What is claimed is:
1. A device with an adjusting bolt, comprising:
a bolt mounting wall 2 in which a female screw hole 1 is formed;
an adjusting bolt 3 which is screw-engaged with the female screw hole 1 so as to be mounted on the bolt mounting wall 2;
a locknut 4 which is screw-engaged with the adjusting bolt 3;
a cover 5 which is rotatably fitted with an outside of the locknut 4; and
a retaining portion 6 which retains the cover 5, wherein
the retaining portion 6 includes: a collar 7 which is fitted with an inside of a peripheral wall 5a of the cover 5 by interference fit: and a collar locking portion 8 supported by the adjusting bolt 3, and
the cover 5 which is to be removed from the locknut 4 in a direction away from the bolt mounting wall 2 is structured to be locked to the collar locking portion 8 via the collar 7.
2. The device with an adjusting bolt according to claim 1, wherein
the locknut 4 includes: a wrench engagement portion 9; and a small diameter
portion 10 which has a diameter smaller than a diameter of the wrench engagement
portion 9 and is positioned more closely to the bolt mounting wall 2 than the wrench
engagement portion 9,
the collar 7 is rotatably fitted with an outside of the small diameter portion 10
and is fitted with an inside of a tip opening portion 11 of the peripheral wall 5a of the
cover 5 by interference fit,
where an end of the peripheral wall 5a of the cover 5 on a side of the bolt
mounting wall 2 is a tip end, and

the collar locking portion 8 is formed between an outer peripheral surface of the wrench engagement portion 9 and an outer peripheral surface of the small diameter portion 10, and is constituted of a circumferential surface 12 of the locknut 4 that faces the collar 7.
3. The device with an adjusting bolt according to claim 1 or 2, wherein
a tip opening verge 13 of the peripheral wall 5a of the cover 5 abuts on the bolt mounting wall 2,
where the end of the peripheral wall 5a of the cover 5 on the side of the bolt mounting wall 2 is the tip end.
4. The device with an adjusting bolt according to claim 1 or 2, wherein
the collar 7 includes a flange 14 that protrudes outwardly in a radial direction of the collar 7, and
a tip opening verge 13 of the peripheral wall 5a of the cover 5 abuts on the flange 14,
where the end of the peripheral wall 5a of the cover 5 on the side of the bolt mounting wall 2 is the tip end.
5. The device with an adjusting bolt according to claim 4, wherein
the collar 7 includes a spacer portion 15 that is led out from the flange 14 toward the bolt mounting wall 2, and the flange 14 is apart from the bolt mounting wall 2 by the spacer portion 15.
6. The device with an adjusting bolt according to any one of claims 1 to 5,

wherein
the wrench engagement portion 9 of the locknut 4 includes:
a wrench engaging surface 16; and
a chamfer portion 17 which is formed on a boundary between the wrench engaging surfaces (16) (16) that are adjacent to each other.
7. The device with an adjusting bolt according to claim 1, comprising
a cap nut 19 which is screw-engaged with the adjusting bolt 3 and covers a tool engagement portion 18 of the adjusting bolt 3, wherein
the cover 5 is rotatably fitted with the outside of the locknut 4 and an outside of the cap nut 19,
the locknut 4 includes: a wrench engagement portion 9; and a small diameter portion 20 which has a diameter smaller than a diameter of the wrench engagement portion 9 and is positioned more closely to the cap nut 19 than the wrench engagement portion 9,
the collar 7 is rotatably fitted with an outside of the small diameter portion 20 and is fitted with an inside of a peripheral wall 5a of the cover 5 by interference fit,
the collar locking portion 8 is formed at a rim portion of an opening 21 of the cap nut 19, and is constituted of a circumferential end surface 22 of the cap nut 19 that faces the collar 7.
8. The device with an adjusting bolt according to claim 1, comprising
a retainer reinforcing portion 23 of the cover, wherein
the retainer reinforcing portion 23 is constituted of: a projecting portion 25 that protrudes from an inner peripheral surface 24 of the peripheral wall 5a of the cover 5;

and the collar (7), and
the cover 5 which is to be removed from the locknut 4 and the cap nut 19 in a direction away from the bolt mounting wall 2 is structured to be locked to the collar 7 via the projecting portion 25.
9. The device with an adjusting bolt according to any one of claims 1 to 8, wherein a base end of the peripheral wall 5a of the cover 5 is provided with an end wall 26, where an end of the peripheral wall 5a of the cover 5 on a side away from the bolt mounting wall 2 is the base end.
10. The device with an adjusting bolt according to claim 9, wherein the end wall 26 is provided with a through hole 27.