上述の様な本例によれば、前記各透孔１３ａに工具を挿入する際に、この工具の先端部と前記外輪２ｃの軸方向外端面とが干渉する事を防止できて、前記各透孔１３ａに工具を挿入して行う、前記車輪支持用転がり軸受ユニット１ｃを前記懸架装置に取り付けたり取り外したりする、或いは制動装置を構成する部品（サポートやキャリパ）を懸架装置に取り付けたり取り外したりする等の作業の作業性が低下する事を防止できる。即ち、前記車輪支持用転がり軸受ユニット１ｃを前記懸架装置に取り付ける場合には、この懸架装置を構成するナックルに設けたねじ孔と、前記静止側フランジ６の貫通孔３６との円周方向に関する位相を互いに一致させると共に、前記回転側フランジ９ａの透孔１３ａの円周方向に関する位相を、前記各貫通孔３６の円周方向に関する位相と一致させる。この状態で、前記各透孔１３ａの軸方向外側から工具を挿入し、この工具により前記各貫通孔３６を軸方向外側から挿通したボルトを前記各ねじ孔に螺合し、更に締め付ける。これにより、前記静止側フランジ６を前記ナックルに結合固定する。又、前記車輪支持用転がり軸受ユニット１ｃを前記懸架装置から取り外す場合も、前記各透孔１３ａの円周方向に関する位相を、前記各貫通孔３６の円周方向に関する位相と一致させた状態で、これら各透孔１３ａの軸方向外側から工具を挿入し、この工具により前記各貫通孔３６を挿通し前記各ねじ孔に螺合したボルトを緩める。何れにしても、本例の場合には、前記外輪２ｃの軸方向外端部外周面のうちで、円周方向に関する位相が前記各貫通孔３６と一致する部分に、前記外輪２ｃの軸方向外端面に開口する状態で径方向内方に凹んだ外輪側凹部３４をそれぞれ設け、前記車輪支持用転がり軸受ユニット１ｃの中心軸を中心とするこれら各外輪側凹部３４の底面の軸方向外端縁に於ける内接円の直径Ｄ３４を、前記車輪支持用転がり軸受ユニット１ｃの中心軸を中心とする前記各透孔１３ａの径方向内端部の内接円の直径Ｄ１３ａよりも小さくしている（Ｄ３４＜Ｄ１３ａ）。この為、前記ボルトを締め付ける或いは緩める作業に際して、前記工具を前記各透孔１３ａの軸方向外側から挿入する際に、この工具の先端部と前記外輪２ｃの軸方向外端面とが干渉（衝合）するのを防止できる。従って、前記車輪支持用転がり軸受ユニット１ｃの中心軸を中心とする前記各透孔１３ａの径方向内端部の内接円の直径Ｄ１３ａが前記外輪２ｃの軸方向外端面の外径Ｄ２ｃよりも小さくなっている（Ｄ１３ａ＜Ｄ２ｃ）場合でも、前記車輪支持用転がり軸受ユニット１ｃの前記懸架装置のナックルへの組み付け性（前記各透孔１３ａに工具を挿入して行う作業の作業性）が損なわれる事を防止できる。更に、本例の場合には、前記各外輪側凹部３４の底面の内接円の直径Ｄ３４を軸方向内方に向かう程大きくしている（外周面からの深さを小さくしている）為、前記工具がこれら各外輪側凹部３４に引っ掛かる事を防止して、軸方向内方に案内する事ができる。
尚、上述の様な外輪側凹部３４は、円周方向に関して制動用回転体３５（図３参照）と共に制動装置を構成する図示しないサポート又はキャリパの固定位置（取付孔等）と一致する部分に設ける事もできる。
その他の部分の構成及び作用は、上述した実施の形態の第１〜２例と同様である。
According to this example as described above, when a tool is inserted into each through hole 13a, it is possible to prevent the tip of the tool from interfering with the axial outer end surface of the outer ring 2c. Inserting a tool into the hole 13a, attaching / detaching the wheel bearing rolling bearing unit 1c to / from the suspension device, or attaching / detaching components (support or caliper) constituting the braking device to / from the suspension device It is possible to prevent the workability of such work from being deteriorated. That is, when the wheel-supporting rolling bearing unit 1c is attached to the suspension device, the phase in the circumferential direction between the screw hole provided in the knuckle constituting the suspension device and the through hole 36 of the stationary side flange 6 is determined. Are made to coincide with each other, and the phase in the circumferential direction of the through hole 13a of the rotation side flange 9a is made to coincide with the phase in the circumferential direction of each through hole 36. In this state, a tool is inserted from the outside in the axial direction of each through hole 13a, and a bolt inserted through each through hole 36 from the outside in the axial direction is screwed into each screw hole by this tool and further tightened. Thereby, the stationary flange 6 is coupled and fixed to the knuckle. Also, when removing the wheel-supporting rolling bearing unit 1c from the suspension device, the phase of each through hole 13a in the circumferential direction is matched with the phase of each through hole 36 in the circumferential direction. A tool is inserted from the outside in the axial direction of each through hole 13a, and the bolts inserted through the through holes 36 and screwed into the screw holes are loosened by the tool. In any case, in the case of this example, the axial direction of the outer ring 2c is located at a portion of the outer peripheral surface of the outer end portion in the axial direction of the outer ring 2c where the phase in the circumferential direction coincides with each through hole 36. Outer ring side recesses 34 that are recessed radially inward while being open to the outer end surface are provided, respectively, and the axial outer ends of the bottom surfaces of these outer ring side recesses 34 centering on the center axis of the wheel support rolling bearing unit 1c. the diameter D 34 of at inscribed circle to the edge, less than the diameter D 13a of the inscribed circle of the radially inner end of each through hole 13a around the central axis of the wheel supporting rolling bearing unit 1c (D 34 <D 13a ). For this reason, when tightening or loosening the bolt, when the tool is inserted from the outside in the axial direction of each through hole 13a, the tip of the tool interferes with the axially outer end surface of the outer ring 2c. ) Can be prevented. Therefore, the outer diameter D 2c of the axially outer end surface of the diameter D 13a of the inscribed circle of the radially inner end of each through hole 13a is the outer ring 2c around the central axis of the wheel supporting rolling bearing unit 1c Even if it is smaller (D 13a <D 2c ), the wheel support rolling bearing unit 1c can be assembled to the knuckle of the suspension device (the work performed by inserting a tool into each through hole 13a) Property) can be prevented from being damaged. Further, in the case of this example, (and to reduce the depth from the outer peripheral surface) of the more largely to that toward the diameter D 34 axially inwardly of the inscribed circle of the bottom surface of the outer wheel side recess 34 Therefore, the tool can be guided inward in the axial direction by preventing the tool from being caught by the outer ring side recesses 34.
Incidentally, the outer ring side recess 34 such as described above, the portion matching the fixed position of not shown support or the caliper constituting the braking device with a braking rotary member 35 (see FIG. 3) with respect to the circumferential direction (mounting holes, etc.) It can also be provided.
The configuration and operation of the other parts are the same as those in the first and second examples of the embodiment described above.