JP2009248246A - Manufacturing method of bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a manufacturing method capable of finish-grinding each of first and second outer-ring raceways 5, 6 with better geometric accuracy. <P>SOLUTION: When subjecting each of the first and second outer-ring raceways 5, 6 to a grinding process, the manufacturing method starts the grinding process, with an integral grinding wheel 14a, first on an inner circumferential surface of a shoulder portion 17, thereby stabilizing a feed rate of the grinding wheel 14a. After that, while maintaining the feed rate stable, the manufacturing method starts grinding each of the first and second outer-ring raceways 5, 6. Employing the manufacturing method like this solves the problem. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a manufacturing method of a bearing device including an outer member having a double row outer ring raceway, such as a bearing unit for supporting a wheel of an automobile.

  The wheels of an automobile are supported on a suspension device by a wheel-supporting bearing unit, which is a kind of bearing device. FIG. 6 shows a first example of a conventional structure of such a wheel support bearing unit. The wheel support bearing unit includes an outer ring 1 that is an outer member, a hub body 2 and an inner ring 3 that are inner members, and a plurality of rolling elements 4 and 4. Of these, the outer ring 1 is formed with first and second outer ring raceways 5 and 6 on the inner peripheral surface and a coupling flange 7 for coupling and fixing to the suspension device on the outer peripheral surface. Further, the hub body 2 has an outer end in the axial direction of the outer peripheral surface ("outside" with respect to the axial direction means the outer side in the width direction of the vehicle in the assembled state to the automobile, and FIGS. 1-4, 6-8, FIG. The left side of Fig. 13. On the contrary, the right side of Fig. 1-4, Fig. 6-8, and Fig. 13, which is the center side in the width direction of the vehicle, is referred to as "inner" in the axial direction. A portion in which a mounting flange 8 for supporting and fixing a wheel and a braking rotating member is formed in a portion, a first inner ring raceway 9 is formed in an axially intermediate portion, and a first inner ring raceway 9 is formed in an axially inner end portion. The small-diameter step portion 11 having a smaller outer diameter is formed.

  The inner ring 3 has a second inner ring raceway 10 on the outer peripheral surface, and is fitted on the small-diameter step portion 11 by an interference fit. Further, in this state, the inner end surface in the axial direction of the inner ring 3 is formed by the caulking portion 13 formed by plastically deforming the distal end portion of the cylindrical portion 12 provided at the inner end portion in the axial direction of the hub body 2 in the radially outward direction. Is suppressed. Thus, the inner ring 3 is coupled and fixed to the hub body 2. Each of the rolling elements 4 and 4 can freely roll between the first and second outer ring raceways 5 and 6 and the first and second inner ring raceways 9 and 10, respectively. Provided. In the example shown in the figure, balls are used as the rolling elements 4 and 4. However, in the case of a heavy-duty automobile bearing unit, tapered rollers may be used.

  By the way, in the wheel support bearing unit as described above, in order to improve the strength and durability of the outer ring 1, the first and second outer ring raceways 5 and 6 of the outer ring 1 (see FIG. 6). A hardened layer formed by induction hardening is formed on each of the parts indicated by the pear ground. The first and second outer ring raceways 5 and 6 are subjected to finishing grinding after the hardened layers are formed. 7 to 8 show two examples of grinding methods for the first and second outer ring raceways 5 and 6, which are conventionally known as described in Patent Document 1, and the like.

  First, a first example of the conventional grinding method shown in FIG. 7 will be described. In the case of this example, by using an integrated grindstone 14, the first and second outer ring raceways 5 and 6 provided on the inner peripheral surface of the outer ring 1 are ground simultaneously (in one behavior). Apply. For this reason, in this example, the first grinding surface 15 for grinding the first outer ring raceway 5 and the second outer ring raceway 6 are ground on the outer peripheral surface of the grindstone 14. The second grinding surface 16 is provided at the same position as the portion to be ground by itself in the axial direction. Of these, the first grinding surface 15 has a generatrix shape that matches the cross-sectional shape of the first outer ring raceway 5 after grinding finish, and the second grinding surface 16 is the second grinding surface 16 after grinding finish. The outer ring raceway 6 has a busbar shape that matches the cross-sectional shape of the outer ring raceway 6.

  When grinding the first and second outer ring raceways 5 and 6 using such a grindstone 14, first, the grindstone 14 is inserted radially inside the outer ring 1, The axial positions of the first and second outer ring raceways 5 and 6 and the first and second grinding surfaces 15 and 16 are made to coincide with each other. At the same time, the outer ring 1 and the grindstone 14 are rotated at different peripheral speeds (for example, in opposite directions) around their own central axes α and β. In this state, the wheel 14 is displaced in the radial direction with respect to the outer ring 1 so that the outer surface of the wheel 14 is brought into contact with the inner surface of the outer ring 1, and the first The first outer ring raceway 5 is ground simultaneously by the grinding surface 15 and the second outer ring raceway 6 is ground simultaneously by the second grinding surface 16.

  In the outer ring 1, the shoulder 17 existing between the first and second outer ring raceways 5, 6 is also affected by heat due to the induction hardening process. Hard carbide called scale may adhere to the surface (cylindrical surface). If this scale falls off during operation and is caught in the rolling contact portion, it is not preferable because it causes generation of vibrations and noise and a decrease in rolling fatigue life. Therefore, as in the first example of the conventional grinding method described above, when grinding is performed only on the first and second outer ring raceways 5 and 6 by the grindstone 14, before and after this, It is preferable to grind the inner peripheral surface of the shoulder portion 17 with another grindstone to remove the scale attached to the inner peripheral surface of the shoulder portion 17.

  Next, a second example of the conventional grinding method shown in FIG. 8 will be described. In the case of this example, using the integrated grindstone 14a, the first and second outer ring raceways 5 and 6 and the inner peripheral surface of the shoulder portion 17 of the outer ring 1 are simultaneously (one Grinding (by behavior). For this reason, in this example, the first grinding surface 15 for grinding the first outer ring raceway 5 and the second outer ring raceway 6 are ground on the outer peripheral surface of the grindstone 14a. The second grinding surface 16 and the third grinding surface 18 for grinding the inner peripheral surface of the shoulder portion 17 are provided at the same positions as the portions to be ground by themselves in the axial direction. Of these, the first grinding surface 15 has a cross-sectional shape that matches the cross-sectional shape of the first outer ring raceway 5 after grinding finish, and the second grinding surface 16 is the second grinding surface 16 after grinding finish. The third grinding surface 18 has a cross-sectional shape that matches the cross-sectional shape of the inner peripheral surface of the shoulder portion 17 after grinding.

  When grinding is performed on the inner peripheral surfaces of the first and second outer ring raceways 5 and 6 and the shoulder portion 17 using such a grindstone 14a, the same as in the case of the first example described above. In this procedure, the outer peripheral surface of the grindstone 14a is brought into contact with the inner peripheral surface of the outer ring 1, and the first and second outer rings are brought into contact with the first and second grinding surfaces 15, 16 as shown in the figure. The inner circumferential surface of the shoulder portion 17 is ground simultaneously with the tracks 5 and 6 by the third grinding surface 18. In this way, in the case of this example, the first and second outer ring raceways 5 and 6 and the inner peripheral surface of the shoulder portion 17 are ground at the same time. The number of processing steps can be reduced compared to the case of applying.

  However, when the first and second examples of the conventional grinding method shown in FIGS. 7 to 8 are performed, the first and second grinding surfaces 15 and 16 provided on the outer peripheral surface of the grindstones 14 and 14a. There is a possibility that a large amount of abrasive grains fall off at a part of the shape, and the first and second outer ring raceways 5 and 6 after grinding finish may be deformed. The reason will be described below.

  When grinding a workpiece, usually, as shown in FIG. 9, a quick approach (a step of bringing a grinding wheel into contact with the workpiece) → rough grinding → finish grinding → spark out (final finish grinding) In the order of the steps, the feed speed (feed amount / time) of the grindstone (outward in the radial direction of the outer ring 1) is decreased stepwise (finally set to zero). Note that the reason why the grindstone feed speed is maximized by the quick approach is to shorten the loss time and improve the work efficiency. In addition, when the grinding machine confirms that contact between the workpiece and the grindstone has occurred using a device called a gap eliminator, it switches the process from quick approach to rough grinding (changes the feed speed of the grindstone). Do.

  On the other hand, although not described in Patent Document 1, the above-described quick approach is performed in the first example of the conventional grinding method shown in FIG. 7 (the outer peripheral surface of the grindstone 14 is changed to the inner peripheral surface of the outer ring 1). The first grinding surface 15 (second grinding surface 16) is in contact with the entire first outer ring raceway 5 (second outer ring raceway 6) from the beginning. is not. That is, in this case, as shown in FIG. 10, first, the first grinding surface 15 (second grinding surface 16) is the first outer ring raceway 5 (second outer ring raceway 6). It contacts the edge (corner P) on the shoulder 17 side. The reason for this is that a uniform thickness allowance 19 (slanted lattice in FIG. 10), which is planned to be removed by grinding, is formed on the surface layer of the first outer ring raceway 5 (second outer ring raceway 6) before grinding finish. This is because there is a portion indicated by.

  Further, in the second example of the conventional grinding method shown in FIG. 8 described above, the above-described quick approach is performed (the outer peripheral surface of the grindstone 14a is displaced radially toward the inner peripheral surface of the outer ring 1). As shown in FIG. 11, first, the first grinding surface 15 (second grinding surface 16) is the edge on the shoulder 17 side of the first outer ring raceway 5 (second outer ring raceway 6). It contacts the part (corner part P). The reason for this is that the first outer ring raceway 5 (second outer ring raceway 6) before grinding finish and the surface layer portion of the inner peripheral surface of the shoulder 17 have a uniform thickness that is planned to be scraped off by this grinding finish. This is because there is a machining allowance 19 (portion shown with an oblique grid in FIG. 11).

  In any case, the contact between the first grinding surface 15 (second grinding surface 16) and the corner P as shown in FIGS. 10 to 11 described above is a point contact or a line contact with a short contact length. Become. Then, vibrations, load loads, changes in motor current, and the like that occur when such point contact or short line contact occurs are small. For this reason, when the gap eliminator performs contact confirmation between the outer ring 1 and the grindstone 14 (14a) based on detection of such vibration, load load, change in motor current, etc. There may be a problem that the timing of the contact confirmation is delayed without detecting small vibrations, load loads, changes in motor current, etc. that occur when contact or short line contact occurs. When such a defect occurs, the grindstone 14 (14a) is fed at the feed speed of the quick approach until the contact is confirmed after the point contact or the short line contact occurs. Become. As a result, as shown in FIG. 12, a large amount of abrasive grains drop off at the portion of the first grinding surface 15 (second grinding surface 16) in contact with the corner portion P (FIGS. 10 to 11). The problem that the concave portion 25 is formed in the portion is likely to occur. When such a problem occurs, as shown in the figure, the machining allowance 19 of the portion of the first outer ring raceway 5 (second outer ring raceway 6) facing the recess 25 is not cut off. This is not preferable because the first outer ring raceway 5 (second outer ring raceway 6) after grinding finish is deformed.

  In addition, the troubles described above are as shown in FIGS. 7 to 8 for the outer ring 1a constituting the second example of the conventional structure of the wheel supporting bearing unit as shown in FIG. This also occurs when each grinding method is performed. This is because, among the inner peripheral surfaces of the outer ring 1a, the pair of outer ring raceways 5a and 6a need to remove the decarburized layer by heat treatment, while the outer ring raceways 5a and 6a are located between the outer ring raceways 5a and 6a. This is because the scale can be removed simply by removing the scale, and the grinding allowance is larger for both the outer ring raceways 5a and 6a. In the second example of the conventional structure of the wheel supporting bearing unit shown in FIG. 13, the diameter of the first outer ring raceway 5a is made larger than the diameter of the second outer ring raceway 6a and the diameter of the first inner ring raceway 9a. Is made larger than the diameter of the second inner ring raceway 10a. As a result, the pitch circle diameter of each rolling element 4, 4 (rolling element row outside in the axial direction) provided between the first outer ring raceway 5a and the first inner ring raceway 9a is set to the second outer ring. It is larger than the pitch circle diameter of each rolling element 4, 4 (rolling element row inside in the axial direction) provided between the track 5a and the second inner ring raceway 10a. By adopting such a configuration, the moment rigidity of the wheel supporting bearing unit is increased. The structure and operation of the other parts are almost the same as those in the first example of the conventional structure described above.

JP 2005-325903 A

  The present invention was invented to realize a manufacturing method capable of preventing the occurrence of the problems as described above and improving the shape accuracy of the double-row outer ring raceway after grinding finish.

The bearing device that is the subject of the manufacturing method of the present invention includes an outer member having a double row outer ring raceway on the inner peripheral surface, an inner member having a double row inner ring raceway on the outer peripheral surface, the outer ring raceways, A plurality of rolling elements provided between the inner ring raceway and the inner ring raceway. And the hardening layer by the induction hardening process is formed in each said outer ring track part among the said outer members, respectively.
In the manufacturing method of the bearing device of the present invention, the hardened layer is formed on each outer ring raceway portion of the outer member in order to manufacture the bearing device having the above-described configuration. A grinding wheel is used to finish grinding the outer ring raceways simultaneously (in one behavior).

In particular, in the case of the method for manufacturing a bearing device according to the present invention, the grinding wheel starts to grind parts other than the outer ring raceways on the inner peripheral surface of the outer member. Stabilize the feed rate (make the feed rate of grinding slower than the quick approach feed rate). Thereafter, the outer ring raceway starts to be ground with the feed rate kept stable.
When carrying out the manufacturing method of the bearing device of the present invention having such a feature, preferably, as described in claim 2, the inner circumferential surface of the outer member is more than the outer ring raceways. The part where the grinding process starts first is defined as at least a part of the part between these outer ring raceways.
More preferably, as described in claim 3, at least finally, the entire portion of the inner peripheral surface of the outer member between the outer ring raceways is ground.

Moreover, the manufacturing method of the bearing device of the present invention as described above can be carried out for a bearing device as described in claims 4 to 5, for example.
Of these, the bearing device described in claim 4 has a pitch circle diameter (and further, the diameter and number of rolling elements) of a pair of rolling element rows provided between the outer ring raceways and the inner ring raceways. , Different bearing devices.
The bearing device according to claim 5 is a bearing unit for supporting a wheel of an automobile, and supports one member of the outer member and the inner member on a suspension device of the automobile in use. A wheel is coupled and fixed to the other member.

As described above, according to the method for manufacturing a bearing device of the present invention, grinding is applied to each outer ring raceway in a state where the feed speed of the grindstone is stabilized (slow so that no excessive force is applied to the grindstone). You can start. For this reason, it is possible to prevent the occurrence of a problem that a large amount of abrasive grains in the outer ring surface of the grindstone drop off from each of the outer ring raceways. Therefore, the shape accuracy of each outer ring raceway after grinding finish can be improved.
When the present invention is carried out, a portion of the outer peripheral surface of the grindstone other than the portion that grinds each outer ring raceway is first placed on a portion of the outer peripheral surface of the outer ring other than each outer ring raceway. Contact. For this reason, with this contact, a large amount of abrasive grains in the outer peripheral surface of the grindstone other than the portion for grinding the outer ring raceways may fall off. However, even if a large amount of abrasive grains fall off, the shape accuracy of each outer ring raceway after grinding finish can be improved, so that the bearing performance is not affected. If the portion of the inner peripheral surface of the outer ring where the outer peripheral surface of the grindstone contacts first is a cylindrical surface, the gap eliminator becomes easier to operate because of the long line contact from the beginning. It is difficult for large-scale omission to occur.
Further, if the configuration described in claims 2 to 3 is adopted, grinding of the portion between the outer ring raceways and grinding of each outer ring raceway can be performed together on the inner peripheral surface of the outer member. Therefore, the number of processing steps can be reduced as compared with the case where it is performed separately.

[First example of embodiment]
1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1 to 3 and 5. The feature of the present example is that the first and second are performed after a hardened layer is formed by induction hardening on the first and second outer ring raceways 5 and 6 provided on the inner peripheral surface of the outer ring 1. The outer ring raceways 5 and 6 are in a grinding finishing method. The wheel support bearing unit including the outer ring 1 is the one shown in FIG. Further, the integrated grindstone 14a used for the above-mentioned grinding finish is the same as that used in the second example of the conventional grinding method shown in FIG. For this reason, the illustration and description which overlap about the said wheel support bearing unit and the said grindstone 14a are abbreviate | omitted or simplified, and it demonstrates below focusing on the characteristic part of this example.

  In this example, when the first and second outer ring raceways 5 and 6 are ground, the integrated type is the same as in the second example of the conventional grinding method shown in FIG. Of the outer ring 1, the first and second outer ring raceways 5 and 6 and the inner peripheral surface of the shoulder portion 17 are simultaneously ground (in one behavior). . Specifically, first, the grindstone 14a is inserted inside the outer ring 1 in the radial direction, and the first and second outer ring raceways 5 and 6 (inner peripheral surface of the shoulder portion 17) and the grindstone 14a. The axial positions of the first and second grinding surfaces 15 and 16 (third grinding surface 18) provided on the outer peripheral surface of each other are matched. At the same time, the outer ring 1 and the grindstone 14a are rotated at different peripheral speeds (for example, in opposite directions) around their own central axes α and β. And in this state, the outer peripheral surface of the said grindstone 14a is made to the inner peripheral surface of the said outer ring | wheel 1 by displacing the said grindstone 14a with respect to the said outer ring | wheel 1 by the feed rate of a quick approach (refer FIG. 9). Make contact. Thereafter, as shown in FIG. 1, while appropriately changing the feed speed of the grindstone 14a, the first and second outer rings are caused by the first to third grinding surfaces 15, 16, and 18, respectively. Grinding is performed on the tracks 5, 6 and the inner peripheral surface of the shoulder 17 in the order of rough grinding → finish grinding → spark out (see FIG. 9).

This point will be described in more detail. In the case of this example, when the outer peripheral surface of the grindstone 14a is brought into contact with the inner peripheral surface of the outer ring 1 at the feed speed of the quick approach as described above, first, FIG. As shown, the first and second ground surfaces 15 and 16 are brought into contact with the first and second outer ring raceways 5 and 6 before the first and second outer ring raceways 5 and 6 are brought into contact with the inner peripheral surface of the shoulder portion 17. The three grinding surfaces 18 are brought into line (straight line) contact with a sufficient length. In order to realize such a long line contact, in the case of this example, the machining allowance 19 provided on the inner peripheral surface of the outer ring 1 (the portion to be scraped off by grinding is shown in FIG. The thickness dimension of the portion) is made larger at the inner peripheral surface portion of the shoulder portion 17 than at the first and second outer ring raceways 5 and 6 portions. At the same time, the axial width W ₁₇ of the inner peripheral surface of the shoulder portion 17 is made smaller (W ₁₇ <W ₁₈₎ than the axial width dimension W ₁₈ of the third grinding face 18.

  Then, based on the third grinding surface 18 being in line contact with the inner peripheral surface of the shoulder 17 as described above, the outer peripheral surface of the grindstone 14a is provided on the inner peripheral surface of the outer ring 1 on the gap eliminator of the grinding machine. Make sure they are in contact. In addition, the vibration, load load, etc. which generate | occur | produce when a long line contact as mentioned above arises become a big thing. Therefore, the gap eliminator can immediately confirm that the outer peripheral surface of the grindstone 14a is in contact with the inner peripheral surface of the outer ring 1 on the basis of detecting such vibration and load. In the case of this example, simultaneously with this confirmation, the feed speed of the grindstone 14a is changed from the feed speed of the quick approach to the feed speed of the rough grinding, and the shoulder portion is moved by the third grinding surface 18. 17 starts rough grinding on the inner peripheral surface. Thereafter, the first and second ground surfaces 15 and 16 are brought into contact with the first and second outer ring raceways 5 and 6 during the progress of rough grinding of the inner peripheral surface of the shoulder portion 17. Thus, rough grinding is started on the first and second outer ring raceways 5 and 6. Thereafter, while appropriately changing the feed speed of the grindstone 14a, the first and second outer ring raceways 5, 6 and the inner peripheral surface of the shoulder portion 17 are each subjected to rough grinding → finish grinding → spark. By performing the grinding process in the order of the out process, the grinding finishing of the first and second outer ring raceways 5 and 6 is completed. In the case of this example, all of the grinding processes described above are performed while supplying the coolant (cooling liquid) 21 ejected from the nozzles 20 and 20 to the grinding part (grinding point) as shown in FIG. . Further, in the case of this example, when a current sensing type gap eliminator is used, when the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the grindstone 14a are close to each other, they are sandwiched between the two peripheral surfaces. It is possible to change the feed speed of the grindstone 14a by detecting the motor current that has increased with the increase in the entrainment and stirring resistance of the coolant.

  As described above, according to the manufacturing method of the bearing device of this example, it is possible to start grinding the outer ring raceways 5 and 6 while the feed speed of the grindstone 14a is stabilized at the feed speed of rough grinding. it can. For this reason, in the case of this example, the abrasive grains are formed on a part of the outer peripheral surface of the grindstone 14a (the portions in contact with the corner portions P and P existing at the edge portions in the width direction of the outer ring raceways 5 and 6). It is possible to prevent the occurrence of a problem that a large amount is dropped, and to improve the shape accuracy of the outer ring raceways 5 and 6 after the grinding finish. In the case of this example also, the grinding of the outer ring raceways 5 and 6 and the grinding of the inner peripheral surface of the shoulder portion 17 can be performed separately using the integrated grindstone 14a. Compared to the case, the number of processing steps can be reduced.

[Second Example of Embodiment]
FIG. 3 shows a second example of an embodiment of the present invention corresponding to claims 1 to 3 and 5. In the case of this example, the axial direction of the shoulder portion 17 of the machining allowance 19 provided on the inner peripheral surface of the outer ring 1 before grinding finish (the portion to be scraped off by grinding and shown with a diagonal grid in FIG. 3). A convex portion 22 having an inner peripheral surface having a convex arc shape in cross section is provided in the central portion over the entire circumference. Thus, in the case of this example, when the outer peripheral surface of the grindstone 14a is brought into contact with the inner peripheral surface of the outer ring 1 at the feed speed of the quick approach, first, the first and second outer ring raceways 5 as shown in the figure. , 6 before the first and second grinding surfaces 15 and 16 come into contact with each other, the tip of the convex portion 22 (the axis of the inner peripheral surface), which is a part of the inner peripheral surface of the shoulder portion 17. The third grinding surface 18 is in contact with the central portion in the direction).

  And also in the case of this example, based on making the 3rd grinding surface 18 contact the front-end | tip part of the convex part 22 as mentioned above, the said grindstone 14a on the internal peripheral surface of the said outer ring | wheel 1 is used for the gap eliminator of a grinding machine. Make sure that the outer peripheral surface of the is in contact. Simultaneously with this confirmation, the feed speed of the grindstone 14 a is changed from the feed speed of the quick approach to the feed speed of the rough grinding, and the third grinding surface 18 is used to roughen the inner peripheral surface of the shoulder portion 17. Start grinding. In the case of this example, the contact between the tip of the convex portion 22 and the third grinding surface 18 is a point contact or a short line contact in the initial state, so that the contact confirmation by the gap eliminator may be slightly delayed. There is sex. However, even if the contact confirmation is slightly delayed in this way, the first and second ground surfaces 15 and 16 contact the first and second outer ring raceways 5 and 6 before the contact confirmation. The height dimension in the radial direction of the convex portion 22 is sufficiently ensured so as not to occur. In the case of this example, rough grinding of both ends in the axial direction of the inner peripheral surface of the shoulder portion 17 (portions deviating from the convex portion 22 with respect to the axial direction) is performed when the entire convex portion 22 is scraped off. Starts from. In other words, in the case of this example, grinding of both axial ends of the inner peripheral surface of the shoulder portion 17 is not necessary until the entire convex portion 22 is scraped (the amount of the convex portion 22 formed). , Can reduce the amount of grinding on the shoulders). Therefore, compared with the case of the first example shown in FIGS. Other configurations and operations are the same as those of the first example shown in FIGS.

[Third example of embodiment]
FIG. 4 shows a third example of the embodiment of the invention corresponding to claims 1 to 3 and 5. In the case of this example, the inner circumference of the shoulder portion 17 in the machining allowance 19 (the portion to be scraped off by grinding, which is shown by attaching a diagonal lattice in FIG. 4) provided on the inner circumferential surface of the outer ring 1 before grinding finish. The surface is a simple cylindrical surface. On the other hand, the convex part 23 which has the outer peripheral surface of a cross-section convex arc shape is provided over the perimeter in the axial direction center part of the 3rd grinding surface 18a provided in the outer peripheral surface of the grindstone 14b. Thus, in the case of this example, when the outer peripheral surface of the grindstone 14b is brought into contact with the inner peripheral surface of the outer ring 1 at the feed speed of the quick approach, first, as shown in FIG. Prior to the first and second grinding surfaces 15 and 16 coming into contact with the first and second grinding surfaces 5 and 6, the tip portion of the convex portion 23 (the axially central portion of the outer peripheral surface) is formed on the inner peripheral surface of the shoulder portion 17. Is in contact.

  And also in the case of this example, based on making the front-end | tip part of the convex part 23 contact the inner peripheral surface of the shoulder part 17 as mentioned above, the said grindstone is used for the gap eliminator of a grinding machine on the inner peripheral surface of the said outer ring | wheel 1. It confirms that the outer peripheral surface of 14b contacted. Simultaneously with this confirmation, the feed speed of the grindstone 14b is changed from the feed speed of the quick approach to the feed speed of rough grinding, and the third grinding surface 18a is used to roughen the inner peripheral surface of the shoulder portion 17. Start grinding. In the case of this example as well, the contact between the inner peripheral surface of the shoulder portion 17 and the tip end portion of the convex portion 23 is a point contact or a short line contact in the initial state, so the contact confirmation by the gap eliminator is a little. There is a possibility of being late. However, even if the contact confirmation is slightly delayed in this way, the first and second ground surfaces 15 and 16 contact the first and second outer ring raceways 5 and 6 before the contact confirmation. The height dimension in the radial direction of the convex portion 23 is sufficiently ensured so as not to occur. Also in this example, the rough grinding of both ends in the axial direction of the inner peripheral surface of the shoulder portion 17 is carried out so that the entire outer peripheral surface of the convex portion 23 is formed at the intermediate portion in the axial direction of the inner peripheral surface of the shoulder portion 17. It starts when the line (curve) comes into contact. In other words, also in this example, grinding of both ends in the axial direction of the inner peripheral surface of the shoulder portion 17 is performed so that the entire outer peripheral surface of the convex portion 23 is formed in the intermediate portion in the axial direction of the inner peripheral surface of the shoulder portion 17. There is no need to do this until the line contacts. Therefore, the grinding efficiency can be increased by that amount as compared with the case of the first example shown in FIGS. Other configurations and operations are the same as those of the first example shown in FIGS.

  In each of the above-described embodiments, the particle size of the integrated grindstone 14a (14b) is not particularly mentioned. However, when the present invention is carried out, the particle size of the grindstone 14a (14b) is generally Can be equal to or different for each part. For example, the grain size of the grindstone 14a (14b) is made larger at the third grinding surface 18 portion than at the first and second grinding surfaces 15 and 16, or the third grinding surface 18 portion is made larger. If it is relatively soft (or if the particle size is increased and softened), the grinding resistance of the inner peripheral surface of the shoulder portion 17 of the outer ring 1 can be reduced. Accordingly, it is possible to make it difficult to generate grinding burns or grinding cracks on the inner peripheral surface of the shoulder portion 17 correspondingly.

  Further, when the inner peripheral surface of the outer ring 1 that is a cylindrical member is ground as in each of the embodiments described above, it is difficult to supply the coolant 21 to the grinding site. In such a case, as shown in FIG. 5, the outer ring 1 positioned in the radial direction by the shoes 24 and 24 and the grindstone 14a (14b) are centered on their own central axes α and β, respectively. Rotate in the same direction at different peripheral speeds. At the same time, the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the grindstone 14a (14b) are brought into contact with each other at a position where these peripheral surfaces are displaced downward from each other. And the said coolant 21 is supplied with respect to the grinding site | part which is a contact position of these both peripheral surfaces through the wedge-shaped space which exists above this grinding site | part. If it does in this way, the said coolant 21 can be easily supplied to the whole grinding region | part (it is easy to draw in).

  Further, in each of the above-described embodiments, the present invention is implemented for the wheel support bearing unit shown in FIG. However, the present invention can also be implemented for various bearing devices that satisfy the requirements described in the claims, such as the second example of the conventional structure of the wheel supporting bearing unit shown in FIG. .

Sectional drawing which shows the 1st example of embodiment of this invention. The principal part expanded sectional view which shows the initial contact state of the inner peripheral surface of an outer ring | wheel, and the outer peripheral surface of a grindstone. The figure similar to FIG. 2 which shows the 2nd example of embodiment of this invention. The figure similar to FIG. 2 which shows the 3rd example. The figure equivalent to the AA cross section of FIG. 1 which shows the rotation direction and positional relationship of an outer ring | wheel and a grindstone which can be preferably employ | adopted in order to make it easy to draw in coolant to a grinding site | part. The half part sectional view showing the 1st example of the conventional structure of the bearing unit for wheel support. Sectional drawing which shows the 1st example of the conventional method which can be employ | adopted when grinding a double row outer ring track | truck provided in the inner peripheral surface of the outer ring. Sectional drawing which shows the 2nd example. The diagram which shows the relationship between the feed position of a grindstone, and time at the time of grinding. The principal part expanded sectional view which shows the initial stage contact state of the inner peripheral surface of an outer ring | wheel and the outer peripheral surface of a grindstone in the case of implementing the 1st example of the said conventional method. The figure similar to FIG. 10 in the case of implementing the 2nd example of the said conventional method. The principal part expanded sectional view which shows the partial breakage of a grindstone and the shape collapse of an outer ring track | truck which may occur when the 1st-2nd example of the said conventional method is implemented. Sectional drawing which shows the 2nd example of the conventional structure of the bearing unit for wheel support.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Outer ring 2, 2a Hub main body 3 Inner ring 4 Rolling element 5, 5a First outer ring raceway 6, 6a Second outer ring raceway 7 Connection flange 8 Mounting flange 9, 9a First inner ring raceway 10, 10a Second Inner ring raceway 11 Small diameter step portion 12 Cylindrical portion 13 Caulking portion 14, 14a, 14b Grinding wheel 15 First grinding surface 16 Second grinding surface 17, 17a Shoulder portion 18, 18a Third grinding surface 19 Cutting allowance 20 Nozzle 21 Coolant 22 Convex part 23 Convex part 24 Shoe 25 Concave part

Claims (5)

  An outer member having a double row outer ring raceway on the inner peripheral surface, an inner member having a double row inner ring raceway on the outer peripheral surface, and a plurality of each can be rolled between each outer ring raceway and each inner ring raceway. Among the outer members, in order to manufacture a bearing device in which a hardened layer is formed by induction hardening on each outer ring raceway portion among the outer members. A method of manufacturing a bearing device in which after the hardened layer is formed on each outer ring raceway portion, the outer ring raceway is simultaneously subjected to finishing grinding with an integrated grindstone, and the outer stone Based on starting to grind parts other than the outer ring raceways in the inner peripheral surface of the member, after stabilizing the feed speed of the grindstone, Start grinding the outer ring raceway Method of manufacturing a bearing device according to symptoms.   2. The bearing device according to claim 1, wherein a portion of the inner peripheral surface of the outer member that starts grinding before each outer ring raceway is at least a part of a portion between the outer ring raceways. Manufacturing method.   The manufacturing of the bearing device according to any one of claims 1 to 2, wherein at least finally, grinding is performed on the entire portion between the outer ring raceways on the inner peripheral surface of the outer member. Method.   The bearing device manufacturing method according to any one of claims 1 to 3, wherein a pair of rolling element rows provided between each outer ring raceway and each inner ring raceway have different pitch circle diameters.   The bearing device is a bearing unit for supporting a wheel of an automobile, and one member of the outer member and the inner member is supported by the suspension device of the automobile in use, and the wheel is coupled and fixed to the other member; The manufacturing method of the bearing apparatus in any one of Claims 1-4.

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