JP2020001101A - Grinding device and hub wheel manufacturing method - Google Patents

Abstract

To achieve a structure of a grinding device, in which a grinding parallel groove in a logarithmic spiral shape formed on an inside surface in a shaft direction of a rotary flange of a hub wheel can be smoothed in a short time and a step of smoothing the grinding parallel groove can be included in a manufacturing line for a hub unit bearing.SOLUTION: A griding device 28 is constituted of: one or a plurality of grindstones 32; a holder 31 for holding the grindstones 32; an angular type first ball bearing device 30 having a back-surface-combination-type contact angle, which is externally fitted to a hub wheel 9a having a rotary flange 12a when used and supports a holder 31 relatively rotatably with respect to the hub wheel 9a; and a spring 33, which is axial-directional energizing means that energizes the grindstones 32 in an axial direction toward the inside surface in the axial direction of the rotary flange 12a, which can smooth a griding parallel groove in a logarithmic spiral shape formed on an inside surface in the axial direction of the rotary flange 12a by relatively rotating the hub wheel 9a and the holder 31 holding the grindstones 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a grinding device for grinding a hub wheel constituting a hub unit bearing for rotatably supporting a wheel of an automobile or the like, and a method of manufacturing a hub wheel using the grinding device.

  A hub unit bearing for rotatably supporting a wheel of an automobile with respect to a suspension device is used in an environment where muddy water splashes directly. For this reason, such a hub unit bearing incorporates a sealing device to prevent foreign substances such as rainwater and mud from entering the space where the rolling elements are installed, and prevent the enclosed grease from leaking to the outside. are doing. FIG. 4 shows a structure described in JP-A-2005-155882 as an example of a hub unit bearing provided with a sealing device.

The hub unit bearing 1 includes an outer ring 2 that does not rotate in use, a hub 3 that rotates in use, a plurality of rolling elements 4, an inner sealing member 5, and an outer sealing member 6.
Note that, with respect to the hub unit bearing 1, the outer side in the axial direction is the left side in FIG. 4, which is the outer side in the width direction of the vehicle when assembled to the vehicle. 4 is the right side of FIG.

  The outer race 2 has double rows of outer raceways 7a and 7b on an inner peripheral surface, and has a stationary flange 8 on an outer peripheral surface. The outer ring 2 does not rotate in use in order to fix the stationary flange 8 to a suspension device such as a knuckle.

  The hub 3 is arranged coaxially with the outer ring 2 on the radially inner side of the outer ring 2, and is configured by combining a hub wheel 9 and an inner ring 10. The hub wheel 9 is a shaft member that externally holds the inner ring 10, and has a shaft portion 11, a rotating flange 12, and a spline hole 13. The shaft portion 11 is provided in a range from the axially inner portion of the hub wheel 9 to the axially intermediate portion. The shaft portion 11 has a small-diameter stepped portion 14 for externally fitting the inner ring 10 on the inner side in the axial direction, and has an inner ring raceway 15a in an axially outer row on the outer peripheral surface of the axially intermediate portion. I have. The rotating flange 12 protrudes radially outward from the axially outer portion of the hub wheel 9 adjacent to the shaft portion 11 in the axial direction and has a substantially circular shape. A wheel and a rotating body for braking that constitute a wheel are fixed to the rotating flange 12. The spline hole 13 extends axially through the center of the hub wheel 9 in the radial direction. A spline shaft constituting a drive shaft member (not shown) is spline-engaged with the spline hole 13. The inner ring 10 is externally fitted to the small-diameter step portion 14 of the hub wheel 9 and has an inner ring raceway 15b in an axially inner row on the outer peripheral surface.

  The rolling element 4 rotatably held by the retainer is disposed between the double-row outer raceways 7a, 7b and the double-row inner raceways 15a, 15b. Further, grease (not shown) is sealed in an annular space 16 which is present between the inner peripheral surface of the outer race 2 and the outer peripheral surface of the hub 3 and in which a plurality of rolling elements 4 are installed. In order to prevent the grease sealed in the space 16 from leaking to the outside and to prevent foreign substances such as muddy water from entering the space 16, the inner opening in the axial direction of the space 16 is closed by the inner sealing member 5. The outer opening in the axial direction of the space 16 is closed by the outer sealing member 6.

  The inner sealing member 5 is a combined seal ring, and includes an inner seal ring 17 fitted inside the outer ring 2 in the axial direction and a slinger 18 fitted outside the inner ring 10 in the axial direction. The tips of the plurality of seal lips provided on the inner seal ring 17 are slidably contacted with the surface of the slinger 18 over the entire circumference.

  The outer sealing member 6 includes an outer sealing ring 19 fitted inside the outer ring 2 in the axial direction. The tips of the plurality of seal lips constituting the outer seal ring 19 are in direct sliding contact with the surface of the hub wheel 9 over the entire circumference. In the illustrated example, the outer seal ring 19 includes two axial lips 20 a and 20 b called side lips, and one radial lip 21. The distal ends of the two axial lips 20a and 20b are brought into sliding contact with the radially inner portion of the inner surface of the rotating flange 12 in the axial direction. Specifically, the distal end of the radially outer axial lip 20a is attached to a flat surface, which is an imaginary plane orthogonal to the center axis of the hub wheel 9 and located on the radially inner side of the axially inner surface of the rotating flange 12. The tip of the axially inner axial lip 20 b is slid and inclined with respect to an imaginary plane orthogonal to the center axis of the hub wheel 9, which is located on the radially inner side of the axially inner side surface of the rotating flange 12. And a curved surface having an arc-shaped cross section. Further, the distal end of one radial lip 21 is slidably contacted with the outer peripheral surface of the axially outer portion of the shaft 11.

JP 2005-155882 A JP-A-2017-180599

Tokushige Chikamori and Yoshio Kawahara "Tribology Series 7 Sealing Device" Koshobo Publishing, December 1, 1975, p155-156

  By the way, the outer peripheral surface of the hub wheel 9 constituting the hub unit bearing 1 having the above-described configuration, that is, the outer peripheral surface ranging from the axially inner portion to the intermediate portion of the shaft portion 11 and the axially inner surface of the rotating flange 12. Is subjected to a finishing process as described in JP-A-2017-180599. That is, as shown in FIG. 5, the hub wheel 9 is rotated by rotating the magnet chuck 22 which is coupled to the axially outer surface of the rotating flange 12 by the magnetic coupling force. At this time, the outer peripheral surface of the hub wheel 9 is rotatably supported by the tips of the two shoes 23, and the hub wheel 9 is positioned in the radial direction. Then, the outer peripheral surface of the forming wheel (rotary grindstone) 24 formed by a diamond wheel is pressed against the outer peripheral surface of the hub wheel 9, and the outer peripheral surface of the hub wheel 9 is subjected to finishing by grinding.

  When the above-described finishing is performed on the outer peripheral surface of the hub wheel 9, a concave portion 25 in the axial direction is formed on the radially inner portion of the inner surface in the axial direction of the rotating flange 12, as shown in FIG. There is a possibility that a logarithmic spiral (spiral) grinding streak 27 in which the convex portions 26 are alternately arranged in the radial direction is formed. Then, when the grinding streaks 27 are formed on the radially inner side of the axially inner side surface of the rotating flange 12, as shown in FIG. 7, they come into sliding contact with the radially inner side of the axially inner side surface of the rotating flange 12. There is a possibility that the leading edge of the axial lip 20a (20b) enters deeply inside the concave portion 25 forming the grinding streak 27 and is reciprocated in the radial direction when the hub wheel 9 rotates. For this reason, the axial lip 20a (20b) may vibrate in the radial direction and generate abnormal noise called seal squeal.

  On the other hand, Non-Patent Document 1 describes that when the surface roughness of the sliding contact surface is equal to or more than 0.8 Rmax, a screw pump action may act on the sliding contact surface. For this reason, when the surface roughness of the inner surface in the axial direction of the rotating flange is 0.8 Rmax or more due to the formation of the grinding streak, the screw pump function works, and depending on the rotating direction of the hub, Grease may leak to the outside from the sliding contact portion between the axial inner surface of the rotating flange and the axial lip. In addition, the space between the axial lip and the radial lip becomes negative pressure, and the axial lip may be pressed (sticked) to the axial inner surface of the rotating flange, thereby increasing the sealing torque.

  Therefore, it is conceivable to perform super finishing, electrodeposition coating, shot peening, or the like on the radially inner portion of the axially inner side surface of the rotating flange where the tip of the axial lip slides. However, superfinishing has the advantage that the surface roughness can be sufficiently reduced, but has the disadvantage that the machining time is longer than grinding. Electrodeposition coating and shot peening processing have a very different processing time (line tact) from the various steps in the hub unit bearing production line, that is, the grinding step and the assembly step. , Waiting time, etc., and line tact is likely to be disturbed. In addition, electrodeposition coating is restricted by factory equipment and equipment because an organic solvent is used. Shot peening is restricted by factory equipment and equipment because it is a dusting operation. For this reason, electrodeposition coating and shot peening may need to be performed at a factory different from the hub unit bearing manufacturing factory, and transport of hub wheels between factories is required, which tends to increase manufacturing costs Become.

  The present invention has been made in view of the above circumstances, and it is possible to smooth a logarithmic spiral grinding streak formed on an axial inner surface of a rotating flange of a hub wheel in a short time, and to provide a hub unit bearing. It has been invented to realize a structure of a grinding apparatus which enables a step of smoothing a grinding streak to be incorporated in the production line without disturbing the line tact of the production line.

Among the grinding device and the method for manufacturing a hub wheel of the present invention, the invention relating to the grinding device includes a grindstone, a holder, a first bearing device, and an axial biasing unit.
The holder holds the whetstone.
The first bearing device is, for example, an angular type ball bearing device having a back-to-back (DB) contact angle, and is externally fitted to a hub wheel having a rotating flange when used, and the holder is attached to the hub wheel. On the other hand, it is supported so that it can rotate relatively. The first bearing device is not limited to a double-row ball bearing device, and a bearing device capable of supporting both a radial load and an axial load can be used. That is, a double-row tapered roller bearing device or a deep groove ball bearing can be used.
The axial urging means axially urges the grindstone toward an axial side surface of the rotating flange.

The shape of the whetstone is not particularly limited, but for example, a stick shape (rod shape) or an annular shape can be adopted. Further, the shape of the holder is not particularly limited, and a shape capable of holding the grindstone can be adopted.
When a ball bearing device having a back-to-back combination type contact angle is used as the first bearing device, a pair of single-row angular contact ball bearings may be arranged in a back-to-back combination type. A pair of single row angular contact ball bearings may be constituted by a double row angular contact ball bearing in which one or both of the outer ring and the inner ring are integrated. Further, the outer ring and the holder constituting the first bearing device can be formed separately or can be formed integrally.
The axial biasing means, for example, elastically biases the grindstone to the axial side surface of the rotating flange, a compression coil spring, a spring such as a disc spring, a leaf spring, or an elastic member such as rubber, or Hydraulic, gas or pneumatic cylinders may be employed, or other mechanisms may be employed.

  In the grinding device of the present invention, the grindstone can be moved in the radial direction when the holder and the hub wheel are relatively rotated. The number of the grindstones moved in the radial direction is not particularly limited, and may be one or more.

In order to move the grindstone in the radial direction, for example, the grinding device of the present invention may further include an eccentric ring, a second bearing device, a circumferential biasing unit, and a stopper.
The eccentric ring has a radial distance from the center of rotation to an outer peripheral surface that varies in a circumferential direction, and is externally fitted to the first bearing device.
The second bearing device is, for example, an angular ball bearing device having a contact angle of a back-to-back combination type, and is externally fitted to the eccentric ring. The second bearing device is not limited to a double-row ball bearing device, and a bearing device capable of supporting both a radial load and an axial load can be used. That is, a double-row tapered roller bearing device or a deep groove ball bearing can be used.
For this reason, the holder is supported by the first bearing device via the second bearing device and the eccentric ring.
The whetstone has a stick shape.
The circumferential biasing means biases the eccentric ring in the circumferential direction in a state before the start of processing so that a phase of the portion of the eccentric ring having the largest radial distance and a phase of the grinding wheel coincide with each other. I do. Thereby, the grindstone is arranged at a position farthest in the radial direction from the center (center of rotation) of the hub wheel.
The stopper prevents relative rotation of the holder with respect to the eccentric ring when the phase of the portion of the eccentric ring having the smallest radial distance and the phase of the grinding stone match. Thereby, the grindstone is arranged at a position closest to the center of the hub wheel.
In the case where a ball bearing device having a back-to-back type contact angle is used for the second bearing device, a pair of single-row angular contact ball bearings may be arranged in a back-to-back type. Alternatively, the outer ring and the inner ring of a pair of single row angular contact ball bearings may be constituted by a double row angular contact ball bearing in which one or both of them are integrated.
Also, as for the circumferential direction urging means, similarly to the axial direction urging means, an elastic member such as a spring or rubber, or a hydraulic, gas or pneumatic cylinder can be used. A mechanism can also be employed.

The method for manufacturing a hub wheel according to the present invention is a method for manufacturing a hub wheel, comprising: a rotating flange protruding radially outward on an axially outer portion; and a shaft portion ranging from an axially inner portion to an axially intermediate portion. It is.
The method for manufacturing a hub wheel of the present invention is performed using the grinding device of the present invention. That is, in a state where the first bearing device is externally fitted to the shaft portion and the grindstone is pressed against the axial inner surface of the rotating flange by the urging force of the axial urging means, the holder and the hub wheel And a step of grinding the inner surface in the axial direction of the rotating flange by relatively rotating the rotating flange.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to smooth the logarithmic spiral grinding streak formed in the axial inner surface of the rotating flange of a hub wheel in a short time. For this reason, it is possible to incorporate a step of smoothing the grinding streaks into the production line of the hub unit bearing without disturbing the line tact of the production line.

FIG. 1 is a schematic cross-sectional view showing a grinding process using a grinding device according to a first example of an embodiment. FIG. 2 is a schematic cross-sectional view illustrating a grinding process using a grinding device according to a second example of the embodiment, in which an upper half shows a mode in which grinding is performed, and a lower half shows a state in which grinding is performed. Shows the state before the start of grinding. 3A and 3B are schematic views of a grinding device according to a second example of the embodiment as viewed from the right side of FIG. 1, wherein FIG. 3A illustrates a state before the start of grinding, and FIG. The running mode is shown. FIG. 4 is a cross-sectional view showing a hub unit bearing provided with a hub wheel to be subjected to the manufacturing method of the present invention. FIG. 5 is a cross-sectional view of an aspect in which finish processing is performed on the outer peripheral surface of the hub wheel using a general-purpose grindstone as viewed from above in the vertical direction. FIG. 6 is a schematic diagram showing grinding streaks formed by finishing on the axially inner surface of the rotating flange, and FIG. 6A is a diagram of the axially inner surface of the rotating flange viewed from the axially inner side; (B) is an AA sectional view of (A). FIG. 7 is a schematic cross-sectional view showing a sliding contact portion between a grinding streak and a leading edge of an axial lip.

[First Example of Embodiment]
A first example of the embodiment will be described with reference to FIG.
The grinding device 28 of this example is a device for grinding a hub wheel 9a constituting a hub unit bearing for rotatably supporting wheels of an automobile or the like as shown in FIG. Specifically, the grinding device 28 includes an outer sealing member 27 (see FIG. 6) formed on the inner surface in the axial direction of the rotary flange 12a by a finishing process using the forming grindstone 24 (see FIG. 5). This is a device for smoothing a portion where a seal lip (axial lip) constituting a member slides. For this reason, the grinding process performed using the grinding device 28 is performed after the finishing process using the forming wheel 24.

  As shown in FIG. 1, the finished hub wheel 9a is a shaft member that externally holds the inner ring 10 (see FIG. 4), and has a shaft portion 11a and a rotating flange 12a. In this example, since the hub wheel 9a to be ground is for the driven wheel, no spline hole is formed at the radial center. However, a hub wheel 9 for driving wheels (see FIG. 4) having a spline hole at the center in the radial direction can also be subjected to grinding.

  The shaft portion 11a is provided in a range from an axially inner portion of the hub wheel 9a to an axially intermediate portion. The shaft portion 11a has a small-diameter stepped portion 14a for externally fitting the inner ring 10 on the inner side in the axial direction, and has an inner ring raceway 15a in an axially outer row on the outer peripheral surface of the axially intermediate portion. I have. The outer peripheral surface of the small-diameter step portion 14a is formed into a highly accurate and smooth cylindrical surface concentric with the hub wheel 9a by a finishing process using the forming grindstone 24.

  The rotating flange 12a protrudes radially outward from the axially outer portion of the hub wheel 9a adjacent to the shaft portion 11a in the axial direction, and has a substantially circular shape. The rotating flange 12a has mounting holes 29, which are through holes, at a plurality of radially intermediate portions at equal intervals in the circumferential direction. A fastening member such as a stud (not shown) is inserted into each of the mounting holes 29. Using these fastening members, nuts (not shown), and the like, the wheels and the rotating body for braking are fixed to the axially outer surface of the rotating flange 12a. A logarithmic spiral grinding streak 27 is formed on the inner surface in the axial direction of the rotating flange 12a with the finishing using the forming grindstone 24.

  The grinding device 28 includes a first ball bearing device 30, which is a first bearing device, a holder 31, a grindstone 32, and a spring 33, which is an axial biasing means.

  The first ball bearing device 30 is of an angular type and has a back-to-back (DB) contact angle. In the illustrated example, the first ball bearing device 30 is configured by arranging a pair of single-row angular ball bearings 34a and 34b in a back-to-back combination type. Such a first ball bearing device 30 fits outside the small-diameter step portion 14a of the hub wheel 9a without backlash when grinding the inner surface in the axial direction of the rotary flange 12a. Further, the axially outer surface of the radially inner portion of the first ball bearing device 30, that is, the axially outer surface of the inner race constituting the single row angular contact ball bearing 34 a is replaced with the outer peripheral surface of the axially intermediate portion of the shaft portion 11 a. And regulates the axial position of the first ball bearing device 30.

  The holder 31 has a substantially cylindrical shape, and is externally fitted to the first ball bearing device 30. That is, the holder 31 is externally fitted to the outer ring that forms the pair of single-row angular contact ball bearings 34a and 34b. For this reason, the holder 31 is supported by the first ball bearing device 30 so as to be rotatable relative to the hub wheel 9a. The inner peripheral surface of the holder 31 has a pair of inward flanges 37a and 37b on both sides in the axial direction of the cylindrical surface 36 externally fitted to the first ball bearing device 30. The inner side surfaces of the inward flange portions 37a and 37b are abutted on both side surfaces of a radially outer portion of the first ball bearing device 30. This prevents the holder 31 from being displaced in the axial direction with respect to the first ball bearing device 30. The inner diameter of the holder 31 is larger at the axially outer portion than at the axially inner portion and the axially intermediate portion. This prevents the inner peripheral surface of the holder 31 from interfering with the outer peripheral surface of the shaft portion 11a of the hub wheel 9a when the first ball bearing device 30 is externally fitted to the small-diameter step portion 14a of the hub wheel 9a. are doing.

  A holding hole 38 for holding the grindstone 32 is provided at an axially outer portion of the holder 31. The holding hole 38 is opened at the axially outer end surface of the holder 31, and the center axis of the holding hole 38 is parallel to the center axis O of the holder 31. The holding holes 38 are provided in the same number as the grindstones 32, and are provided at equal intervals in the circumferential direction in the illustrated example. The holding hole 38 holds the grindstone 32 without allowing the grindstone 32 to be displaced in the radial direction and the circumferential direction, although the axial displacement of the grindstone 32 is allowed. For this reason, the cross-sectional shape of the holding hole 38 with respect to the virtual plane orthogonal to the central axis O of the holder 31 matches the cross-sectional shape of the grindstone 32 with respect to the same direction.

  The grindstones 32 are provided at a plurality of positions in the circumferential direction on the outer side in the axial direction of the holder 31. The grindstone 32 has a stick shape such as a cylindrical shape or a polygonal pillar shape in the illustrated example, and the inner half in the axial direction is held (inserted) inside the holding hole 38 so as to be capable of being displaced in the axial direction. I have. The tip end surface, which is the outer end surface in the axial direction, of the grindstone 32 has a flat surface in an unused state. The circumscribed circle diameter of the tip surfaces of the plurality of whetstones 32 is larger than the sliding contact diameter Sout of the seal lip located at the outermost in the radial direction among the seal lips of the outer sealing member slidingly contacting the inner surface in the axial direction of the rotating flange 12a. large. In addition, the inscribed circle diameter of the tip surfaces of the plurality of grinding wheels 32 is the sliding contact diameter of the seal lip located most inward in the radial direction among the seal lips of the outer sealing member slidingly contacting the axial inner surface of the rotating flange 12a. Smaller than Sin. In other words, the radial width of the tip end surface of the grindstone 32 is wider than the sliding contact width (sliding contact range S in the radial direction) of a plurality of or one seal lip sliding on the axial inner surface of the rotary flange 12a. ing.

  The same number of the springs 33 as the axial direction urging means are provided as the number of the grindstones 32 and the holding holes 38, and in the illustrated example, the springs 33 are compression coil springs. The spring 33 is arranged inside the holding hole 38, and is sandwiched between the bottom surface of the holding hole 38 and the axial inner end surface of the grindstone 32. Thereby, the spring 33 elastically urges the grindstone 32 outward in the axial direction. The magnitude of the elasticity (biasing force) of the spring 33 is determined by the tip surface of the grinding wheel 32 when the hub wheel 9a to be ground is set on the grinding device 28 and the grinding wheel 32 and the rotary flange 12a are relatively rotated. The size is adjusted to such an extent that the streaks 27 can be removed. The reaction force of the spring 33 is supported by a support (not shown) of the holder 31.

  As a manufacturing process of the hub wheel 9a, in order to perform the grinding process on the hub wheel 9a after the finishing process using the forming wheel 24 using the above-described grinding device 28, the hub wheel 9a has a small diameter. The first ball bearing device 30 is externally fitted to the step portion 14a without play. That is, inside the first ball bearing device 30, the small-diameter stepped portion 14a of the hub wheel 9a is inserted from the outside in the axial direction, and is pressed by a support (not shown). Thereby, the tip surfaces of the plurality of grindstones 32 held on the axially outer portion of the holder 31 elastically abut on the radially inner portion of the axially inner side surface of the rotary flange 12a. Then, while grinding oil such as honing oil or coolant is jetted from a nozzle (not shown) to a contact portion between the tip end surface of the grindstone 32 and the axial inner surface of the rotary flange 12a, the holder 31 having the grindstone 32 and the hub wheel 9a is relatively rotated. At this time, one of the holder 31 and the hub wheel 9a is fixed to a fixing table (not shown), and the other of the holder 31 and the hub wheel 9a is rotationally driven by a rotation driving device (not shown). At this time, the center axis O of the hub wheel 9a can be arranged in a horizontal direction or in a vertical direction. In any case, the holder 31 and the hub wheel 9a are held together with the tip surfaces of the plurality of grindstones 32 pressed against a radially inner portion (a portion including the sliding range S) of the inner surface in the axial direction of the rotating flange 12a. By performing the relative rotation, the radially inner portion of the axially inner side surface of the rotating flange 12a is brought into sliding contact with the tip surfaces of the plurality of grindstones 32. As a result, the convex portion 26 constituting the grinding streak 27 formed on the radially inner portion of the inner surface in the axial direction of the rotating flange 12a is thinly scraped off. As a result, the grinding streak 27 is smoothed, and a new concentric grinding streak is formed on the radially inner portion of the axially inner side surface of the rotating flange 12a. Unlike the logarithmic spiral grinding streaks 27, the concentric grinding streaks do not cause seal squeal and are formed by smoothing the grinding streaks 27, so that the surface roughness is sufficiently low. The screw pump function does not work.

In this example as described above, of the axial inner surface of the rotating flange 12a of the hub wheel 9a, the grinding streaks 27 formed on the radially inner portion where the seal lip slides can be smoothed in a short processing time. Will be possible. Therefore, it is possible to incorporate a step of smoothing the grinding streaks 27 into the production line of the hub unit bearing 1 (see FIG. 4) without disturbing the line tact of the production line.
That is, if the grinding device 28 is used, after the first ball bearing device 30 is externally fitted to the small-diameter step portion 14a of the hub wheel 9a, the grinding streaks 27 are smoothed only by relatively rotating the hub wheel 9a and the holder 31. Can be For this reason, the grinding streaks 27 can be smoothed in a short processing time as compared with the super-finishing processing, the electrodeposition coating, and the shot peening processing. For this reason, there is no need to generate a waiting time in various processes such as an assembling process already incorporated in the production line of the hub unit bearing 1, and the production line is not disturbed, and the production line has no grinding streaks. This step for smoothing 27 can be incorporated. Further, the size when the hub wheel 9a is set in the grinding device 28 is as compact as the hub unit bearing 1, and the installation area is small, so that it can be easily installed on the production line. Further, since there is no need to transport the hub wheel 9a to another factory, an increase in the manufacturing cost of the hub unit bearing 1 can be suppressed.
In the case where the present example is carried out, a wheel having an annular shape can be used as the grindstone 32. In this case, the holding hole 38 is a concave groove formed over the entire outer peripheral surface of the holder 31 in the axial direction.

[Second Example of Embodiment]
A second example of the embodiment will be described with reference to FIGS.
The grinding device 28a of this example has a function of automatically dressing the grindstone 32a. Specifically, the grinding device 28a performs dressing on the distal end surface of the grinding wheel 32a by moving the grinding wheel 32a in the radial direction with respect to the rotating flange 12a in an initial stage of the grinding process. For this purpose, the grinding device 28a includes a first ball bearing device 30, which is a first bearing device, a holder 31a, a grindstone 32a, and an eccentric ring 39 in addition to a spring 33, which is an axial biasing means. , A second ball bearing device 40 as a second bearing device, a circumferential biasing means 41, and a stopper 42. The first ball bearing device 30 that constitutes the grinding device 28a has a configuration similar to that of the first example of the embodiment.

  The eccentric ring 39 has a radial distance R from the rotation center O (= the center of the hub wheel 9a) to the outer peripheral surface in the circumferential direction, and has a substantially circular ring shape as a whole. That is, in the eccentric ring 39, the center position Oin of the inner peripheral surface and the center position Oout of the outer peripheral surface are shifted in the radial direction, and the central position Oin of the inner peripheral surface coincides with the rotation center O. In addition, the eccentric ring 39 is disposed at a position (radially opposite position) where a portion X having the smallest radial distance R and a portion Y having the largest radial distance R are out of phase by approximately 180 degrees. In the present example, such an eccentric ring 39 is externally fitted to the first ball bearing device 30. The inner peripheral surface of the eccentric ring 39 has a pair of inward flange portions 44a and 44b on both axial sides of the cylindrical surface portion 43 fitted to the first ball bearing device 30 outside. The inner side surfaces of the inward flange portions 44a, 44b abut against both side surfaces of the radially outer portion of the first ball bearing device 30. Thereby, the eccentric ring 39 is prevented from being displaced in the axial direction with respect to the first ball bearing device 30. Further, an outward flange portion 45 protruding radially outward is provided on the inner side in the axial direction of the outer peripheral surface of the eccentric ring 39.

  The second ball bearing device 40 is fitted around the eccentric ring 39 without play. Like the first ball bearing device 30, the second ball bearing device 40 is an angular type and has a back-to-back (DB) contact angle. In the illustrated example, the second ball bearing device 40 is configured by arranging a pair of single-row angular ball bearings 46a and 46b in a back-to-back combination type. Further, the axially inner side surface of the radially inner portion of the second ball bearing device 40, that is, the axially inner side surface of the inner race constituting the single-row angular contact ball bearing 46 b is connected to the outward flange portion 45 provided on the eccentric ring 39. To regulate the axial position of the second ball bearing device 40.

  The holder 31a has a substantially cylindrical shape, and is externally fitted to the second ball bearing device 40 unlike the structure of the first example of the embodiment. That is, the holder 31a is externally fitted to the outer ring that forms the pair of single-row angular contact ball bearings 46a and 46b. For this reason, the holder 31a is supported by the first ball bearing device 30 via the second ball bearing device 40 and the eccentric ring 39. The inner peripheral surface of the holder 31a has a pair of inward flanges 37c and 37d on both sides in the axial direction of the cylindrical surface portion 36a externally fitted to the second ball bearing device 40. The inner side surfaces of the inward flange portions 37c and 37d abut against both side surfaces of a radially outer portion of the second ball bearing device 40. This prevents the holder 31a from being displaced in the axial direction with respect to the second ball bearing device 40. The holder 31a has a holding arm 47 projecting outward in the axial direction at one location in the circumferential direction. The holding arm 47 has a holding hole 38 for holding the grindstone 32a. The holding hole 38 is opened on the axially outer end face of the holder 31a, and only one holding hole 38 is provided. The holding hole 38 allows the axial displacement of the grindstone 32a, but holds the grindstone 32a such that the radial displacement and circumferential displacement of the grindstone 32a are not possible.

  Only one grinding stone 32a is provided on the holding arm 47 provided on the outer side in the axial direction of the holder 31a. For this reason, when the hub wheel 9a is set in the grinding device 28a, the grindstone 32a is held by the holder 31a so as to face one location in the circumferential direction of the inner surface in the axial direction of the rotary flange 12a. The grindstone 32a has a stick shape such as a cylindrical shape or a polygonal pillar shape in the illustrated example, and the inner half in the axial direction is held (inserted) inside the holding hole 38 so as to be capable of being displaced in the axial direction. I have. The tip end surface, which is the outer end surface in the axial direction, of the grindstone 32a is flat when not in use.

  Only one spring 33, which is an axial biasing means, is provided, and in the illustrated example, is a compression coil spring. The spring 33 is disposed inside the holding hole 38 and is sandwiched between the bottom surface of the holding hole 38 and the axial inner end surface of the grindstone 32a. Thus, the spring 33 elastically urges the grindstone 32a outward in the axial direction. The reaction force of the spring 33 is supported by a support (not shown) that supports the eccentric ring 39 via the holder 31a, the second ball bearing device 40, and the eccentric ring 39.

  The circumferential biasing means 41 is an elastic member such as a spring or rubber, and the phase of the portion Y of the eccentric ring 39 having the largest radial distance R and the phase of the grindstone 32a match before starting the processing. To urge the eccentric ring 39 in the circumferential direction. In the illustrated example, since the center axis O of the hub wheel 9a and the center axis O of the holder 31a are horizontally arranged to perform the grinding, the initial phase of the holder 31a is determined by the weight of the grindstone 32a and the holding arm 47. Before the start of the grinding, the grindstone 32a is located at the lower end in the vertical direction. For this reason, the circumferential urging means 41 urges the eccentric ring 39 in the circumferential direction such that the portion Y having the largest radial distance R is located at the lower end in the vertical direction. Thereby, the grindstone 32a is arranged at a position farthest in the radial direction from the center of the hub wheel 9a. Specifically, among the seal lips that slide in contact with the axially inner side surface of the rotary flange 12a, the tip end surface of the grindstone 32a is located radially outward from the sliding contact diameter Sout of the seal lip that is located radially outward. The grindstone 32a is arranged so as to perform. Such a circumferential biasing means 41 is provided, for example, between a support (not shown) for fixing the eccentric ring 39 during grinding and the eccentric ring 39.

  In the present example, at an initial stage of the grinding process, the holder 31a holding the grindstone 32a is relatively rotated with respect to the eccentric ring 39, but the stopper 42 is connected to the portion X of the eccentric ring 39 having the smallest radial distance R. In a state where the phase with the grinding stone 32a matches, the relative rotation of the holder 31a with respect to the eccentric ring 39 is prevented. That is, the stopper 42 rotates the holder 31a approximately 180 degrees (half a rotation) with respect to the eccentric ring 39 from the state before the start of the grinding processing, and the holder 31a and the eccentric ring The relative rotation with respect to 39 is prevented. Thereby, the grindstone 32a is arranged at a position closest to the center of the hub wheel 9a. Specifically, the grindstone 32a is positioned at a position where the tip end surface of the grindstone 32a can cover the entire sliding contact width (sliding contact range S in the radial direction) of the plurality of seal lips sliding on the inner surface in the axial direction of the rotating flange 12a. Deploy. Although the specific configuration of the stopper 42 is not particularly limited, for example, as shown in the structure shown in the drawing, the stopper 42 is formed by a stopper piece 48a provided at one location in the circumferential direction of the holder 31a and a circumferential piece 1 of the eccentric ring 39. And the stopper piece 48b provided at the position. By engaging the pair of stopper pieces 48a and 48b in the circumferential direction, the relative rotation of the holder 31a with respect to the eccentric ring 39 can be prevented.

  In order to grind the hub wheel 9a using the grinding device 28a as described above, the first ball bearing device 30 is fitted to the small-diameter step portion 14a of the hub wheel 9a without looseness, and then the eccentric ring is formed. 39 is pressed by a support (not shown). Further, the hub wheel 9a is connected to a rotation driving device (not shown), the center axis O of the hub wheel 9a is arranged in the horizontal direction, and the holder 31a is set in a free state. Thereby, as shown in the lower half of FIG. 2 and FIG. 3A, the tip end surface of the grindstone 32a held on the axially outer portion of the holder 31a and located at the lower end in the vertical direction is rotated by the rotating flange 12a. Of the inner axial surface of the seal lip is elastically in contact with a portion located radially outward of the sliding contact diameter Sout of the seal lip. Then, while grinding oil such as honing oil or coolant is jetted from a nozzle (not shown) to a contact portion between the tip end surface of the grindstone 32a and the axial inner surface of the rotary flange 12a, the hub wheel 9a is rotated by a rotary drive device (not shown). Is driven to rotate. Then, in a state before the start of the grinding, the grindstone 32a positioned at the lower end in the vertical direction rotates along with the rotating flange 12a due to a frictional force generated between the tip surface and the axial inner surface of the rotating flange 12a. Being rotated. The stopper 42 prevents the holder 31a from rotating relative to the eccentric ring 39 in a state where the phase of the portion X of the eccentric ring 39 having the smallest radial distance R and the phase of the grinding stone 32a match. For this reason, as shown in the upper half of FIG. 2 and FIG. 3B, the grindstone 32a is arranged at the vertical upper end position closest to the center of the hub wheel 9a. In this state, the whetstone 32a is disposed at a position where the tip end surface covers the entire sliding contact width (radial sliding range S in the radial direction) of the plurality of seal lips sliding on the axially inner side surface of the rotating flange 12a. I have. As described above, in this example, at the initial stage of the grinding process, the distal end surface of the grindstone 32a is moved in the radial direction (radially inward) with respect to the axially inner side surface of the rotating flange 12a.

  After the grindstone 32a moves to the upper end position in the vertical direction, the eccentric ring 39 is pressed and fixed by a support (not shown), and the holder 31a and the hub wheel 9a are relatively rotated. Then, the radially inner portion of the axially inner side surface of the rotary flange 12a is brought into sliding contact with the tip end surface of the grindstone 32a. Thereby, the grinding streaks 27 (see FIG. 6) formed on the radially inner portion of the axially inner side surface of the rotating flange 12a are smoothed.

In the present example as described above, in the initial stage of the grinding process, the tip surface of the grindstone 32a is dressed by moving the tip surface of the grindstone 32a in the radial direction with respect to the axial inner surface of the rotating flange 12a. Can be. For this reason, by continuously using the grinding device 28a, the wear of the tip surface of the grindstone 32a becomes uneven (the tip surface is not a flat surface), thereby effectively preventing the grinding streaks 27 from being difficult to remove. it can.
Other configurations and operational effects are the same as those of the first example of the embodiment.

  In practicing the present invention, a stick-shaped whetstone can be used. The shape of the holder is not particularly limited, and for example, a cylindrical or block-shaped holder can be used. Further, double-row angular contact ball bearings can be used as the first ball bearing device and the second ball bearing device. Further, as the axial urging means and the circumferential urging means, an elastic member such as a spring or rubber can be used, or another mechanism can be used.

  Further, with the hub wheel set in the grinding device, the center axis of the hub wheel can be arranged in a horizontal direction or in a vertical direction. When the hub wheel and the holder are relatively rotated, the hub wheel can be driven to rotate and the holder can be fixed, or the hub wheel can be fixed and the holder can be driven to rotate.

DESCRIPTION OF SYMBOLS 1 Hub unit bearing 2 Outer ring 3 Hub 4 Rolling element 5 Inner sealing member 6 Outer sealing member 7a, 7b Outer ring track 8 Stationary flange 9, 9a Hub wheel 10 Inner ring 11, 11a Shaft part 12, 12a Rotating flange 13 Spline hole 14, 14a Small-diameter step 15a, 15b Inner ring raceway 16 Space 17 Inner seal ring 18 Slinger 19 Outer seal ring 20a, 20b Axial lip 21 Radial lip 22 Magnet chuck 23 Shoe 24 Overall grindstone 25 Concave 26 Convex part 27 Grinding line 28, 28a Grinding device 29 mounting hole 30 first ball bearing device 31, 31a holder 32, 32a grinding wheel 33 spring 34a, 34b single row angular ball bearing 35 step surface 36 cylindrical surface portions 37a to 37d inward flange 38 holding hole 39 eccentric ring 40 second Ball bearing device 1 circumferential biasing means 42 stopper 43 cylindrical surface portion 44a, 44b inward flange portion 45 outward flange portion 46a, 46b single-row angular contact ball bearing 47 holding arms 48a, 48b stop piece

Claims (4)

With a whetstone,
A holder for holding the whetstone,
A first bearing device, which is externally fitted to a hub wheel having a rotating flange during use and supports the holder so as to be rotatable relative to the hub wheel;
An axial biasing means for axially biasing the grindstone toward an axial side surface of the rotary flange.   The grinding device according to claim 1, wherein the grindstone moves in a radial direction when the holder and the hub wheel are relatively rotated. An eccentric ring externally fitted to the first bearing device and having a radial distance from the rotation center to the outer peripheral surface changed in a circumferential direction; a second bearing device externally fitted to the eccentric ring; Further comprising a biasing means and a stopper,
The holder is supported by the first bearing device via the second bearing device and the eccentric ring,
The whetstone has a stick shape,
The circumferential biasing means biases the eccentric ring in the circumferential direction in a state before the start of processing so that a phase of the portion of the eccentric ring having the largest radial distance and a phase of the grinding wheel match. And
The stopper prevents relative rotation of the holder with respect to the eccentric ring in a state in which the phase of the portion having the smallest radial distance in the eccentric ring matches the phase of the grinding stone.
The grinding device according to claim 2. A method of manufacturing a hub wheel, having a rotating flange protruding radially outward on an axially outer portion, having a shaft portion in a range from an axially inner portion to an axially intermediate portion,
The manufacturing method uses the grinding device according to any one of claims 1 to 3,
In a state where the first bearing device is externally fitted to the shaft portion, and the grinding wheel is pressed against the axially inner side surface of the rotating flange by the biasing force of the axial biasing means, the holder and the hub wheel are separated from each other. A method of manufacturing a hub wheel, comprising a step of grinding an inner surface in the axial direction of the rotating flange by relative rotation.

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