Manufacturing method for wheel bearing devices

Abstract

In matching wheel bearing devices, this method reduces product-to-product variations in axial clearance and the difference from the target value without increasing costs. [Solution] First, the dimensions of the outer ring 11, hub ring 13, and inner ring 14 are measured. Then, multiple parts for the hub ring 13 and inner ring 14 whose dimensions have been measured are set aside. Subsequently, combinations of the outer ring 11, hub ring 13, and inner ring 14 are created using each of the set aside parts, and the axial clearance of the wheel bearing device 10 is calculated for all combinations. Then, based on the calculated axial clearance, one combination is selected from all combinations, and the wheel bearing device 10 is assembled using the outer ring 11, hub ring 13, and inner ring 14 of that combination.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a wheel bearing device.

Background Art

[0002] FIG. 1 shows a configuration example of a wheel bearing device. The wheel bearing device 10 shown in the figure includes an outer ring 11 having a first outer raceway surface Sa1 and a second outer raceway surface Sa2, an inner member 12 having a first inner raceway surface Sb1 and a second inner raceway surface Sb2, and a plurality of balls 15 as rolling elements that are rotatably disposed between the first outer raceway surface Sa1 and the first inner raceway surface Sb1 facing each other, and between the second outer raceway surface Sa2 and the second inner raceway surface Sb2, and a cage (not shown) that holds the plurality of balls 15 at predetermined intervals in the circumferential direction. The inner member 12 includes a hub ring 13 having a first inner raceway surface Sb1 formed on the outer peripheral surface thereof, and an inner ring 14 having a second inner raceway surface Sb2 formed on the outer peripheral surface thereof. On the outboard side (left side in the figure) of the first inner raceway surface Sb1 of the hub ring 13, a flange 13b for wheel mounting is provided. The inner ring 14 is press-fitted into an inner ring mounting surface 13d provided at the inboard side (right side in the figure) end of the outer peripheral surface of the hub ring 13.

[0003] In the wheel bearing device 10, preload is applied by pushing the balls 15 to the outboard side with the inner ring 14 press-fitted into the inner ring mounting surface 13d of the hub ring 13. At this time, the internal clearance calculated from the dimensions of each component of the wheel bearing device 10, particularly the axial internal clearance (hereinafter referred to as "axial clearance"), is desirably set to a predetermined target value (a negative value when preload is applied). However, in reality, due to the influence of machining errors of each component of the wheel bearing device 10 and assembly errors between components, it is inevitable that the axial clearance deviates significantly from the target value or variations occur between products, so there is concern about a quality decline associated with a decrease in the accuracy of bearing preload management.

[0004] For example, Patent Document 1 below describes a method for matching components to suppress variations in the axial clearance of a wheel bearing device from product to product. Specifically, rolling elements are classified in advance into several ranks according to the difference from a reference value of their outer diameter. Then, the groove diameter of the outer raceway surface formed on the outer ring, the groove diameter of the inner raceway surface formed on the inner members (hub ring and inner ring), the inner diameter of the inner ring, and the outer diameter of the hub ring that fits with it are measured, and from these measured values, rolling elements of the rank (outer diameter) that result in the smallest difference from the target value of the axial clearance are selected and assembled. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-116689 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, with the matching method described above, the outer diameter of the balls used changes significantly depending on the dimensional accuracy of the extracted outer ring, inner ring, and hub ring. Therefore, in order to reduce variations in axial clearance, it becomes necessary to prepare many types of balls, which increases costs. For example, reducing the number of ball ranks, that is, increasing the range of each rank, reduces the number of ball types that need to be prepared and thus reduces costs. However, in this case, the effect of reducing variations in axial clearance and the difference from the target value is also reduced.

[0007] Therefore, the present invention aims to reduce variations in axial clearance between products and the difference from the target value in the matching of wheel bearing devices without increasing costs. [Means for solving the problem]

[0008] To solve the aforementioned problems, the present invention provides a method for assembling a wheel bearing device comprising: an outer member having first and second outer raceway surfaces formed on its inner circumferential surface; a first inner member having a first inner raceway surface and a cylindrical mounting surface formed on its outer circumferential surface; a second inner member having a second inner raceway surface formed on its outer circumferential surface and fitted to the mounting surface of the first inner member; a flange for wheel mounting provided on the outer member or the inner member; and a plurality of rolling elements arranged to roll freely between the first outer raceway surface and the first inner raceway surface, and between the second outer raceway surface and the second inner raceway surface, wherein A step of measuring the dimensions of the outer member, the first inner member, and the second inner member, A step of storing multiple parts for which dimensional measurement has been completed in at least one of the outer member, the first inner member, and the second inner member, A step of creating combinations of the outer member, the first inner member, and the second inner member using each of the retained plurality of parts, and calculating the axial gap of the wheel bearing device for all combinations, A step of selecting one combination from all the combinations based on the calculated value of the axial gap, The present invention provides a method for assembling a wheel bearing device, comprising the step of assembling the wheel bearing device using the selected combination of the outer member, the first inner member, and the second inner member.

[0009] As described above, multiple parts for which dimensional measurements have been completed are kept for at least one of the outer member, the first inner member (e.g., hub ring), and the second inner member (e.g., inner ring), and combinations of the outer member, the first inner member, and the second inner member are created using each of these multiple parts. This increases the number of combination patterns used when calculating the theoretical value of the axial clearance, and by selecting the optimal combination from these combinations based on the calculated value of the axial clearance, it becomes possible to reduce the variation in the axial clearance and the difference from the target value.

[0010] For example, it is possible to select the combination from all possible combinations that minimizes the difference between the axial gap and the target value.

[0011] However, in a matching method that continuously selects the part whose axial gap is closest to the target value from among multiple parts that have been kept in storage, parts with relatively poor dimensional accuracy, such as parts whose dimensions are within the standard range but near the upper or lower limits, are less likely to be selected in the matching process and may remain in storage for a long period of time. When such long-term storage occurs, parts with relatively good dimensional accuracy, such as parts whose dimensions are near the median of the standard range, which are frequently selected in the matching process, cannot be kept in storage, raising concerns that the effect of reducing axial gap variation through matching will be reduced. Furthermore, just before the completion of production for a target lot, the matching process may have to select parts with relatively poor dimensional accuracy that have been stored for a long time, resulting in a larger difference between the target value and the actual axial gap, and a larger variation in axial gap within the target lot, which can lead to the generation of defective products.

[0012] Therefore, if there are parts that have been sitting around for longer than a predetermined period, the combination containing those parts may be selected if the difference between the axial gap and the target value is less than or equal to a predetermined value. In this way, if there are parts that have been sitting around for a long time without being used in matching, and the calculated value of the axial gap is within an acceptable range, the part can be preferentially selected even if it is not the part that comes closest to the target value, thereby preventing the part from remaining in the matching process any longer. This allows parts with relatively good dimensional accuracy to be kept in the matching process, thus reducing variations in the axial gap during matching.

[0013] In the assembly method described above, it is preferable to retain multiple parts for which dimensional measurements have been completed for two of the outer member, the first inner member, and the second inner member, and it is even more preferable to retain multiple parts for which dimensional measurements have been completed for all of the outer member, the first inner member, and the second inner member. This further increases the number of combinations of parts used when calculating the axial gap, and is expected to further reduce the variation in the axial gap and the difference from the target value. [Effects of the Invention]

[0014] As described above, according to the present invention, in matching wheel bearing devices, it is possible to reduce product-to-product variations in axial clearance and the difference from the target value without increasing costs, thereby improving the accuracy of bearing preload management and leading to improved product quality. [Brief explanation of the drawing]

[0015] [Figure 1] This is an axial cross-sectional view of a wheel bearing device. [Figure 2] This is a flowchart of the assembly method for one embodiment of the present invention. [Figure 3] This is a conceptual diagram of the assembly line for the wheel bearing device mentioned above. [Figure 4] This is an axial cross-sectional view of the outer ring of the above-mentioned wheel bearing device. [Figure 5] This is an axial cross-sectional view of the hub wheel of the bearing device for the wheel described above. [Figure 6] This is an axial cross-sectional view of the inner ring of the above-mentioned wheel bearing device. [Figure 7] A conceptual diagram of an assembly line according to another embodiment. [Figure 8] This is a flowchart of the assembly method according to another embodiment. [Figure 9] This figure shows the difference between the axial gap and the target value when matching is performed without any component stagnation. [Figure 10] This figure shows the difference between the axial gap and the target value when matching is performed with multiple parts in place. [Figure 11] It is a diagram showing the difference between the axial clearance and the target value when matching is performed to retain a plurality of parts and preferentially select long-term retained parts.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0017] In this embodiment, a method of assembling the wheel bearing device 10 shown in FIG. 1 will be described. The wheel bearing device 10 mainly includes an outer ring 11 as an outer member, an inner member 12, a plurality of balls 15, and a cage. Although not shown in the figure, the annular space defined between the outer ring 11 and the inner member 12 is filled with a lubricant such as grease. In order to prevent external leakage of this lubricant and intrusion of foreign matter into the annular space, the end openings on one side and the other side in the axial direction of the annular space are respectively sealed by a seal member not shown in the figure.

[0018] The outer ring 11 integrally has a substantially cylindrical tubular portion 11a and a flange 11b for vehicle body attachment that extends radially outward from the outer peripheral surface of the tubular portion 11a. On the inner peripheral surface of the tubular portion 11a, a first outer raceway surface Sa1 and a second outer raceway surface Sa2 having an arcuate cross-section are formed at intervals in the axial direction. The flange 11b for vehicle body attachment is formed with a plurality of bolt mounting holes (not shown) penetrating it in the axial direction at intervals in the circumferential direction. The outer ring 11 is attached to the vehicle body using bolt members attached to each bolt mounting hole.

[0019] The inner member 12 has a hub ring 13 as a first inner member and an inner ring 14 as a second inner member.

[0020] The hub wheel 13 integrally comprises a substantially cylindrical cylindrical portion 13a and a wheel mounting flange 13b extending radially outward from the outer circumferential surface of the cylindrical portion 13a. The outer circumferential surface of the cylindrical portion 13a has a first inner raceway surface Sb1 with a circular arc cross-section facing the first outer raceway surface Sa1 of the outer ring 11, and a cylindrical inner ring mounting surface 13d. The wheel mounting flange 13b is provided on the outboard side (left side in the figure) of the first inner raceway surface Sb1, and the inner ring mounting surface 13d is provided on the inboard side (right side in the figure) of the first inner raceway surface Sb1. The wheel mounting flange 13b has a plurality of bolt mounting holes (not shown) that penetrate it axially and are spaced apart in the circumferential direction. The hub wheel 13 is attached to the wheel using bolt members fitted into each bolt mounting hole. The shaft portion (not shown) of the outer coupling member that constitutes a constant velocity universal joint provided on the drive shaft is connected to the central hole of the hub wheel 13 in a manner that allows for torque transmission.

[0021] The outer circumferential surface of the inner ring 14 has a second inner raceway surface Sb2 with a circular arc cross-section that faces the second outer raceway surface Sa2 of the outer ring 11. The inner circumferential surface of the inner ring 14 is fitted onto the inner ring mounting surface 13d of the hub ring 13. In this embodiment, the inner ring 14 and the hub ring 13 are fixed together by press-fitting the inner circumferential surface of the inner ring 14 onto the inner ring mounting surface 13d of the hub ring 13.

[0022] The straight lines connecting the contact points between the ball 15 and the first outer raceway surface Sa1 and the first inner raceway surface Sb1, and the straight lines connecting the contact points between the ball 15 and the second outer raceway surface Sa2 and the second inner raceway surface Sb2, are inclined in opposite directions with respect to the radial direction. The inner ring 14 is pressed onto the inner ring mounting surface 13d of the hub ring 13 from the inboard side, and while the inner ring 14 pushes the ball 15 towards the outboard side, the outboard end of the inner ring 14 is brought into contact with the annular shoulder surface 13e provided near the axial center of the cylindrical portion 13a, thereby applying a predetermined preload to the wheel bearing device 10.

[0023] The following describes in detail the procedure for assembling the wheel bearing device 10 according to one embodiment of the present invention.

[0024] First, the dimensions of the outer ring 11, hub ring 13, and inner ring 14 of the wheel bearing device 10 are measured (step S1 in Figure 2). Specifically, as shown in Figure 3, the outer ring 11, hub ring 13, and inner ring 14 are placed into measuring instruments 21 to 23, respectively, and the dimensions of predetermined parts are measured.

[0025] The measurement targets for the outer ring 11 are the groove diameters A1 and A2 of the first outer raceway surface Sa1 and the second outer raceway surface Sa2 (see Figure 4). The groove diameters A1 and A2 of the outer raceway surfaces Sa1 and Sa2 are the inner diameters at the portion that contacts the ball 15. Specifically, the groove diameters A1 and A2 of both outer raceway surfaces Sa1 and Sa2 of the outer ring 11 at predetermined axial distances L1 and L2 from the reference surface (in the illustrated example, the end face on the inboard side of the flange 11b for vehicle body mounting) are measured by the measuring means 51.

[0026] The measurement targets for the hub wheel 13 are the outer diameter B1 of the inner ring mounting surface 13d and the groove diameter B2 of the first inner raceway surface Sb1 (see Figure 5). The groove diameter B2 of the first inner raceway surface Sb1 is the outer diameter at the point where it contacts the ball 15. Specifically, the outer diameter B1 of the inner ring mounting surface 13d is measured by the measuring means 52, and the groove diameter B2 of the first inner raceway surface Sb1 at a predetermined axial distance L3 from the reference surface (in the illustrated example, the shoulder surface 13e of the hub wheel 13) is measured by the measuring means 53.

[0027] The measurement targets for the inner ring 14 are the groove diameter C1 and inner diameter C2 of the second inner raceway surface Sb2 (see Figure 6). The groove diameter C1 of the second inner raceway surface Sb2 is the outer diameter at the point where it contacts the ball 15. Specifically, the groove diameter C1 of the second inner raceway surface Sb2 at a predetermined axial distance L4 from the reference surface (in the illustrated example, the end face on the outboard side of the inner ring 14) is measured by the measuring means 54, and the inner diameter C2 of the inner ring 14 is measured by the measuring means 55.

[0028] Next, the dimensions of each part to be measured—the outer ring 11, the hub ring 13, and the inner ring 14—are checked to see if they are outside the standard (Step S2 in Figure 2). If the dimensions of the part to be measured are outside the standard, the part is discarded as a defective product (Step S3).

[0029] After confirming that the dimensions are within specifications, multiple parts are stored for at least one of the outer ring 11, hub ring 13, and inner ring 14. In this embodiment, as shown in Figure 3, storage units 31 and 32 are provided for storing the hub ring 13 and inner ring 14 after dimensional measurement. Each storage unit 31 and 32 stores a predetermined number of parts (four in the illustrated example). After confirming that the dimensions of the hub ring 13 and inner ring 14 are within specifications in step S2 above, it is checked whether the number of parts in storage units 31 and 32 has reached the predetermined number (step S4 in Figure 2). If the number of parts in storage units 31 and 32 is less than the predetermined number, the parts whose dimensions have been confirmed to be within specifications are transferred from the measuring instruments 22 and 23 to storage units 31 and 32, and the process returns to step S1. If the number of parts in storage units 31 and 32 has reached the predetermined number, the process proceeds to the next step S5. In this embodiment, there is no storage for stocking the outer rings 11, and the outer rings 11, whose dimensions have been confirmed to be within specifications, are held inside the measuring instrument 21.

[0030] In the next step S5, the axial clearance of the wheel bearing device 10 is calculated based on the dimensions of the outer ring 11, hub ring 13, and inner ring 14. In this embodiment, the theoretical value of the axial clearance is calculated using the outer ring 11 in the measuring instrument 21, a total of 5 hub rings 13 stored in the measuring instrument 22 and storage 31, and a total of 5 inner rings 14 stored in the measuring instrument 23 and storage 32. That is, a total of 25 combinations are created using one outer ring 11, five hub rings 13, and five inner rings 14, and the axial clearance is calculated from the dimensions of each component in all combinations.

[0031] First, for one of the 25 possible combinations selected (hereinafter referred to as the "selected combination"), the ball 15 with the optimal rank (outer diameter) is selected from the pre-ranked balls 15. Specifically, the ball 15 with the optimal rank to be inserted between the groove diameter A1 of the first outer raceway surface Sa1 of the outer ring 11 and the groove diameter B2 of the first inner raceway surface Sb1 of the hub ring 13 is selected. In addition, the groove diameter C1' of the second inner raceway surface Sb2 in the state when the hub ring 13 and the inner ring 14 are press-fitted is calculated from the outer diameter B1 of the inner ring mounting surface 13d of the hub ring 13, the inner diameter C2 of the inner ring 14 and the groove diameter C1 of the second inner raceway surface Sb2. The ball 15 with the optimal rank to be inserted between these is selected from this groove diameter C1' and the groove diameter A2 of the second outer raceway surface Sa2 of the outer ring 11. Then, using the dimensions of each part of the "selected combination"—the outer ring 11, the hub ring 13, and the inner ring 14—and the rank (outer diameter) of the ball 15 selected for that combination, the axial clearance of the wheel bearing device 10 in the "selected combination" is calculated, and the difference between this axial clearance and the target value is calculated.

[0032] Next, it is checked whether the difference between the axial gap and the target value in the "selected combination" is smaller than the difference between the axial gap and the target value in the "combination to be used" (step S6 in Figure 2). The "combination to be used" is the combination in which the difference between the axial gap and the target value is smallest among the combinations for which the axial gap has been calculated up to that point, and is the optimal combination at that time. If the difference between the axial gap and the target value in the "selected combination" is smaller than the difference between the axial gap and the target value in the "combination to be used", the "selected combination" is updated as the "combination to be used" (step S7 in Figure 2). On the other hand, if the difference between the axial gap and the target value in the "selected combination" is not smaller than the difference between the axial gap and the target value in the "combination to be used", the "combination to be used" is not updated, and the process moves to the next step S8.

[0033] Step S8 checks whether the axial gap has been calculated for all combinations (25 possibilities). If the axial gap has not been calculated for all combinations, the process returns to Step S5 and calculates the axial gaps for the remaining combinations. If the axial gap has been calculated for all combinations, the "combination to use" at that time will be the one with the axial gap closest to the target value among all combinations.

[0034] Table 1 below shows an example of the calculation results for the difference (in μm) between the axial clearance and the target value for all combinations of wheel bearing devices 10. According to these calculation results, the axial clearance when using hub wheel No. 4 13 and inner ring No. 2 14 is closest to the target value. Therefore, the combination of hub wheel No. 4 13, inner ring No. 2 14, outer ring 11 in the measuring instrument 21, and ball 15 of the rank selected in the axial clearance calculation becomes the final "combination to use".

[0035] [Table 1]

[0036] Once the "combination to be used" is determined as described above, the outer ring 11, hub ring 13, inner ring 14, and balls 15 that constitute the "combination to be used" are transported to the assembly machine 40 (see Figure 3) (step S9), and the wheel bearing device 10 is assembled using these parts. After the outer ring 11, hub ring 13, and inner ring 14 of the "combination to be used" are transported to the assembly machine 40, if any hub ring 13 and inner ring 14 remain in the measuring instruments 22 and 23, they are transported to the storage 31 and 32, and new outer ring 11, hub ring 13, and inner ring 14 are brought into the measuring instruments 21, 22, and 23. By repeating the above, the matching and assembly of the wheel bearing device 10 are performed sequentially.

[0037] As described above, for the hub ring 13 and inner ring 14, the number of combination patterns can be increased by storing multiple parts for which dimensional measurement has been completed and combining each of these stored parts. Then, by selecting the combination from these combinations that brings the axial gap closest to the target value, the variation in the axial gap and the difference from the target value can be reduced, thereby improving the accuracy of bearing preload management and leading to improved product quality.

[0038] The present invention is not limited to the embodiments described above. Other embodiments of the present invention will be described below, but redundant explanations of points similar to those described above will be omitted.

[0039] In the above embodiment, there is a possibility that components may remain in storage 31 and 32 for a long period of time. Therefore, in order to reduce the likelihood of such long-term retention, priority may be given to matching components that have been in storage for a predetermined period of time or longer. That is, if there are components that have been in storage 31 and 32 for a predetermined period of time or longer, the axial gap when using those components may be calculated, and if the difference between this calculated value and the target value is less than or equal to a predetermined value, those components may be selected.

[0040] In the assembly line shown in Figure 7, the number of times the outer ring 11, hub ring 13, and inner ring 14 have been held in the assembly line is shown in parentheses. For example, the hub ring 13(6) in storage 31 was held in the assembly line after its dimensions were measured by the measuring instrument 21, and was not selected during the assembly of the six wheel bearing units 10. An example of the calculation results of the difference (in μm) between the axial clearance and the target value for all combinations at this time is shown in Table 2 below.

[0041] [Table 2]

[0042] This embodiment shows a case where items with a retention count of 10 or more are preferentially selected. Specifically, if there are parts with a retention count of 10 or more (long-term retention items) in storage 31 and 32, and the difference between the axial gap and the target value of a combination using such parts is less than or equal to a predetermined value (for example, 1 μm or less), then those parts are selected. In this embodiment, the inner ring 14 of No. 4 stocked in storage 32 has a retention count of 10 and is therefore a long-term retention item. According to the calculation results in Table 2 above, the combination using the inner ring 14 of No. 4 and the hub ring 13 of No. 3 has a difference between the axial gap and the target value of 1 μm or less. In this case, although there are other combinations with a smaller difference between the axial gap and the target value (for example, the combination of the hub ring 13 of No. 1 and the inner ring 14 of No. 5), the above combination including the inner ring 14 of No. 4, which is a long-term retention item, is preferentially selected.

[0043] The matching procedure of this embodiment will be explained in detail using Figure 8. After calculating the axial gap in the "selected combination" (step S5), it is checked whether the "combination to be used," which is the optimal combination at that time, includes long-stagnant items that have been in place for a predetermined period of time or longer (10 times or more) (step S10). If the "combination to be used" does not include long-stagnant items, it is checked whether the "selected combination" includes long-stagnant parts and whether the difference between the axial gap and the target value is less than or equal to a predetermined value (1 μm or less) (step S11). If these conditions are met, the "selected combination" is updated as the "combination to be used" (step S12), and the process proceeds to step S8. If these conditions are not met, that is, if the "selected combination" does not include long-stagnant items, or if the "selected combination" includes long-stagnant items but the difference between the axial gap and the target value exceeds a predetermined value, the process proceeds to step S6, and then, if necessary, through step S7, and then to step S8.

[0044] On the other hand, in step S10 above, if the "combination to use" includes long-stagnant components, it is checked whether the "selected combination" includes components with a longer stagnant period than the long-stagnant components of the "combination to use", and whether the difference between the axial gap and the target value is less than or equal to a predetermined value (1 μm or less) (step S13). If these conditions are met, the "selected combination" is updated as the "combination to use" (step S14). On the other hand, if these conditions are not met, that is, if the "selected combination" does not include components with a longer stagnant period than the long-stagnant components of the "combination to use", or if the "selected combination" includes components with a longer stagnant period than the long-stagnant components of the "combination to use", but the difference between the axial gap and the target value exceeds a predetermined value, the "combination to use" is not updated and the process proceeds to the next step S8.

[0045] Long-term stagnant items that remain in storage 31 and 32 for a predetermined period of time are often parts with relatively poor dimensional accuracy, for example, parts whose dimensions at the measurement target are within the standard range but near the upper or lower limits. Therefore, as described above, by prioritizing the selection of long-term stagnant items and preventing them from remaining in storage, parts with relatively good dimensional accuracy, for example, parts whose dimensions at the measurement target are near the median of the standard range, which are frequently selected in matching, can be left in storage. This prevents large variations in axial clearance.

[0046] In the embodiments described above, a case was shown where multiple parts whose dimensions have been measured are stored in the hub ring 13 and the inner ring 14, but the invention is not limited to this. For example, multiple parts whose dimensions have been measured may be stored by providing storage in the outer ring 11 and the hub ring 13, or in the outer ring 11 and the inner ring 14. Alternatively, multiple parts whose dimensions have been measured may be stored by providing storage in any one of the outer ring 11, the hub ring 13, and the inner ring 14. Or, multiple parts whose dimensions have been measured may be stored by providing storage in all of the outer ring 11, the hub ring 13, and the inner ring 14.

[0047] Furthermore, the configuration of the wheel bearing device 10 is not limited to the above. For example, in the above embodiment, the wheel bearing device 10 is shown as an inner-ring rotating type in which a flange 13b for wheel mounting is provided on the inner member 12 (hub ring 13), but it may also be an outer-ring rotating type in which a flange for wheel mounting is provided on the outer member. Also, the wheel bearing device 10 may be for a driven wheel to which a constant velocity universal joint of the drive shaft is not connected. In addition, the rolling elements provided in the wheel bearing device 10 are not limited to balls, but may also be rollers (for example, tapered rollers). [Examples]

[0048] In the assembly of wheel bearing units (134 units), matching was performed according to conditions 1 to 3 shown in Table 3 below. In condition 1, no inner rings, hub rings, or outer rings were retained, and only ball matching was performed using parts for which dimensional measurement had been completed. In condition 2, five inner rings, hub rings, and outer rings were retained, and matching was performed according to the flow chart in Figure 2. In condition 3, similar to condition 2, five inner rings, hub rings, and outer rings were retained, and matching was performed according to the flow chart in Figure 8, prioritizing the selection of parts that had been retained for a long time. Specifically, if a part had been retained 10 or more times, and the difference between the axial clearance and the target value in the combination using that part was 0.5 μm or less, that part was given priority for selection.

[0049] [Table 3]

[0050] Figures 9 to 11 show the difference between the axial gap and the target value for each product under matching conditions 1 to 3. In these figures, the difference between the axial gap and the target value for each product is plotted from left to right in the order in which they were assembled, with the rightmost plot representing the difference between the axial gap and the target value for the last product assembled in the target lot. Table 4 below shows the variation in axial gap σ under matching conditions 1 to 3, and the difference between the maximum and minimum values ​​of the difference between the axial gap and the target value (maximum difference R).

[0051] [Table 4]

[0052] As shown in Figures 9-10 and Table 4, compared to condition 1 in which no components were left behind on the inner ring, outer ring, or hub ring, conditions 2 and 3, in which multiple components were left behind on each of the inner ring, outer ring, and hub ring during matching, were able to reduce the difference between the axial clearance and the target value, as well as the variation σ and maximum difference R of the axial clearance.

[0053] On the other hand, in matching under condition 2, as shown in Figure 10, the difference between the axial clearance and the target value is extremely small for most products. However, it can be seen that the absolute value of the difference between the axial clearance and the target value, as well as the maximum difference R, suddenly increases just before the completion of production of the target lot (near the right edge of the figure). This is thought to be because one of the inner ring, outer ring, or hub ring remained in storage for a long period of time, and this long-stagnant product remained until just before the completion of production of the target lot, forcing its use at the very end of production.

[0054] In contrast, under matching condition 3, because parts that have been in storage for a predetermined period of time or longer are used preferentially, as shown in Figure 11, the difference between the axial gap and the target value is larger in many products than in condition 2 (see Figure 10), and the variation in the axial gap σ is slightly larger than in condition 2 (see Table 4). However, under condition 3 (see Figure 11), the difference between the axial gap and the target value does not suddenly become large, as in condition 2 (see Figure 10), and the maximum difference R between the axial gap and the target value is smaller than in condition 2 (see Table 4). From these results, it was confirmed that by preferentially using parts that have been in storage for a predetermined period of time or longer, it is possible to avoid having long-term storage products remaining until just before the completion of production for the target lot, and to avoid the occurrence of products with axial gaps that deviate significantly from the target value. [Explanation of Symbols]

[0055] 10 Wheel bearing device 11. Outer ring (outer member) 12 Inner member 13 Hub ring (first inner member) 13b Flange for wheel mounting 13d Inner ring mounting surface (mounting surface) 14 Inner ring (second inner member) 15. Ball (rolling element) 31, 32 Storage Sa1 1st outer raceway surface Sa2 2nd outer raceway surface Sb1 1st inner raceway surface Sb2 2nd inner raceway surface

Claims

1. A method for assembling a wheel bearing device comprising: an outer member having first and second outer raceway surfaces formed on its inner circumferential surface; a first inner member having a first inner raceway surface and a cylindrical mounting surface formed on its outer circumferential surface; a second inner member having a second inner raceway surface formed on its outer circumferential surface and fitted to the mounting surface of the first inner member; a flange for wheel mounting provided on the outer member or the inner member; and a plurality of rolling elements arranged to roll freely between the first outer raceway surface and the first inner raceway surface, and between the second outer raceway surface and the second inner raceway surface, wherein A step of measuring the dimensions of the outer member, the first inner member, and the second inner member, A step of storing a plurality of parts for which dimensional measurements have been completed in at least one of the outer member, the first inner member, and the second inner member, A step of creating combinations of the outer member, the first inner member, and the second inner member using each of the retained plurality of parts, and calculating the axial gap of the wheel bearing device for all combinations, A step of selecting one combination from all the combinations based on the calculated value of the axial gap, A method for assembling a wheel bearing device, comprising the step of assembling the wheel bearing device using the selected combination of the outer member, the first inner member, and the second inner member.

2. The method for assembling a wheel bearing device according to claim 1, wherein a combination is selected from all the aforementioned combinations that minimizes the difference between the axial gap and the target value.

3. The method for assembling a wheel bearing device according to claim 1, wherein if there is a part that has been in place for a predetermined period of time or longer, the difference between the axial gap and the target value in a combination including the part is less than or equal to a predetermined value, and the combination is selected.

4. The assembly method for a wheel bearing device according to claim 1, wherein a plurality of parts for which dimensional measurements have been completed are stored with respect to two of the outer member, the first inner member, and the second inner member.

5. The assembly method for a wheel bearing device according to claim 1, wherein a plurality of parts for which dimensional measurements have been completed are stored for all of the outer member, the first inner member, and the second inner member.

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