hub 10a even during use. . On the other hand, in the case of a third generation hub unit for driving wheels, an outer ring for constant velocity joint is coupled to the hub during use. However, unlike the above-described fourth generation hub unit, the constant velocity joint outer ring is handled as a separate part from the hub unit. In any case, in the case of this example, the encoder 27a is externally fitted and fixed to the intermediate portion of the hub 10a, and the rolling elements 4, 4 are arranged in a double row at the axial intermediate portion of the outer ring 2. A pair of sensors 28a and 28b are provided in the intermediate portion in a state where the respective detection portions are closely opposed to the outer peripheral surface of the encoder 27a which is the detection surface.

  In this example, a permanent magnet is used as the encoder 27a. On the outer peripheral surface of the encoder 27a, which is the detection surface, portions magnetized in the S pole and portions magnetized in the N pole are arranged alternately at equal intervals in the circumferential direction. And the axial half of this outer peripheral surface (left half of FIG. 10, upper half of FIG. 11) is the phase of the boundary between the S pole and the N pole with respect to the axial direction of the outer peripheral surface. The first characteristic changing unit 31 gradually changes at a predetermined angle in a predetermined direction. In contrast, the other half of the outer peripheral surface in the axial direction (the right half of FIG. 10 and the lower half of FIG. 11) has a phase at the boundary between the S pole and the N pole in the axial direction of the outer peripheral surface. On the other hand, the second characteristic changing unit 32 gradually changes in the opposite direction to the predetermined direction at the same angle as the predetermined angle. Therefore, the S pole and the N pole have a "V" shape (or "<" shape) in which the central portion in the axial direction protrudes most (or is recessed) in the circumferential direction. Although the detection accuracy is inferior, only the boundary of one of the characteristic change parts 31 and 32 is inclined with respect to the axial direction, and the boundary of the other characteristic change part is parallel to the axial direction. You can also do it.

  Of the pair of sensors 28a and 28b, the detection part of one sensor 28a is close to the first characteristic change part 31, and the detection part of the other sensor 28b is close to the second characteristic change part 32. I am letting. The positions where the detection units of both the sensors 28a and 28b face both the characteristic change units 31 and 32 are the same with respect to the circumferential direction of the encoder 27a. Further, in the state where an axial load is not applied between the outer ring 2 and the hub 10a, the most projecting portion in the circumferential direction at the axial center of the S pole and the N pole (the S pole and the N pole). The portion where the inclination direction of the boundary changes) is located at the center position between the detection portions of the sensors 28a and 28b. In the case of this example as well, the magnetic detection elements as described above are incorporated in the detection portions of the sensors 28a and 28b.

  In the case of this example configured as described above, when an axial load is applied between the outer ring 2 and the hub 10a, the phase at which the output signals of the sensors 28a and 28b change is shifted. That is, in the neutral state in which no axial load is applied between the outer ring 2 and the hub 10a, and the outer ring 2 and the hub 10a are not relatively displaced, the detection portions of the sensors 28a and 28b are 11 is opposed to the solid lines a and b in FIG. 11A, that is, the portion shifted from the most protruding portion by the same amount in the axial direction. Therefore, the phases of the output signals of the sensors 28a and 28b coincide as shown in FIG. On the other hand, when the downward axial load acts in FIG. 11A on the hub 10a to which the encoder 27a is fixed (the outer ring 2 and the hub 10a are relatively displaced in the axial direction (axial direction)). The detectors of both the sensors 28a and 28b are opposed to the portions where the deviations in the axial direction from the broken lines b and b in FIG. In this state, the phases of the output signals of the sensors 28a and 28b are shifted as shown in FIG. Further, when the upward axial load in FIG. 11A is applied to the hub 10a to which the encoder 27a is fixed, the detecting portions of both the sensors 28a and 28b are connected to the chain line hub of FIG. , C, that is, the deviation in the axial direction from the most projecting portion opposes different portions in the opposite direction. In this state, the phases of the output signals of the sensors 28a and 28b are shifted as shown in FIG.

  As described above, in the case of this example, the phase of the output signals of the sensors 28a and 28b depends on the direction of the axial load applied between the outer ring 2 and the hub 10a (the outer ring 2 and the hub 10a In the direction of the relative displacement in the axial direction). Further, the degree to which the phase of the output signals of the sensors 28a and 28b is shifted due to this axial load (relative displacement) increases as the axial load (relative displacement) increases. Accordingly, the direction of relative displacement in the axial direction between the outer ring 2 and the hub 10a based on the presence / absence of the phase shift of the output signals of the sensors 28a, 28b and the direction and magnitude of the shift, if any. The magnitude and the direction and magnitude of the axial load acting between the outer ring 2 and the hub 10a can be obtained. The processing for calculating the relative displacement and the load in the axial direction based on the phase difference between the output signals of the sensors 28a and 28b is performed by a calculator (not shown). For this reason, in this computing unit, the relationship between the phase difference, which has been examined in advance by theoretical calculation or experiment, and the relative displacement and load in the axial direction is incorporated in a model such as a calculation formula or a map.

  In the case of the above-described example of the structure of the prior invention, only one sensor set including a pair of sensors is provided in which each detection unit is opposed to the first and second characteristic change units. On the other hand, Japanese Patent Application Nos. 2006-143097 and 2006-214197 disclose structures in which a plurality of sensor sets each consisting of a pair of sensors are provided so that multidirectional displacement or external force can be obtained. Yes.

  Next, FIGS. 12 to 13 show what is described in Patent Document 3 as a second example of a conventional structure of a wheel supporting hub unit with a state quantity measuring device. In the case of this example, the encoder 27b is fitted and fixed to an intermediate portion of the hub 10a constituting the wheel supporting hub unit 30, and the rolling elements 4, 4 are arranged in a double row at the axial intermediate portion of the outer ring 2. One sensor 28 is provided in the intermediate portion in a state in which the detection portion is close to and opposed to the outer peripheral surface of the encoder 27b which is a detection surface.

  Also in this example, the encoder 27b is made of a permanent magnet. S poles and N poles are alternately arranged at equal intervals in the circumferential direction on the outer peripheral surface of the encoder 27b, which is the detected surface. And as shown in FIG. 13, while making the boundary of the said S pole and the said N pole into the linear shape inclined only the predetermined angle with respect to the axial direction of the said outer peripheral surface, between each boundary adjacent to the circumferential direction The inclination directions with respect to the axial direction are opposite to each other. Thereby, the shape of the S pole and the N pole as seen from the radial direction is a trapezoid, and the width dimension of the S pole and the N pole in the circumferential direction is gradually changed with respect to the axial direction. And the detection part of the said one sensor 28 is made to oppose and adjoin to the outer peripheral surface of such an encoder 27b. In the case of this example configured as described above, when the outer ring 2 and the hub 10a are relatively displaced in the axial direction based on the axial load, the duty ratio (high potential duration / one cycle) of the output signal of the sensor 28 is set. Change. Therefore, based on this duty ratio, the direction and magnitude of the relative displacement, and further the direction and magnitude of the axial load can be obtained.

  In the first and second examples of the conventional structure described above, a configuration is adopted in which the detection surface of the encoder is a cylindrical surface, and the detection portion of the sensor is opposed to the detection surface in the radial direction. On the other hand, if the detection surface of the encoder is an annular surface and the sensor detection unit is opposed to the detection surface in the axial direction, the relative displacement in the radial direction between the outer ring and the hub, and these The radial load acting between the outer ring and the hub can be obtained.

  By the way, as shown in Patent Documents 2 to 3 and the like in which the first and second examples of the conventional structure described above are described, conventionally, a wheel support hub unit with a state quantity measuring device intended for a third generation hub unit. The specific structure of the wheel support hub unit with a state quantity measuring device for the fourth generation hub unit was not known. For this reason, it is desired to realize a specific structure of the drive wheel hub unit with a state quantity measuring device for the fourth generation hub unit. In this case, in particular, it is desired to realize a structure that can sufficiently improve the measurement accuracy of the state quantity by devising the installation position of the encoder and the sensor that constitute the state quantity measurement device for the fourth generation hub unit. .

JP-A-2005-140146 JP 2006-133045 A JP 2006-1113017 A Motoo Aoyama, “Red Badge Super Illustrated Series / A book that shows the latest mechanics of cars”, p. 138-139, p. 146-149, Sangensha Co., Ltd./Kodansha Co., Ltd., December 20, 2001

  In view of the circumstances as described above, the present invention is a specific structure of a drive wheel hub unit with a state quantity measuring device for a fourth generation hub unit, and has good state quantity measurement accuracy. It was invented to realize a possible structure.

The drive wheel hub unit with a state quantity measuring device according to claim 1 of the present invention includes a drive wheel hub unit and a state quantity measuring device.
Of these, the drive wheel hub unit is a so-called fourth generation hub unit, which has first and second outer ring raceways on the inner peripheral surface, and is an outer ring that does not rotate in a state of being coupled to a suspension device during use. And a mounting flange for supporting the wheel on the outer peripheral surface near the outer end in the axial direction, the first and second inner ring raceways in the middle part, and the outer ring for the constant velocity joint in the inner end part in the axial direction, respectively. An inner member that rotates during use, and a plurality of rolling elements provided in a freely rotatable manner between each of the first and second outer ring raceways and the first and second inner ring raceways. And a pair of sealing devices for sealing the opening at both ends of the space where the rolling elements are installed between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner member. The inner member includes a hub having the mounting flange and the first inner ring raceway on the outer peripheral surface, the second inner ring raceway on the outer peripheral surface, and the outer ring for the constant velocity joint on the inner end in the axial direction. The drive shaft members respectively having the above are fixedly coupled to each other.
The state quantity measuring device includes an encoder, a sensor device, and a calculator.
Among these, the encoder is supported and fixed to a part of the inner member and has a detection surface concentric with the inner member. The characteristics of the surface to be detected are alternately changed in the circumferential direction, and the phase or pitch at which the characteristics of the surface to be detected change in the circumferential direction is set to the width at least in a part of the width of the surface to be detected. The direction is continuously changed.
The sensor device is supported by a portion that does not rotate during use, and includes at least one sensor. The at least one sensor has its detection portion opposed to a portion of the detected surface where the phase or pitch of the characteristic change continuously changes in the width direction. The output signal is changed in response to changes in the surface characteristics.
Further, the computing unit is configured to output the outer ring and the outer ring based on information related to the output signals of the sensors (phase difference existing between the output signals of a pair of sensors, duty ratio of the output signal of one sensor, etc.). It has a function of calculating a state quantity between the inner member (relative displacement between the outer ring and the inner member, an external force acting between the outer ring and the inner member).
Particularly, in the case of the drive wheel hub unit with the state quantity measuring device of the present invention, the encoder and the sensor are arranged in a space sealed by the both sealing devices.

  When carrying out the invention described in claim 1 as described above, preferably, as described in claim 2, of the pair of sealing devices, the proximal end portion is used as a sealing device inside in the axial direction. An annular cover that is fitted and fixed to the inner end of the outer ring in the axial direction, and its base end is fixed to the front end of the cover over the entire circumference, and the tip edge is extended over the entire surface of the drive shaft member. Use a material that consists of a sealing material in sliding contact. The encoder is supported and fixed to a portion between the second inner ring raceway and the portion where the seal material is slidably contacted on the outer peripheral surface of the intermediate portion of the drive shaft member. At the same time, the sensor device is supported and fixed to the outer ring through the cover.

When carrying out the invention described in claim 2, the encoder is made of a permanent magnet (rubber magnet, plastic magnet, sintered magnet) as described in claim 3, for example. In order to alternately change the characteristics of the detected surface of the encoder in the circumferential direction, S poles and N poles are alternately arranged in the circumferential direction on the detected surface.
In carrying out the invention described in claim 3, preferably, the encoder is fixedly attached to the entire circumference of an annular cored bar made of a magnetic material, as described in claim 4. The encoder is supported and fixed to the inner member by fitting and fixing the metal core to a part of the inner member.
When the invention described in claim 4 is carried out, as described in claim 5, for example, the encoder is attached and fixed to the entire circumference of the core metal using an adhesive.
Alternatively, as described in claim 6, the encoder is attached and fixed to the entire circumference of the core bar by insert molding the core bar as an insert part.

Further, when carrying out the invention described in claims 4 to 6 described above, for example, as described in claim 7, a portion of the surface of the core metal that is out of a portion where the encoder is attached and fixed. Then, a part of the sealing material constituting the axially inner sealing device is brought into sliding contact.
In carrying out the invention described in the third to seventh aspects, preferably, as described in the eighth aspect, the edge in the width direction of the detection surface of the encoder and the inner member or the A gap in the width direction of the surface to be detected (preferably a gap having a width dimension equal to or larger than the thickness dimension of the encoder) is provided between the cored bar.
Further, when carrying out the invention described in claims 3 to 8 above, preferably, as described in claim 9, the S pole and the N pole are provided at the end in the width direction of the detected surface of the encoder. A non-magnetized region that is not arranged is provided.

According to the drive wheel hub unit with a state quantity measuring device of the present invention configured as described above, a specific structure of the drive wheel hub unit with a state quantity measuring device for a fourth generation hub unit can be realized. . In the case of the present invention, since the encoder and sensor constituting the state quantity measuring device are arranged in a space sealed by a pair of sealing devices, foreign matter such as dust or muddy water is placed on the encoder and sensor. Can be prevented from adhering. Therefore, the state quantity measurement accuracy can be improved.
Moreover, if the structure described in Claim 2 is employ | adopted, the said encoder and sensor can be arrange | positioned inside the recessed part which exists between an outer ring | wheel and a drive shaft member. For this reason, the hub unit for drive wheels provided with the said encoder and sensor can be comprised small.

  Further, when the encoder is made of a permanent magnet as described in claim 3, if the configuration described in claim 4 is adopted, such an inconvenience occurs when the encoder itself is press-fitted into the inner member { For example, when the inner member thermally expands due to inconvenience that the encoder generates excessive stress due to press-fitting and this encoder is damaged, or due to temperature rise during use, it is made of rubber magnet or plastic When the magnet encoder causes creep (a phenomenon in which the amount of deformation of the resin increases with time when the stress acting on the resin is kept constant), and the inner member thermally contracts due to a subsequent temperature drop, The inconvenience that a gap is generated between the outer peripheral surface of the inner member and the inner peripheral surface of the encoder, and the assembly position of the encoder is deviated (measurement error of state quantity occurs). It is possible to prevent that occurs. In other words, if the configuration described in claim 4 is adopted, the internal metal stress caused by press-fitting can be made sufficiently small because the core metal attached and fixed to the encoder can be press-fitted into the inner member instead of the encoder itself. it can. Therefore, the encoder can be effectively prevented from being damaged by the internally generated stress. In addition, this encoder is fixedly attached to the entire circumference of the core bar, and even if the inner member repeats thermal expansion and thermal contraction during use, a gap is generated between the encoder and the core bar. Therefore, the encoder mounting position can be prevented from shifting. Furthermore, if the structure described in claim 4 is adopted, the magnetizing strength of the encoder can be improved and the magnetizing strength can be made uniform based on the presence of the core bar made of a magnetic material.

  Further, when the encoder is made of a permanent magnet as described in claims 3 to 7, if the configuration described in claims 8 to 9 is adopted, the magnetic flux entering and exiting the detected surface of the encoder is made of a magnetic material. It is possible to effectively prevent the inconvenience that the state quantity cannot be accurately measured by flowing into the inner member or the cored bar. That is, when the edge in the width direction of the detected surface of the encoder is abutted against a stepped surface existing on a part of the inner member or the core metal, the magnetic flux entering and exiting from the end in the width direction of the detected surface is A large amount of fluid flows toward the periphery of the step surface. The reason is that the magnetic permeability of the inner member and the cored bar is much larger than that of air, and the magnetic flux tends to pass through the inner member and the cored bar. Because of that. In any case, when the flow direction of the magnetic flux is distorted due to the above-described causes, the magnetic flux density of the portion that is close to and faces the detection surface (the portion where the detection portion of each sensor is arranged) is the width of the detection surface. The size may be significantly different on both sides of the direction, and as a result, the state quantity may not be accurately measured.

  On the other hand, if the structure described in claim 8 is adopted, a gap in the width direction of the detected surface is provided between the edge in the width direction of the detected surface and the inner member or the cored bar. Therefore, it is possible to effectively prevent the magnetic flux entering and exiting from the detected surface from flowing into the inner member or the cored bar and distorting the flow direction of the magnetic flux. Further, if the configuration described in claim 9 is adopted, since the non-magnetized region is provided at the end in the width direction of the detected surface of the encoder, the end edge in the width direction of the encoder is connected to the inner member or the core. Of course, when not hitting a part of the gold, even if it hits, the magnetic flux entering and exiting from the detected surface (magnetized region) flows to the inner member or the core metal, and the flow direction of the magnetic flux changes. Distortion can be effectively prevented. Therefore, if the configuration described in claims 8 to 9 is employed, the magnetic flux density of the portion (the portion where the detection portion of each sensor is arranged) that is close to and faces the detection surface (magnetization region) of the encoder is detected. It is possible to effectively prevent the size from becoming significantly different on both sides in the width direction of the surface. As a result, it is possible to effectively prevent the inconvenience that the state quantity cannot be measured accurately. In addition, if the configuration described in claim 8, that is, the configuration in which the edge in the width direction of the encoder is not abutted against a part of the inner member, when the encoder is press-fitted into the inner member, the encoder Since the compression is not performed between the step surface and the press-fitting jig, it is possible to prevent the inconvenience that the encoder is damaged during the press-fitting.

[First example of embodiment]
FIGS. 1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1, 2, 3, 4, 6 and 9. The feature of this example is that the drive wheel hub unit 1 shown in FIGS. 6 to 7 described above, which is a fourth generation hub unit, includes an encoder 27c and a pair of sensors 28a and 28b constituting a state quantity measuring device. To realize a specific structure of the drive wheel hub unit with the state quantity measuring device for the fourth generation hub unit, and the state quantity (relative in the axial direction between the outer ring 2 and the inner member 3). This is to realize a structure capable of improving the measurement accuracy of the displacement and the axial load acting between the outer ring 2 and the inner member 3. The overall structure of the drive wheel hub unit 1 is the same as that shown in FIGS. 6 to 7 described above, and is a state quantity measuring device that includes the encoder 27c and the sensors 28a and 28b. The basic structure and the principle of state quantity measurement by this state quantity measuring device are substantially the same as in the case of the first example of the conventional structure shown in FIGS. For this reason, equivalent parts are denoted by the same reference numerals, and overlapping illustrations and explanations are omitted or simplified. Hereinafter, the characteristic parts of this example and parts different from the conventional structure will be mainly described.

  In the case of this example, the encoder 27c made of a plastic magnet is attached to the second cylindrical surface portion 25 provided on the outer peripheral surface of the intermediate portion of the steel drive shaft member 11 constituting the drive wheel hub unit 1, and the mild steel plate. It is made of (magnetic material) and is fitted and fixed via a cylindrical cored bar 33. That is, in the case of this example, the inner peripheral surface of the encoder 27c is adhered and fixed to the outer peripheral surface of the core bar 33 over the entire periphery. In this state, the core bar 33 is press-fitted into the second cylindrical surface portion 25 (externally fitted with an interference fit). Further, in this state, the inner end edges of the core metal 33 and the encoder 27c are abutted against the second step surface 26 existing at the inner end edge of the second cylindrical surface portion 25, thereby positioning in the axial direction. I am trying. In the case of this example, as shown in FIG. 2, the S pole and the N pole are not arranged at the inner end in the axial direction on the outer peripheral surface of the encoder 27c, which is the detected surface. A non-magnetized region 34 is provided. At the same time, in the case of the present example, the boundary between the first and second characteristic changing portions 31 and 32 is formed in the central portion in the width direction of the outer peripheral surface of the encoder 27c excluding the non-magnetized region 34. It is arranged. A sensor holder 35 made of synthetic resin is supported and fixed inside a cover 16 constituting the seal ring 15 that is externally fitted and fixed to the inner end of the outer ring 2, and the pair of sensors is attached to the sensor holder 35. 28a and 28b are embedded and supported. And the detection part of both these sensors 28a and 28b is made to adjoin and oppose the said both 1st and 2nd characteristic change parts 31 and 32. FIG.

  According to the drive wheel hub unit with a state quantity measuring device of the present example configured as described above, a specific structure of the drive wheel hub unit with a state quantity measuring device for the fourth generation hub unit can be realized. . In the case of this example, the encoder 27c and the pair of sensors 28a and 28b constituting the state quantity measuring device are provided by a pair of seal rings 14 and 15 (see FIG. 6 for the seal ring 14). Since it is arranged in a sealed space, it is possible to prevent foreign matters such as dust and muddy water from adhering to the encoder 27c and the sensors 28a and 28b. Therefore, the state quantity measurement accuracy can be improved. In the case of this example, the encoder 27c and the sensors 28a and 28b are arranged inside a recessed portion that is present in the portion between the outer ring 2 and the drive shaft member 11 and opens radially outward. is doing. For this reason, the drive wheel hub unit with a state quantity measuring device, which includes the encoder 27c and the sensors 28a and 28b, can be made compact.

  Further, in the case of this example, not the encoder 27c itself but the core metal 33 to which the encoder 27c is bonded and fixed is press-fitted into the second cylindrical surface portion 25 provided on the outer peripheral surface of the intermediate portion of the drive shaft member 11. The configuration is adopted. For this reason, the stress generated inside the encoder 27c due to the press-fitting can be sufficiently reduced. Therefore, it is possible to effectively prevent the encoder 27c from being damaged by this stress. Further, since the encoder 27c is adhesively fixed to the entire circumference of the outer peripheral surface of the core bar 33, the encoder 27c and the core can be used even if the drive shaft member 11 repeats thermal expansion and contraction during use. There is no gap between the gold 33. Therefore, the assembly position of the encoder 27c can be prevented from shifting.

  In the case of this example, the inner end edge of the encoder 27 c is abutted against the second step surface 26 provided on the outer peripheral surface of the intermediate portion of the drive shaft member 11. However, by providing a non-magnetized region 34 at the inner end in the axial direction of the outer peripheral surface of the encoder 27c, both the first and second characteristic changing portions 31, 32 existing at the outer end or intermediate portion of the outer peripheral surface. And a gap between the second step surface 26 and the second step surface 26. For this reason, the magnetic flux entering and exiting from the second characteristic change portion 32 on the second step surface 26 side out of the first and second characteristic change portions 31 and 32 is around the second step surface 26. It can prevent effectively flowing toward the part. Therefore, the magnetic flux density of the portion (a portion where the detection portions of the pair of sensors 28a and 28b are arranged) close to and opposed to the first and second characteristic changing portions 31 and 32 is the same as the both characteristic changing portions 31 and 32. It is possible to effectively prevent the size from being significantly different between the two. As a result, it is possible to effectively prevent the inconvenience that the state quantity cannot be measured accurately.

  In the first example of the above-described embodiment, instead of the encoder 27c described above, the width of the encoder 27d having the detected surface as shown in FIG. An encoder 27d that is larger than the width dimension of the characteristic changing unit 31 can also be used. If such an encoder 27d is used, even if the flow direction of the magnetic flux changes due to the above-described cause at the inner end portion (region on the right side of the chain line α) of the second characteristic changing portion 32, the detection region can It is possible to prevent the flow direction of the magnetic flux from changing at a certain outer end portion to intermediate portion (region on the left side of the chain line α) due to the reasons described above. Therefore, in this case as well, it is effective that the magnetic flux density of the portion close to and opposite to the detection region (the portion where the detection portions of the pair of sensors 28a and 28b are arranged) becomes significantly different on both sides in the axial direction. Can be prevented.

[Second Example of Embodiment]
Next, FIG. 4 shows a second example of an embodiment of the present invention corresponding to claims 1, 2, 3, 4, 6, and 8. In the case of this example, the encoder 27a shown in the above-described FIGS. 9 to 11 is used as the encoder 27a. The encoder 27a does not have a non-magnetized region on the outer peripheral surface that is the detection surface. Instead, in the case of this example, the thickness of the encoder 27a is between the inner end edges of the encoder 27a and the cored bar 33 and the second step surface 26 present on the outer peripheral surface of the intermediate portion of the drive wheel member 11. A gap 36 having a width dimension (dimension in the left-right direction in FIG. 4) comparable to the dimension is provided. As a result, a gap corresponding to the width of the gap 36 is provided between the outer peripheral surface of the encoder 27a, which is the detected surface, and the second stepped surface 26. For this reason, also in the case of this example, it is possible to effectively prevent the magnetic flux entering and exiting from the outer peripheral surface of the encoder 27a from flowing to the peripheral portion of the second step surface 26 and changing the flow direction of the magnetic flux. Therefore, it is effective that the magnetic flux density of the portion (the portion where the detection portions of the pair of sensors 28a and 28b are disposed) close to and opposed to the outer peripheral surface of the encoder 27a become significantly different on both sides in the axial direction. Can be prevented. As a result, it is possible to effectively prevent the inconvenience that the state quantity cannot be measured accurately. The configuration and operation of the other parts are the same as in the case of the first example of the embodiment described above.

[Third example of embodiment]
Next, FIG. 5 shows a third example of the embodiment of the invention corresponding to claims 1, 2, 3, 4, 6, 7, and 8. Also in this example, the encoder 27a shown in FIGS. 9 to 11 is used as the encoder 27a. The encoder 27a does not have a non-magnetized region on the outer peripheral surface that is the detection surface. In addition, as the core metal 33a for attaching and fixing the encoder 27a, a core having a cross-sectional crank shape and an annular shape as a whole is used. The core bar 33 a includes a large-diameter cylindrical portion 37, a small-diameter cylindrical portion 38, and an annular portion 39 that connects both the cylindrical portions 37, 38. The inner peripheral surface of the encoder 27a is bonded and fixed to the outer peripheral surface of the small diameter cylindrical portion 38 over the entire periphery. Further, in this state, the gap 36 between the inner edge of the encoder 27a and the annular ring portion 39 has a width dimension (dimension in the left-right direction in FIG. 5) comparable to the thickness dimension of the encoder 27a. Is provided. In addition, the metal core 33 a that supports and fixes the encoder 27 a in this way press-fits the large-diameter cylindrical portion 37 into the cylindrical surface portion 23 provided on the outer peripheral surface of the intermediate portion of the drive shaft member 11, thereby driving the drive shaft member 11. It is fixed to support. Further, in this state, the annular ring portion 39 is abutted against the second step surface 26 present at the outer end portion of the cylindrical surface portion 23 to achieve axial positioning. In this state, the two seal lips 22a, 22b of the three seal lips 22a, 22b, 22c formed on the seal material 17 constituting the seal ring 15 are formed on the outer peripheral surface of the large-diameter cylindrical portion 37. The tip edge of the is slid over the entire circumference.

  In the case of this example configured as described above, out of each portion constituting the cored bar 33a, not the small-diameter cylindrical portion 38 to which the encoder 27a is externally fixed, but the large-diameter cylindrical portion to which the encoder 27a is not externally fixed. 37 is press-fitted into the cylindrical surface portion 23 of the drive shaft member 11. For this reason, the amount by which the encoder 27a expands during the press-fitting can be made smaller than in the case of the above-described embodiments. Therefore, the stress generated inside the encoder 27a during the press-fitting can be further reduced. As a result, it is possible to more effectively prevent the encoder 27a from being damaged by this stress. In the case of this example, an interval corresponding to the width dimension of the gap 36 is provided between the outer peripheral surface of the encoder 27a, which is a detected surface, and the annular portion 39 constituting the cored bar 33a. . For this reason, it is possible to effectively prevent the magnetic flux flowing in and out from the outer peripheral surface of the encoder 27a from flowing into the annular portion 39 and changing the flow direction of the magnetic flux. Therefore, it is effective that the magnetic flux density of the portion (the portion where the detection portions of the pair of sensors 28a and 28b are disposed) close to and opposed to the outer peripheral surface of the encoder 27a become significantly different on both sides in the axial direction. Can be prevented. As a result, it is possible to effectively prevent the inconvenience that the state quantity cannot be measured accurately. The configuration and operation of the other parts are the same as those in the first example of the embodiment shown in FIG.

  In each of the above-described embodiments, the phase difference detection type state quantity measuring device shown in FIGS. 9 to 11 described above is adopted as the state quantity measuring device including the encoder and the sensor. However, when the present invention is implemented, the state quantity measuring device of the duty ratio detection method shown in FIGS.

The figure similar to FIG. 7 which shows the 1st example of embodiment of this invention. The figure which looked at a part of to-be-detected surface of the encoder incorporated in this 1st example from the radial direction outer side. The figure similar to FIG. 2 which shows another example of the to-be-detected surface of an encoder. The figure similar to FIG. 1 which shows the 2nd example of embodiment of this invention. The figure similar to FIG. 1 which shows the 3rd example. Sectional drawing which shows an example of the conventional structure of the hub unit for drive wheels with a rotational speed detection apparatus. The A section enlarged view of FIG. The figure which looked at a part of to-be-detected surface of the encoder integrated in an example of this conventional structure from the radial direction outer side. Sectional drawing which shows the 1st example of the conventional structure of the hub unit for wheel support with a state quantity measuring device. The figure which looked at a part of to-be-detected surface of the encoder incorporated in this 1st example from the radial direction outer side. The diagram which shows the output signal of the sensor which changes with the fluctuation | variation of an axial load. Sectional drawing which shows the 2nd example of the conventional structure of the hub unit for wheel support with a state quantity measuring device. The figure which looked at a part of to-be-detected surface of the encoder incorporated in this 2nd example from the radial direction outer side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive wheel hub unit 2 Outer ring 3 Inner member 4 Rolling element 5a, 5b Outer ring raceway 6 Coupling flange 7 Mounting flange 8a, 8b Inner ring raceway 9 Outer ring for constant velocity joint 10, 10a Hub 11 Drive shaft member 12 Shaft part 13 Uneven surface part 14 Seal ring 15 Seal ring 16 Cover 17 Seal material 18 Large diameter cylindrical portion 19 Large diameter annular portion 20 Small diameter cylindrical portion 21 Small diameter annular portion 22a, 22b, 22c Seal lip 23 Cylindrical surface portion 24 Step surface 25 Second cylindrical surface portion 26 Second step surface 27, 27a to 27d Encoder 28, 28a, 28b Sensor 29 Through hole 30 Wheel support hub unit 31 First characteristic change part 32 Second characteristic change part 33, 33a Core metal 34 Non-magnetized area 35 Sensor holder 36 Clearance 37 Large diameter cylindrical portion 38 Small diameter cylindrical portion 39 Ring portion

Claims (9)

A drive wheel hub unit and a state quantity measuring device;
Of these, the drive wheel hub unit has first and second outer ring raceways on the inner peripheral surface, and is connected to a suspension device when in use and does not rotate, and a portion of the outer peripheral surface near the axial outer end. An inner member that has a mounting flange for supporting the wheel, a first inner ring raceway, a second inner ring raceway in the middle part, and a constant velocity joint outer ring at the inner end part in the axial direction. A plurality of rolling elements provided between the first and second outer ring raceways and the first and second inner ring raceways, respectively, and an inner peripheral surface of the outer ring and the inner member. And a pair of sealing devices for sealing both end openings of the space in which each of the rolling elements is installed between the outer peripheral surface and the inner member includes the mounting flange and the first inner ring raceway on the outer peripheral surface. The second inner ring raceway on the outer peripheral surface, and the constant velocity on the inner end in the axial direction. The Yointo outer race, and a drive shaft member having respectively, are those formed by binding fixed to each other,
The state quantity measuring device includes an encoder, a sensor device, and a calculator.
Among these, the encoder is supported and fixed to a part of the inner member, has a detected surface concentric with the inner member, and alternately changes the characteristics of the detected surface in the circumferential direction. The phase or pitch at which the characteristic of the detected surface changes in the circumferential direction is continuously changed in the width direction at least in a part of the width direction of the detected surface,
The sensor device is supported by a portion that does not rotate even when in use, and includes at least one sensor, and the at least one sensor has a phase of the characteristic change in the detection surface of the detection unit. Alternatively, the pitch is opposed to a portion where the pitch continuously changes in the width direction, and the output signal is changed in response to the change in the characteristics of the detected surface.
The computing unit has a function of calculating a state quantity between the outer ring and the inner member based on information on the output signal of the sensor.
A drive wheel hub unit with a state quantity measuring device,
A drive wheel hub unit with a state quantity measuring device, wherein the encoder and the sensor are arranged in a space sealed by the both sealing devices.   Of the pair of sealing devices, the axially inner sealing device includes an annular cover whose base end is fitted and fixed to the inner end of the outer ring in the axial direction, and the base end of the entire periphery around the front end of the cover. And a seal member whose tip edge is slidably contacted with the entire surface of the drive shaft member, and the encoder includes the second inner ring raceway and the above-mentioned inner ring raceway on the outer peripheral surface of the intermediate portion of the drive shaft member. 2. The drive wheel hub unit according to claim 1, wherein the sensor device is supported and fixed to a portion between which the seal material is slidably contacted, and the sensor device is supported and fixed to the outer ring via the cover.   The encoder is made of a permanent magnet, and S poles and N poles are alternately arranged in the circumferential direction on the detected surface in order to alternately change the characteristics of the detected surface of the encoder in the circumferential direction. A hub unit for a drive wheel with a state quantity measuring device according to any one of claims 1 and 2.   The encoder is fixedly attached to the entire circumference of an annular cored bar made of a magnetic material, and the encoder is supported and fixed to the inner member by fitting and fixing the cored bar to a part of the inner member. A hub unit for a drive wheel with a state quantity measuring device according to claim 3.   The drive wheel hub unit with a state quantity measuring device according to claim 4, wherein an encoder is attached and fixed to the entire circumference of the core metal using an adhesive.   The drive wheel hub unit with a state quantity measuring device according to claim 4, wherein the encoder is attached and fixed to the entire circumference of the core metal by insert molding the core metal as an insert part.   The part of the sealing material which comprises the sealing device of an axial direction inner side is slidably contacted with the part which remove | deviated from the part which attached and fixed the encoder among the surfaces of a metal core. A hub unit for a drive wheel with a state quantity measuring device described in item 1.   The gap in the width direction of the detected surface is provided between the edge in the width direction of the detected surface of the encoder and the inner member or the cored bar. Drive wheel hub unit with state quantity measuring device described. The state quantity measuring device according to any one of claims 3 to 8, wherein a non-magnetized region in which the S pole and the N pole are not provided is provided at an end in the width direction of the detected surface of the encoder. Hub unit for attached drive wheels.

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