【００２４】
一方、前記センサユニット３９に設けた前記鍔部４２の基端面（先端側挿入部４１と反対側の面で、図１、３、４の上端面）には、上記結合ばね４５の抑え部４７をがたつきなく係合させる為の抑え溝５７を形成している。この抑え溝５７は、前記ハーネス４０の基端部を囲む状態で設けた湾曲部５８と、この湾曲部５８の両端から互いに逆方向に折れ曲がり、上記鍔部４２の外周縁に開口した１対の直線部５９、５９とから成る。又、上記鍔部４２の基端面の一部外周寄り部分で、上記湾曲部５８の凸側に対向する部分には、傾斜面６０を形成している。この傾斜面６０は、上記鍔部４２の厚さが、この鍔部４２の端縁に向かう程小さくなる方向に傾斜している。又、上記抑え溝５７は、上記結合ばね４５の抑え部４７を係合させた状態で、この抑え部４７が不用意に外れる事を防止すると共に、前記挿入孔３０内での上記センサユニット３９の円周方向に関する位置決めを図る。尚、上記外輪１ａに平面部３８を形成せずに、センサユニット３９の位置決め部として機能する鍔部４２の内周側面を、断面が上記外輪１ａの外周面と同じ曲率を有する円弧状凹面とする事もできる。この様な凹面の加工は、高精度で行なえる為、上記センサユニット３９の円周方向（挿入孔３０内での回転方向）に関する位置決めをより正確に行なえる。[0024]
Meanwhile, a retaining groove 57 for engaging the retaining portion 47 of the coupling spring 45 without rattle is formed in the base end surface (the surface opposite the tip-side insertion portion 41, and the upper end surface in FIGS. 1, 3, and 4) of the flange 42 of the sensor unit 39. This retaining groove 57 is composed of a curved portion 58 provided in a state of surrounding the base end of the harness 40 and a pair of straight portions 59, 59 that bend in opposite directions from both ends of the curved portion 58 and open at the outer periphery of the flange 42. A sloped surface 60 is formed in a portion of the base end surface of the flange 42 near the outer periphery, facing the convex side of the curved portion 58. This sloped surface 60 is inclined in a direction such that the thickness of the flange 42 becomes thinner as it approaches the edge of the flange 42. Furthermore, the retaining groove 57 prevents the retaining portion 47 of the coupling spring 45 from accidentally coming off while the retaining portion 47 is engaged, and also positions the sensor unit 39 in the circumferential direction within the insertion hole 30. Incidentally, without forming the flat portion 38 on the outer ring 1a, the inner peripheral side surface of the flange portion 42, which functions as a positioning portion for the sensor unit 39, can be made into an arc-shaped concave surface whose cross section has the same curvature as the outer peripheral surface of the outer ring 1a. Because such a concave surface can be machined with high precision, the sensor unit 39 can be more accurately positioned in the circumferential direction (the direction of rotation within the insertion hole 30).
【００３０】
上述の様にして、上記抑え部４７を上記抑え溝５４に係合させた状態では、上記結合ばね４５の抑え部４７が、結合ばね４５自体の弾力により、上記鍔部４２を上記外輪１ａの平面部３８に向け、十分に大きな力（例えば１０kgf 程度）で抑え付けて、上記センサユニット３９を上記外輪１ａに結合固定する。上記抑え部４７と抑え溝５７との係合力は十分に大きい為、自動車の走行時の振動等により、上記結合ばね４５が上記センサユニット３９から外れる事はない。又、上記抑え部４７と抑え溝５７との係合により、上記センサユニット３９が前記挿入孔３０の内側で回転する事を防止する。従って、センサの検出部と前記エンコーダ３ａの内側面とを、確実に対向させたままの状態に維持できる。[0030]
With the retaining portion 47 engaged with the retaining groove 54 as described above, the retaining portion 47 of the connecting spring 45 presses the flange portion 42 toward the flat portion 38 of the outer ring 1a with a sufficiently large force (e.g., approximately 10 kgf) due to the elasticity of the connecting spring 45 itself, thereby connecting and fixing the sensor unit 39 to the outer ring 1a. Because the engagement force between the retaining portion 47 and the retaining groove 57 is sufficiently large, the connecting spring 45 will not come off the sensor unit 39 due to vibrations while the automobile is running, etc. Furthermore, the engagement between the retaining portion 47 and the retaining groove 57 prevents the sensor unit 39 from rotating inside the insertion hole 30. Therefore, the detection portion of the sensor and the inner surface of the encoder 3a can be reliably maintained facing each other.